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Coatings
Special Issues
Corrosion and Degradation of Materials
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Corrosion and Degradation of Materials

A special issue of Coatings (ISSN 2079-6412). This special issue belongs to the section "Corrosion, Wear and Erosion".

Deadline for manuscript submissions: closed (30 March 2022) | Viewed by 64564

Printed Edition Available!
A printed edition of this Special Issue is available here.

Special Issue Editors

Prof. Dr. Jian Chen

E-Mail Website
Guest Editor
Department of Chemistry and Surface Science Western, The University of Western Ontario, London, ON, N6A 5B7, Canada
Interests: nuclear waste disposal; corrosion and stress corrosion cracking; copper; lightweight alloys; metallic waste forms
Special Issues, Collections and Topics in MDPI journals
Dr. Yanxin Qiao

E-Mail Website
Guest Editor
School of Materials Science and Engineering, Jiangsu University of Science and Technology, Jiangsu 212003, China
Interests: corrosion; wear; stainless steel; electrochemical; titanium alloys
Special Issues, Collections and Topics in MDPI journals
Dr. Fanjiang Meng

E-Mail Website
Guest Editor
Shanghai Nuclear Engineering Research and Design Institute, Shanghai 200233, China
Interests: nickel-based alloy; coatings; aging management
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Yuxin Wang

E-Mail Website
Guest Editor
School of Materials Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China
Interests: corrosion & surface protection; rapid solidification & powder metallurgy; microstructure & micro-defects of materials; magnetic materials
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Corrosion and degradation of materials, deteriorating materials via chemical/electrochemical reactions with their surrounding environments, are extremely common and costly. The global cost of corrosion is estimated to be 3–5% of the global gross domestic product (GDP), not including individual safety or environmental consequences. To reduce the corrosion cost, the research community has been performing corrosion studies and using the corrosion control practices available to understand the corrosion fundamentals, inspect the corrosion performance of structural components or materials, and evaluate their safety issues, analyze and report the corrosion failure, develop advanced corrosion control techniques, etc. This benefits the selection and design of the materials used in modern society, which can not only improve the performance of the material in service, but also decrease corrosion loss and avoid catastrophic consequences.

The aim of the present issue is to consolidate recent findings related to the corrosion and degradation of materials and to provide an opportunity for researchers to publish the latest results, reviews, methodology, and failure case reports to understand or solve material corrosion issues. We welcome the submission of original, high-quality papers and critical reviews. 

Potential topics include but are not limited to in the following areas:

  • Corrosion fundamentals
  • High-temperature oxidation
  • Anodic oxidation
  • Biochemical corrosion
  • Stress corrosion cracking, corrosion fatigue, and corrosion creep
  • Corrosion control and protection

Prof. Dr. Jian Chen
Dr. Yanxin Qiao
Dr. Fanjiang Meng
Prof. Dr. Yuxin Wang
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Coatings is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • corrosion
  • stress corrosion cracking
  • coating
  • surface characterization techniques

Published Papers (33 papers)

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Editorial

Jump to: Research, Review

2 pages, 166 KiB  
Editorial
Corrosion and Degradation of Materials
by Jian Chen, Yanxin Qiao, Fanjiang Meng and Yuxin Wang
Coatings 2022, 12(7), 969; https://doi.org/10.3390/coatings12070969 - 08 Jul 2022
Cited by 4 | Viewed by 1216
Abstract
The corrosion and degradation of materials, i [...] Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)

Research

Jump to: Editorial, Review

12 pages, 6293 KiB  
Article
An Experimental Study on Dynamic Characteristics of Coarse-Grained Soil under Step Cyclic Loading
by Peisen Wang, Wenjun Hu, Pingyun Liu, Zhenqiang Yan, Xianghui Kong, Quanman Zhao and Wenhao Yin
Coatings 2022, 12(5), 640; https://doi.org/10.3390/coatings12050640 - 07 May 2022
Cited by 2 | Viewed by 1299
Abstract
The accumulated plastic deformation induced by a cyclic traffic load will lead to destruction of the subgrade. Coarse-grained soil is a widely used subgrade filler. The GDS dynamic triaxial test was carried out on typical coarse-grained soil fillers to investigate the influence of [...] Read more.
The accumulated plastic deformation induced by a cyclic traffic load will lead to destruction of the subgrade. Coarse-grained soil is a widely used subgrade filler. The GDS dynamic triaxial test was carried out on typical coarse-grained soil fillers to investigate the influence of different confining pressures, consolidation ratios and numbers of cyclic actions on the hysteresis curve under step cyclic loading. The results show that surrounding pressure can significantly reduce the energy lost from a soil sample under cyclic loading. Under the same stress level, increasing the consolidation ratio can effectively reduce the area enclosed by the hysteresis curve. When the stress is increased above a certain value, the strain of the response clearly changes with an increase in the number of cyclic loading. The research findings can theoretically guide the design of coarse-grained soil roadbeds in practical engineering. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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8 pages, 2730 KiB  
Article
Self-Formed Diffusion Layer in Cu(Re) Alloy Film for Barrierless Copper Metallization
by Bin Cheng, Hongmei Chen, Isaac Asempah, Jiheng Wang, Yilin Zhu, Jun Wan, Feiran Jiang, Ze Wang, Yang Shui, Lei Wang, Lei Jin and Yanxin Qiao
Coatings 2022, 12(5), 613; https://doi.org/10.3390/coatings12050613 - 29 Apr 2022
Cited by 4 | Viewed by 2124
Abstract
The barrier properties and diffusion behavior of Cu(Re) alloy films were studied. The films were deposited onto barrierless SiO2/Si by magnetron sputtering. X-ray diffraction patterns and electric resistivity results proved that the Cu(Re) alloy films without a barrier layer were thermally [...] Read more.
The barrier properties and diffusion behavior of Cu(Re) alloy films were studied. The films were deposited onto barrierless SiO2/Si by magnetron sputtering. X-ray diffraction patterns and electric resistivity results proved that the Cu(Re) alloy films without a barrier layer were thermally stable up to 550 °C. Transmission electron microscopy images and energy-dispersive spectrometry employing scanning transmission electron microscopy provided evidence for a self-formed Re-enriched diffusion layer between the Cu(Re) alloy and SiO2/Si substrate. Furthermore, the chemical states of Re atoms at the Cu(Re)/SiO2 interface were analyzed by X-ray photoemission spectroscopy. The self-formed diffusion layer was found to be composed of Re metal, ReO, ReO2 and ReO3. At 650 °C, the Cu(Re) layer was completely destroyed due to atom diffusion. The low electrical resistivity in combination with the high thermal stability suggests that the Cu(Re) alloy could be the ultimate Cu interconnect diffusion barrier. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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12 pages, 3516 KiB  
Article
Study of Mask Electrochemical Machining for Ring Narrow Groove under the Action of Multiple Physical Fields
by Ruochen Zhao, Liang Huang, Haiyue Zhao, Yan Cao, Weijun Tian and Ning Wang
Coatings 2022, 12(5), 605; https://doi.org/10.3390/coatings12050605 - 29 Apr 2022
Cited by 5 | Viewed by 1668
Abstract
Deep and narrow groove structures are widely used in aviation, aerospace, weapons, and other industries, and play a very important role. In order to solve the problems of machining tool deformation, machining flying edge, burr in traditional Computerized Numerical Control (CNC) milling for [...] Read more.
Deep and narrow groove structures are widely used in aviation, aerospace, weapons, and other industries, and play a very important role. In order to solve the problems of machining tool deformation, machining flying edge, burr in traditional Computerized Numerical Control (CNC) milling for deep and narrow grooves, and the problems of serious motor loss and low machining efficiency in non-contact electrical discharge machining (EDM), electrochemical mask machining through the mask treatment of the non-processed part mask processing, and with no loss of the processing cathode tool, was suggested as an efficient way to solve these problems. Considering that the corrosion removal of the anodic workpiece is mainly subject to the multi-physical field coupling action between the electric field, the flow field, and the temperature field, it is necessary to construct a multi-physical field coupling model of electrochemical mask machining and combine this with the numerical simulation analysis to realize the distribution state of the multi-physical field, so as to realize the optimization guidance of the overall processing process. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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12 pages, 2203 KiB  
Article
Numerical Simulation of Crevice Corrosion of Stainless Steel–Titanium in NaCl Solution
by Jiawei Ding, Weiping He, Yuanhai Liu, Chenyu Zhang, Haitao Wang and En-Hou Han
Coatings 2022, 12(5), 592; https://doi.org/10.3390/coatings12050592 - 26 Apr 2022
Cited by 3 | Viewed by 1827
Abstract
A multiphysics model based on the finite element method was adopted, emphasizing a deeper insight into the rarely studied crevice corrosion behavior of stainless steel and titanium overlapping. The model takes into account damage due to corrosion inside the crevice, different species transportation, [...] Read more.
A multiphysics model based on the finite element method was adopted, emphasizing a deeper insight into the rarely studied crevice corrosion behavior of stainless steel and titanium overlapping. The model takes into account damage due to corrosion inside the crevice, different species transportation, local electrochemical reactions, homogeneous reactions in the electrolyte, and formation of a corrosion product and its influence on electrochemical reaction. The simulation results show that the location of the greatest attack for stainless steel is at the crevice opening; this finding is consistent with the IR drop theory. The potential increases gradually from the tip to the opening of the crevice, and the current changes smoothly following a sharp rise at the opening. The minimum and maximum values of pH and Cl− concentration are both in the middle and opening of the crevice. The influence of the crevice size on corrosion is also discussed in detail. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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10 pages, 1692 KiB  
Article
Effect of Edible Coating on the Quality and Antioxidant Enzymatic Activity of Postharvest Sweet Cherry (Prunusavium L.) during Storage
by Wenzhong Hu, Sarengaowa and Ke Feng
Coatings 2022, 12(5), 581; https://doi.org/10.3390/coatings12050581 - 24 Apr 2022
Cited by 16 | Viewed by 2780
Abstract
The effects of edible chitosan coating (0.1%, 0.3%, 0.5% and 0.75% w/v) on the changes in the quality, respiration rate, total phenolic content and anthocyanin of postharvest sweet cherry (Prunus avium L.) at 10 °C were investigated. The activities [...] Read more.
The effects of edible chitosan coating (0.1%, 0.3%, 0.5% and 0.75% w/v) on the changes in the quality, respiration rate, total phenolic content and anthocyanin of postharvest sweet cherry (Prunus avium L.) at 10 °C were investigated. The activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were also determined. The result showed that the treatments of chitosan edible coating were effective at delaying the evolution of the parameters related to postharvest ripening, such as color and firmness, and respiration rate. The edible coatings also showed that the lower total phenolics and total antioxidant activity were maintained compared to that in the control associated with the overripening. It was suggested that the optimal quality and enhanced antioxidant enzymatic activities of postharvest cherry fruits were obtained by an edible coating of chitosan 0.5% up to 24 days at 10 °C. The chitosan edible coating could be favorable for extending shelf-life, maintaining the quality of sweet cherries. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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11 pages, 7617 KiB  
Article
Microstructure and Micro-Hardness of Dissimilar Metal Cladding from a Pipe–Nozzle Mockup for PWR
by Jiazhen Wang, Hongliang Ming, Zhiming Zhang, Jian Chen and Jianqiu Wang
Coatings 2022, 12(4), 525; https://doi.org/10.3390/coatings12040525 - 13 Apr 2022
Cited by 2 | Viewed by 1833
Abstract
In this study, the dissimilar metal cladding from a pressure vessel pipe–nozzle mockup for PWR was studied using an optical microscope, scanning electron microscopy, energy-dispersive X-ray spectrometry, electron back-scattering diffraction, and micro-hardness measurement. The microstructure of the SA508 side is non-uniform along the [...] Read more.
In this study, the dissimilar metal cladding from a pressure vessel pipe–nozzle mockup for PWR was studied using an optical microscope, scanning electron microscopy, energy-dispersive X-ray spectrometry, electron back-scattering diffraction, and micro-hardness measurement. The microstructure of the SA508 side is non-uniform along the fusion boundary, especially at the concave and convex areas. Martensitic layer (type I and type II) boundaries are found at the fusion boundary area. The chemical composition, residual strain, and microstructure across the SA508–309L fusion boundary are very complex and hence result in a complicated micro-hardness distribution. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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15 pages, 4295 KiB  
Article
Effect of Annealing and Oxidation on the Microstructure Evolution of Hot-Dipped Aluminide Q345 Steel with Silicon Addition
by Yujian Ma, Binbin Yuan, Ya Liu, Jianhua Wang and Xuping Su
Coatings 2022, 12(4), 503; https://doi.org/10.3390/coatings12040503 - 08 Apr 2022
Cited by 2 | Viewed by 1473
Abstract
Q345 steel was coated by hot dipping into molten pure aluminum and Al-Si baths. The coatings were annealed at 800 and 900 °C for 1–3 h and subsequently oxidized at 900 °C for 15 h in air. The results revealed that the thickness [...] Read more.
Q345 steel was coated by hot dipping into molten pure aluminum and Al-Si baths. The coatings were annealed at 800 and 900 °C for 1–3 h and subsequently oxidized at 900 °C for 15 h in air. The results revealed that the thickness of the intermetallic layer increased with increasing hot-dipping time in the range of 700–750 °C, while it decreased when the hot-dipping aluminizing temperature was 800 °C. As the silicon content in the aluminum bath increased, the thickness of the intermetallic layer decreased, and the intermetallic layer/steel-substrate interface transformed from an irregular morphology into a flat morphology. The hot-dipped Al-2.5Si samples were subjected to annealing; the higher the annealing temperature and longer the annealing time, the faster the transformation of the intermediate phase in the coating. The Fe2Al5 phase was fully transformed into the ductile FeAl phase after the hot-dipped samples annealed at 900 °C for 3 h. When the outermost layer of Q345 steel was the FeAl phase, oxidation resistance of the oxide was the best. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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14 pages, 40586 KiB  
Article
Obtaining Uniform High-Strength and Ductility of 2A12 Aluminum Alloy Cabin Components via Predeformation and Annular Channel Angular Extrusion
by Kai Chen, Xi Zhao, Deng-Kui Wang, La-Feng Guo and Zhi-Min Zhang
Coatings 2022, 12(4), 477; https://doi.org/10.3390/coatings12040477 - 31 Mar 2022
Cited by 6 | Viewed by 1698
Abstract
A 2A12 aluminum alloy component with uniform high-strength and ductility was developed via predeformation (one-pass repetitive upsetting extrusion) and annular channel angular extrusion (ACAE). Moreover, the microstructure evolution and age-hardening behavior were investigated. The results show that the upsetting-extrusion predeformation improved the cumulative [...] Read more.
A 2A12 aluminum alloy component with uniform high-strength and ductility was developed via predeformation (one-pass repetitive upsetting extrusion) and annular channel angular extrusion (ACAE). Moreover, the microstructure evolution and age-hardening behavior were investigated. The results show that the upsetting-extrusion predeformation improved the cumulative strain of the component and refined the grain size, and that the second Al–Cu–Mg phases were obviously broken and refined, and that, especially, the distribution of the second phases along the extrusion direction was weakened. Thus, compared with directly ACAE-formed components, after the T6 heat treatment, the axial ultimate tensile strength (UTS) of the cabin increased from 476 to 484 MPa, and the elongation (EL) increased from 12.9% to 17.5%. The circumferential UTS increased from 426 to 482 MPa, and the EL increased from 9.24% to 16.8%. A large number of dislocations were introduced into the upsetting extrusion (UE) + ACAE method, which resulted in strain hardening and higher precipitation strengthening in the late artificial aging process. The finer and denser grains and s precipitates significantly enhanced the strength and ensured the good ductility of the alloy. It is suggested that the combination of predeformation and annular channel angular extrusion is an effective method for forming aluminum alloy cabin components with higher and more uniform mechanical properties. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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14 pages, 5657 KiB  
Article
The Corrosion Behaviors of an As-Rolled Mg-8Li (in wt.%) Alloy in Two Differently Concentrated NaCl Solutions
by Baojie Wang, Jiyu Hou, Jiyu Luan, Daokui Xu, Haijing Sun and Jie Sun
Coatings 2022, 12(3), 406; https://doi.org/10.3390/coatings12030406 - 18 Mar 2022
Cited by 7 | Viewed by 1847
Abstract
By means of an electrochemical workstation, hydrogen evolution device, optical microscope (OM) and scanning electron microscope (SEM), the corrosion behaviors of an as-rolled Mg-8%Li alloy with a dual phase structure in 0.9 wt.% NaCl and 3.5 wt.% NaCl solutions have been investigated and [...] Read more.
By means of an electrochemical workstation, hydrogen evolution device, optical microscope (OM) and scanning electron microscope (SEM), the corrosion behaviors of an as-rolled Mg-8%Li alloy with a dual phase structure in 0.9 wt.% NaCl and 3.5 wt.% NaCl solutions have been investigated and compared. The results show that when the immersion time exceeds 8 h, the hydrogen evolution rate of the alloy in the 0.9 wt.% NaCl is 3 times higher than that in the 3.5 wt.% NaCl solution. Moreover, the corrosion behaviors of the alloy are obviously different in the two differently concentrated NaCl solutions. In the 3.5 wt.% NaCl solution, the localized corrosion is much more severe and can occur simultaneously in the interior of both the α-Mg and β-Li matrix phases. However, the localized corrosion in the 0.9 wt.% NaCl solution is obviously weak and mainly occurs at the α-Mg phase. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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14 pages, 4123 KiB  
Article
Properties of Micro-Arc Oxidation Coatings on 5052 Al Alloy Sealed by SiO2 Nanoparticles
by Siqi Liu, Jiahuan Chen, Dongdong Zhang, Yuxin Wang, Zhen He and Pingyi Guo
Coatings 2022, 12(3), 373; https://doi.org/10.3390/coatings12030373 - 11 Mar 2022
Cited by 15 | Viewed by 2378
Abstract
Micro-arc oxidation (MAO) treatment can effectively improve the wear resistance, corrosion resistance, and mechanical strength of aluminum alloy substrates. Improving the porous structure of MAO film and effectively sealing the pores is a significant research issue. In this study, the MAO treatment of [...] Read more.
Micro-arc oxidation (MAO) treatment can effectively improve the wear resistance, corrosion resistance, and mechanical strength of aluminum alloy substrates. Improving the porous structure of MAO film and effectively sealing the pores is a significant research issue. In this study, the MAO treatment of 5052 aluminum alloy was carried out in silicate electrolytes. The MAO films were sealed with different concentrations of SiO2 nanoparticles. The effects of SiO2 nanoparticle content on the MAO films’ microstructure, mechanical properties, and corrosion performance were systematically investigated. When adding SiO2 nanoparticles to electrolytes, the particles were deposited at the micropores of the film, which could effectively seal the porous MAO film and significantly improve its corrosion and wear resistance. The corrosion resistance and wear resistance properties were optimal with 5.0 g/L SiO2 addition. Compared to the unsealed film, the corrosion current density and corrosion rate decreased from 1.24 × 10−9 A/cm2 and 1.47 × 10−5 mm/a to 7.78 × 10−10 A/cm2 and 9.15 × 10−6 mm/a, respectively. Moreover, the average friction coefficient of the sealed film was 0.606, which was ~19.3% lower than that of the substrate and 3.3% lower than for the unsealed film. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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12 pages, 5380 KiB  
Article
Ti/SnO2-Sb2Ox-TiO2 Electrodeposited from Methanesulfonate Electrolytes: Preparation, Properties, and Performance
by Shengping Zhang, Chen Yu, Jingyi Tan, Yuxin Wang and Zhen He
Coatings 2022, 12(3), 366; https://doi.org/10.3390/coatings12030366 - 09 Mar 2022
Cited by 4 | Viewed by 1606
Abstract
In this study, Ti/SnO2-Sb2Ox-TiO2 electrodes were produced using a sol-enhanced electrodeposition technique from methanesulfonate electrolytes. The surface microstructures of Ti/SnO2-Sb2Ox-TiO2 were observed, and their phase constituents were determined. The [...] Read more.
In this study, Ti/SnO2-Sb2Ox-TiO2 electrodes were produced using a sol-enhanced electrodeposition technique from methanesulfonate electrolytes. The surface microstructures of Ti/SnO2-Sb2Ox-TiO2 were observed, and their phase constituents were determined. The surface features were analyzed by X-ray photoelectron spectroscopy. Linear sweep voltammetry and degradation tests were also conducted to determine the degradation performance. The results show that the addition of TiO2 sol affects the microstructures of Ti/SnO2-Sb2Ox-TiO2 electrodes, while a uniform coating surface can be obtained at a proper sol concentration in electrolytes. Adding TiO2 sol also causes deep oxidation of Sb and generates more adsorbed oxygen on the electrode surface. The favorable surface features and the well-dispersed TiO2 in the coatings of 10 mL/L TiO2 modified Ti/SnO2-Sb2Ox-TiO2 electrodes award them the best electrocatalytic performance, and their uniform coating surface prolongs the electrode service life. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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10 pages, 5097 KiB  
Article
Environmental Fatigue Behavior of a Z3CN20.09M Stainless Steel in High Temperature Water
by Kewei Fang, Kunjie Luo, Li Wang, Chengtao Li, Lei Wang and Yanxin Qiao
Coatings 2022, 12(3), 317; https://doi.org/10.3390/coatings12030317 - 28 Feb 2022
Cited by 3 | Viewed by 1645
Abstract
The low-cycle fatigue behavior of a Z3CN20.09M austenitic stainless steel was investigated and its fatigue life in high temperature water was compared to that in the air at room temperature. It is found that the fatigue life in water at 300 °C was [...] Read more.
The low-cycle fatigue behavior of a Z3CN20.09M austenitic stainless steel was investigated and its fatigue life in high temperature water was compared to that in the air at room temperature. It is found that the fatigue life in water at 300 °C was shorter than that in air, and it decreased with the decreasing strain rate from 0.4% to 0.004%/s. The ductile striations having streamed down features were observed at the strain rate of 0.004%/s, indicating that Z3CN20.09M austenitic stainless steel experienced anodic dissolution. The fatigue life obtained in the present experiment was consistent with that using prediction models. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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36 pages, 15003 KiB  
Article
Bridge Structure Damage Identification Based on Dynamic Characteristics
by Yunkai Zhang, Xixue Tan, Guohua Li, Jun Dong, Jingyi Guo and Fanyue Liu
Coatings 2022, 12(3), 313; https://doi.org/10.3390/coatings12030313 - 25 Feb 2022
Cited by 1 | Viewed by 1809
Abstract
With the increasing traffic volume and years of usage during the operation process, a bridge structure will experience aging and damage to different degrees, leading to the decline in bridge reliability and seriously affecting its operation safety. In this study, the bridge was [...] Read more.
With the increasing traffic volume and years of usage during the operation process, a bridge structure will experience aging and damage to different degrees, leading to the decline in bridge reliability and seriously affecting its operation safety. In this study, the bridge was abstracted into a beam structure for damage identification. Next, the influence of damage on the bridge structure was explored from the angles of its inherent frequency and displacement mode, respectively. Our results showed that whether the structure was damaged could be accurately judged by its inherent frequency, but the specific damage could not be further judged. Through the structural displacement curve, the rough range of structural damage could be judged; however, the damage could not be accurately positioned. The damage position could be accurately identified to some extent by taking the derivatives from the difference value of the structural displacement curve. The above conclusions were verified based on a double-span beam. We found that the above conclusions still held true for the double-span beam, thus proving their universality. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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24 pages, 11256 KiB  
Article
Impact Analysis of Initial Cracks’ Angle on Fatigue Failure of Flange Shafts
by Zhiqiang Xu, Yunxian Cui, Baoliang Li, Ketong Liu, Feiting Shi and Peng Cao
Coatings 2022, 12(2), 276; https://doi.org/10.3390/coatings12020276 - 18 Feb 2022
Cited by 3 | Viewed by 2009
Abstract
A fatigue test on the failure mode of flange shafts was conducted. The propagation characteristics of the initial crack at the junction between the shaft and the flange as well as its angle effect were studied. This study developed an analysis program of [...] Read more.
A fatigue test on the failure mode of flange shafts was conducted. The propagation characteristics of the initial crack at the junction between the shaft and the flange as well as its angle effect were studied. This study developed an analysis program of fatigue crack propagation, based on the APDL (ANSYS Parametric Design Language). It obtained the effective angle interval within which the initial crack is able to propagate. The fitting calculation formula was derived and the results showed that: (1) The initial crack at the junction between the shaft and the flange would propagate in the radial and axial directions; the unstable crack propagation would cause an abrupt fracture of the cross-section, failing connection; and the angle of initial crack was uncertain. (2) The crack followed the I-II-III mixed mode, which was dominated by mode I. An initial crack with a larger angle showed more noticeable II-III characteristics; KII and KIII affected the crack’s propagation angle in the radial and axial directions and they also affected the structure’s surface direction. (3) The deepest point A of the crack was located at the junction between the shaft and the flange. Its crack propagation can be divided into three stages: rapid growth (stage 1), steady decline (stage 2, buffer stage), and instability (stage 3). The initial crack angle not only affected the propagation rate at stage 1 but also influenced the fatigue life distribution of the structure during propagation. The larger the initial crack angle was, the smaller the proportion of buffer stage in the total fatigue life would be. Moreover, the propagation of crack with a larger initial angle reached instability faster after stage 1, which would cause an abrupt fracture of the cross-section. This was unfavorable for deciding the crack detection time or carrying out maintenance and reinforcement. (4) The crack propagation at the junction between the shaft and the flange was determined by the size relation between ΔKI and ΔKth, instead of the effective stress intensity factor. The effective stress intensity factor can partly reflect the law of crack propagation, but cannot serve as the only criterion for crack propagation; it must be combined with the effective angle interval, which was negatively correlated with the crack’s shape ratio, to determine whether the crack would propagate. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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15 pages, 5051 KiB  
Article
Evolution Law and Mechanism of Freeze–Thaw Damage of Cement-Stabilized Weathered Sand
by Xianghui Kong, Shuai Cui, Gaoqiang Wang, Wenjun Hu, Yunpeng Liang and Zhibin Zhang
Coatings 2022, 12(2), 272; https://doi.org/10.3390/coatings12020272 - 18 Feb 2022
Cited by 2 | Viewed by 1717
Abstract
To explore the damage evolution law of cement-stabilized weathered sand under the action of freeze–thaw cycles, relevant experimental research was carried out on stabilized weathered sand with a cement content of 3%, including unconfined compressive strength (UCS), scanning electron microscope (SEM), and mercury [...] Read more.
To explore the damage evolution law of cement-stabilized weathered sand under the action of freeze–thaw cycles, relevant experimental research was carried out on stabilized weathered sand with a cement content of 3%, including unconfined compressive strength (UCS), scanning electron microscope (SEM), and mercury intrusion porosimetry (MIP) testing. Using the surface appearance, mass, and UCS of the specimen, combined with the changes of microscopic characteristics, the freeze–thaw damage law and microscopic degradation mechanism of cement-stabilized weathered sand were analyzed. The test results showed that with the increase of the number of freeze–thaw cycles, the surface appearance of the specimen continued to deteriorate, the unconfined compressive strength gradually decreased, and the mass of the specimen first increased and then decreased. After nine freeze–thaw cycles, the specimen was seriously damaged, and the strength loss was as high as 55%. From a microscopic point of view, the freeze–thaw cycles caused the pore water inside the specimen to continuously change between ice crystals and liquid. Frost heave and shrinkage weakened the cement bond between the weathered sand particles and made the pores in the specimen develop and expand continuously. With the decrease of the number of micropores and the increase of the number of medium and large pores, the particle skeleton changed from a dense structure to a porous structure, which eventually led to the deterioration of the macroscopic properties of the cement-stabilized weathered sand. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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13 pages, 29313 KiB  
Article
Reconstruction Method of Old Well Logging Curves Based on BI-LSTM Model—Taking Feixianguan Formation in East Sichuan as an Example
by Chao Cheng, Yan Gao, Yan Chen, Shixiang Jiao, Yuqiang Jiang, Juanzi Yi and Liang Zhang
Coatings 2022, 12(2), 113; https://doi.org/10.3390/coatings12020113 - 20 Jan 2022
Cited by 2 | Viewed by 1582
Abstract
In order to define a favorable oil and gas accumulation area, this study focused on reservoir recognition which is based on logging data of old wells. The Gaofengchang structure in eastern Sichuan is used as a test area to discuss the necessity and [...] Read more.
In order to define a favorable oil and gas accumulation area, this study focused on reservoir recognition which is based on logging data of old wells. The Gaofengchang structure in eastern Sichuan is used as a test area to discuss the necessity and feasibility of curve construction by combining new and old wells. Analysis of the reasons for the inaccuracy of the traditional curve reconstruction method is also provided. Given the interdependence of the well log in the depth domain sample sequence, a new intelligent construction method (BI-LSTM) based on the cyclic neural network is proposed. A discussion on the effect of data increments on prediction accuracy is also provided. The following four conclusions were achieved through curve reconstruction experiments: a high-precision CNL pseudo-curve was obtained; an underdetermined equation in optimization logging interpretation method needed to be extended to a positive definite equation; the quantitative processing of the complex lithologic reservoir parameters for the old wells was realized; and the processing result of the lithology physical property were basically consistent with the core data. Therefore, the BI-LSTM proposed in this paper could improve the accuracy of logging curve construction and has a good promotion significance for the old well review. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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17 pages, 3027 KiB  
Article
Dual Synergistic Effects of MgO-GO Fillers on Degradation Behavior, Biocompatibility and Antibacterial Activities of Chitosan Coated Mg Alloy
by Mohammad Zolfaghari Baghbaderani, Somayeh Abazari, Hamid Reza Bakhsheshi-Rad, Ahmad Fauzi Ismail, Safian Sharif, Aliakbar Najafinezhad, Seeram Ramakrishna, Mohammadreza Daroonparvar and Filippo Berto
Coatings 2022, 12(1), 63; https://doi.org/10.3390/coatings12010063 - 06 Jan 2022
Cited by 5 | Viewed by 1809
Abstract
The aim of this work was to establish and characterize chitosan/graphene oxide- magnesium oxide (CS/GO-MgO) nanocomposite coatings on biodegradable magnesium-zinc-cerium (Mg-Zn-Ce) alloy. In comparison to that of pure CS coatings, all composite coatings encapsulating GO-MgO had better adhesion strength to the Mg-Zn-Ce alloy [...] Read more.
The aim of this work was to establish and characterize chitosan/graphene oxide- magnesium oxide (CS/GO-MgO) nanocomposite coatings on biodegradable magnesium-zinc-cerium (Mg-Zn-Ce) alloy. In comparison to that of pure CS coatings, all composite coatings encapsulating GO-MgO had better adhesion strength to the Mg-Zn-Ce alloy substrate. The result depicted that the co-encapsulation of GO-MgO into the CS layer leads to diminish of contact angle value and hence escalates the hydrophilic characteristic of coated Mg alloy. The electrochemical test demonstrated that the CS/GO-MgO coatings significantly increased the corrosion resistance because of the synergistic effect of the GO and MgO inside the CS coating. The composite coating escalated cell viability and cell differentiation, according to cytocompatibility tests due to the presence of GO and MgO within the CS. The inclusion of GO-MgO in CS film, on the other hand, accelerates the formation of hydroxyapatite (HA) during 14 days immersion in SBF. Immersion results, including weight loss and hydrogen evolution tests, presented that CS/GO-MgO coating enables a considerably reduced degradation rate of Mg-Zn-Ce alloy when compared to the bare alloy. In terms of antibacterial-inhibition properties, the GO-MgO/CS coatings on Mg substrates showed antibacterial activity against Escherichia coli (E. coli), with a large inhibition area around the specimens, particularly for the coating containing a higher concentration of GO-MgO. Bacterial growth was not inhibited by the bare Mg alloy samples. The CS/GO-MgO composite coating is regarded as a great film to enhance the corrosion resistance, bioactivity, and antibacterial performance of Mg alloy implants. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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19 pages, 8474 KiB  
Article
On the Effects of High and Ultra-High Rotational Speeds on the Strength, Corrosion Resistance, and Microstructure during Friction Stir Welding of Al 6061-T6 and 316L SS Alloys
by Zhipeng Li, Shujin Chen, Lingfei Meng, Yang Gao, Zhidong Yang, Mingxiao Shi, Xinyi Chen, Hao Zhang and Yuye Zhang
Coatings 2021, 11(12), 1550; https://doi.org/10.3390/coatings11121550 - 17 Dec 2021
Cited by 5 | Viewed by 1988
Abstract
In this study, under the conditions of using tools at a high rotational speed (HRS) of 10,000 rpm and an ultra-high rotational speed (ultra-HRS) of 18,000 rpm, the produced welding heat input was utilized to weld two specimens of Al alloy 6061-T6 with [...] Read more.
In this study, under the conditions of using tools at a high rotational speed (HRS) of 10,000 rpm and an ultra-high rotational speed (ultra-HRS) of 18,000 rpm, the produced welding heat input was utilized to weld two specimens of Al alloy 6061-T6 with 1.0 mm thickness and 316L SS with 0.8 mm thickness. The microstructural characteristics, mechanical properties, and electrochemical corrosion properties of the aluminum alloy–steel joints were analyzed. The higher tool offset forms an intermetallic compound layer of less than 1 µm at the Fe-Al interface on the advancing side (AS) at different speeds. This results in a mixed zone structure. The lower tool offset forms intermetallic compounds of only 2 µm. The formation of a composite material based on aluminum alloy in the weld nugget zone improves the hardness value. The intermetallic compounds are Fe3Al and FeAl3, respectively. It was observed that the formation of intermetallic compounds is solely related to the rotational speed, and the iron-rich intermetallic compounds produced under ultra-HRS parameters have higher corrosion resistance. When the tool offset is 0.55 mm, using the HRS parameters, the tensile strength is 220.8 MPa (about 75.9% of that of the base metal). Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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12 pages, 2632 KiB  
Article
Laboratory Experimental Study on Influencing Factors of Drainage Pipe Crystallization in Highway Tunnel in Karst Area
by Huaming Li, Shiyang Liu, Shuai Xiong, Hao Leng, Huiqiang Chen, Bin Zhang and Zhen Liu
Coatings 2021, 11(12), 1493; https://doi.org/10.3390/coatings11121493 - 03 Dec 2021
Cited by 6 | Viewed by 1995
Abstract
The crystalline blockage of tunnel drainage pipes in a karst area seriously affects the normal operation of drainage system and buries hidden dangers for the normal operation of the tunnel. In order to obtain the influencing factors and laws of tunnel drainage pipe [...] Read more.
The crystalline blockage of tunnel drainage pipes in a karst area seriously affects the normal operation of drainage system and buries hidden dangers for the normal operation of the tunnel. In order to obtain the influencing factors and laws of tunnel drainage pipe crystallization in a karst area, based on the field investigation of crystallization pipe plugging, the effects of groundwater velocity, drainage pipe diameter, drainage pipe material, and structure on the crystallization law of tunnel drainage pipe in karst area are studied by indoor model test. The results show that: (1) With the increase of drainage pipe diameter (20–32 mm), the crystallinity of drainage pipes first increases and then decreases. (2) With the increase of water velocity in the drainage pipe (22.0–63.5 cm·s−1), the crystallinity of the drainage pipes gradually decreases from 1.20 g to 0.70 g. (3) The crystallinity of existing material drainage pipe is: M3 (poly tetra fluoroethylene) > M2 (pentatricopeptide repeats) > M4 (high density polyethylene) > M1 (polyvinyl chloride); M8 (polyvinyl chloride + coil magnetic field) is used to change the crystallinity of drain pipe wall material. (4) When the groundwater flow rate is 34.5 cm·s−1, M1 (polyvinyl chloride) and M8 (polyvinyl chloride + coil magnetic field) can be selected for the tunnel drainage pipe. The research on the influencing factors of tunnel drainage pipe crystallization plugging fills a gap in the research of tunnel drainage pipe crystallization plugging. The research results can provide a basis for the prevention and treatment technology of tunnel drainage pipe crystallization plugging. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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16 pages, 1363 KiB  
Article
Optimization Model of Engineering Specifications Based on Grey Quality Gain-Loss Function
by Bo Wang, Qi Yang, Chen Liu, Qikai Li and Xiangtian Nie
Coatings 2021, 11(11), 1327; https://doi.org/10.3390/coatings11111327 - 29 Oct 2021
Cited by 2 | Viewed by 1197
Abstract
In view of the fact that the target values of some quality characteristics are grey, the grey quality gain-loss function model was applied in the analysis of the quality characteristics. At the same time, based on the analysis of engineering specifications and process [...] Read more.
In view of the fact that the target values of some quality characteristics are grey, the grey quality gain-loss function model was applied in the analysis of the quality characteristics. At the same time, based on the analysis of engineering specifications and process capability, an optimization model of engineering specifications was proposed to minimize the expected total loss of each product and maximize the expected compensation with inspection costs, scrap costs and grey quality gain-loss into consideration. The optimal engineering specification can be obtained by using the optimization model. Through the example analysis and its application in dam concrete construction, the practicability of the model is verified, which provides an important reference for the research of the new theory of dam concrete construction quality control. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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15 pages, 5323 KiB  
Article
Adsorption Features of Loess Calcareous Nodules to Heavy-Metal Ions in Aqueous Solution
by Qi Li and Yanan Li
Coatings 2021, 11(11), 1314; https://doi.org/10.3390/coatings11111314 - 28 Oct 2021
Viewed by 1226
Abstract
This paper explores the use of calcareous tuberculosis as an adsorbent and heavy-metal ions (Cu2+, Zn2+, Cd2+, and Pb2+) as adsorbates, and the influence of varying levels of particle size, adsorption time, pH, adsorbent dosage, [...] Read more.
This paper explores the use of calcareous tuberculosis as an adsorbent and heavy-metal ions (Cu2+, Zn2+, Cd2+, and Pb2+) as adsorbates, and the influence of varying levels of particle size, adsorption time, pH, adsorbent dosage, and initial concentration of heavy metals is studied through an experiment of single heavy-metal adsorption. In addition, the impact of the temperature and other factors on the adsorption of heavy-metal ions by calcareous nodules is analyzed to identify the optimal conditions for the adsorption of heavy-metal ions by calcareous nodules. As shown by the research findings, the adsorption rates of Cu2+, Zn2+, and Pb2+ gradually declined with the increase in particle size, with no evident effect on Cd2+. In the meantime, with further increases in factors such as the adsorption time, adsorbent dosage, and temperature, the adsorption rates of Cu2+, Zn2+, Cd2+, and Pb2+ experienced gradual increases. The adsorption rates of Cu2+, Zn2+, and Cd2+ gradually declined with the increase in initial concentration of heavy-metal ions, whereas the adsorption rate of Pb2+ experience increased first and then declined. As the pH increased, the adsorption rate of Cd2+ experience increased first and then declined at a slow pace. The adsorption rates of Cu2+, Zn2+, and Pb2+ increased first and then decreased. The adsorption capacity of calcareous nodules toward the four heavy-metal ions was in the order of Pb2+ > Zn2+ > Cu2+ > Cd2+. When the particle size was set to 0.25 mm, the adsorption time was set to 120 min, and the dosage was set to 0.6 g, the calcareous nodules included Pb2+, Zn2+, and Cu2+. Moreover, Cd2+ was able to achieve stronger adsorption capacity, with the adsorption rate able to reach 83.33%, 77.78%, 73.81%, and 81.93% of its maximum level. Therefore, as the particle size of the heavy-metal ions decreased, the adsorption capacity generally became stronger. As the adsorption time increased, the temperature and the amount of adsorbent also increased. The optimal pH value for the adsorption of calcareous nodules toward Pb2+, Zn2+, Cu2+, and Cd2+ was found to be 7, 6, 5, and 8, respectively, and the optimal temperature was 50 °C. In summary, calcareous nodules are a natural, low-cost, and effective adsorbent. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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14 pages, 15847 KiB  
Article
Friction and Wear Behaviors of Fe-19Cr-15Mn-0.66N Steel at High Temperature
by Shaolong Sheng, Huiling Zhou, Xiaojing Wang, Yanxin Qiao, Hongtao Yuan, Jian Chen, Lanlan Yang, Dongpeng Wang, Zhenguang Liu, Jiasheng Zou, Zhibin Zheng and Jingyong Li
Coatings 2021, 11(11), 1285; https://doi.org/10.3390/coatings11111285 - 22 Oct 2021
Cited by 11 | Viewed by 1806
Abstract
The friction and wear behaviors of Fe-19Cr-15Mn-0.66N steel were investigated under applied loads of 5 N and 15 N at the wear-testing temperatures of 300 °C and 500 °C using a ball-on-disc tribometer. The wear tracks were evaluated by scanning electron microscopy (SEM) [...] Read more.
The friction and wear behaviors of Fe-19Cr-15Mn-0.66N steel were investigated under applied loads of 5 N and 15 N at the wear-testing temperatures of 300 °C and 500 °C using a ball-on-disc tribometer. The wear tracks were evaluated by scanning electron microscopy (SEM) and laser scanning confocal microscopy (LSCM) to reveal the variation in morphologies. Energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) were used to determine the components of oxide layers formed on wear surfaces. The results demonstrated that the oxide layers are favorable for obtaining a low friction coefficient under all conditions. The average friction coefficient decreased with increasing load at 300 °C, while it increased with the increase in applied load at 500 °C. At 300 °C, severe abrasive wear characterized by grooves resulted in a high friction coefficient with 5 N applied, whereas the formation of a denser oxide layer consisting of Cr2O3, FeCr2O4, Fe2O3, etc., and the increased hardness caused by work hardening led to a decrease in friction characterized by mild adhesive wear. At 500 °C, the transformation of Fe2O3 to the relatively softer Fe3O4 and the high production of lubricating Mn2O3 resulted in a minimum average friction coefficient (0.34) when 5 N was applied. However, the softening caused by high temperature weakened the hardening effect, and thus the friction coefficient increased with 15 N applied at 500 °C. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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12 pages, 1106 KiB  
Article
Numerical Simulation of the Effect of Freeze–Thaw Cycles on the Durability of Concrete in a Salt Frost Environment
by Hao Li, Yuan Zhang and Haolong Guo
Coatings 2021, 11(10), 1198; https://doi.org/10.3390/coatings11101198 - 30 Sep 2021
Cited by 5 | Viewed by 1776
Abstract
In order to improve the accuracy of the analysis of the impact of freeze–thaw cycle on concrete durability in a salt freezing environment, the numerical simulation of the impact of the freeze–thaw cycle on concrete durability in a salt freezing erosion environment is [...] Read more.
In order to improve the accuracy of the analysis of the impact of freeze–thaw cycle on concrete durability in a salt freezing environment, the numerical simulation of the impact of the freeze–thaw cycle on concrete durability in a salt freezing erosion environment is studied in this paper. Firstly, considering the influence of axial force and bending moment on the relationship between bending moment and curvature, a concrete fiber beam column model is established. Then, according to the joint influence of temperature field, stress field and seepage field on concrete in the process of freezing and thawing, the control differential equation of the freezing and thawing cycle is established. The freeze–thaw damage section is divided, the non-uniform distribution of freeze–thaw damage is determined, and the division of the freeze–thaw damage section is completed. According to the linear relationship between freeze–thaw damage degree, relative dynamic elastic modulus, freeze–thaw cycle times and position variables, the durability of concrete is numerically simulated, and the attenuation law of bond strength at different section depths after freeze–thaw is determined. The results show that the temperature curve simulated by the design method is consistent with the actually measured temperature curve, which can better reduce the temperature change of the inner core of the test block during freezing and thawing, and the relative dynamic elastic modulus is in good agreement with the actual value, which can prove that the method in this paper has certain practical application value. It is expected to provide some reference for solving the durability problem of concrete in a salt frost erosion environment and the optimal design of concrete structures. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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14 pages, 4998 KiB  
Article
Wear and Corrosion Resistance of CoCrFeNiSiMoW Medium-Entropy Alloy Coatings on Q235 Steel
by Qingxian Hu, Xiaoli Wang, Xinwang Shen, Fanglian Fu and Zemin Tan
Coatings 2021, 11(9), 1053; https://doi.org/10.3390/coatings11091053 - 31 Aug 2021
Cited by 4 | Viewed by 1888
Abstract
CoCrFeNiSiMoW medium-entropy alloy coatings (MEACs) were fabricated by plasma-arc surfacing welding on Q235 steel. The microstructures and mechanical properties of CoCrFeNiSiMoW MEACs were studied. CoCrFeNiSiMoW MEACs are made from a mixture of NiCrCoMo cubic (FCC) solid solution phase, (Fe, Ni), Mo1.24Ni0.76, and CoCx [...] Read more.
CoCrFeNiSiMoW medium-entropy alloy coatings (MEACs) were fabricated by plasma-arc surfacing welding on Q235 steel. The microstructures and mechanical properties of CoCrFeNiSiMoW MEACs were studied. CoCrFeNiSiMoW MEACs are made from a mixture of NiCrCoMo cubic (FCC) solid solution phase, (Fe, Ni), Mo1.24Ni0.76, and CoCx phases by XRD analysis. The average hardness values of the one- and two-layer CoCrFeNiSiMoW MEACs obtained were 186 ± 1.56 and 198 ± 1.78 HV, respectively. Compared with the one-layer CoCrFeNiSiMoW coating, the two-layer coating has a better wear performance due to its higher hardness. Its corrosion resistance is better because of its higher Ni content. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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16 pages, 4289 KiB  
Article
Effect of Intermediate Principal Stress on the Bearing Capacity of Footings in Soft Rock
by Zongyuan Ma, Faning Dang and Hongjian Liao
Coatings 2021, 11(9), 1019; https://doi.org/10.3390/coatings11091019 - 25 Aug 2021
Viewed by 1827
Abstract
The bearing capacity for footings is a fundamental scientific problem in civil engineering. The evaluation of the bearing capacity of footings usually does not take into account the effect of the intermediate principal stress. In practice, the intermediate principal stress has certain influences [...] Read more.
The bearing capacity for footings is a fundamental scientific problem in civil engineering. The evaluation of the bearing capacity of footings usually does not take into account the effect of the intermediate principal stress. In practice, the intermediate principal stress has certain influences on the strength of geomaterials (e.g., rock and soil) or concrete. In this paper, a series of numerical solutions are presented to evaluate the bearing capacity of footings in a soft rock foundation via a two-dimensional finite difference code (FLAC) with a strain hardening/softening constitutive model based on the unified strength theory (UST). The values of the bearing capacity factor Nc and Nγ for strip, circular and square footings in a soft rock foundation were evaluated using the strain hardening/softening constitutive model. The effect of the intermediate principal stress on the bearing capacity of strip, circular and square footings in a soft rock foundation was analyzed. The results of the numerical computation show that the intermediate principal stress has a significant influence on the bearing capacity and failure mechanisms of a soft rock medium. The influence of the intermediate principal stress on the peak and residual values of the bearing capacity for a strip footing is much greater than for circular and square footings. Research works for the reasonable estimation of the bearing capacity of footings in soft rock are facilitated by this study. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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11 pages, 15152 KiB  
Article
Anti-Blocking Mechanism of Flocking Drainage Pipes in Tunnels Based on Mathematical Modeling Theory
by Shiyang Liu, Xuefu Zhang and Feng Gao
Coatings 2021, 11(8), 961; https://doi.org/10.3390/coatings11080961 - 13 Aug 2021
Cited by 2 | Viewed by 1903
Abstract
Crystalline pipe plugging in tunnel drainage systems is one of the causes of tunnel lining cracking and water leakage. Therefore, effective prevention of crystalline pipe blockage in tunnel drainage systems is very important to ensure the safety and stability of the lining structure [...] Read more.
Crystalline pipe plugging in tunnel drainage systems is one of the causes of tunnel lining cracking and water leakage. Therefore, effective prevention of crystalline pipe blockage in tunnel drainage systems is very important to ensure the safety and stability of the lining structure during tunnel operation. Combined with the theories of fluid mechanics, structural mechanics and basic physics, the flocking and anti-blocking mechanism of drainage pipe was comprehensively analyzed by using the method of mathematical modeling, including: (1) the calculation expression of average velocity of the flocked section of a flocked drainage pipe v = Q/(C1 − C2(r + r′)) and the calculation formula of flowing water pressure under the action of groundwater Fw =  KAγQ2/(2g(C1 − C2(r + r′))2); (2) the flow velocity v0 in the flocked drainage pipe shall meet v2 < 4gπrlτ1/γKA, crystals will be attached to the fluff and the crystals will maintain dynamic balance; (3) the flow velocity v0 in the flocked drainage pipe shall meet v2 ≥ 4gπrlτ1/γKA, crystals will not adhere to the fluff and the flocked drainage pipe will remain unobstructed. The research on the mechanism of preventing blockage of flocking drainage pipes fills the gap in research theory in this regard, contributes to the popularization and application of blocking prevention technology of flocking drainage pipes, reduces the maintenance cost during operation of tunnel drainage systems and ensures the safe and normal operation of tunnels. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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24 pages, 11529 KiB  
Article
Multi-Damage Identification of Multi-Span Bridges Based on Influence Lines
by Yunkai Zhang, Qingli Xie, Guohua Li and Yali Liu
Coatings 2021, 11(8), 905; https://doi.org/10.3390/coatings11080905 - 28 Jul 2021
Cited by 3 | Viewed by 2009
Abstract
The framework security of a bridge is essential as a critical component of traffic engineering. Even though the bridge structure is damaged to various degrees due to various reasons, the bridge will be wrecked when the damage reaches a particular level, suggesting a [...] Read more.
The framework security of a bridge is essential as a critical component of traffic engineering. Even though the bridge structure is damaged to various degrees due to various reasons, the bridge will be wrecked when the damage reaches a particular level, suggesting a negative influence on people’s lives. Based on the current situation and existing problems of structural damage identification of bridges, a structural damage identification technology of continuous beam bridges based on deflection influence lines is proposed in this paper in order to keep track of and always detect broken bridge elements, thereby extending the bridge’s service life and reducing the risk of catastrophic accidents. The line function expression of deflection impact on a multi-span continuous beam bridge was first obtained using Graphic Multiplication theory. From the theoretical level, the influence line function of the continuous beam bridge without extensive damage was computed, and a graph was generated. The photographs of the DIL as well as the first and second derivatives, the deflection influence line distinction and its first and second derivatives, and the DIL distinction and its first and second derivatives of a continuous beam bridge in a single position and multi-position destruction were fitted in this paper. Finally, after comparing multiple work conditions and multiple measuring points, it was found that the first derivative of deflection influence line difference had the best damage identification effect. The design was completed and tested, which had verified the feasibility of this theory. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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15 pages, 3576 KiB  
Article
Effects of Mechanical Activation on Physical and Chemical Characteristics of Coal-Gasification Slag
by Feng Wu, Hui Li and Kang Yang
Coatings 2021, 11(8), 902; https://doi.org/10.3390/coatings11080902 - 28 Jul 2021
Cited by 31 | Viewed by 2290
Abstract
Coal-gasification slag (CGS) was subjected to mechanical grinding by three different methods. We studied the effects of mechanical activation on various physical and chemical characteristics of the CGS, including particle-size distribution, specific surface area, mineral composition, degree of crystallinity, particle morphology, chemical bonding, [...] Read more.
Coal-gasification slag (CGS) was subjected to mechanical grinding by three different methods. We studied the effects of mechanical activation on various physical and chemical characteristics of the CGS, including particle-size distribution, specific surface area, mineral composition, degree of crystallinity, particle morphology, chemical bonding, surface activity and binding energy, anionic-polymerization degree and hydration properties. The results show that there are different effects on CGS characteristics depending on the type of activation applied. Mechanical activation also can increase the specific surface area and the dissolution rates of activated SiO2 and Al2O3, and the major elements (O, Si, Al, Ca) in CGS, whereas the degree of crystallinity and of polymerization of [SiO4] and [AlO6] are reduced by mechanical activation. We also found that the effects of different mechanical-activation methods on the compressive strength and activity were similar and could accelerate the hydration process. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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11 pages, 6323 KiB  
Article
Optimization Study of Fluffy Materials Flocking Drainage Pipes to Resist Blockage Based on MD Binding Energy
by Shiyang Liu, Xuefu Zhang, Yuanfu Zhou and Feng Gao
Coatings 2021, 11(7), 853; https://doi.org/10.3390/coatings11070853 - 15 Jul 2021
Cited by 4 | Viewed by 1846
Abstract
Drainage pipe blockage resulting from crystals is one of the causes for cracking and leakage of tunnel lining. Therefore, effective prevention from drainage pipe blockage caused by crystals is crucial to ensure the safety and stability of lining structures during the operation of [...] Read more.
Drainage pipe blockage resulting from crystals is one of the causes for cracking and leakage of tunnel lining. Therefore, effective prevention from drainage pipe blockage caused by crystals is crucial to ensure the safety and stability of lining structures during the operation of tunnel drainage system. Based on a large number of indoor model tests and numerical simulation analyses, binding energy between four materials and the calcium carbonate aqueous solution (“solid + liquid” system) and that between the four materials and the two typical growth crystals of calcium carbonate (“solid + solid” system) were studied. The research results indicated that: (1) The four materials all had an adsorption effect on the calcium carbonate aqueous solution system, and the PA6 had the greatest adsorption effect while the PP had the smallest adsorption effect; (2) There was spontaneous adsorption between the PVC or PA6 and the two typical growth crystals of calcium carbonate and no adsorption between the PP or SiC and the two typical growth crystals of calcium carbonate unless external energy was in place; (3) The PP and SiC can be used as the materials for drainage pipe flocking, but it shall be ensured that the fluffy material has a good geometrical property. The prevention technology for crystallization that causes drainage pipe blockage fills the gap in the research of drainage pipe blockage caused by crystals, which can reduce the maintenance cost for the operation of the tunnel drainage system and ensure safe and normal operation of the tunnel. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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12 pages, 5635 KiB  
Article
Facile Synthesis of Copper(I) Oxide Nanochains and the Photo-Thermal Conversion Performance of Its Nanofluids
by Zhongjin Ni, Xiaohai Cao, Xinyi Wang, Shiyu Zhou, Caixia Zhang, Bin Xu and Yihua Ni
Coatings 2021, 11(7), 749; https://doi.org/10.3390/coatings11070749 - 22 Jun 2021
Cited by 69 | Viewed by 3468
Abstract
In this thesis, Cu2O nanochains were synthesized by thermal decomposition with copper formate-octylamine as the precursor, oleic acid and oleylamine as the catalyst stabilizer agent and paraffin as the solvent. The phase structure and micromorphology of Cu2O nanochains were [...] Read more.
In this thesis, Cu2O nanochains were synthesized by thermal decomposition with copper formate-octylamine as the precursor, oleic acid and oleylamine as the catalyst stabilizer agent and paraffin as the solvent. The phase structure and micromorphology of Cu2O nanochains were characterized by X-ray diffraction and transmission electron microscopy. The effect of reaction time and concentration of the precursor on the Cu2O nanochains were discussed, and the formation mechanism of the Cu2O nanochains was analyzed. The results show that Cu2O nanochains were self-assembled by Cu2O nanocrystals; with the extension of the reaction time, Cu2O nanochains gradually become granular; increasing the concentration of the precursor will increase the entanglement degree of the nanochains. Oleic acid contributes to the formation of Cu2O, and oleylamine plays a directional role in the formation of nanochains. On the basis of those phenomenon, a comparison of the Cu2O nanochain-water nanofluids with that of a water-based liquid showed that after irradiating for 3000 s, the temperature of nanofluids reached 91.1 °C while the water was only 75.7 °C. This demonstrates the better performance of the Cu2O nanochain-water nanofluid in the ability of light absorption, thermal conductivity and photothermal conversion. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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12 pages, 4003 KiB  
Article
Corrosion Behavior of FeB-30 wt.% Al0.25FeNiCoCr Cermet Coating in Liquid Zinc
by Xiaolong Xie, Bingbing Yin, Fucheng Yin and Xuemei Ouyang
Coatings 2021, 11(6), 622; https://doi.org/10.3390/coatings11060622 - 22 May 2021
Cited by 8 | Viewed by 1940
Abstract
The corrosion of galvanizing equipment parts by liquid zinc is an urgent problem that needs solving. In this work, FeB-30 wt.% Al0.25FeNiCoCr cermet coating was deposited on the surface of 316L stainless steel by AC-HVAF to protect galvanizing equipment parts from [...] Read more.
The corrosion of galvanizing equipment parts by liquid zinc is an urgent problem that needs solving. In this work, FeB-30 wt.% Al0.25FeNiCoCr cermet coating was deposited on the surface of 316L stainless steel by AC-HVAF to protect galvanizing equipment parts from corrosion by liquid zinc. The microstructures and phase compositions of powders and the coating were determined by SEM, EDS, and XRD in detail. Additionally, the microhardness, fracture toughness, abrasion wear resistance, and corrosion resistance of the coating to liquid zinc were also studied. The results indicate that the abrasion wear resistance and corrosion resistance of the coating are much better than that of the 316L stainless steel substrate. The failure of the coating in liquid zinc is mainly due to the penetration of liquid zinc into macro-cracks, which causes the coating to peel off. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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Review

Jump to: Editorial, Research

23 pages, 8665 KiB  
Review
Research Progress of Self-Healing Thermal Barrier Coatings: A Review
by Bin Liu, Jianping Zhou, Liang Wang and You Wang
Coatings 2022, 12(11), 1724; https://doi.org/10.3390/coatings12111724 - 11 Nov 2022
Cited by 1 | Viewed by 2010
Abstract
Reliability and durability are two important performance indicators for thermal barrier coatings (TBCs). The reliability of TBCs usually includes high adhesive strength, low thermal conductivity and high thermal shock resistance. The high reliability of TBCs ensures basic usage requirements. Durability demands TBCs have [...] Read more.
Reliability and durability are two important performance indicators for thermal barrier coatings (TBCs). The reliability of TBCs usually includes high adhesive strength, low thermal conductivity and high thermal shock resistance. The high reliability of TBCs ensures basic usage requirements. Durability demands TBCs have a long service lifetime before their eventual failure. The lifetimes of TBCs under actual service conditions are strongly dependent on crack initiation and propagation. Controlling and delaying the dynamic process of crack initiation and propagation is a direct approach to prolonging the service lifetime of TBCs. Self-healing TBCs usually have the specific function of inhibiting crack propagation, and thus promote the self-healing process of TBCs. The research progress of self-healing TBCs was reviewed. Firstly, the concept of self-healing or self-healing materials is clarified. Secondly, the research progress about some self-healing ceramic materials as well as self-healing TBCs is reviewed. Based on the review, the micro-structure design, propagation patterns of the crack and self-healing mechanism are discussed systematically. Additionally, the future development trend of the self-healing TBCs is also overviewed in this paper. Full article
(This article belongs to the Special Issue Corrosion and Degradation of Materials)
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