Advanced Coatings with Noble and Refractory Alloy Metals in Extreme Environments

A special issue of Coatings (ISSN 2079-6412). This special issue belongs to the section "Surface Characterization, Deposition and Modification".

Deadline for manuscript submissions: closed (28 February 2025) | Viewed by 5089

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Guest Editor
School of Mechanical Engineering and Rail Transit, Changzhou University, Changzhou 213164, China
Interests: metal/alloy coating and film for corrosion, oxidation, and catalysis
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Special Issue Information

Dear Colleagues,

Recent theoretical and experimental developments in noble metal and its alloy coatings, refractory metal coatings, and surface modification technologies are among the most highly exploited research systems in the field of materials science and engineering and engineering mechanical components. They are spurred primarily by durability in demanding the environmental conditions required by current applications ranging from aerospace, medical, and automotive and chemical industries to oil and gas technologies. Driven by the current state of knowledge of high-temperature protection and corrosion prevention mechanisms, the need to maintain structural material integrity and reliability assets under harsh environments and a renewed impetus towards the durability of new nanostructured coating systems have seen a huge demand in experimental, theoretical, and modelling activities.

The manufacture, design, and test of high-performance nanostructured coating materials that are either high in terms of conductivity and corrosion-resistant noble metals (e.g., platinum, gold, silver, etc.) or are capable of serving as physical protection layers with high-temperature and wear-resistant refractory metals (tungsten, molybdenum, etc.), or a combination of these, provides unprecedented functionality and opportunities for multifunctional coatings protecting metallic structures (steels, stainless steels, aluminium, and magnesium, etc.).

This scope of this Special Issue will serve as a forum for papers in the following areas:

  1. Theoretical and experimental research, knowledge, and new ideas in corrosion protective and preventive coatings mechanisms of noble metal and refractory metal coatings.
  2. Recent developments in surface modification and strengthening techniques for multi-functional coatings, involving noble and refractory metals.
  3. A new initiative aims to reduce the amount of noble metal in its alloy coatings and to enhance their performance.
  4. Coatings produced by different processes, including, but not limited to, additive manufacturing processes, thermal spray, laser and plasma processing, CVD, electrodeposition, etc.
  5. Experiment and processing of high-performance coatings with exposure to high temperatures, high stress, and other extreme environment applications.
  6. Understanding the degradation mechanisms of coatings through friction, wear, or other dynamic loading condition and corrosion.
  7. The latest development of test methods considering the interplay between mechanical, chemical, and electrochemical interactions and the ability to predict performance and reliability.
  8. Computer modelling, simulation to predict coating properties, performance, durability, and reliability in service environments.

Dr. Wangping Wu
Guest Editor

Manuscript Submission Information

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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

  • protective coatings
  • extreme environments
  • noble metal
  • refractory metal
  • surface reinforcement

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Published Papers (5 papers)

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Research

15 pages, 19211 KiB  
Article
Microstructure and Properties Study of TA18 Titanium Alloy Tube Differential Temperature Necking and Thickening Forming Based on Temperature Gradient Positioning
by Jun Xie, Xuefeng Xu, Liming Wei, Feng Cui and Jiawei Nie
Coatings 2025, 15(4), 392; https://doi.org/10.3390/coatings15040392 - 26 Mar 2025
Viewed by 231
Abstract
A finite element model was established to simulate the necking and thickening process of TA18 titanium alloy thin-wall tubes to compare the effect of differential temperature and isothermal methods on the temperature and wall thickness distributions of the tubes. It is found that [...] Read more.
A finite element model was established to simulate the necking and thickening process of TA18 titanium alloy thin-wall tubes to compare the effect of differential temperature and isothermal methods on the temperature and wall thickness distributions of the tubes. It is found that the temperature gradient of differential temperature tubes shifts from the force transfer area to the necking area, and these tubes exhibit a thicker thickening area and a thinner necking area compared to their isothermal counterparts. The experiments on the necking and thickening of TA18 titanium alloy tubes were conducted using both differential temperature and isothermal methods. The results show that the differential temperature method is a superior forming method compared to the isothermal process. The major thickening occurs in the thickening area of the differential temperature tube, while it occurs in the necking area of the isothermal tube. The average wall thickness of the differential temperature tubes is 25% greater in the thickening area, while it is 23% thinner in the necking area, compared to the isothermal tubes. We conducted EBSD tests on TA18 titanium alloy thin-walled tubes; the results showed that dynamic recrystallization occurred in the necking and thickening regions, with significant grain refinement. The grain size in the necking region was smaller than that in the thickening region. Full article
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23 pages, 25481 KiB  
Article
Research on Microstructure Evolution Rules of TA18 Titanium Alloy Tube During the Differential Heating Push-Bending Forming Process
by Yanfang Li, Xuefeng Xu, Liming Wei, Yubin Fan, Jun Xie, Shijian Luo and Xiang Zeng
Coatings 2025, 15(3), 256; https://doi.org/10.3390/coatings15030256 - 21 Feb 2025
Viewed by 448
Abstract
The evolution of the microstructure of TA18 titanium alloy tube during the differential heating push-bending forming process has a significant impact on its macroscopic mechanical properties. This paper obtained the experimental stress–strain data of TA18 titanium alloy through high-temperature tensile tests, solved the [...] Read more.
The evolution of the microstructure of TA18 titanium alloy tube during the differential heating push-bending forming process has a significant impact on its macroscopic mechanical properties. This paper obtained the experimental stress–strain data of TA18 titanium alloy through high-temperature tensile tests, solved the key parameters of the cellular automata (CA) model through fitting calculation, established a finite-element model of differential heating push-bending of TA18 titanium alloy tube using DEFORM-3D, and simulated the evolution of the microstructure during the bending process of the tube based on the CA method. The study investigated the influence of heating temperature, internal pressure, and feed speed of the pusher on the average grain size of the material on the outer side of the bent tube. Experiments were conducted, and the key areas of the manufactured tube were analyzed through metallographic observation. The research indicated that the average grain size of the material on the outer side of the bent tube increases slightly and then decreases with the rise in heating temperature and decreases continuously with the increase of internal pressure or feed speed of the pusher. This study provides theoretical support for optimizing the differential heating push-bending forming of TA18 titanium alloy tube at a microscopic level. Full article
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15 pages, 4491 KiB  
Article
Performance Study and Machine Learning Model Evaluation of Embedded Micro-Agglomerated Particle TBCs Based on Plasma-Spraying Process
by Shuheng Xu, Zhou Xu, Changdong Yin, Yiwen Wu, Feixiang Wu, Houli Liu, Zhijun Zhang, Guoqing Yang, Jibo Huang and Dongdong Ye
Coatings 2025, 15(2), 203; https://doi.org/10.3390/coatings15020203 - 7 Feb 2025
Viewed by 714
Abstract
The spraying process affects the microstructure and service life of thermal barrier coatings. In this work, by changing the plasma-spraying process, the second-phase micron-agglomerated particles were introduced to prepare embedded micron-agglomerated particle thermal barrier coatings. Conventional thermal barrier coatings and embedded micron-agglomerated particle [...] Read more.
The spraying process affects the microstructure and service life of thermal barrier coatings. In this work, by changing the plasma-spraying process, the second-phase micron-agglomerated particles were introduced to prepare embedded micron-agglomerated particle thermal barrier coatings. Conventional thermal barrier coatings and embedded micron-agglomerated particle thermal barrier coatings were prepared by setting spraying process parameters with different powder feeding rates and distances between powder feeders. Sintering experiments and thermal cycling experiments were carried out on conventional thermal barrier coatings and embedded micron-agglomerated particle thermal barrier coatings. The effects of spraying process parameters on the microstructure and thermal cycle life of embedded micron-agglomerated particle thermal barrier coatings were systematically studied. Three machine learning models of BP, SVM, and GA-SVM were established to evaluate the relationship between spraying parameters and coating microstructure and thermal cycle life. The results show that the sintering resistance of the new thermal barrier coating is 500% higher than that of the conventional thermal barrier coating. When the distance between the two powder feeders is 35 mm and the powder feeder 1 rate is 12 g/min, the thermal cycle life of the coating is the best. When using machine learning model evaluation, the evaluation results of the three machine learning models have certain accuracy. Among them, the GA-SVM machine learning model has the best prediction effect and the smallest prediction error. The results of this paper provide a new paradigm for further preparation of thermal barrier coatings with high performance and long life. Full article
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17 pages, 5240 KiB  
Article
Tailoring the Silicon Cementation Applied to P265GH Grade Steel
by Mihai Branzei, Mihai Ovidiu Cojocaru, Mircea Dan Morariu and Leontin Nicolae Druga
Coatings 2024, 14(1), 74; https://doi.org/10.3390/coatings14010074 - 4 Jan 2024
Viewed by 1298
Abstract
Increasing the serviceability of industrial components intended for the petrochemical industry is possible through their superficial saturation with silicon (silicon cementation). Obtaining a silicon-rich surface coating results in a considerable increase in corrosion resistance, refractoriness, and wear resistance. One of the most economically [...] Read more.
Increasing the serviceability of industrial components intended for the petrochemical industry is possible through their superficial saturation with silicon (silicon cementation). Obtaining a silicon-rich surface coating results in a considerable increase in corrosion resistance, refractoriness, and wear resistance. One of the most economically convenient options for silicon cementation is pack siliconizing in powdery solid media. This paper presents the possibility of pack siliconizing that contains ferrosilicon (FeSi75C) and a thermite mixture (SiO2 + Al) as active, silicon-providing components, in P265GH grade steel, which is frequently used in the petrochemical industry. The aim of the study was to determine the most suitable active component of the two that were analyzed and at the same time identify the processing conditions in which the siliconized coating has the greatest thickness, is free of porosity, and is in direct contact with the support. The use of experimental programming methods allowed the optimization of the operation to obtain the optimal solution. It was concluded that the thermite mixture is not compatible with pack siliconizing because it results in a superficial saturation predominantly composed of aluminum. When ferrosilicon is used as the active component, it determines the particularly intense formation kinetics of the non-porous siliconized coating with its maximum thickness being reached at high processing temperature values (over 1100 °C) with a proportion of 60% FeSi75 and, simultaneously, with the lowest possible proportion of ammonium chloride (max. 3%), which is the surface activation/cleaning component. Full article
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19 pages, 8114 KiB  
Article
Enhanced Wear Behavior of a Stainless Steel Coating Deposited on a Medium-Carbon Low-Alloy Steel Using Ultrasonic Impact Treatment
by Li Li, Shudong Guo, Lu Jia, Li Zhang, Jiangang Li, Xigang Wang, Nannan Zhang, Hongyan Gan, Yanhui Guo and Suyan Zhao
Coatings 2023, 13(12), 2024; https://doi.org/10.3390/coatings13122024 - 30 Nov 2023
Cited by 1 | Viewed by 1753
Abstract
This study aims to explore the effects of ultrasonic impact parameters on the surface modification of a stainless steel coating deposited on a medium-carbon low-alloy steel using argon arc surfacing welding. Ultrasonic impact treatment (UIT), at three different vibration strike numbers (40,000 times/(mm [...] Read more.
This study aims to explore the effects of ultrasonic impact parameters on the surface modification of a stainless steel coating deposited on a medium-carbon low-alloy steel using argon arc surfacing welding. Ultrasonic impact treatment (UIT), at three different vibration strike numbers (40,000 times/(mm2), 57,600 times/(mm2), and 75,000 times/(mm2)) marked UIT–1, UIT–2, and UIT–3, respectively, was carried out to modify the surface structure and properties of the stainless steel coating. The surface morphological and structural features, phase compositions, grain size, topography, micro-mechanical properties, as well as the wear resistance of the coating before and after UIT with different impact parameters were experimentally investigated. The results of optical microscopy (OM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD), and X-ray diffraction (XRD) analyses revealed that the grain refinement accompanied by the formation of the strain-induced α′–martensite occurred on the UIT-treated coating surface. With the increase in the vibration strike number, the surface grain size and roughness decreased, while the α′–martensite content increased. Micro-hardness after UIT was increased by about 19% (UIT–1), 39% (UIT–2), and 57% (UIT–3), and the corresponding wear rate obtained was decreased by 39%, 72%, and 85%, respectively. Significant improvements in wear resistance were achieved using UIT. However, an excessive vibration strike number on the per unit area (/mm2) might result in unwanted micro-cracks and delamination on the treated surface, deteriorating the performance of the coating. These findings validate that UIT parameters (such as the vibration strike number on per unit area) are of great importance to bringing about improvements in wear performance, and UIT is found to have a high potential in modifying the surface characteristics and optimizing the mechanical performances of the deposited coating for a wide range of potential applications. Full article
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