Materials

Research

11 pages, 2299 KiB

Open AccessArticle

The Corrosion Inhibition of Montmorillonite Nanoclay for Steel in Acidic Solution

by Ehab AlShamaileh, Abdelmnim M. Altwaiq, Ahmed Al-Mobydeen, Imad Hamadneh, Bety S. Al-Saqarat, Arwa Hamaideh and Iessa Sabbe Moosa

Materials 2023, 16(18), 6291; https://doi.org/10.3390/ma16186291 - 20 Sep 2023

Cited by 5 | Viewed by 1590

Abstract

The aim of this research is to study the anticorrosive behavior of a coating consisting of modified montmorillonite nanoclay as an inorganic green inhibitor. The anticorrosion protection for mild steel in 1.0 M HCl solution is studied via weight loss, electrochemical methods, SEM, [...] Read more.

The aim of this research is to study the anticorrosive behavior of a coating consisting of modified montmorillonite nanoclay as an inorganic green inhibitor. The anticorrosion protection for mild steel in 1.0 M HCl solution is studied via weight loss, electrochemical methods, SEM, and XRD. The results proved that montmorillonite nanoclay acts as a good inhibitor with a mixed-type character for steel in an acidic solution. Both anodic and cathodic processes on the metal surface are slowed down. There is a clear direct correlation between the added amount of montmorillonite nanoclay and the inhibition efficiency, reaching a value of 75%. The inhibition mechanism involves the adsorption of the montmorillonite nanoclay onto the metal surface. Weight loss experiments are carried out with steel samples in 1.0 M HCl solution at room temperature, and the same trend of inhibition is produced. SEM was used to image the surface at the different stages of the corrosion inhibition process, and also to examine the starting nanoclay and steel. XRD was used to characterize the nanoparticle structure of the coating. Montmorillonite nanoclay is an environmentally friendly material that improved the corrosion resistance of mild steel in an acidic medium. Full article

(This article belongs to the Special Issue Advances in Coating Materials Research: From Preparation to Application)

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12 pages, 2912 KiB

Open AccessArticle

In Vivo Safety of New Coating for Biodegradable Magnesium Implants

by Bohdan Dryhval, Yevheniia Husak, Oksana Sulaieva, Volodymyr Deineka, Mykola Pernakov, Mykola Lyndin, Anatolii Romaniuk, Wojciech Simka and Maksym Pogorielov

Materials 2023, 16(17), 5807; https://doi.org/10.3390/ma16175807 - 24 Aug 2023

Cited by 3 | Viewed by 1458

Abstract

Biodegradable Magnesium (Mg) implants are promising alternatives to permanent metallic prosthesis. To improve the biocompatibility and with the aim of degradation control, we provided Plasma Electrolytic Oxidation (PEO) of pure Mg implant in silicate-based solution with NaOH (S1 250 V) and Ca(OH)₂ [...] Read more.

Biodegradable Magnesium (Mg) implants are promising alternatives to permanent metallic prosthesis. To improve the biocompatibility and with the aim of degradation control, we provided Plasma Electrolytic Oxidation (PEO) of pure Mg implant in silicate-based solution with NaOH (S1 250 V) and Ca(OH)₂ (S2 300 V). Despite the well-structured surface, S1 250 V implants induced enormous innate immunity reaction with the prevalence of neutrophils (MPO+) and M1-macrophages (CD68+), causing secondary alteration and massive necrosis in the peri-implant area in a week. This reaction was also accompanied by systemic changes in visceral organs affecting animals’ survival after seven days of the experiment. In contrast, S2 300 V implantation was associated with focal lymphohistiocytic infiltration and granulation tissue formation, defining a more favorable outcome. This reaction was associated with the prevalence of M2-macrophages (CD163+) and high density of αSMA+ myofibroblasts, implying a resolution of inflammation and effective tissue repair at the site of the implantation. At 30 days, no remnants of S2 300 V implants were found, suggesting complete resorption with minor histological changes in peri-implant tissues. In conclusion, Ca(OH)₂-contained silicate-based solution allows generating biocompatible coating reducing toxicity and immunogenicity with appropriate degradation properties that make it a promising candidate for medical applications. Full article

(This article belongs to the Special Issue Advances in Coating Materials Research: From Preparation to Application)

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13 pages, 4043 KiB

Open AccessArticle

Properties of SiCN Films Relevant to Dental Implant Applications

by Xinyi Xia, Chao-Ching Chiang, Sarathy K. Gopalakrishnan, Aniruddha V. Kulkarni, Fan Ren, Kirk J. Ziegler and Josephine F. Esquivel-Upshaw

Materials 2023, 16(15), 5318; https://doi.org/10.3390/ma16155318 - 28 Jul 2023

Cited by 7 | Viewed by 1788

Abstract

The application of surface coatings is a popular technique to improve the performance of materials used for medical and dental implants. Ternary silicon carbon nitride (SiCN), obtained by introducing nitrogen into SiC, has attracted significant interest due to its potential advantages. This study [...] Read more.

The application of surface coatings is a popular technique to improve the performance of materials used for medical and dental implants. Ternary silicon carbon nitride (SiCN), obtained by introducing nitrogen into SiC, has attracted significant interest due to its potential advantages. This study investigated the properties of SiCN films deposited via PECVD for dental implant coatings. Chemical composition, optical, and tribological properties were analyzed by adjusting the gas flow rates of NH₃, CH₄, and SiH₄. The results indicated that an increase in the NH₃ flow rate led to higher deposition rates, scaling from 5.7 nm/min at an NH₃ flow rate of 2 sccm to 7 nm/min at an NH₃ flow rate of 8 sccm. Concurrently, the formation of N-Si bonds was observed. The films with a higher nitrogen content exhibited lower refractive indices, diminishing from 2.5 to 2.3 as the NH₃ flow rate increased from 2 sccm to 8 sccm. The contact angle of SiCN films had minimal differences, while the corrosion rate was dependent on the pH of the environment. These findings contribute to a better understanding of the properties and potential applications of SiCN films for use in dental implants. Full article

(This article belongs to the Special Issue Advances in Coating Materials Research: From Preparation to Application)

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15 pages, 4745 KiB

Open AccessArticle

The Effect of Zirconia Nanoparticles on Thermal, Mechanical, and Corrosion Behavior of Nanocomposite Epoxy Coatings on Steel Substrates

by Mohammad Asif Alam, Ubair Abdus Samad, Arfat Anis, El-Sayed M. Sherif, Hany S. Abdo and Saeed M. Al-Zahrani

Materials 2023, 16(13), 4813; https://doi.org/10.3390/ma16134813 - 4 Jul 2023

Cited by 9 | Viewed by 2020

Abstract

Zirconia (ZrO₂) nanoparticles (1–3 wt.%) were incorporated into the epoxy matrix using the ultra-sonication mixing method of dispersion to manufacture nanocomposite coatings. An automatic applicator was used to prepare the coating samples on a stainless steel substrate. The influence of ZrO [...] Read more.

Zirconia (ZrO₂) nanoparticles (1–3 wt.%) were incorporated into the epoxy matrix using the ultra-sonication mixing method of dispersion to manufacture nanocomposite coatings. An automatic applicator was used to prepare the coating samples on a stainless steel substrate. The influence of ZrO₂ nanoparticles on the physicochemical characteristics of epoxy coatings was evaluated using energy dispersive X-ray spectroscopy (EDS), field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FTIR), thermos-gravimetric analysis (TGA), elastic modulus, and micro-hardness measurement with the nano-indentation technique. The corrosion stability during immersion in 3.5% NaCl solution was monitored using electrochemical impedance spectroscopy (EIS). All ZrO₂-containing coatings showed better corrosion stability and adhesion than pure epoxy coating. Epoxy coating incorporated with 2% ZrO₂ exhibited the greatest values of corrosion resistance and adhesion due to the effect of nanoparticle properties and their better de-agglomeration in the epoxy matrix than pure epoxy coating. Full article

(This article belongs to the Special Issue Advances in Coating Materials Research: From Preparation to Application)

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16 pages, 16269 KiB

Open AccessArticle

Effect of Chromium Carbide Addition on the Microstructures and Properties in Dual Carbide Phases Reinforced Ni-Based Composite Coatings by Plasma Cladding

by Zhanji Geng, Mengling Zhang, Jianyong Zhu, Yingbo Peng, Wei Zhang and Feng Liu

Materials 2023, 16(13), 4580; https://doi.org/10.3390/ma16134580 - 25 Jun 2023

Cited by 2 | Viewed by 1694

Abstract

Cr₃C₂-modified NiCr–TiC composite coatings were prepared using the plasma spraying technique for different Cr₃C₂ contents on the microstructure and the properties of the Ni-based TiC cladding layer were investigated. The microstructures of the coatings were characterized [...] Read more.

Cr₃C₂-modified NiCr–TiC composite coatings were prepared using the plasma spraying technique for different Cr₃C₂ contents on the microstructure and the properties of the Ni-based TiC cladding layer were investigated. The microstructures of the coatings were characterized using scanning electron microscopy, and the friction and wear performance of the coating was evaluated by the wear tests. The results revealed that the surfaces of the Cr₃C₂-modified NiCr–TiC composite coatings with varying Cr₃C₂ contents were dense and smooth. TiC was uniformly distributed throughout the entire coating, forming a gradient interface between the binder phase of the Ni-based alloy and the hard phase of TiC. At high temperatures, Cr₃C₂ decomposes, with some chromium diffusing and forming complex carbides around TiC, some chromium solubilizes with Fe, Ni, and other elements. An increase in chromium carbide content leads to an upward trend in hardness. The measured hardness of the coatings ranged from 600 to 850 HV3 and tended to increase with increasing Cr₃C₂ content. When the mass fraction of Cr₃C₂ reached 30%, the hardness increased to 850 HV3, and the cracks and defects were observed in the coating, resulting in a wear resistance decline. Full article

(This article belongs to the Special Issue Advances in Coating Materials Research: From Preparation to Application)

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13 pages, 12303 KiB

Open AccessArticle

Fucoidan-Containing, Low-Adhesive Siloxane Coatings for Medical Applications: Inhibition of Bacterial Growth and Biofilm Development

by Todorka G. Vladkova, Anna D. Staneva, Ivalina A. Avramova, Iliana A. Ivanova and Dilyana N. Gospodinova

Materials 2023, 16(10), 3651; https://doi.org/10.3390/ma16103651 - 10 May 2023

Cited by 4 | Viewed by 2041

Abstract

The deposition of low-adhesive siloxane coatings is a current trend for the non-toxic control of bacterial growth and biofilm formation. Total elimination of biofilm formation has not been reported so far. The aim of this investigation was to study the ability of a [...] Read more.

The deposition of low-adhesive siloxane coatings is a current trend for the non-toxic control of bacterial growth and biofilm formation. Total elimination of biofilm formation has not been reported so far. The aim of this investigation was to study the ability of a non-toxic, natural, biologically active substance, such as fucoidan, to inhibit bacterial growth on similar medical coatings. The fucoidan amount was varied, and its impact on the bioadhesion-influencing surface characteristics, as well as on bacterial cell growth, was investigated. The inclusion of up to 3–4 wt.% brown algae-derived fucoidan in the coatings increases their inhibitory effect, more significantly on the Gram-positive bacterium S. aureus than on the Gram-negative bacterium Escherichia coli. The biological activity of the studied siloxane coatings was ascribed to the formation of a low-adhesive, biologically active surface top layer consisting of siloxane oil and dispersed water-soluble fucoidan particles. This is the first report on the antibacterial activity of fucoidan-containing medical siloxane coatings. The experimental results give reason to expect that relevantly selected, natural biologically active substances can be efficient in the non-toxic control of bacterial growth on medical devices and, as a result, medical device-associated infections. Full article

(This article belongs to the Special Issue Advances in Coating Materials Research: From Preparation to Application)

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12 pages, 7301 KiB

Open AccessEditor’s ChoiceArticle

Structure and Wear Performance of a Titanium Alloy by Using Low-Temperature Plasma Oxy-Nitriding

by Haidong Li, Haifeng Wang, Shijie Wang, Yange Yang, Yunsong Niu, Shenglong Zhu and Fuhui Wang

Materials 2023, 16(10), 3609; https://doi.org/10.3390/ma16103609 - 9 May 2023

Cited by 3 | Viewed by 1972

Abstract

To solve the problems of high nitriding temperature and long nitriding time with conventional plasma nitriding technologies, a kind of low-temperature plasma oxy-nitriding technology containing two-stage processes with different ratios of N to O was developed on a TC4 alloy in this paper. [...] Read more.

To solve the problems of high nitriding temperature and long nitriding time with conventional plasma nitriding technologies, a kind of low-temperature plasma oxy-nitriding technology containing two-stage processes with different ratios of N to O was developed on a TC4 alloy in this paper. A thicker permeation coating can be obtained with this new technology compared to conventional plasma nitriding technology. The reason for this is that the oxygen introduction in the first two-hour oxy-nitriding step can break the continuous TiN layer, which facilitates the quick and deep diffusion of the solution-strengthening elements of O and N into the titanium alloy. Moreover, an inter-connected porous structure was formed under a compact compound layer, which acts as a buffer layer to absorb the external wear force. Therefore, the resultant coating showed the lowest COF values during the initial wear state, and almost no debris and cracks were detected after the wear test. For the treated samples with low hardness and no porous structure, fatigue cracks can easily form on the surface, and bulk peeling-offcan occur during the wear course. Full article

(This article belongs to the Special Issue Advances in Coating Materials Research: From Preparation to Application)

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12 pages, 6035 KiB

Open AccessArticle

High-Temperature Oxidation Behaviour of CrSi Coatings on 316 Austenitic Stainless Steel

by Mikdat Gurtaran, Zhenxue Zhang, Xiaoying Li and Hanshan Dong

Materials 2023, 16(9), 3533; https://doi.org/10.3390/ma16093533 - 5 May 2023

Cited by 4 | Viewed by 2370

Abstract

In this study, a closed-field unbalanced magnetron sputtering system, which is environmentally friendly and has high deposition efficiency, was used to deposit CrSi coatings on 316 austenitic stainless steel. This system utilised separate Cr and Si targets, and the appropriate content of Cr [...] Read more.

In this study, a closed-field unbalanced magnetron sputtering system, which is environmentally friendly and has high deposition efficiency, was used to deposit CrSi coatings on 316 austenitic stainless steel. This system utilised separate Cr and Si targets, and the appropriate content of Cr and Si of the coatings was adjusted by changing the currents applied to the targets. A series of CrSi coatings with different Si/Cr ratios were produced, and their oxidation behaviour at elevated temperatures was investigated. By analysing the weight gain, surface morphology and microstructure, composition and phase constituents, the oxidation behaviour at 600 °C, 700 °C and 800 °C was investigated and the optimized coating to protect the stainless steel has been identified. The outcome of the research indicated that a small amount of Si (between 4–7 at.%) in Cr coatings is effective in protecting the austenitic stainless steel against oxidation at high temperatures, while a high Si content (around 10 at.% or more) makes the coating more brittle and prone to cracking or delamination during oxidation at 800 °C. Full article

(This article belongs to the Special Issue Advances in Coating Materials Research: From Preparation to Application)

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17 pages, 12142 KiB

Open AccessArticle

Oxidation Behavior of (Mo,Hf)Si₂-Al₂O₃ Coating on Mo-Based Alloy at Elevated Temperature

by Yongqi Lv, Huichao Cheng, Zhanji Geng and Wei Li

Materials 2023, 16(8), 3215; https://doi.org/10.3390/ma16083215 - 19 Apr 2023

Cited by 3 | Viewed by 1514

Abstract

To improve the oxidation resistance of Mo-based alloys, a novel (Mo,Hf)Si₂-Al₂O₃ composite coating was fabricated on a Mo-based alloy by the method of slurry sintering. The isothermal oxidation behavior of the coating was evaluated at 1400 °C. The [...] Read more.

To improve the oxidation resistance of Mo-based alloys, a novel (Mo,Hf)Si₂-Al₂O₃ composite coating was fabricated on a Mo-based alloy by the method of slurry sintering. The isothermal oxidation behavior of the coating was evaluated at 1400 °C. The microstructure evolution and phase composition of the coating before and after oxidation exposure were characterized. The anti-oxidant mechanism for the good performance of the composite coating during high-temperature oxidation was discussed. The coating had a double-layer structure consisting of a MoSi₂ inner layer and a (Mo,Hf)Si₂-Al₂O₃ outer composite layer. The composite coating could offer more than 40 h of oxidation-resistant protection at 1400 °C for the Mo-based alloy, and the final weight gain rate was only 6.03 mg/cm² after oxidation. A SiO₂-based oxide scale embedded with Al₂O₃, HfO₂, mullite, and HfSiO₄ was formed on the surface of the composite coating during oxidation. The composite oxide scale exhibited high thermal stability, low oxygen permeability, and enhanced thermal mismatch between oxide and coating layers, thus improving the oxidation resistance of the coating. Full article

(This article belongs to the Special Issue Advances in Coating Materials Research: From Preparation to Application)

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8 pages, 1821 KiB

Open AccessCommunication

Excellent Uniformity and Properties of Micro-Meter Thick Lead Zirconate Titanate Coatings with Rapid Thermal Annealing

by Youcao Ma, Jian Song, Yuyao Zhao, Kiyotaka Tanaka, Shijunbo Wu, Chao Dong, Xubo Wang, Isaku Kanno, Jun Ouyang, Jia Zhou and Yue Liu

Materials 2023, 16(8), 3185; https://doi.org/10.3390/ma16083185 - 18 Apr 2023

Cited by 2 | Viewed by 1686

Abstract

Lead zirconate titanate (PZT) films have shown great potential in piezoelectric micro-electronic-mechanical system (piezo-MEMS) owing to their strong piezoelectric response. However, the fabrication of PZT films on wafer-level suffers with achieving excellent uniformity and properties. Here, we successfully prepared perovskite PZT films with [...] Read more.

Lead zirconate titanate (PZT) films have shown great potential in piezoelectric micro-electronic-mechanical system (piezo-MEMS) owing to their strong piezoelectric response. However, the fabrication of PZT films on wafer-level suffers with achieving excellent uniformity and properties. Here, we successfully prepared perovskite PZT films with similar epitaxial multilayered structure and crystallographic orientation on 3-inch silicon wafers, by introducing a rapid thermal annealing (RTA) process. Compared to films without RTA treatment, these films exhibit (001) crystallographic orientation at certain composition that expecting morphotropic phase boundary. Furthermore, dielectric, ferroelectric and piezoelectric properties on different positions only fluctuate within 5%. The relatively dielectric constant, loss, remnant polarization and transverse piezoelectric coefficient are 850, 0.1, 38 μC/cm² and −10 C/m², respectively. Both uniformity and properties have reached the requirement for the design and fabrication of piezo-MEMS devices. This broadens the design and fabrication criteria for piezo-MEMS, particularly for piezoelectric micromachined ultrasonic transducers. Full article

(This article belongs to the Special Issue Advances in Coating Materials Research: From Preparation to Application)

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15 pages, 2957 KiB

Open AccessArticle

Indentation Reverse Algorithm of Mechanical Response for Elastoplastic Coatings Based on LSTM Deep Learning

by Xu Long, Xiaoyue Ding, Jiao Li, Ruipeng Dong, Yutai Su and Chao Chang

Materials 2023, 16(7), 2617; https://doi.org/10.3390/ma16072617 - 25 Mar 2023

Cited by 21 | Viewed by 2913

Abstract

The load-penetration depth (P–h) curves of different metallic coating materials can be determined by nanoindentation experiments, and it is a challenge to obtain stress–strain response and elastoplastic properties directly using P–h curves. These problems can be solved [...] Read more.

The load-penetration depth (P–h) curves of different metallic coating materials can be determined by nanoindentation experiments, and it is a challenge to obtain stress–strain response and elastoplastic properties directly using P–h curves. These problems can be solved by means of finite element (FE) simulation along with reverse analyses and methods, which, however, typically occupy a lengthy time, in addition to the low generality of FE methodologies for different metallic materials. To eliminate the challenges that exist in conventional FE simulations, a long short-term memory (LSTM) neural network is proposed in this study and implemented to deep learn the time series of P–h curves, which is capable of mapping P–h curves to the corresponding stress–strain responses for elastoplastic materials. Prior to the operation of the neural network, 1000 sets of indentation data of metallic coating materials were generated using the FE method as the training and validating sets. Each dataset contains a set of P–h curves as well as the corresponding stress–strain curves, which are used as input data for the network and as training targets. The proposed LSTM neural networks, with various numbers of hidden layers and hidden units, are evaluated to determine the optimal hyperparameters by comparing their loss curves. Based on the analysis of the prediction results of the network, it is concluded that the relationship between the P–h curves of metallic coating materials and their stress–strain responses is well predicted, and this relationship basically coincides with the power-law equation. Furthermore, the deep learning method based on LSTM is advantageous to interpret the elastoplastic behaviors of coating materials from indentation measurement, making the predictions of stress–strain responses much more efficient than FE analysis. The established LSTM neural network exhibits the prediction accuracy up to 97%, which is proved to reliably satisfy the engineering requirements in practice. Full article

(This article belongs to the Special Issue Advances in Coating Materials Research: From Preparation to Application)

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13 pages, 7300 KiB

Open AccessArticle

Properties of Coatings Based on Calcium Phosphate and Their Effect on Cytocompatibility and Bioactivity of Titanium Nickelide

by Ekaterina S. Marchenko, Gulsharat A. Baigonakova, Kirill M. Dubovikov, Oleg V. Kokorev, Ivan I. Gordienko and Ekaterina A. Chudinova

Materials 2023, 16(7), 2581; https://doi.org/10.3390/ma16072581 - 24 Mar 2023

Cited by 8 | Viewed by 2211

Abstract

Coatings based on calcium phosphate with thicknesses of 0.5 and 2 μm were obtained by high-frequency magnetron sputtering on NiTi substrates in an argon atmosphere. The coating was characterized using X-ray diffraction, scanning electron microscopy, atomic force microscopy, and in vitro cytocompatibility and [...] Read more.

Coatings based on calcium phosphate with thicknesses of 0.5 and 2 μm were obtained by high-frequency magnetron sputtering on NiTi substrates in an argon atmosphere. The coating was characterized using X-ray diffraction, scanning electron microscopy, atomic force microscopy, and in vitro cytocompatibility and bioactivity studies. A biphasic coating of tricalcium phosphate (Ca₃(PO₄)₂) and hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂) with a 100% degree of crystallinity was formed on the surface. The layer enriched in calcium, phosphorus, and oxygen was observed using scanning electron microscopy and energy-dispersive X-ray spectroscopy. Scanning electron microscopy showed that the surface structure is homogeneous without visible defects. The 2 µm thick coating obtained by sputtering with a deposition time of 4 h and a deposition rate of 0.43 µm/h is uniform, contains the highest amount of the calcium phosphate phase, and is most suitable for the faster growth of cells and accelerated formation of apatite layers. Samples with calcium phosphate coatings do not cause hemolysis and have a low cytotoxicity index. The results of immersion in a solution simulating body fluid show that NiTi with the biphasic coating promotes apatite growth, which is beneficial for biological activity. Full article

(This article belongs to the Special Issue Advances in Coating Materials Research: From Preparation to Application)

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16 pages, 13852 KiB

Open AccessArticle

Microstructure and Properties of Nickel-Based Gradient Coatings Prepared Using Cold Spraying Combined with Laser Cladding Methods

by Sainan Liu, Yangyang Sun, Pengyuan Zhai, Pengyu Fan, Yongtong Zhang, Muyang Li, Jianxiao Fang, Ruilin Wu and Zhenyang Cai

Materials 2023, 16(4), 1627; https://doi.org/10.3390/ma16041627 - 15 Feb 2023

Cited by 8 | Viewed by 2933

Abstract

A cold spray–laser cladding composite gradient coating (CLGC) was successfully formed on a Cu substrate. In comparison with traditional laser cladding gradient coatings (LGC), cold spraying the pre-set Ni-Cu alloy’s intermediate transition layer not only mitigates the negative impacts due to the high [...] Read more.

A cold spray–laser cladding composite gradient coating (CLGC) was successfully formed on a Cu substrate. In comparison with traditional laser cladding gradient coatings (LGC), cold spraying the pre-set Ni-Cu alloy’s intermediate transition layer not only mitigates the negative impacts due to the high reflectivity of the copper substrate but also helps to minimize the difference in the coefficients of thermal expansion (CTE) between the substrate and coating. This reduces the overall crack sensitivity and improves the cladding quality of the coating. Besides this, the uniform distribution of hard phases in CLGC, such as Ni₁₁Si₁₂ and Mo₅Si₃, greatly increases its microhardness compared to the Cu substrate, thus resulting in the value of 478.8 HV_0.5 being approximately 8 times that of the Cu substrate. The friction coefficient of CLGC is lowered compared to both the Cu substrate and LGC with respective values of 0.28, 0.54, and 0.43, and its wear rate is only one-third of the Cu substrate’s. These results suggest CLGC has excellent anti-wear properties. In addition, the wear mechanism was determined from the microscopic morphology and element distribution and was found to be oxidative and abrasive. This approach combines cold spraying and laser cladding to form a nickel-based gradient coating on a Cu substrate without cracks, holes, or other faults, thus improving the wear resistance of the Cu substrate and improving its usability. Full article

(This article belongs to the Special Issue Advances in Coating Materials Research: From Preparation to Application)

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14 pages, 5051 KiB

Open AccessArticle

Comparison of CoW/SiO₂ and CoB/SiO₂ Interconnects from the Perspective of Electrical and Reliability Characteristics

by Yi-Lung Cheng, Kai-Hsieh Wang, Chih-Yen Lee, Giin-Shan Chen and Jau-Shiung Fang

Materials 2023, 16(4), 1452; https://doi.org/10.3390/ma16041452 - 9 Feb 2023

Cited by 1 | Viewed by 1385

Abstract

As the feature size of integrated circuits has been scaled down to 10 nm, the rapid increase in the electrical resistance of copper (Cu) metallization has become a critical issue. To alleviate the resistance increases of Cu lines, co-sputtered CoW and CoB alloying [...] Read more.

As the feature size of integrated circuits has been scaled down to 10 nm, the rapid increase in the electrical resistance of copper (Cu) metallization has become a critical issue. To alleviate the resistance increases of Cu lines, co-sputtered CoW and CoB alloying metals were investigated as conductors and barriers in this study. Annealing CoM (M = W or B)/SiO₂/p-Si structures reduced the resistivity of CoM alloys, removed sputtering-deposition-induced damage, and promoted adhesion. Additionally, both annealed CoW/SiO₂ or CoB/SiO₂ structures displayed a negligible V_fb shift from capacitance-voltage measurements under electrical stress, revealing an effective barrier capacity, which is attributed to the formation of MO_x layers at the CoM/SiO₂ interface. Based on the thermodynamics, the B₂O₃ layer tends to form more easily than the WO_x layer. Hence, the annealed CoB/SiO₂/p-Si MIS capacitor had a higher capacitance and a larger breakdown strength did than the annealed CoW/SiO₂/p-Si MIS capacitor. Full article

(This article belongs to the Special Issue Advances in Coating Materials Research: From Preparation to Application)

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23 pages, 9495 KiB

Open AccessArticle

Feasibility Study for the Remanufacturing of H13 Steel Heat-Treated TBM Disc Cutter Rings with Uniform Wear Failure Using GMAW

by Kui Zhang, Shuhao Dai, Boyan Jiang, Xuejun Zheng, Jingang Liu and Xuhui Zhang

Materials 2023, 16(3), 1093; https://doi.org/10.3390/ma16031093 - 27 Jan 2023

Cited by 5 | Viewed by 1869

Abstract

Given that the heat treatment states of the base metal have a great influence on the surfacing repair layer, this paper carried out a feasibility study for the remanufacturing of the failed cutter rings of TBM disc cutters with uniform wear (hereinafter referred [...] Read more.

Given that the heat treatment states of the base metal have a great influence on the surfacing repair layer, this paper carried out a feasibility study for the remanufacturing of the failed cutter rings of TBM disc cutters with uniform wear (hereinafter referred to as normally-worn ring) using the gas metal arc welding technology (GMAW). Firstly, this paper developed a heat treatment process route for H13 steel cutter rings. Secondly, the heat treatment process is numerically analyzed based on the developed route, and the rationality of the route is verified from the distribution characteristics of temperature, phase, and stress fields. Subsequently, heat treatment tests were carried out, and the physical and mechanical properties of the base metal samples prepared under laboratory conditions were evaluated respectively and systematically. Based on the comprehensive performance evaluation value calculated by the weighted comparative analysis method, it was clear that the comprehensive performance of the quenched base metal samples was 7.6% higher than that of the engineering cutter ring interior. Therefore, it is reasonable to replace the failed engineering cutter rings repaired under laboratory conditions with the prepared samples as economical alternatives. Finally, the remanufacturing of the base metal samples using GMAW was carried out, and then the remanufacturing performance of the base metal samples was analyzed. The study concluded that the comprehensive performance of the surfacing repair layer was slightly lower than that of the engineering cutter ring edge (4.1%), thus proving that the idea of surfacing remanufacturing of the normally-worn ring proposed in this paper was basically feasible. Full article

(This article belongs to the Special Issue Advances in Coating Materials Research: From Preparation to Application)

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16 pages, 5702 KiB

Open AccessArticle

Microstructure and Wear Resistance of Laser-Clad Ni–Cu–Mo–W–Si Coatings on a Cu–Cr–Zr Alloy

by Xiaojun Zhao, Qi Zhong, Pengyuan Zhai, Pengyu Fan, Ruiling Wu, Jianxiao Fang, Yuxiang Xiao, Yuxiang Jiang, Sainan Liu and Wei Li

Materials 2023, 16(1), 284; https://doi.org/10.3390/ma16010284 - 28 Dec 2022

Cited by 7 | Viewed by 2614

Abstract

To improve the wear resistance of high-strength and high-conductivity Cu–Cr–Zr alloys in high-speed and heavy load friction environments, coatings including Ni–Cu, Ni–Cu-10(W,Si), Ni–Cu–10(Mo,W,Si), and Ni–Cu–15(Mo,W,Si) (with an atomic ratio of Mo,W to Si of 1:2) were prepared using coaxial powder-feeding laser cladding technology. [...] Read more.

To improve the wear resistance of high-strength and high-conductivity Cu–Cr–Zr alloys in high-speed and heavy load friction environments, coatings including Ni–Cu, Ni–Cu-10(W,Si), Ni–Cu–10(Mo,W,Si), and Ni–Cu–15(Mo,W,Si) (with an atomic ratio of Mo,W to Si of 1:2) were prepared using coaxial powder-feeding laser cladding technology. The microstructure and wear performance of coatings were chiefly investigated. The results revealed that (Mo,W)Si₂ and MoNiSi phases are found in the Ni–Cu–10(Mo,W,Si) and Ni–Cu–15(Mo,W,Si) coating. WSi₂ phases are found in the Ni–Cu–10(W,Si) coating. The degree of grain refinement in Ni–Cu–10(Mo,W,Si) was greater than that of the Ni–Cu–10(W,Si) coating after the effect of Mo. The excellent wear resistance and micro-hardness of the Ni–Cu–15(Mo,W,Si) coating were attributed to the increase in its dispersion phase, which were approximately 34.72 mg/km and 428 HV, 27.1% and 590% higher than the Cu–Cr–Zr substrate, respectively. The existence of silicide plays an important role in grain refinement due to the promotion of nucleation and the inhibition of grain growth. In addition, the wear mechanism transformed from adhesive wear in the Ni–Cu coating with no silicides to abrasive wear in the Ni–Cu–15(Mo,W,Si) coating with high levels of silicides. Full article

(This article belongs to the Special Issue Advances in Coating Materials Research: From Preparation to Application)

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15 pages, 71021 KiB

Open AccessArticle

Preparation and Performance Evolution of Plasma Sprayed Abradable CuAl/PHB–NiAl Layered Seal Coatings

by Shuting Zhang, Wei Sun, Tong Liu, Jinhe Yang, Jianming Liu, Chao Wu and Peixuan Ouyang

Materials 2023, 16(1), 227; https://doi.org/10.3390/ma16010227 - 27 Dec 2022

Cited by 3 | Viewed by 2332

Abstract

In this study, a double-layered CuAl/PHB-NiAl seal coating was prepared on a GH4169 substrate by atmospheric plasma spraying. The evolution of the microstructure and mechanical properties of the coating under simulated working conditions was studied. The surface hardness of as-sprayed coating decreased with [...] Read more.

In this study, a double-layered CuAl/PHB-NiAl seal coating was prepared on a GH4169 substrate by atmospheric plasma spraying. The evolution of the microstructure and mechanical properties of the coating under simulated working conditions was studied. The surface hardness of as-sprayed coating decreased with an increase in the temperature from 25 to 700 °C, decreasing from 90.42 HR15Y to 66.83 HR15Y. A CuO phase was formed in the coating and the oxidation weight gain rate increased with an increase in the temperature when the coating was constantly oxidized at 500~700 °C for 100 h. The hardness of metal matrix in the coating increased with the extension in the oxidation time at 600 °C, increasing from 120.8 HV_0.1 to 143.02 HV_0.1. The residual stress of the as-sprayed porous CuAl top-coating was less than that of the top-coating/bond-coating interface, and it is further relieved by about 15~20 MPa after heat treatment. The coating porosity first increased and then decreased when the oxidation time was 1000 h. The further ablation of PHB and the formation of oxide were concluded to be the main reasons for the evolution of porosity. Full article

(This article belongs to the Special Issue Advances in Coating Materials Research: From Preparation to Application)

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10 pages, 1458 KiB

Open AccessArticle

Construction of Durable Self-Cleaning PDMS Film on Polyester Fabric Surface

by Yong Xia, Nan Zhu, Ying Zhao, Jiehui Zhu, Huajie Chen, Liyun Xu and Lirong Yao

Materials 2023, 16(1), 52; https://doi.org/10.3390/ma16010052 - 21 Dec 2022

Cited by 3 | Viewed by 2335

Abstract

The superhydrophobic surface can be prepared by two methods; one is by reducing the surface energy, and the other is by constructing a micro-nano rough structure. To achieve high superhydrophobic performance in terms of durability, the firm combination of hydrophobic coating and substrate [...] Read more.

The superhydrophobic surface can be prepared by two methods; one is by reducing the surface energy, and the other is by constructing a micro-nano rough structure. To achieve high superhydrophobic performance in terms of durability, the firm combination of hydrophobic coating and substrate is particularly important. Here, we use polydimethylsiloxane (PDMS) as a low surface energy monomer, water-borne polyurethane (WPU) as a dispersing aid, and use high-power ultrasound to disperse PDMS in water to make emulsion. The polyester matrix is etched by atmospheric plasma, dipped in PDMS emulsion, dried, and finally baked to induce PDMS on the surface of polyester fiber to cross-link into film. A series of tests on the self-cleaning polyester fabric prepared by this method show that when the concentration of PDMS is 8 g/L and the mass ratio of PDMS to WPU is 20:1, the water contact angle (WCA) reaches the maximum value of 148.2°, which decreases to 141.5° after 200 times of washing and 138.6° after 5000 times of rubbing. Before and after PDMS coating, the tensile strength of polyester fabric increases from 489.4 N to 536.4 N, and the water vapor transmission decreases from 13,535.7 g/(m²·d) to 12,224.3 g/(m²·d). This research is helpful to the large-scale production of self-cleaning polyester fabric. In the future, on the basis of this research, we will add functional powder to endow self-cleaning polyester fabric with higher hydrophobicity and other properties. Full article

(This article belongs to the Special Issue Advances in Coating Materials Research: From Preparation to Application)

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14 pages, 4430 KiB

Open AccessArticle

Influence of Plasma Treatment Parameters on the Structural-Phase Composition, Hardness, Moisture-Resistance, and Raman-Enhancement Properties of Nitrogen-Containing Titanium Dioxide

by Arsen E. Muslimov, Makhach Kh. Gadzhiev and Vladimir M. Kanevsky

Materials 2022, 15(23), 8514; https://doi.org/10.3390/ma15238514 - 29 Nov 2022

Cited by 3 | Viewed by 1658

Abstract

The paper shows, for the first time, the prospects of treatment with a quasi-equilibrium low-temperature nitrogen plasma in an open atmosphere for the formation of super-hard, super-hydrophobic TiN/TiO₂ composite coatings with pronounced Raman-enhancement properties. X-ray diffractometry (XRD), scanning electron microscopy (SEM), atomic [...] Read more.

The paper shows, for the first time, the prospects of treatment with a quasi-equilibrium low-temperature nitrogen plasma in an open atmosphere for the formation of super-hard, super-hydrophobic TiN/TiO₂ composite coatings with pronounced Raman-enhancement properties. X-ray diffractometry (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and Raman spectroscopy, as well as the analysis of hardness and moisture-resistance properties, are used as analytical research methods. During plasma treatment of titanium films on sapphire with a mass average temperature of 4–6 kK, an X-ray amorphous hydrophilic titanium oxide film with a low nitrogen content is formed. The nitrogen content in titanium oxide films increases with increasing treatment temperature up to 6–7 kK. In this case, an X-ray amorphous hydrophobic film is formed. With a further increase in temperature to 7–10 kK, a TiN/TiO₂ composite structure based on polycrystalline rutile is formed with increased hydrophobicity and pronounced Raman enhancement properties due to the effective excitation of surface plasmon polaritons. The presence of the crystalline phase increases the dephasing time, which determines the quality of the resonance and the achievable amplification of the electromagnetic field near the TiN inclusions. All treated films on sapphire have a super-hardness above 25 GPa (Vickers hardness test) due to high grain size, the presence of nitrogen-containing inclusions concentrated along grain boundaries, and compressive stresses. Full article

(This article belongs to the Special Issue Advances in Coating Materials Research: From Preparation to Application)

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