This study designed laser engraving and resin pre-coating (RPC) treatments on an aluminum alloy (AA) surface to construct through-the-thickness “epoxy pins” for improving the bonding strength with carbon fiber reinforced polymer (CFRP). A laser engraving treatment was used to create a pitted structure on the AA surface; higher wettability was acquired and greater vertical spaces were formed to impregnate epoxy resin, resulting in stronger mechanical interlocking. The RPC technique was further used to guide high-viscosity epoxy resin into pits to form the epoxy coatings and to minimize defects between the resin and the substrate. The bonding strength of the specimen treated with both laser engraving with a unit dimension of 0.3 mm and RPC increased up to 227.1% in comparison with that of the base. The failure modes of the hybrid composites changed from the debonding failure of the AA surface to the delamination-dominated failure of the laminated CFRP composites. It was confirmed that laser engraving is a feasible and effective method when combined with RPC for treating AAs to improve the bonding strength of AA-CFRP composites, which provides a reference for preparing high-performance hybrid composites with metals.
本研究设计了在铝合金（AA）表面进行激光雕刻和树脂预涂层（RPC）处理的方法，以构建贯穿厚度的 "环氧树脂栓"，从而提高与碳纤维增强聚合物（CFRP）的粘接强度。通过激光雕刻处理在铝合金表面形成凹坑结构，获得更高的润湿性，并形成更大的垂直空间来浸渍环氧树脂，从而实现更强的机械互锁。RPC 技术还用于引导高粘度环氧树脂进入凹坑，形成环氧涂层，并最大限度地减少树脂与基材之间的缺陷。与基底相比，经过单位尺寸为 0.3 毫米的激光雕刻和 RPC 处理的试样的粘接强度提高了 227.1%。混合复合材料的失效模式从 AA 表面的脱粘失效转变为层状 CFRP 复合材料以分层为主的失效。研究证实，激光雕刻结合 RPC 处理 AA 以提高 AA-CFRP 复合材料的结合强度是一种可行且有效的方法，为制备高性能金属混合复合材料提供了参考。
{"title":"Forming Epoxy Coatings on Laser-Engraved Surface of Aluminum Alloy to Reinforce the Bonding Joint with a Carbon Fiber Composite","authors":"Hongping Zhu, Jinheng Zhang, Fei Cheng, Jiangzhou Li, Bo Wu, Zhijie Zhao","doi":"10.3390/coatings14091201","DOIUrl":"https://doi.org/10.3390/coatings14091201","url":null,"abstract":"This study designed laser engraving and resin pre-coating (RPC) treatments on an aluminum alloy (AA) surface to construct through-the-thickness “epoxy pins” for improving the bonding strength with carbon fiber reinforced polymer (CFRP). A laser engraving treatment was used to create a pitted structure on the AA surface; higher wettability was acquired and greater vertical spaces were formed to impregnate epoxy resin, resulting in stronger mechanical interlocking. The RPC technique was further used to guide high-viscosity epoxy resin into pits to form the epoxy coatings and to minimize defects between the resin and the substrate. The bonding strength of the specimen treated with both laser engraving with a unit dimension of 0.3 mm and RPC increased up to 227.1% in comparison with that of the base. The failure modes of the hybrid composites changed from the debonding failure of the AA surface to the delamination-dominated failure of the laminated CFRP composites. It was confirmed that laser engraving is a feasible and effective method when combined with RPC for treating AAs to improve the bonding strength of AA-CFRP composites, which provides a reference for preparing high-performance hybrid composites with metals.","PeriodicalId":10520,"journal":{"name":"Coatings","volume":"53 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142263352","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study explores the influence of oxygen and nitrogen flow ratios on the microstructure and mechanical properties of AlCrTaTiZr high-entropy oxynitride films. Oxygen flow rates (0%–0.75%) were adjusted while maintaining a fixed nitrogen flow ratio (RN = 15%) to fabricate films with similar compositions. The results show that increasing oxygen flow enhanced hardness through solid solution strengthening and grain refinement, though excessive oxygen caused an amorphous structure and reduced hardness. After annealing at 900 °C, the hardness of all films was further increased. The film with a nitrogen flow ratio 40 times higher than oxygen exhibited the highest hardness of 21.8 GPa, along with superior mechanical performance. These findings highlight the potential of high-entropy oxynitride films for applications requiring high wear resistance and adhesion.
{"title":"Influence of Oxygen and Nitrogen Flow Ratios on the Microstructure Evolution in AlCrTaTiZr High-Entropy Oxynitride Films","authors":"Yung-Chu Liang, Ching-Yin Lee, Miao-I Lin, Ting-En Shen, Jung-Fan Hung, Jien-Wei Yeh, Che-Wei Tsai","doi":"10.3390/coatings14091199","DOIUrl":"https://doi.org/10.3390/coatings14091199","url":null,"abstract":"This study explores the influence of oxygen and nitrogen flow ratios on the microstructure and mechanical properties of AlCrTaTiZr high-entropy oxynitride films. Oxygen flow rates (0%–0.75%) were adjusted while maintaining a fixed nitrogen flow ratio (RN = 15%) to fabricate films with similar compositions. The results show that increasing oxygen flow enhanced hardness through solid solution strengthening and grain refinement, though excessive oxygen caused an amorphous structure and reduced hardness. After annealing at 900 °C, the hardness of all films was further increased. The film with a nitrogen flow ratio 40 times higher than oxygen exhibited the highest hardness of 21.8 GPa, along with superior mechanical performance. These findings highlight the potential of high-entropy oxynitride films for applications requiring high wear resistance and adhesion.","PeriodicalId":10520,"journal":{"name":"Coatings","volume":"9 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142263351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The wear of small-caliber barrels is one of the key factors affecting barrel life. Based on the Archard wear model, a high-temperature pin plate wear experiment was carried out, and wear models of chrome-plated layers and gun barrel materials were established. In addition, a finite element model of the interaction between the bullet and the barrel was established. The movement of the projectile along the barrel was simulated and analyzed, and the force distribution of the spatial geometry structure of the rifling was mastered through simulation. The wear law of the gun barrel along the axial direction was obtained based on the wear model of the chrome-plated layer and gun barrel material. A position 100 mm away from the barrel breech wears very fast; this position is where the cone of the bullet is engraved in the barrel. At the position 150–350 mm away from the barrel breech, the barrel bore wears even faster. The barrel chrome layer is mainly affected by the gunpowder impact and projectile engraving, which is consistent with the actual failure of the coating. When the distance to the barrel breech is 350 m, the wear becomes stable. Through an analysis of the diameter of the barrel, it was found that, when the diameter of the barrel exceeded 12.85 mm, the barrel reached the end of its life.
{"title":"The Construction of a Small-Caliber Barrel Wear Model and a Study of the Barrel Wear Rule","authors":"Libo Zou, Jiangtao Fan, Jianwen Huang, Jiahao Chen","doi":"10.3390/coatings14091200","DOIUrl":"https://doi.org/10.3390/coatings14091200","url":null,"abstract":"The wear of small-caliber barrels is one of the key factors affecting barrel life. Based on the Archard wear model, a high-temperature pin plate wear experiment was carried out, and wear models of chrome-plated layers and gun barrel materials were established. In addition, a finite element model of the interaction between the bullet and the barrel was established. The movement of the projectile along the barrel was simulated and analyzed, and the force distribution of the spatial geometry structure of the rifling was mastered through simulation. The wear law of the gun barrel along the axial direction was obtained based on the wear model of the chrome-plated layer and gun barrel material. A position 100 mm away from the barrel breech wears very fast; this position is where the cone of the bullet is engraved in the barrel. At the position 150–350 mm away from the barrel breech, the barrel bore wears even faster. The barrel chrome layer is mainly affected by the gunpowder impact and projectile engraving, which is consistent with the actual failure of the coating. When the distance to the barrel breech is 350 m, the wear becomes stable. Through an analysis of the diameter of the barrel, it was found that, when the diameter of the barrel exceeded 12.85 mm, the barrel reached the end of its life.","PeriodicalId":10520,"journal":{"name":"Coatings","volume":"20 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142263350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-18DOI: 10.3390/coatings14091202
Manmin Zhang, Di Xiao, Congfei Zhu, Kaiser Younis, Owais Yousuf
In-demand fresh-cut fruits are highly perishable and require shelf stability. Starch, such as sago, is a naturally available polysaccharide with good gas barrier properties. The study aimed to develop an edible coating and examine the effect of its application on the quality parameters of fresh-cut apples. The coating solution was prepared with sago and soy oil in concentrations of 3, 4, and 5% and 0, 0.25, and 0.50%, respectively. Lecithin (0.50%) was used as an emulsifier and glycerol (1.5%) as a plasticizer. Coated fresh-cut apples were evaluated for physicochemical properties (TSS, pH, non-enzymatic browning index, moisture content, weight loss, headspace gas, and color attributes) during a 12-day shelf-life study at 4 °C. Sensory analysis was also performed to assess consumer acceptability, and microbial analysis to investigate its inhibiting effect against yeast and mold. Compared to the control, developed coatings reduced browning, respiration rate, moisture, weight loss, and microbial load in fresh-cut apples. The study indicates that the blend of 5% sago and 0.5% soy oil produced the best coatings which were most effective for retaining the original quality attributes and in extending the shelf life of apple slices for 12 days in storage at 4 °C.
需求量大的鲜切水果极易变质，需要货架稳定性。西米等淀粉是一种天然多糖，具有良好的气体阻隔特性。这项研究旨在开发一种可食用的涂层，并研究其应用对鲜切苹果质量参数的影响。涂层溶液由西米和大豆油配制而成，浓度分别为 3%、4%、5% 和 0%、0.25%、0.50%。卵磷脂（0.50%）用作乳化剂，甘油（1.5%）用作增塑剂。在 4 °C 下进行为期 12 天的货架期研究期间，对涂层鲜切苹果的理化特性（总悬浮固体含量、pH 值、非酶促褐变指数、水分含量、重量损失、顶空气体和颜色属性）进行了评估。此外，还进行了感官分析以评估消费者的接受程度，以及微生物分析以研究其对酵母和霉菌的抑制作用。与对照组相比，开发的涂层降低了鲜切苹果的褐变、呼吸速率、水分、重量损失和微生物负荷。研究表明，5% 的西米和 0.5% 的大豆油混合制成的涂层效果最好，能最有效地保持苹果片原有的质量属性，并能延长苹果片在 4 °C 下储存 12 天的货架期。
{"title":"Shelf-Life Extension and Quality Changes of Fresh-Cut Apple via Sago and Soy-Oil-Based Edible Coatings","authors":"Manmin Zhang, Di Xiao, Congfei Zhu, Kaiser Younis, Owais Yousuf","doi":"10.3390/coatings14091202","DOIUrl":"https://doi.org/10.3390/coatings14091202","url":null,"abstract":"In-demand fresh-cut fruits are highly perishable and require shelf stability. Starch, such as sago, is a naturally available polysaccharide with good gas barrier properties. The study aimed to develop an edible coating and examine the effect of its application on the quality parameters of fresh-cut apples. The coating solution was prepared with sago and soy oil in concentrations of 3, 4, and 5% and 0, 0.25, and 0.50%, respectively. Lecithin (0.50%) was used as an emulsifier and glycerol (1.5%) as a plasticizer. Coated fresh-cut apples were evaluated for physicochemical properties (TSS, pH, non-enzymatic browning index, moisture content, weight loss, headspace gas, and color attributes) during a 12-day shelf-life study at 4 °C. Sensory analysis was also performed to assess consumer acceptability, and microbial analysis to investigate its inhibiting effect against yeast and mold. Compared to the control, developed coatings reduced browning, respiration rate, moisture, weight loss, and microbial load in fresh-cut apples. The study indicates that the blend of 5% sago and 0.5% soy oil produced the best coatings which were most effective for retaining the original quality attributes and in extending the shelf life of apple slices for 12 days in storage at 4 °C.","PeriodicalId":10520,"journal":{"name":"Coatings","volume":"16 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142263353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-18DOI: 10.3390/coatings14091198
Xiao Han, Yan Wang, Jianxiong Ma, Xinglong Ma
The surface corrosion of magnesium alloys is effectively addressed currently by the creation of a micro-arc oxidation (MAO) ceramic layer. However, oxide film porousness restricts magnesium alloy use. Thus, this work used atomic layer deposition (ALD) to create a TiO2 coating on MAO-coated AZ31B magnesium alloy to plug micropores and increase corrosion resistance and biological characteristics. The samples were analyzed using SEM, EDS, XPS, and XRD to determine their surface appearance, chemical content, and microstructure. Micro-arc oxidation produced a 20 μm oxide coating. The TiO2 film reached 47.41 nm after 400 atomic layer deposition cycles. All corroded samples were tested for corrosion resistance using electrochemical and hydrogen evolution methods and examined for surface morphology. In vitro cell experiments examined biocompatibility. The results indicate that the TiO2 layer sealed the MAO coating’s micro-pores and micro-cracks, enhanced corrosion resistance, and preserved surface morphology following corrosion. The TiO2/MAO composite coating is more biocompatible than the substrate and MAO coating. This research proposes coating AZ31B magnesium alloy for bio-remediation to increase corrosion resistance and biocompatibility.
目前，通过创建微弧氧化（MAO）陶瓷层可以有效解决镁合金的表面腐蚀问题。然而，氧化膜的多孔性限制了镁合金的使用。因此，本研究利用原子层沉积（ALD）技术在 MAO 涂层 AZ31B 镁合金上形成 TiO2 涂层，以堵塞微孔，提高耐腐蚀性和生物特性。样品通过 SEM、EDS、XPS 和 XRD 进行分析，以确定其表面外观、化学成分和微观结构。微弧氧化产生了 20 μm 的氧化物涂层。经过 400 次原子层沉积循环后，TiO2 膜达到 47.41 nm。使用电化学和氢进化方法测试了所有腐蚀样品的耐腐蚀性，并检查了表面形态。体外细胞实验检验了生物相容性。结果表明，TiO2 层封闭了 MAO 涂层的微孔和微裂缝，增强了耐腐蚀性，并在腐蚀后保持了表面形态。与基底和 MAO 涂层相比，TiO2/MAO 复合涂层的生物相容性更好。本研究建议对 AZ31B 镁合金进行生物修复涂层处理，以提高其耐腐蚀性和生物相容性。
{"title":"Corrosion Resistance and In Vitro Biological Properties of TiO2 on MAO-Coated AZ31 Magnesium Alloy via ALD","authors":"Xiao Han, Yan Wang, Jianxiong Ma, Xinglong Ma","doi":"10.3390/coatings14091198","DOIUrl":"https://doi.org/10.3390/coatings14091198","url":null,"abstract":"The surface corrosion of magnesium alloys is effectively addressed currently by the creation of a micro-arc oxidation (MAO) ceramic layer. However, oxide film porousness restricts magnesium alloy use. Thus, this work used atomic layer deposition (ALD) to create a TiO2 coating on MAO-coated AZ31B magnesium alloy to plug micropores and increase corrosion resistance and biological characteristics. The samples were analyzed using SEM, EDS, XPS, and XRD to determine their surface appearance, chemical content, and microstructure. Micro-arc oxidation produced a 20 μm oxide coating. The TiO2 film reached 47.41 nm after 400 atomic layer deposition cycles. All corroded samples were tested for corrosion resistance using electrochemical and hydrogen evolution methods and examined for surface morphology. In vitro cell experiments examined biocompatibility. The results indicate that the TiO2 layer sealed the MAO coating’s micro-pores and micro-cracks, enhanced corrosion resistance, and preserved surface morphology following corrosion. The TiO2/MAO composite coating is more biocompatible than the substrate and MAO coating. This research proposes coating AZ31B magnesium alloy for bio-remediation to increase corrosion resistance and biocompatibility.","PeriodicalId":10520,"journal":{"name":"Coatings","volume":"196 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142263355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-17DOI: 10.3390/coatings14091196
Lingling Zhang, Chao Yang, Yingzhi Guo
The corrosion problem affecting ancient Chinese bronze relics and the protective measures required post-excavation are crucial for the study of historical cultural heritage and for ensuring heritage revitalization and sustainable development. This work includes a statistical analysis, clusters information, and thoroughly examines international research on bronze relic corrosion and protection. It delves into the timeline and trends of research, the main countries leading the research efforts, the research content, and the relationships between these factors. A comprehensive review is provided on the corrosion principles, materials, detection methods, and protection techniques for bronze. The study explores the corrosion principles and processes of bronze from a materials science perspective both before and after excavation. It summarizes non-destructive detection methods and examines specific factors that influence corrosion. Furthermore, the article reviews current corrosion protection methods for bronze and related protection materials, including commonly used strategies such as surface corrosion inhibitors and organic resin coatings for protection. It also discusses the potential application of advanced corrosion protection methods in the realm of metal materials in recent years to safeguard bronze. Proposing innovative solutions, the study suggests the possibility of constructing biomimetic superhydrophobic surfaces to create a barrier isolating humid air from contacting bronze materials, thereby reducing the adhesion of corrosive media to the substrate and significantly diminishing the likelihood of corrosion. In conclusion, the article looks towards the future, considering the challenges and potential development directions for the corrosion protection of bronze and related protection materials.
{"title":"Corrosion and Protection of Chinese Bronze Relics: A Review","authors":"Lingling Zhang, Chao Yang, Yingzhi Guo","doi":"10.3390/coatings14091196","DOIUrl":"https://doi.org/10.3390/coatings14091196","url":null,"abstract":"The corrosion problem affecting ancient Chinese bronze relics and the protective measures required post-excavation are crucial for the study of historical cultural heritage and for ensuring heritage revitalization and sustainable development. This work includes a statistical analysis, clusters information, and thoroughly examines international research on bronze relic corrosion and protection. It delves into the timeline and trends of research, the main countries leading the research efforts, the research content, and the relationships between these factors. A comprehensive review is provided on the corrosion principles, materials, detection methods, and protection techniques for bronze. The study explores the corrosion principles and processes of bronze from a materials science perspective both before and after excavation. It summarizes non-destructive detection methods and examines specific factors that influence corrosion. Furthermore, the article reviews current corrosion protection methods for bronze and related protection materials, including commonly used strategies such as surface corrosion inhibitors and organic resin coatings for protection. It also discusses the potential application of advanced corrosion protection methods in the realm of metal materials in recent years to safeguard bronze. Proposing innovative solutions, the study suggests the possibility of constructing biomimetic superhydrophobic surfaces to create a barrier isolating humid air from contacting bronze materials, thereby reducing the adhesion of corrosive media to the substrate and significantly diminishing the likelihood of corrosion. In conclusion, the article looks towards the future, considering the challenges and potential development directions for the corrosion protection of bronze and related protection materials.","PeriodicalId":10520,"journal":{"name":"Coatings","volume":"189 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142263354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-17DOI: 10.3390/coatings14091197
Funsho Olaitan Kolawole, Shola Kolade Kolawole, Newton Kiyoshi Fukumasu, Luis Bernardo Varela, Paulo Konrad Vencovsky, Danilo Assad Ludewigs, Roberto Martins de Souza, André Paulo Tschiptschin
This study investigates the impact of temperature on the tribological performance of duplex layer CrN/DLC and nano-multilayers DLC-W coatings deposited using hybrid PVD-PECVD techniques on carburized and hardened 16MnCr5 discs cut from internal combustion engines valve tappets. Reciprocating dry sliding experiments were conducted at 25 °C, 150 °C, 200 °C, and 250 °C to analyze the high-temperature tribological behavior of the coatings. The wear mechanisms were characterized using SEM, EDS mapping, Raman spectroscopy, and nanoindentation. The lowest coefficient of friction was obtained for CrN/DLC at 25 °C. The CrN/DLC coefficients of friction (COF) increase with temperatures due to increasing adhesive wear. Similarly, DLC-W exhibited a comparable trend with increasing temperature from 25 °C to 250 °C. Both coatings’ wear resistance decreased with higher temperatures due to the transformation of sp3 C bonds to sp2 C bonds, facilitating the plastic deformation of the coatings and afterward of the substrate. The CrN/DLC displayed superior wear resistance to the DLC-W coating across all temperatures. The DLC-W multilayer coating showed poor wear resistance above 150 °C, being completely removed during the testing. Compared to both coatings, the uncoated 16MnCr5 discs exhibited higher coefficients of friction and wear rates at all temperatures. Predominant wear mechanisms observed in the coated discs were adhesive and abrasive. The study revealed a decrease in the coatings’ structural and mechanical properties with rising temperatures. Hard abrasive WC particles were identified as contributing to increased wear rates in the multilayer DLC-W coatings.
本研究探讨了温度对采用 PVD-PECVD 混合技术沉积在从内燃机气门挺杆上切割下来的渗碳和硬化 16MnCr5 盘上的双相层 CrN/DLC 和纳米多层 DLC-W 涂层的摩擦学性能的影响。在 25 ℃、150 ℃、200 ℃ 和 250 ℃ 下进行了往复式干滑动实验，以分析涂层的高温摩擦学行为。使用扫描电镜、EDS 图谱、拉曼光谱和纳米压痕法对磨损机制进行了表征。在 25 °C 时，CrN/DLC 的摩擦系数最低。由于粘合磨损加剧，CrN/DLC 的摩擦系数（COF）随温度升高而增大。同样，DLC-W 在 25 °C 至 250 °C 的温度升高过程中也表现出类似的趋势。两种涂层的耐磨性都随着温度升高而降低，这是由于 sp3 C 键转变为 sp2 C 键，从而促进了涂层的塑性变形，之后又促进了基体的塑性变形。在所有温度下，CrN/DLC 的耐磨性都优于 DLC-W 涂层。DLC-W 多层涂层在 150 °C 以上的耐磨性较差，在测试过程中被完全去除。与这两种涂层相比，未涂层的 16MnCr5 盘在所有温度下都表现出更高的摩擦系数和磨损率。在涂层圆盘上观察到的主要磨损机制是粘着磨损和研磨磨损。研究表明，涂层的结构和机械性能随着温度的升高而降低。在多层 DLC-W 涂层中，硬质磨料 WC 颗粒被认为是导致磨损率增加的原因。
{"title":"Elevated Temperature Tribological Behavior of Duplex Layer CrN/DLC and Nano Multilayer DLC-W Coatings Deposited on Carburized and Hardened 16MnCr5 Steel","authors":"Funsho Olaitan Kolawole, Shola Kolade Kolawole, Newton Kiyoshi Fukumasu, Luis Bernardo Varela, Paulo Konrad Vencovsky, Danilo Assad Ludewigs, Roberto Martins de Souza, André Paulo Tschiptschin","doi":"10.3390/coatings14091197","DOIUrl":"https://doi.org/10.3390/coatings14091197","url":null,"abstract":"This study investigates the impact of temperature on the tribological performance of duplex layer CrN/DLC and nano-multilayers DLC-W coatings deposited using hybrid PVD-PECVD techniques on carburized and hardened 16MnCr5 discs cut from internal combustion engines valve tappets. Reciprocating dry sliding experiments were conducted at 25 °C, 150 °C, 200 °C, and 250 °C to analyze the high-temperature tribological behavior of the coatings. The wear mechanisms were characterized using SEM, EDS mapping, Raman spectroscopy, and nanoindentation. The lowest coefficient of friction was obtained for CrN/DLC at 25 °C. The CrN/DLC coefficients of friction (COF) increase with temperatures due to increasing adhesive wear. Similarly, DLC-W exhibited a comparable trend with increasing temperature from 25 °C to 250 °C. Both coatings’ wear resistance decreased with higher temperatures due to the transformation of sp3 C bonds to sp2 C bonds, facilitating the plastic deformation of the coatings and afterward of the substrate. The CrN/DLC displayed superior wear resistance to the DLC-W coating across all temperatures. The DLC-W multilayer coating showed poor wear resistance above 150 °C, being completely removed during the testing. Compared to both coatings, the uncoated 16MnCr5 discs exhibited higher coefficients of friction and wear rates at all temperatures. Predominant wear mechanisms observed in the coated discs were adhesive and abrasive. The study revealed a decrease in the coatings’ structural and mechanical properties with rising temperatures. Hard abrasive WC particles were identified as contributing to increased wear rates in the multilayer DLC-W coatings.","PeriodicalId":10520,"journal":{"name":"Coatings","volume":"18 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142263356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-16DOI: 10.3390/coatings14091195
Beata Kucharska, Kamil Bochra, Tadeusz Wierzchoń, Jerzy Robert Sobiecki
In this study, the use of Cr/CrN+CrCN/Cr-C:H, Cr/W-C:H, and Cr/CrN+Ag/Cr-C:H coatings deposited on copper beryllium were investigated. These protective coatings were prepared using the Magnetron Sputtering Physical Vapor Deposition (MSPVD) method. The tests were carried out in order to qualify the outer DLC (Diamond-Like Carbon) layers for use as the protective function and for regulating the thermo-optical properties. The objective of this study was to compare the properties of chromium and chromium nitride-based coatings. The microstructure, architecture, and chemical composition were studied using scanning electron microscopy (SEM), Photo Diode BackScattered Electrons (PDBS), and X-ray dispersion spectroscopy (EDX). The adhesion was evaluated using a scratch test and a peel and pull-off method. The level of protection against the cold welding effect was tested. Thermo-optical, microhardness, and surface electric resistivity tests were performed. It was found that in cases where increased resistance to cold welding is required, DLC2 and DLC3 proved to be the best solutions. An example of such an application is tubular boom antennas, which are stored in a rolled-up form until deployed in space. They are susceptible to cold welding due to vibration during rocket launch and subsequent exposure to high vacuum.
{"title":"Protective Magnetron Sputtering Physical Vapor Deposition Coatings for Space Application","authors":"Beata Kucharska, Kamil Bochra, Tadeusz Wierzchoń, Jerzy Robert Sobiecki","doi":"10.3390/coatings14091195","DOIUrl":"https://doi.org/10.3390/coatings14091195","url":null,"abstract":"In this study, the use of Cr/CrN+CrCN/Cr-C:H, Cr/W-C:H, and Cr/CrN+Ag/Cr-C:H coatings deposited on copper beryllium were investigated. These protective coatings were prepared using the Magnetron Sputtering Physical Vapor Deposition (MSPVD) method. The tests were carried out in order to qualify the outer DLC (Diamond-Like Carbon) layers for use as the protective function and for regulating the thermo-optical properties. The objective of this study was to compare the properties of chromium and chromium nitride-based coatings. The microstructure, architecture, and chemical composition were studied using scanning electron microscopy (SEM), Photo Diode BackScattered Electrons (PDBS), and X-ray dispersion spectroscopy (EDX). The adhesion was evaluated using a scratch test and a peel and pull-off method. The level of protection against the cold welding effect was tested. Thermo-optical, microhardness, and surface electric resistivity tests were performed. It was found that in cases where increased resistance to cold welding is required, DLC2 and DLC3 proved to be the best solutions. An example of such an application is tubular boom antennas, which are stored in a rolled-up form until deployed in space. They are susceptible to cold welding due to vibration during rocket launch and subsequent exposure to high vacuum.","PeriodicalId":10520,"journal":{"name":"Coatings","volume":"8 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142263390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper describes the behavior of some epoxy, acrylic and polyurethane paints used in the protection of electrical equipment under the action of different degradation factors. The degradation factors chosen were temperature and UV radiation. The behavior of the paints under the action of these factors was interpreted by the variation of the tangent of the dielectric loss angle (tg Delta) as well as by FTIR and TG DSC analyses. Tg Delta was considered the reference dielectric characteristic because it best simulates the functionality of the material. The results presented in this paper lead to the conclusion that exposure to thermal cycles and UV radiation is necessary for each paint to give indications about their possibility of use in these conditions. At the same time, the evaluation of thermal stability, even if the exposure is at lower temperatures (than those at which we performed the tests) and/or for shorter periods, is very important for placing the paint in an insulation class. The tests that were the subject of this work provide us with the following information about the three types of paints analyzed: the highest resistance to thermal cycles is presented by S3, followed by S2 and then S1; thermal endurance tests place the polyurethane paint (S3) in insulation class E and the epoxy paint (S1) in insulation class B; and the tests to determine resistance to UV radiation qualify the best paint as acrylic (S2) and the worst as polyurethane (S3). Thus, it can be said that in applications where it is necessary for the protective film to withstand high temperatures, the use of S3 paint (polyurethane) is recommended, and in applications where the films are kept under the influence of UV radiation for a longer time, it is recommended to use coded paint S2 (acrylic). The results presented in this paper lead to the conclusion that the exposure to thermal cycles simulating the use in outdoor conditions and the resilience of paints under UV radiation conditions must be performed for each paint according to its specific use, and the dielectric characteristics must be carefully evaluated because they can reach values under the accepted limit—e.g., thermal stability evaluation—even if the exposure is at lower temperatures and/or for shorter periods. The conclusions of the experimental work must be generalized at different types of electrical insulating paints, and maybe a new standard is necessary to assess the paints’ behavior under usage conditions, with the paints needing to be treated separately from the classical polymeric insulation systems.
{"title":"Comparative Analysis of Dielectric Behavior under Temperature and UV Radiation Exposure of Insulating Paints for Electrical Equipment Protection—The Necessity of a New Standard?","authors":"Alina Ruxandra Caramitu, Magdalena Valentina Lungu, Romeo Cristian Ciobanu, Mihaela Aradoaei, Eduard-Marius Lungulescu, Virgil Marinescu","doi":"10.3390/coatings14091194","DOIUrl":"https://doi.org/10.3390/coatings14091194","url":null,"abstract":"This paper describes the behavior of some epoxy, acrylic and polyurethane paints used in the protection of electrical equipment under the action of different degradation factors. The degradation factors chosen were temperature and UV radiation. The behavior of the paints under the action of these factors was interpreted by the variation of the tangent of the dielectric loss angle (tg Delta) as well as by FTIR and TG DSC analyses. Tg Delta was considered the reference dielectric characteristic because it best simulates the functionality of the material. The results presented in this paper lead to the conclusion that exposure to thermal cycles and UV radiation is necessary for each paint to give indications about their possibility of use in these conditions. At the same time, the evaluation of thermal stability, even if the exposure is at lower temperatures (than those at which we performed the tests) and/or for shorter periods, is very important for placing the paint in an insulation class. The tests that were the subject of this work provide us with the following information about the three types of paints analyzed: the highest resistance to thermal cycles is presented by S3, followed by S2 and then S1; thermal endurance tests place the polyurethane paint (S3) in insulation class E and the epoxy paint (S1) in insulation class B; and the tests to determine resistance to UV radiation qualify the best paint as acrylic (S2) and the worst as polyurethane (S3). Thus, it can be said that in applications where it is necessary for the protective film to withstand high temperatures, the use of S3 paint (polyurethane) is recommended, and in applications where the films are kept under the influence of UV radiation for a longer time, it is recommended to use coded paint S2 (acrylic). The results presented in this paper lead to the conclusion that the exposure to thermal cycles simulating the use in outdoor conditions and the resilience of paints under UV radiation conditions must be performed for each paint according to its specific use, and the dielectric characteristics must be carefully evaluated because they can reach values under the accepted limit—e.g., thermal stability evaluation—even if the exposure is at lower temperatures and/or for shorter periods. The conclusions of the experimental work must be generalized at different types of electrical insulating paints, and maybe a new standard is necessary to assess the paints’ behavior under usage conditions, with the paints needing to be treated separately from the classical polymeric insulation systems.","PeriodicalId":10520,"journal":{"name":"Coatings","volume":"77 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142263357","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-15DOI: 10.3390/coatings14091192
Luis Chávez, Lucien Veleva, Andrea Castillo-Atoche
Electroless ZnO (≈900 nm) was deposited on the surface of an Mg-Al alloy (AM60) to reduce its degradation in the marine environment. Uncoated and coated ZnO samples were exposed to an SME simulated marine solution for up to 30 days. The AFM and optical images revealed that the corrosion attack on the ZnO-AM60 surface was reduced due to an increase in the surface hydrophobicity of the ZnO coating (contact angle of ≈91.6°). The change in pH to more alkaline values over time was less pronounced for ZnO-AM60 (by ≈13%), whereas the release of Mg2+ ions was reduced by 34 times, attributed to the decrease in active sites on the Mg-matrix provided by the electroless ZnO coating. The OCP (free corrosion potential) of ZnO-AM60 shifted towards less negative values of ≈100 mV, indicating that electroless ZnO may serve as a good barrier for AM60 in a marine environment. The calculated polarization resistance (Rp), based on EIS data, was ≈3 times greater for ZnO-AM60 than that of the uncoated substrate.
{"title":"Electroless ZnO Deposition on Mg-Al Alloy for Improved Corrosion Resistance to Marine Environments","authors":"Luis Chávez, Lucien Veleva, Andrea Castillo-Atoche","doi":"10.3390/coatings14091192","DOIUrl":"https://doi.org/10.3390/coatings14091192","url":null,"abstract":"Electroless ZnO (≈900 nm) was deposited on the surface of an Mg-Al alloy (AM60) to reduce its degradation in the marine environment. Uncoated and coated ZnO samples were exposed to an SME simulated marine solution for up to 30 days. The AFM and optical images revealed that the corrosion attack on the ZnO-AM60 surface was reduced due to an increase in the surface hydrophobicity of the ZnO coating (contact angle of ≈91.6°). The change in pH to more alkaline values over time was less pronounced for ZnO-AM60 (by ≈13%), whereas the release of Mg2+ ions was reduced by 34 times, attributed to the decrease in active sites on the Mg-matrix provided by the electroless ZnO coating. The OCP (free corrosion potential) of ZnO-AM60 shifted towards less negative values of ≈100 mV, indicating that electroless ZnO may serve as a good barrier for AM60 in a marine environment. The calculated polarization resistance (Rp), based on EIS data, was ≈3 times greater for ZnO-AM60 than that of the uncoated substrate.","PeriodicalId":10520,"journal":{"name":"Coatings","volume":"20 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142263389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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