Pub Date : 2024-08-07DOI: 10.3390/coatings14081002
Shuling Zhang, Xiangdong Yang, Tenglong Huang, Feng Guo, Longjie Dai, Yi Liu, Bo Zhang
CrN and diamond-like carbon (DLC) coatings are deposited on the surface of 431 stainless steel by the direct current magnetron sputtering technique. The surface morphology, micro-structure, hardness, friction, and wear properties of CrN, CrN/DLC and multi-layer composite DLC coatings are investigated by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, nanoindentation tester, scratch tester, and friction and wear tester. The results show that the surface of the single CrN coating is very rough for the columnar crystal structure with preferred orientation. When it serves as inner transition layers to form the composite DLC coatings, the surface gets much smoother, with reduced defects. The friction and wear results indicate that the composite DLC coatings exhibit lower coefficients of friction, and better wear and corrosion resistance in dry friction, deionized water, and seawater. In the dry wear and friction process, the single CrN coating is easily worn out, and severe friction oxidation and furrow wear both appear with a friction coefficient of 0.48. But the friction coefficient of a CrN coating in seawater is reduced to 0.16, and friction oxidation and wear loss are further reduced with water lubrication. The CrN/DLC coating has excellent tribological performance in three test concoctions and has the lowest friction coefficient of 0.08 in seawater, which is related to the higher sp3 bond content, density (1.907 g/cm3) and high degree of amorphization, contributing to high hardness and a self-lubrication effect. However, due to the limited thickness of CrN/DLC (1.14 µm), it easily peels off and fails during friction and wear in different testing conditions. In multi-layer composite DLC coatings, there are more sp2 bonds with decreased amorphization, high enough thickness (4.02 µm), and increased bonding strength for the formation of different carbides and nitrides of chromium as transition layers, which gives rise to the further decreased average friction coefficient and the lowest wear loss. Therefore, the CrN coating alone has good wear resistance, and, as with the inner transition layer with a DLC coating, it can effectively improve the overall thickness and the bonding strength of the multi-layer films by optimizing the chemical compounds of DLC coatings. These results provide experimental support and reference for the design and selection of surface coatings for 431 stainless steels in different working conditions.
{"title":"Tribological Properties of CrN/DLC and CrN Coatings Under Different Testing Conditions","authors":"Shuling Zhang, Xiangdong Yang, Tenglong Huang, Feng Guo, Longjie Dai, Yi Liu, Bo Zhang","doi":"10.3390/coatings14081002","DOIUrl":"https://doi.org/10.3390/coatings14081002","url":null,"abstract":"CrN and diamond-like carbon (DLC) coatings are deposited on the surface of 431 stainless steel by the direct current magnetron sputtering technique. The surface morphology, micro-structure, hardness, friction, and wear properties of CrN, CrN/DLC and multi-layer composite DLC coatings are investigated by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, nanoindentation tester, scratch tester, and friction and wear tester. The results show that the surface of the single CrN coating is very rough for the columnar crystal structure with preferred orientation. When it serves as inner transition layers to form the composite DLC coatings, the surface gets much smoother, with reduced defects. The friction and wear results indicate that the composite DLC coatings exhibit lower coefficients of friction, and better wear and corrosion resistance in dry friction, deionized water, and seawater. In the dry wear and friction process, the single CrN coating is easily worn out, and severe friction oxidation and furrow wear both appear with a friction coefficient of 0.48. But the friction coefficient of a CrN coating in seawater is reduced to 0.16, and friction oxidation and wear loss are further reduced with water lubrication. The CrN/DLC coating has excellent tribological performance in three test concoctions and has the lowest friction coefficient of 0.08 in seawater, which is related to the higher sp3 bond content, density (1.907 g/cm3) and high degree of amorphization, contributing to high hardness and a self-lubrication effect. However, due to the limited thickness of CrN/DLC (1.14 µm), it easily peels off and fails during friction and wear in different testing conditions. In multi-layer composite DLC coatings, there are more sp2 bonds with decreased amorphization, high enough thickness (4.02 µm), and increased bonding strength for the formation of different carbides and nitrides of chromium as transition layers, which gives rise to the further decreased average friction coefficient and the lowest wear loss. Therefore, the CrN coating alone has good wear resistance, and, as with the inner transition layer with a DLC coating, it can effectively improve the overall thickness and the bonding strength of the multi-layer films by optimizing the chemical compounds of DLC coatings. These results provide experimental support and reference for the design and selection of surface coatings for 431 stainless steels in different working conditions.","PeriodicalId":10520,"journal":{"name":"Coatings","volume":"6 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141946356","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 : 2024-08-07DOI: 10.3390/coatings14081001
Honglei Xi, Rijun Wang, Fulong Liang, Yesheng Chen, Guanghao Zhang, Bo Wang
Wood surface defect detection is a challenging task due to the complexity and variability of defect types. To address these challenges, this paper introduces a novel deep learning approach named SiM-YOLO, which is built upon the YOLOv8 object detection framework. A fine-grained convolutional structure, SPD-Conv, is introduced with the aim of preserving detailed defect information during the feature extraction process, thus enabling the model to capture the subtle variations and complex details of wood surface defects. In the feature fusion stage, a SiAFF-PANet-based wood defect feature fusion module is designed to improve the model’s ability to focus on local contextual information and enhance defect localization. For classification and regression tasks, the multi-attention detection head (MADH) is employed to capture cross-channel information and the accurate spatial localization of defects. In addition, MPDIoU is employed to optimize the loss function of the model to reduce the leakage of detection due to defect overlap. The experimental results show that SiM-YOLO achieves superior performance compared to the state-of-the-art YOLO algorithm, with a 9.3% improvement in mAP over YOLOX and a 4.3% improvement in mAP over YOLOv8. The Grad-CAM visualization further illustrates that SiM-YOLO provides more accurate defect localization and effectively reduces misdetection and omission issues. This study highlights the effectiveness of SiM-YOLO for wood surface defect detection and offers valuable insights for future research and practical applications in quality control.
{"title":"SiM-YOLO: A Wood Surface Defect Detection Method Based on the Improved YOLOv8","authors":"Honglei Xi, Rijun Wang, Fulong Liang, Yesheng Chen, Guanghao Zhang, Bo Wang","doi":"10.3390/coatings14081001","DOIUrl":"https://doi.org/10.3390/coatings14081001","url":null,"abstract":"Wood surface defect detection is a challenging task due to the complexity and variability of defect types. To address these challenges, this paper introduces a novel deep learning approach named SiM-YOLO, which is built upon the YOLOv8 object detection framework. A fine-grained convolutional structure, SPD-Conv, is introduced with the aim of preserving detailed defect information during the feature extraction process, thus enabling the model to capture the subtle variations and complex details of wood surface defects. In the feature fusion stage, a SiAFF-PANet-based wood defect feature fusion module is designed to improve the model’s ability to focus on local contextual information and enhance defect localization. For classification and regression tasks, the multi-attention detection head (MADH) is employed to capture cross-channel information and the accurate spatial localization of defects. In addition, MPDIoU is employed to optimize the loss function of the model to reduce the leakage of detection due to defect overlap. The experimental results show that SiM-YOLO achieves superior performance compared to the state-of-the-art YOLO algorithm, with a 9.3% improvement in mAP over YOLOX and a 4.3% improvement in mAP over YOLOv8. The Grad-CAM visualization further illustrates that SiM-YOLO provides more accurate defect localization and effectively reduces misdetection and omission issues. This study highlights the effectiveness of SiM-YOLO for wood surface defect detection and offers valuable insights for future research and practical applications in quality control.","PeriodicalId":10520,"journal":{"name":"Coatings","volume":"6 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141969855","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 : 2024-08-07DOI: 10.3390/coatings14080997
Xiong Zhao, Junying Zhang, Lu Ma, Wubin Wang, Mingxing Zhang
A series of morpholine salt volatile corrosion inhibitors (VCIs) were synthesized via solid-phase chemical reactions. The corrosion inhibition performance was assessed using evaporation weight loss, VCI capability, and corrosion weight loss tests. The corrosion inhibition mechanisms of the morpholine salt VCIs for carbon steel in atmospheric conditions were explored through electrochemical testing under thin film electrolytes, X-ray photoelectron spectroscopy (XPS), and computational simulations. Morpholine carbonate exhibited higher volatility. Corrosion weight loss tests showed an >85% reduction for steel treated with morpholine benzoate or morpholine carbonate. The inhibitors’ inhibition mechanism, elucidated through X-ray photoelectron spectroscopy (XPS) and computational simulations, revealed that morpholine carbonate and benzoate form protective layers via physical and chemical adsorption on the steel surface, coordinating with iron atoms through nitrogen and oxygen atoms. Quantum chemical calculations demonstrated that morpholine carbonate had stronger adsorption energy and electron transfer capabilities, indicating superior corrosion inhibition performance over morpholine benzoate.
通过固相化学反应合成了一系列吗啉盐挥发性缓蚀剂（VCIs）。采用蒸发失重、VCI 能力和腐蚀失重测试评估了其缓蚀性能。通过薄膜电解质下的电化学测试、X 射线光电子能谱（XPS）和计算模拟，探索了吗啉盐 VCIs 在大气条件下对碳钢的缓蚀机理。碳酸吗啉表现出较高的挥发性。腐蚀失重测试表明，使用苯甲酸吗啉或碳酸吗啉处理的钢材的腐蚀失重降低了 85%以上。通过 X 射线光电子能谱（XPS）和计算模拟阐明的抑制剂抑制机理表明，碳酸吗啉和苯甲酸吗啉通过物理和化学吸附作用在钢表面形成保护层，并通过氮原子和氧原子与铁原子配位。量子化学计算表明，碳酸吗啉具有更强的吸附能和电子转移能力，表明其缓蚀性能优于苯甲酸吗啉。
{"title":"Study on the Performance and Mechanism of Morpholine Salt Volatile Corrosion Inhibitors on Carbon Steel","authors":"Xiong Zhao, Junying Zhang, Lu Ma, Wubin Wang, Mingxing Zhang","doi":"10.3390/coatings14080997","DOIUrl":"https://doi.org/10.3390/coatings14080997","url":null,"abstract":"A series of morpholine salt volatile corrosion inhibitors (VCIs) were synthesized via solid-phase chemical reactions. The corrosion inhibition performance was assessed using evaporation weight loss, VCI capability, and corrosion weight loss tests. The corrosion inhibition mechanisms of the morpholine salt VCIs for carbon steel in atmospheric conditions were explored through electrochemical testing under thin film electrolytes, X-ray photoelectron spectroscopy (XPS), and computational simulations. Morpholine carbonate exhibited higher volatility. Corrosion weight loss tests showed an >85% reduction for steel treated with morpholine benzoate or morpholine carbonate. The inhibitors’ inhibition mechanism, elucidated through X-ray photoelectron spectroscopy (XPS) and computational simulations, revealed that morpholine carbonate and benzoate form protective layers via physical and chemical adsorption on the steel surface, coordinating with iron atoms through nitrogen and oxygen atoms. Quantum chemical calculations demonstrated that morpholine carbonate had stronger adsorption energy and electron transfer capabilities, indicating superior corrosion inhibition performance over morpholine benzoate.","PeriodicalId":10520,"journal":{"name":"Coatings","volume":"39 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141946351","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 : 2024-08-04DOI: 10.3390/coatings14080984
Guoqiang Qin, Ziyuan Zhao, Ao Wang, Wentao Wang, Shengjian Qin, Hongya Wu, Zhigang Yang, Gang Yu, Guanglei Zhang
This research article presents a comprehensive first-principles study on the piezoelectric properties of Wurtzite Aluminum Nitride (AlN) films under in-plane strain conditions. By calculating the piezoelectric tensor coefficients (e33, e31, and e15), we investigate the variation patterns of these constants with respect to in-plane strain. Our results indicate significant changes in the piezoelectric constants within the range of in-plane strain considered, exhibiting a linear trend despite opposite trends for e33 compared to e31 and e15. This study highlights the extreme sensitivity of AlN films’ piezoelectric performance to in-plane strain, suggesting its potential as an effective means for tuning and optimizing the piezoelectric properties of AlN-based devices.
{"title":"Investigation of Piezoelectric Properties of Wurtzite AlN Films under In-Plane Strain: A First-Principles Study","authors":"Guoqiang Qin, Ziyuan Zhao, Ao Wang, Wentao Wang, Shengjian Qin, Hongya Wu, Zhigang Yang, Gang Yu, Guanglei Zhang","doi":"10.3390/coatings14080984","DOIUrl":"https://doi.org/10.3390/coatings14080984","url":null,"abstract":"This research article presents a comprehensive first-principles study on the piezoelectric properties of Wurtzite Aluminum Nitride (AlN) films under in-plane strain conditions. By calculating the piezoelectric tensor coefficients (e33, e31, and e15), we investigate the variation patterns of these constants with respect to in-plane strain. Our results indicate significant changes in the piezoelectric constants within the range of in-plane strain considered, exhibiting a linear trend despite opposite trends for e33 compared to e31 and e15. This study highlights the extreme sensitivity of AlN films’ piezoelectric performance to in-plane strain, suggesting its potential as an effective means for tuning and optimizing the piezoelectric properties of AlN-based devices.","PeriodicalId":10520,"journal":{"name":"Coatings","volume":"11 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141946358","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 : 2024-08-03DOI: 10.3390/coatings14080981
Xingfa Ma, Xintao Zhang, Mingjun Gao, You Wang, Guang Li
Non-conjugated polymer-derived functional nanocomposites are one of the important ways to develop multifunctional hybrids. By increasing the degree of crosslinking, their photophysical properties can be improved. PbS is a class of narrow bandgap infrared active materials. To avoid aggregation and passivation of the surface defects of PbS nanomaterials, a large number of organic and inorganic ligands are usually used. In this study, PbS/C composite nanosheets were synthesized with Pb2+ ion-crosslinked sodium alginate gel by one-pot carbonization. The resulting nanosheets were coated on untreated A4 printing paper, and the electrodes were the graphite electrodes with 5B pencil drawings. The photocurrent signals of the products were measured using typical 650, 808, 980, and 1064 nm light sources. The results showed that the photocurrent switching signals were effectively extracted in the visible and near-infrared regions, which was attributed to the mutual passivation of defects during the in situ preparation of PbS and carbon nanomaterials. At the same time, the resulting nanocomposite exhibited electrical switching responses to the applied strain to a certain extent. The photophysical and defect passivation mechanisms were discussed based on the aggregation state of the carbon hybrid and the interfacial electron interaction. This material would have potential applications in broadband flexible photodetectors, tentacle sensors, or light harvesting interdisciplinary areas. This study provided a facile approach to prepare a low-cost hybrid with external stimulus response and multifunctionality. These results show that the interfacial charge transfer is the direct experimental evidence of interfacial interaction, and the regulation of interfacial interaction can improve the physical and chemical properties of nanocomposites, which can meet the interdisciplinary application. The interdisciplinary and application of more non-conjugated polymer systems in some frontier areas will be expanded upon.
{"title":"Polymer-Gel-Derived PbS/C Composite Nanosheets and Their Photoelectronic Response Properties Studies in the NIR","authors":"Xingfa Ma, Xintao Zhang, Mingjun Gao, You Wang, Guang Li","doi":"10.3390/coatings14080981","DOIUrl":"https://doi.org/10.3390/coatings14080981","url":null,"abstract":"Non-conjugated polymer-derived functional nanocomposites are one of the important ways to develop multifunctional hybrids. By increasing the degree of crosslinking, their photophysical properties can be improved. PbS is a class of narrow bandgap infrared active materials. To avoid aggregation and passivation of the surface defects of PbS nanomaterials, a large number of organic and inorganic ligands are usually used. In this study, PbS/C composite nanosheets were synthesized with Pb2+ ion-crosslinked sodium alginate gel by one-pot carbonization. The resulting nanosheets were coated on untreated A4 printing paper, and the electrodes were the graphite electrodes with 5B pencil drawings. The photocurrent signals of the products were measured using typical 650, 808, 980, and 1064 nm light sources. The results showed that the photocurrent switching signals were effectively extracted in the visible and near-infrared regions, which was attributed to the mutual passivation of defects during the in situ preparation of PbS and carbon nanomaterials. At the same time, the resulting nanocomposite exhibited electrical switching responses to the applied strain to a certain extent. The photophysical and defect passivation mechanisms were discussed based on the aggregation state of the carbon hybrid and the interfacial electron interaction. This material would have potential applications in broadband flexible photodetectors, tentacle sensors, or light harvesting interdisciplinary areas. This study provided a facile approach to prepare a low-cost hybrid with external stimulus response and multifunctionality. These results show that the interfacial charge transfer is the direct experimental evidence of interfacial interaction, and the regulation of interfacial interaction can improve the physical and chemical properties of nanocomposites, which can meet the interdisciplinary application. The interdisciplinary and application of more non-conjugated polymer systems in some frontier areas will be expanded upon.","PeriodicalId":10520,"journal":{"name":"Coatings","volume":"27 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141885569","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}
In this study, a microbial–enzymatic strategy was pursued to address the challenge of degrading thermoplastic and thermosetting polymers. Environmental microorganisms were isolated, and their enzymatic activities were assessed using colorimetric assays to evaluate their potential for producing enzymes capable of degrading these polymers. Microorganisms demonstrating higher positivity in the enzymatic assays were selected for a 30-day biodegradation experiment, in which epoxy resins, polyethylene terephthalate, or polystyrene served as the sole carbon source. The effectiveness of biodegradation was assessed through the ATR-FTIR analysis of the chemical composition and the SEM examination of surface characteristics before and after degradation. The results indicated that thermoplastic compounds were more susceptible to microbial degradation, exhibiting greater changes in absorbance. In particular, PET treated with Stenotrophomonas sp. showed the most significant efficacy, achieving a 60.18% reduction in the area under the curve with a standard error of ± 3.42 when analyzed by FTIR spectroscopy. Significant alterations in surface morphology were noticed in thermoplastic compounds. In contrast, thermosetting compounds demonstrated lower reactivity, as evidenced by the absence of band shifts in FTIR spectra and minor changes in bond absorbance and surface morphology.
本研究采用微生物酶策略来应对降解热塑性和热固性聚合物的挑战。研究人员分离了环境微生物，并使用比色法评估了它们的酶活性，以评估它们产生能够降解这些聚合物的酶的潜力。在酶测定中表现出较高阳性的微生物被选中进行为期 30 天的生物降解实验，实验中环氧树脂、聚对苯二甲酸乙二酯或聚苯乙烯是唯一的碳源。通过对降解前后的化学成分进行 ATR-FTIR 分析和对表面特征进行 SEM 检查，评估了生物降解的效果。结果表明，热塑性化合物更容易被微生物降解，吸光度变化更大。其中，用 Stenotrophomonas sp.处理 PET 的效果最为显著，在用傅立叶变换红外光谱分析时，曲线下面积减少了 60.18%，标准误差为 ± 3.42。热塑性化合物的表面形态发生了显著变化。相比之下，热固性化合物的反应活性较低，这体现在傅立叶变换红外光谱中没有条带偏移，而且键的吸光度和表面形态发生了轻微变化。
{"title":"Evaluation of Microbial Degradation of Thermoplastic and Thermosetting Polymers by Environmental Isolates","authors":"Pierluca Nuccetelli, Francesca Maisto, Lucia Kraková, Alfredo Grilli, Alžbeta Takáčová, Alena Opálková Šišková, Domenico Pangallo","doi":"10.3390/coatings14080982","DOIUrl":"https://doi.org/10.3390/coatings14080982","url":null,"abstract":"In this study, a microbial–enzymatic strategy was pursued to address the challenge of degrading thermoplastic and thermosetting polymers. Environmental microorganisms were isolated, and their enzymatic activities were assessed using colorimetric assays to evaluate their potential for producing enzymes capable of degrading these polymers. Microorganisms demonstrating higher positivity in the enzymatic assays were selected for a 30-day biodegradation experiment, in which epoxy resins, polyethylene terephthalate, or polystyrene served as the sole carbon source. The effectiveness of biodegradation was assessed through the ATR-FTIR analysis of the chemical composition and the SEM examination of surface characteristics before and after degradation. The results indicated that thermoplastic compounds were more susceptible to microbial degradation, exhibiting greater changes in absorbance. In particular, PET treated with Stenotrophomonas sp. showed the most significant efficacy, achieving a 60.18% reduction in the area under the curve with a standard error of ± 3.42 when analyzed by FTIR spectroscopy. Significant alterations in surface morphology were noticed in thermoplastic compounds. In contrast, thermosetting compounds demonstrated lower reactivity, as evidenced by the absence of band shifts in FTIR spectra and minor changes in bond absorbance and surface morphology.","PeriodicalId":10520,"journal":{"name":"Coatings","volume":"55 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141885570","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 : 2024-08-03DOI: 10.3390/coatings14080979
Patricia Fernández-López, Sofia A. Alves, Aleksey Rogov, Aleksey Yerokhin, Iban Quintana, Aitor Duo, Aitor Aguirre-Ortuzar
PEO constitutes a promising surface technology for the development of protective and functional ceramic coatings on lightweight alloys. Despite its interesting advantages, including enhanced wear and corrosion resistances and eco-friendliness, the industrial implementation of PEO technology is limited by its relatively high energy consumption. This study explores the development and optimization of novel PEO processes by means of machine learning (ML) to improve the coating thickness. For this purpose, ML models random forest and XGBoost were employed to predict the thickness of the developed PEO coatings based on the key process variables (frequency, current density, and electrolyte composition). The predictive performance was significantly improved by including the composition of the used electrolyte in the models. Furthermore, Shapley values identified the pulse frequency and the TiO2 concentration in the electrolyte as the most influential variables, with higher values leading to increased coating thickness. The residual analysis revealed a certain heteroscedasticity, which suggests the need for additional samples with high thickness to improve the accuracy of the model. This study reveals the potential of artificial intelligence (AI)-driven optimization in PEO processes, which could pave the way for more efficient and cost-effective industrial applications. The findings achieved further emphasize the significance of integrating interactions between variables, such as frequency and TiO2 concentration, into the design of processing operations.
{"title":"Data-Driven Optimization of Plasma Electrolytic Oxidation (PEO) Coatings with Explainable Artificial Intelligence Insights","authors":"Patricia Fernández-López, Sofia A. Alves, Aleksey Rogov, Aleksey Yerokhin, Iban Quintana, Aitor Duo, Aitor Aguirre-Ortuzar","doi":"10.3390/coatings14080979","DOIUrl":"https://doi.org/10.3390/coatings14080979","url":null,"abstract":"PEO constitutes a promising surface technology for the development of protective and functional ceramic coatings on lightweight alloys. Despite its interesting advantages, including enhanced wear and corrosion resistances and eco-friendliness, the industrial implementation of PEO technology is limited by its relatively high energy consumption. This study explores the development and optimization of novel PEO processes by means of machine learning (ML) to improve the coating thickness. For this purpose, ML models random forest and XGBoost were employed to predict the thickness of the developed PEO coatings based on the key process variables (frequency, current density, and electrolyte composition). The predictive performance was significantly improved by including the composition of the used electrolyte in the models. Furthermore, Shapley values identified the pulse frequency and the TiO2 concentration in the electrolyte as the most influential variables, with higher values leading to increased coating thickness. The residual analysis revealed a certain heteroscedasticity, which suggests the need for additional samples with high thickness to improve the accuracy of the model. This study reveals the potential of artificial intelligence (AI)-driven optimization in PEO processes, which could pave the way for more efficient and cost-effective industrial applications. The findings achieved further emphasize the significance of integrating interactions between variables, such as frequency and TiO2 concentration, into the design of processing operations.","PeriodicalId":10520,"journal":{"name":"Coatings","volume":"87 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141946357","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}
In this paper, a self-designed and enhanced thermovoltage measuring device was built to capture thermovoltage curves of 45 steel during continuous cooling. The phase zones of the thermovoltage curve were interpreted based on the Engel–Brewer electron theory and Fe-Fe3C phase diagram. The results show that the curve was stratified into three homogeneous phase zones and two-phase transition zones as follows: Zone Ι: single-phase austenite (A) zone; Zone III: austenite and ferrite (A+F) homogeneous phase zone; Zone V: ferrite and pearlite (P+F) homogeneous phase zone; Zone II: austenite to ferrite (A-F) phase transition zone; and Zone IV: austenite to pearlite (A-P) phase transition zone. Notably, the deflection point marked the transition temperature, which indicates that the thermovoltage curve can quantitatively characterize phase formation and transformation, as well as the phase transformation process. Furthermore, the sample was quenched at the measured ferrite phase transition temperature. Microstructure observations, electron probe microanalyzer (EPMA) and microhardness measurements corroborated our findings. Specifically, our experiments reveal ferrite precipitation first from the cold end at the phase transition temperature, leading to increased carbon content in adjacent austenite. The results of this study achieved the in situ characterization of bulk transformations during the materials heat treatment process, which expands the author’s research work conducted previously.
{"title":"Study on Characterization of Phase Transition in Continuous Cooling of Carbon Steel Using In Situ Thermovoltage Measurement","authors":"Qihui Wang, Kun Chen, Kejia Liu, Lianbo Wang, Yu Chu, Bichen Xie","doi":"10.3390/coatings14080980","DOIUrl":"https://doi.org/10.3390/coatings14080980","url":null,"abstract":"In this paper, a self-designed and enhanced thermovoltage measuring device was built to capture thermovoltage curves of 45 steel during continuous cooling. The phase zones of the thermovoltage curve were interpreted based on the Engel–Brewer electron theory and Fe-Fe3C phase diagram. The results show that the curve was stratified into three homogeneous phase zones and two-phase transition zones as follows: Zone Ι: single-phase austenite (A) zone; Zone III: austenite and ferrite (A+F) homogeneous phase zone; Zone V: ferrite and pearlite (P+F) homogeneous phase zone; Zone II: austenite to ferrite (A-F) phase transition zone; and Zone IV: austenite to pearlite (A-P) phase transition zone. Notably, the deflection point marked the transition temperature, which indicates that the thermovoltage curve can quantitatively characterize phase formation and transformation, as well as the phase transformation process. Furthermore, the sample was quenched at the measured ferrite phase transition temperature. Microstructure observations, electron probe microanalyzer (EPMA) and microhardness measurements corroborated our findings. Specifically, our experiments reveal ferrite precipitation first from the cold end at the phase transition temperature, leading to increased carbon content in adjacent austenite. The results of this study achieved the in situ characterization of bulk transformations during the materials heat treatment process, which expands the author’s research work conducted previously.","PeriodicalId":10520,"journal":{"name":"Coatings","volume":"55 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141885568","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 investigated the meteorological conditions leading to ice formation on wind turbines in a coastal mountainous area. An enhanced ice formation similarity criterion was developed for the experimental design, utilizing a scaled-down model of a 1.5 MW horizontal-axis wind turbine in icing wind tunnel tests. Three-dimensional ice shapes on the rotating blades were obtained and scanned using advanced 3D laser measurement technology. Post-processing of the scanned data facilitated the construction of solid models of the ice-covered blades. This study analyzed the maximum ice thickness, ice-covered area, and dimensionless parameters such as the maximum dimensionless ice thickness and dimensionless ice-covered area along the blade. Under the experimental conditions, the maximum ice thickness reached 0.5102 m, and the ice-covered area extended up to 0.5549 m2. The dimensionless maximum ice thickness and dimensionless ice-covered area consistently increased along the blade direction. Our analysis of 3D ice shape characteristics and the ice volume under different test conditions demonstrated that wind speed and the liquid water content (LWC) are critical factors affecting ice formation on blade surfaces. For a constant tip speed ratio, higher wind speeds and a greater LWC resulted in increased ice volumes on the blade surfaces. Specifically, increasing the wind speed can augment the ice volume by up to 57.2%, while increasing the LWC can enhance the ice volume by up to 149.2% under the experimental conditions selected in this study.
{"title":"Enhanced Analysis of Ice Accretion on Rotating Blades of Horizontal-Axis Wind Turbines Using Advanced 3D Scanning Technology","authors":"Zhen Lei, Yuxiao Dong, Qinghui Wang, Hailin Li, Yexue Han, Fang Feng","doi":"10.3390/coatings14080970","DOIUrl":"https://doi.org/10.3390/coatings14080970","url":null,"abstract":"This study investigated the meteorological conditions leading to ice formation on wind turbines in a coastal mountainous area. An enhanced ice formation similarity criterion was developed for the experimental design, utilizing a scaled-down model of a 1.5 MW horizontal-axis wind turbine in icing wind tunnel tests. Three-dimensional ice shapes on the rotating blades were obtained and scanned using advanced 3D laser measurement technology. Post-processing of the scanned data facilitated the construction of solid models of the ice-covered blades. This study analyzed the maximum ice thickness, ice-covered area, and dimensionless parameters such as the maximum dimensionless ice thickness and dimensionless ice-covered area along the blade. Under the experimental conditions, the maximum ice thickness reached 0.5102 m, and the ice-covered area extended up to 0.5549 m2. The dimensionless maximum ice thickness and dimensionless ice-covered area consistently increased along the blade direction. Our analysis of 3D ice shape characteristics and the ice volume under different test conditions demonstrated that wind speed and the liquid water content (LWC) are critical factors affecting ice formation on blade surfaces. For a constant tip speed ratio, higher wind speeds and a greater LWC resulted in increased ice volumes on the blade surfaces. Specifically, increasing the wind speed can augment the ice volume by up to 57.2%, while increasing the LWC can enhance the ice volume by up to 149.2% under the experimental conditions selected in this study.","PeriodicalId":10520,"journal":{"name":"Coatings","volume":"189 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141885624","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 : 2024-08-02DOI: 10.3390/coatings14080977
Chao Song, Jie Song, Xiang Wang
A room-temperature photoluminescence (PL) study of amorphous Si/amorphous silicon oxynitride multilayer films prepared by plasma-enhanced chemical vapor deposition is reported. The PL peak position can be tuned from 800 nm to 660 nm by adjusting the oxygen/nitride ratio in the a-SiOxNy:H sublayer. The Fourier transform infrared (FTIR) absorption spectra indicate that the shift of the PL peak position is accompanied by an increase in the Si-O-Si absorption peak’s intensity, which induces the structural disorder at the interface, resulting in an increase in band gap energy. The effects of size on the photoluminescence spectrum have been studied. As a result, it has been observed that the addition of oxygen atoms introduces a large number of localized states at the interface, causing a blue shift in the emission peak position. With an increase in oxygen atoms, the localized states tend to saturate, and the quantum phenomenon caused by the a-Si sublayer becomes more pronounced. It is found that, as the thickness of the a-Si sublayer decreases, the increase in the [O/N] ratio is more likely to cause an increase in disordered states, leading to a decrease in luminescence intensity. For a-Si/a-SiOxNy:H samples with thinner a-Si sublayers, an appropriate value of [O/N] is required to achieve luminescence enhancement. When the value of [O/N] is one, the enhanced luminescence is obtained. It is also suggested that the PL originates from the radiative recombination in the localized states’ T3- level-related negatively charged silicon dangling bond in the band tail of the a-Si:H sublayer embedded in an a-Si/a-SiOxNy:H multilayer structure.
{"title":"Interface and Size Effects of Amorphous Si/Amorphous Silicon Oxynitride Multilayer Structures on the Photoluminescence Spectrum","authors":"Chao Song, Jie Song, Xiang Wang","doi":"10.3390/coatings14080977","DOIUrl":"https://doi.org/10.3390/coatings14080977","url":null,"abstract":"A room-temperature photoluminescence (PL) study of amorphous Si/amorphous silicon oxynitride multilayer films prepared by plasma-enhanced chemical vapor deposition is reported. The PL peak position can be tuned from 800 nm to 660 nm by adjusting the oxygen/nitride ratio in the a-SiOxNy:H sublayer. The Fourier transform infrared (FTIR) absorption spectra indicate that the shift of the PL peak position is accompanied by an increase in the Si-O-Si absorption peak’s intensity, which induces the structural disorder at the interface, resulting in an increase in band gap energy. The effects of size on the photoluminescence spectrum have been studied. As a result, it has been observed that the addition of oxygen atoms introduces a large number of localized states at the interface, causing a blue shift in the emission peak position. With an increase in oxygen atoms, the localized states tend to saturate, and the quantum phenomenon caused by the a-Si sublayer becomes more pronounced. It is found that, as the thickness of the a-Si sublayer decreases, the increase in the [O/N] ratio is more likely to cause an increase in disordered states, leading to a decrease in luminescence intensity. For a-Si/a-SiOxNy:H samples with thinner a-Si sublayers, an appropriate value of [O/N] is required to achieve luminescence enhancement. When the value of [O/N] is one, the enhanced luminescence is obtained. It is also suggested that the PL originates from the radiative recombination in the localized states’ T3- level-related negatively charged silicon dangling bond in the band tail of the a-Si:H sublayer embedded in an a-Si/a-SiOxNy:H multilayer structure.","PeriodicalId":10520,"journal":{"name":"Coatings","volume":"23 1","pages":""},"PeriodicalIF":3.4,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141885567","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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