Pub Date : 2021-05-25DOI: 10.3390/COATINGS11060634
N. Attarzadeh, C. Ramana
Recently, a significant number of research projects have been directed towards designing and developing ceramic coatings for zirconium-based substrates due to their outstanding surface properties and utilization in modern technologies. The plasma electrolytic oxidation (PEO) coating is an environmentally friendly wet coating method that can be performed in a wide range of electrolytes. The surface characteristics of PEO coatings can be tailored by changing electrochemical parameters, electrolyte composition, and substrate alloying elements to adopt a conformal and adhesive PEO ceramic coating for the final demanding applications in chemical, electronics, and energy technologies. This review focuses on deriving a deeper fundamental understanding of the PEO growth mechanisms and the effect of process parameters on transient discharge behavior at breakdown, initiation, and growth of the oxide layer and incorporating species from the electrolyte. It highlights the fundamental microstructural properties associated with structural defects, phase transformation, and the role of additives.
{"title":"Plasma Electrolytic Oxidation Ceramic Coatings on Zirconium (Zr) and ZrAlloys: Part I—Growth Mechanisms, Microstructure, and Chemical Composition","authors":"N. Attarzadeh, C. Ramana","doi":"10.3390/COATINGS11060634","DOIUrl":"https://doi.org/10.3390/COATINGS11060634","url":null,"abstract":"Recently, a significant number of research projects have been directed towards designing and developing ceramic coatings for zirconium-based substrates due to their outstanding surface properties and utilization in modern technologies. The plasma electrolytic oxidation (PEO) coating is an environmentally friendly wet coating method that can be performed in a wide range of electrolytes. The surface characteristics of PEO coatings can be tailored by changing electrochemical parameters, electrolyte composition, and substrate alloying elements to adopt a conformal and adhesive PEO ceramic coating for the final demanding applications in chemical, electronics, and energy technologies. This review focuses on deriving a deeper fundamental understanding of the PEO growth mechanisms and the effect of process parameters on transient discharge behavior at breakdown, initiation, and growth of the oxide layer and incorporating species from the electrolyte. It highlights the fundamental microstructural properties associated with structural defects, phase transformation, and the role of additives.","PeriodicalId":22482,"journal":{"name":"THE Coatings","volume":"77 1","pages":"634"},"PeriodicalIF":0.0,"publicationDate":"2021-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78416422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-24DOI: 10.3390/COATINGS11060629
A. Shinkaryov, M. Cherkasova, I. Pelevin, D. Ozherelkov, S. V. Chernyshikhin, N. Kharitonova, A. Gromov, A. Nalivaiko
This work aims to study the possibility of using an electrostatic drum-type separator to prepare a powder with a narrow size distribution curve for usage in additive manufacturing. The size distributions of the uncoated commercial aluminum powders ASP-30, ASP-22, and ASP-5 were analyzed. It was shown that the powders ASP-30 and ASP-22 have similar asymmetric distributions with a SPAN of 1.480 and 1.756, respectively. ASP-5 powder, in turn, has a narrow distribution with a SPAN of 0.869. ASP-30 powder was chosen for further experiment because, traditionally, separators are used to classify large-sized materials with particle size more than 100 μm. The optimal mode of electrostatic classification was proposed for the selected powder. Various classification methods, including centrifugal and electrostatic, were compared. The powders before and after classification were studied by XRD, SEM, TEM, and TG–DSC analyses. The obtained results showed that electrostatic classification does not lead to the formation of coatings on the processed powders. Electrostatic separation effectively narrows the particle size distribution, making it a suitable and valuable method to classify initial powders for additive manufacturing.
{"title":"Aluminum Powder Preparation for Additive Manufacturing Using Electrostatic Classification","authors":"A. Shinkaryov, M. Cherkasova, I. Pelevin, D. Ozherelkov, S. V. Chernyshikhin, N. Kharitonova, A. Gromov, A. Nalivaiko","doi":"10.3390/COATINGS11060629","DOIUrl":"https://doi.org/10.3390/COATINGS11060629","url":null,"abstract":"This work aims to study the possibility of using an electrostatic drum-type separator to prepare a powder with a narrow size distribution curve for usage in additive manufacturing. The size distributions of the uncoated commercial aluminum powders ASP-30, ASP-22, and ASP-5 were analyzed. It was shown that the powders ASP-30 and ASP-22 have similar asymmetric distributions with a SPAN of 1.480 and 1.756, respectively. ASP-5 powder, in turn, has a narrow distribution with a SPAN of 0.869. ASP-30 powder was chosen for further experiment because, traditionally, separators are used to classify large-sized materials with particle size more than 100 μm. The optimal mode of electrostatic classification was proposed for the selected powder. Various classification methods, including centrifugal and electrostatic, were compared. The powders before and after classification were studied by XRD, SEM, TEM, and TG–DSC analyses. The obtained results showed that electrostatic classification does not lead to the formation of coatings on the processed powders. Electrostatic separation effectively narrows the particle size distribution, making it a suitable and valuable method to classify initial powders for additive manufacturing.","PeriodicalId":22482,"journal":{"name":"THE Coatings","volume":"9 1","pages":"629"},"PeriodicalIF":0.0,"publicationDate":"2021-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73915984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-21DOI: 10.3390/COATINGS11060612
Hao Yang, S. Lian, P. Chapon, Y. Song, J. Wang, Congkang Xu
Pulsed-radio frequency glow discharge optical emission spectrometry (Pulsed-RF-GDOES) has exhibited great potential for high resolution (HR) depth profiling. In this paper, the measured GDOES depth profile of 60 × Mo (3 nm)/B4C (0.3 nm)/Si (3.7 nm) was quantified by employing the newly extended Mixing-Roughness-Information depth (MRI) model. We evaluated the influences of the thickness and sputtering rate on the depth profile of very thin layers. We demonstrated that a method using the full width at half maximum (FWHM) value of the measured time-concentration profile for determining the sputtering rate and the corresponding thickness was not reliable if preferential sputtering took place upon depth profiling.
{"title":"Quantification of High Resolution Pulsed RF GDOES Depth Profiles for Mo/B4C/Si Nano-Multilayers","authors":"Hao Yang, S. Lian, P. Chapon, Y. Song, J. Wang, Congkang Xu","doi":"10.3390/COATINGS11060612","DOIUrl":"https://doi.org/10.3390/COATINGS11060612","url":null,"abstract":"Pulsed-radio frequency glow discharge optical emission spectrometry (Pulsed-RF-GDOES) has exhibited great potential for high resolution (HR) depth profiling. In this paper, the measured GDOES depth profile of 60 × Mo (3 nm)/B4C (0.3 nm)/Si (3.7 nm) was quantified by employing the newly extended Mixing-Roughness-Information depth (MRI) model. We evaluated the influences of the thickness and sputtering rate on the depth profile of very thin layers. We demonstrated that a method using the full width at half maximum (FWHM) value of the measured time-concentration profile for determining the sputtering rate and the corresponding thickness was not reliable if preferential sputtering took place upon depth profiling.","PeriodicalId":22482,"journal":{"name":"THE Coatings","volume":"67 1","pages":"612"},"PeriodicalIF":0.0,"publicationDate":"2021-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89874510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-20DOI: 10.3390/COATINGS11050610
S. Samal, O. Tyc, J. Cizek, Jakub Klecka, F. Lukáč, O. Molnárová, E. de Prado, Z. Weiss, J. Kopeček, L. Heller, P. Šittner, T. Chráska
Thick NiTi shape memory alloy coatings (300–500 µm) were produced on graphite and AISI 304 substrates by radio frequency inductively-coupled plasma spray technology (RF-ICP) from feedstock NiTi powders. Their microstructure as well as chemical and phase composition were characterized and a methodology for the characterization of functional shape memory properties of the thick coatings was developed. The coatings exhibited cubic to monoclinic martensitic transformation and shape memory effect. The presented results prove that NiTi coatings with functional thermomechanical properties can be easily produced on structural materials by RF-ICP. Further optimization will be needed to prepare NiTi coatings with better microstructural and chemical homogeneity.
{"title":"Fabrication of Thermal Plasma Sprayed NiTi Coatings Possessing Functional Properties","authors":"S. Samal, O. Tyc, J. Cizek, Jakub Klecka, F. Lukáč, O. Molnárová, E. de Prado, Z. Weiss, J. Kopeček, L. Heller, P. Šittner, T. Chráska","doi":"10.3390/COATINGS11050610","DOIUrl":"https://doi.org/10.3390/COATINGS11050610","url":null,"abstract":"Thick NiTi shape memory alloy coatings (300–500 µm) were produced on graphite and AISI 304 substrates by radio frequency inductively-coupled plasma spray technology (RF-ICP) from feedstock NiTi powders. Their microstructure as well as chemical and phase composition were characterized and a methodology for the characterization of functional shape memory properties of the thick coatings was developed. The coatings exhibited cubic to monoclinic martensitic transformation and shape memory effect. The presented results prove that NiTi coatings with functional thermomechanical properties can be easily produced on structural materials by RF-ICP. Further optimization will be needed to prepare NiTi coatings with better microstructural and chemical homogeneity.","PeriodicalId":22482,"journal":{"name":"THE Coatings","volume":"23 1","pages":"610"},"PeriodicalIF":0.0,"publicationDate":"2021-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90747526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-19DOI: 10.3390/COATINGS11050597
Hu Jie, Yaojia Ren, Qianli Huang, Hao He, Luxin Liang, Jingbo Liu, Rui-di Li, Hong Wu
Ti-23Nb (at.%) coatings on an NiTi alloy with metallurgical bonding were prepared by laser cladding (LC) technology using Ti-Nb mixture powders. The effects of laser processing parameters on the microstructure and mechanical properties of the coatings were systematically investigated and the corrosion resistance of the coatings was assessed. The coatings were composed of TiNb, (Ti, Nb)2Ni, and β-Nb phases. The coatings increased the hardness of the NiTi alloy by a combined strengthening effect of the eutectics and fine microstructure. The corrosion resistance of the coated part was improved. The coatings with great corrosion resistance could keep the coated parts inert in an aggressive environment, and effectively restrain the release of toxic Ni ions, which means that the Ti-Nb alloy coatings are likely to be used as a biomaterial for medical applications.
{"title":"Microstructure and Corrosion Behavior of Ti-Nb Coatings on NiTi Substrate Fabricated by Laser Cladding","authors":"Hu Jie, Yaojia Ren, Qianli Huang, Hao He, Luxin Liang, Jingbo Liu, Rui-di Li, Hong Wu","doi":"10.3390/COATINGS11050597","DOIUrl":"https://doi.org/10.3390/COATINGS11050597","url":null,"abstract":"Ti-23Nb (at.%) coatings on an NiTi alloy with metallurgical bonding were prepared by laser cladding (LC) technology using Ti-Nb mixture powders. The effects of laser processing parameters on the microstructure and mechanical properties of the coatings were systematically investigated and the corrosion resistance of the coatings was assessed. The coatings were composed of TiNb, (Ti, Nb)2Ni, and β-Nb phases. The coatings increased the hardness of the NiTi alloy by a combined strengthening effect of the eutectics and fine microstructure. The corrosion resistance of the coated part was improved. The coatings with great corrosion resistance could keep the coated parts inert in an aggressive environment, and effectively restrain the release of toxic Ni ions, which means that the Ti-Nb alloy coatings are likely to be used as a biomaterial for medical applications.","PeriodicalId":22482,"journal":{"name":"THE Coatings","volume":"13 1","pages":"597"},"PeriodicalIF":0.0,"publicationDate":"2021-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77142897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-19DOI: 10.3390/COATINGS11050599
H. Huang, Li Jiang, Yiyun Yao, Zhong Zhang, Zhanshan Wang, R. Qi
The laterally graded multilayer collimator is a vital part of a high-precision diffractometer. It is applied as condensing reflectors to convert divergent X-rays from laboratory X-ray sources into a parallel beam. The thickness of the multilayer film varies with the angle of incidence to guarantee every position on the mirror satisfies the Bragg reflection. In principle, the accuracy of the parameters of the sputtering conditions is essential for achieving a reliable result. In this paper, we proposed a precise method for the fabrication of the laterally graded multilayer based on a planetary motion magnetron sputtering system for film thickness control. This method uses the fast and slow particle model to obtain the particle transport process, and then combines it with the planetary motion magnetron sputtering system to establish the film thickness distribution model. Moreover, the parameters of the sputtering conditions in the model are derived from experimental inversion to improve accuracy. The revolution and rotation of the substrate holder during the final deposition process are achieved by the speed curve calculated according to the model. Measurement results from the X-ray reflection test (XRR) show that the thickness error of the laterally graded multilayer film, coated on a parabolic cylinder Si substrate, is less than 1%, demonstrating the effectiveness of the optimized method for obtaining accurate film thickness distribution.
{"title":"Controlling Film Thickness Distribution by Magnetron Sputtering with Rotation and Revolution","authors":"H. Huang, Li Jiang, Yiyun Yao, Zhong Zhang, Zhanshan Wang, R. Qi","doi":"10.3390/COATINGS11050599","DOIUrl":"https://doi.org/10.3390/COATINGS11050599","url":null,"abstract":"The laterally graded multilayer collimator is a vital part of a high-precision diffractometer. It is applied as condensing reflectors to convert divergent X-rays from laboratory X-ray sources into a parallel beam. The thickness of the multilayer film varies with the angle of incidence to guarantee every position on the mirror satisfies the Bragg reflection. In principle, the accuracy of the parameters of the sputtering conditions is essential for achieving a reliable result. In this paper, we proposed a precise method for the fabrication of the laterally graded multilayer based on a planetary motion magnetron sputtering system for film thickness control. This method uses the fast and slow particle model to obtain the particle transport process, and then combines it with the planetary motion magnetron sputtering system to establish the film thickness distribution model. Moreover, the parameters of the sputtering conditions in the model are derived from experimental inversion to improve accuracy. The revolution and rotation of the substrate holder during the final deposition process are achieved by the speed curve calculated according to the model. Measurement results from the X-ray reflection test (XRR) show that the thickness error of the laterally graded multilayer film, coated on a parabolic cylinder Si substrate, is less than 1%, demonstrating the effectiveness of the optimized method for obtaining accurate film thickness distribution.","PeriodicalId":22482,"journal":{"name":"THE Coatings","volume":"8 1","pages":"599"},"PeriodicalIF":0.0,"publicationDate":"2021-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73817050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-09DOI: 10.3390/COATINGS11050557
E. Kashkarov, B. Afornu, D. Sidelev, M. Krinitcyn, Veronica Gouws, A. Lider
Zirconium-based alloys have served the nuclear industry for several decades due to their acceptable properties for nuclear cores of light water reactors (LWRs). However, severe accidents in LWRs have directed research and development of accident tolerant fuel (ATF) concepts that aim to improve nuclear fuel safety during normal operation, operational transients and possible accident scenarios. This review introduces the latest results in the development of protective coatings for ATF claddings based on Zr alloys, involving their behavior under normal and accident conditions in LWRs. Great attention has been paid to the protection and oxidation mechanisms of coated claddings, as well as to the mutual interdiffusion between coatings and zirconium alloys. An overview of recent developments in barrier coatings is introduced, and possible barrier layers and structure designs for suppressing mutual diffusion are proposed.
{"title":"Recent Advances in Protective Coatings for Accident Tolerant Zr-Based Fuel Claddings","authors":"E. Kashkarov, B. Afornu, D. Sidelev, M. Krinitcyn, Veronica Gouws, A. Lider","doi":"10.3390/COATINGS11050557","DOIUrl":"https://doi.org/10.3390/COATINGS11050557","url":null,"abstract":"Zirconium-based alloys have served the nuclear industry for several decades due to their acceptable properties for nuclear cores of light water reactors (LWRs). However, severe accidents in LWRs have directed research and development of accident tolerant fuel (ATF) concepts that aim to improve nuclear fuel safety during normal operation, operational transients and possible accident scenarios. This review introduces the latest results in the development of protective coatings for ATF claddings based on Zr alloys, involving their behavior under normal and accident conditions in LWRs. Great attention has been paid to the protection and oxidation mechanisms of coated claddings, as well as to the mutual interdiffusion between coatings and zirconium alloys. An overview of recent developments in barrier coatings is introduced, and possible barrier layers and structure designs for suppressing mutual diffusion are proposed.","PeriodicalId":22482,"journal":{"name":"THE Coatings","volume":"42 1","pages":"557"},"PeriodicalIF":0.0,"publicationDate":"2021-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87153110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-09DOI: 10.3390/COATINGS11050558
E. Salca, T. Krystofiak, B. Lis, S. Hiziroglu
The objective of this study was to evaluate the glossiness of black alder wood (Alnus glutinosa L.) samples coated with two varnish types as a function of exposure to dry heat and artificial aging. The chemical resistance of the coated samples to cold liquids was also evaluated. Based on the findings in this work, it appears that the varnish types and their structural differences influenced the overall glossiness of the coated samples. The UV varnish exhibited higher gloss values than those coated with the water-borne product within the range of silky gloss and silky matte grades. The heat exposure influenced the surface glossiness of the UV-coated samples more than the samples coated with water-borne varnish. The overall gloss values of the samples decreased with the exposure time to artificial aging, resulting in no layer cracks. The cold household liquids left less visible traces on the surfaces and alcohol was found to be the strongest agent. This study could have practical applications in the furniture industry to produce value-added furniture units according to their specific conditions of indoor use.
{"title":"Glossiness Evaluation of Coated Wood Surfaces as Function of Varnish Type and Exposure to Different Conditions","authors":"E. Salca, T. Krystofiak, B. Lis, S. Hiziroglu","doi":"10.3390/COATINGS11050558","DOIUrl":"https://doi.org/10.3390/COATINGS11050558","url":null,"abstract":"The objective of this study was to evaluate the glossiness of black alder wood (Alnus glutinosa L.) samples coated with two varnish types as a function of exposure to dry heat and artificial aging. The chemical resistance of the coated samples to cold liquids was also evaluated. Based on the findings in this work, it appears that the varnish types and their structural differences influenced the overall glossiness of the coated samples. The UV varnish exhibited higher gloss values than those coated with the water-borne product within the range of silky gloss and silky matte grades. The heat exposure influenced the surface glossiness of the UV-coated samples more than the samples coated with water-borne varnish. The overall gloss values of the samples decreased with the exposure time to artificial aging, resulting in no layer cracks. The cold household liquids left less visible traces on the surfaces and alcohol was found to be the strongest agent. This study could have practical applications in the furniture industry to produce value-added furniture units according to their specific conditions of indoor use.","PeriodicalId":22482,"journal":{"name":"THE Coatings","volume":"26 1","pages":"558"},"PeriodicalIF":0.0,"publicationDate":"2021-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75689941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-08DOI: 10.3390/COATINGS11050553
Miao Pan, H. Huang, Wenzhi Chen, Shuai-Nan Li, Qin Xie, Feng Xu, Dongwei Wei, Jun Fang, Baodian Fan, L. Cai
In this paper, using the surface plasmon and Fabry–Perot (FP) cavity, the design of a symmetric silicon grating absorber is proposed. The time-domain finite difference method is used for simulation calculations. The basic unit structure is a dielectric grating composed of silicon dioxide, metal and silicon. Through the adjustment of geometric parameters, we have achieved the best of the symmetric silicon grating absorber. A narrowband absorption peak with an absorption rate greater than 99% is generated in the 3000–5000 nm optical band, and the wavelength of the absorption peak is λ = 3750 nm. The physical absorption mechanism is that silicon light generates surface plasmon waves under the interaction with incident light, and the electromagnetic field coupling of surface plasmon waves and light causes surface plasmon resonance, thereby exciting strong light response modulation. We also explore the influence of geometric parameters and polarization angle on the performance of silicon grating absorbers. Finally, we systematically study the refractive index sensitivity of these structures. These structures can be widely used in optical filtering, spectral sensing, gas detection and other fields.
{"title":"Design of Narrow-Band Absorber Based on Symmetric Silicon Grating and Research on Its Sensing Performance","authors":"Miao Pan, H. Huang, Wenzhi Chen, Shuai-Nan Li, Qin Xie, Feng Xu, Dongwei Wei, Jun Fang, Baodian Fan, L. Cai","doi":"10.3390/COATINGS11050553","DOIUrl":"https://doi.org/10.3390/COATINGS11050553","url":null,"abstract":"In this paper, using the surface plasmon and Fabry–Perot (FP) cavity, the design of a symmetric silicon grating absorber is proposed. The time-domain finite difference method is used for simulation calculations. The basic unit structure is a dielectric grating composed of silicon dioxide, metal and silicon. Through the adjustment of geometric parameters, we have achieved the best of the symmetric silicon grating absorber. A narrowband absorption peak with an absorption rate greater than 99% is generated in the 3000–5000 nm optical band, and the wavelength of the absorption peak is λ = 3750 nm. The physical absorption mechanism is that silicon light generates surface plasmon waves under the interaction with incident light, and the electromagnetic field coupling of surface plasmon waves and light causes surface plasmon resonance, thereby exciting strong light response modulation. We also explore the influence of geometric parameters and polarization angle on the performance of silicon grating absorbers. Finally, we systematically study the refractive index sensitivity of these structures. These structures can be widely used in optical filtering, spectral sensing, gas detection and other fields.","PeriodicalId":22482,"journal":{"name":"THE Coatings","volume":"15 1","pages":"553"},"PeriodicalIF":0.0,"publicationDate":"2021-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88541355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-05-08DOI: 10.3390/COATINGS11050554
R. Roncon, G. Borsoi, J. Parracha, I. Flores-Colen, R. Veiga, L. Nunes
External Thermal Insulation Composite Systems (ETICS) are constructive solutions widely used to increase the thermal insulation in new and retrofitted buildings. However, these systems can present several anomalies due to their constant exposure to weathering agents and anthropic factors. Water is generally the major cause of degradation. Thus, the application of water-repellent products can minimize the appearance of anomalies and increase the durability of the systems. In this paper, acrylic-based and siloxane-based hydrophobic products were applied to ETICS, with the aim of assessing the compatibility, effectiveness, and durability of these products. The moisture transport properties and mould susceptibility were assessed through laboratory tests on untreated and treated specimens. The durability of the hydrophobic treatments was also evaluated through artificial aging tests (heat-cold and freeze-thaw cycles). Results show that the protection products generally decreased water absorption, slightly decreased the drying rate, and presented adequate water vapor permeability. After aging, the products still had reasonable effectiveness and, with one exception, improved the water vapor diffusion of the systems. Additionally, ETICS underwent an alteration in the finishing coat (possible modification of the porosity) due to the aging cycles. No clear linear correlation was found between the contact angle values and water absorption results, evidencing the influence of other factors related to the composition of the water-repellent products.
{"title":"Impact of Water-Repellent Products on the Moisture Transport Properties and Mould Susceptibility of External Thermal Insulation Composite Systems","authors":"R. Roncon, G. Borsoi, J. Parracha, I. Flores-Colen, R. Veiga, L. Nunes","doi":"10.3390/COATINGS11050554","DOIUrl":"https://doi.org/10.3390/COATINGS11050554","url":null,"abstract":"External Thermal Insulation Composite Systems (ETICS) are constructive solutions widely used to increase the thermal insulation in new and retrofitted buildings. However, these systems can present several anomalies due to their constant exposure to weathering agents and anthropic factors. Water is generally the major cause of degradation. Thus, the application of water-repellent products can minimize the appearance of anomalies and increase the durability of the systems. In this paper, acrylic-based and siloxane-based hydrophobic products were applied to ETICS, with the aim of assessing the compatibility, effectiveness, and durability of these products. The moisture transport properties and mould susceptibility were assessed through laboratory tests on untreated and treated specimens. The durability of the hydrophobic treatments was also evaluated through artificial aging tests (heat-cold and freeze-thaw cycles). Results show that the protection products generally decreased water absorption, slightly decreased the drying rate, and presented adequate water vapor permeability. After aging, the products still had reasonable effectiveness and, with one exception, improved the water vapor diffusion of the systems. Additionally, ETICS underwent an alteration in the finishing coat (possible modification of the porosity) due to the aging cycles. No clear linear correlation was found between the contact angle values and water absorption results, evidencing the influence of other factors related to the composition of the water-repellent products.","PeriodicalId":22482,"journal":{"name":"THE Coatings","volume":"91 1","pages":"554"},"PeriodicalIF":0.0,"publicationDate":"2021-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80367372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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