Journal articles on the topic 'Coatings'
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1
Dunčková, Lucia, Tatiana Durmeková, and Renáta Adamcová. "Factors Affecting the Efficiency of Hydrophobic Coatings—Experience from Application on Sandstone." Applied Sciences 14, no. 11 (May 25, 2024): 4541. http://dx.doi.org/10.3390/app14114541.
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Protecting stone on facades or exterior art works from deterioration is primarily about protecting them from rainwater. Hydrophobic coatings are widely used for this purpose. Here, two factors affecting the long-term efficiency of some coatings applied on stones were investigated: the number of coating layers and the curing time after their application. Tests of water absorption by capillarity, absorption at total immersion in water, and a visual check of the penetration depth have been carried out. The coating’s efficiency coefficient Cef was defined as the ratio of the maximum water absorption of a treated sample to an untreated one. Two commercial silicon-based coatings were applied on the highly porous Hořice sandstone alternatively. Curing times of 2 days vs. 2 weeks, and 2 coating layers vs. 3 layers were compared. The experiments showed that the coating’s efficiency is affected more by the curing time than by the number of applied coating layers. The curing time of 2 days after coating’s application is too short, but 2 weeks proved to be sufficient for both tested coatings. There was no big difference regarding the number of coating layers; two layers seem to be sufficient if a long rain-free curing time can be guaranteed.
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Renner, Peter, Ajinkya Raut, and Hong Liang. "High-Performance Ni-SiC Coatings Fabricated by Flash Heating." Lubricants 10, no. 3 (March 14, 2022): 42. http://dx.doi.org/10.3390/lubricants10030042.
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In this research, a novel flash heating coating application technique was utilized to create Ni-SiC coatings on carbon steel substrates with SiC contents much higher than is achievable using certain conventional coating techniques. Hardness profiles showed that the coatings improved the substrate by as much as 121%, without affecting the substrate. Tribotests showed that the wear performance was improved by as much as 4.7× in terms of the wear rate (mm3/N·m) for the same coating when using an Al2O3 counterpart. Pure SiC coatings as a reference were also fabricated. However, the SiC coatings experienced elemental diffusion of Fe from the carbon steel substrate into the coating during fabrication. This occurred due to the increased heat input required for pure SiC to fuse to the substrate compared to the Ni-SiC coatings and resulted in decreased tribological performance. Diffusion of Fe into the coating weakened the coating’s hardness and reduced the resistance to wear. It was concluded that ceramic–metallic composite coatings can successfully be fabricated utilizing this novel flash heating technique to improve the wear resistance of ceramic counterparts.
3
Zhang, Dawei, Haiyang Li, Xiaoli Chen, Hongchang Qian, and Xiaogang Li. "Effect of Surface Microstructures on Hydrophobicity and Barrier Property of Anticorrosive Coatings Prepared by Soft Lithography." Advances in Materials Science and Engineering 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/342184.
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Enhancing the hydrophobicity of organic coatings retards their interaction with water and often leads to better protectiveness over metal corrosion. In this study, a soft lithography method was used to prepare epoxy coatings which showed surface microstructures in high replication to sandpapers. The effect of microstructures on coating’s hydrophobicity and barrier property was investigated. Compared to flat coatings, the microstructured coatings showed much higher water contact angles, which further increased with finer sandpapers. Determined by electrochemical impedance spectroscopy (EIS), the flat coating exhibited a higher anticorrosive performance than the microstructured coatings. With the use of finer sandpaper, the groove size of the corresponding microstructured coating was reduced. And a lower anticorrosive performance was observed since more defects might be formed in a given area of coating during the imprinting process. As the groove size of the coatings was further decreased to 5.7 µm, the microstructures became too small for water to easily penetrate through. Therefore, trapped air acted as an additional barrier and contributed to an increased anticorrosive performance compared to other microstructured coatings.
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Xu, Zhong Ping, Wen Li Han, Ying Ying Zhang, and Bei Bei Xie. "Study on Epoxy Coating which Could Be Applied on High Temperature (70°C) Steel Surface." Applied Mechanics and Materials 159 (March 2012): 311–16. http://dx.doi.org/10.4028/www.scientific.net/amm.159.311.
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When common epoxy coatings were applied directly on high temperature (usually about 70°C) steel surface, some defects would occur in coating film, such as bubbles, pinholes, loosen and poor quality flow leveling property, etc. These defects lead to reduction in coating’s adhesion, physical properties and anti-penetrability, shorten service life of coatings greatly, making coating losing their protection function. Main reasons for those defects were analyzed briefly in this paper. In high temperature environment, solvents or other volatile organic compounds (VOC) in coatings will volatilize faster than in normal temperature environment, coating may undergo poor quality flow leveling properties, which couldn’t be fixed by itself. Research and development of a new type epoxy coating were introduced in this paper. Several methods were proposed, including selecting suitable resins, adding high boiling point solvent into coating, using leveling agent and other additives. After these modifications, coating’s construction adaptability was improved and could be applied directly on high temperature steel surface. The scanning electron microscopy (SEM) results show that the coating film prepared in high temperature condition have equivalent fine structure with film prepared in normal condition. The physical properties, anti-penetrability and anti-corrosion were also discussed in this paper
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Thunaipragasam, Selvakumaran, Aniket Bhanudas Kolekar, Koli Gajanan Chandrashekhar, Rohit Pandey, Mohammad Shahid, K. Rajesh, P. Ragupathi, Asheesh Kumar, and Balkeshwar Singh. "Investigation of Mechanical Behavior and Surface Characteristics of Cold Spray Metallized B4C/AA7075 Composites Coated by AZ64 Alloy through Plasma Electrolytic Oxidation." Journal of Nanomaterials 2023 (April 20, 2023): 1–11. http://dx.doi.org/10.1155/2023/7267093.
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Metallized cold-spray coatings were employed to make B4C/AA7075 and aluminum + plasma electrolytic oxidation (PEO) duplex coatings on AZ64. In addition, the phase structure, mechanical characteristics, wear, and PEO ceramic coatings examine the corrosion resistance. According to the findings, the PEO ceramic coating comprises α-aluminum oxide and γ-aluminum oxide, with some remnants of B4C still being preserved. PEO ceramic coatings outperformed their corresponding CS counterparts regarding mechanical characteristics and wear resistance. For example, the PEO-B4C coating achieved a hardness of 13.8 GPa and an elastic modulus of 185.5 GPa, which were 21.0% and 23.5%, respectively, more significant than the comparable values for the coating with CS. The PEO-B4C coating was 58% and 15.7% less abrasive than the equivalent CS coating due to its lower wear rate of 4.84 × 10−5 mm3/Nm and relatively lower of 0.64. The density of corrosion current in the PEO-treated B4C-AA7075 coating (3.735 × 106 A/cm2) is similar to the corrosion current density in the untreated CS coatings. Finally, compared to untreated CS B4C-AA7075, the coating’s mechanical characteristics and wear resistance are considerably enhanced by the PEO treatment.
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Chen, Xuanyu, Hao Wang, Cancan Liu, Wenqiang Wang, and Bo Chen. "Influence of Additives on the Macroscopic Color and Corrosion Resistance of 6061 Aluminum Alloy Micro-Arc Oxidation Coatings." Materials 17, no. 11 (May 29, 2024): 2621. http://dx.doi.org/10.3390/ma17112621.
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In this study, we successfully employed the plasma electrolytic oxidation (PEO) technique to create a uniform white ceramic layer on the surface of the 6061 aluminum alloy using K2ZrF6 and Na2WO4 as colorants. A scanning electron microscope (SEM) equipped with an energy-dispersive X-ray spectrometer (EDS) and X-ray diffraction (XRD) were used to characterize the coatings, and we used an electrochemical workstation to test their corrosion protection properties. The corrosion resistance of the coatings was analyzed using potentiodynamic polarization curves. The results showed that K2ZrF6 addition whitened the coating with ZrO2 as the main phase composition, inhibiting Al substrate depletion and enhancing coating corrosion resistance. A small amount of Na2WO4 decreased the coating’s L* value, successfully constructing ceramic coatings with L* (coating brightness) values ranging from 70 to 86, offering broad application prospects for decorative coatings.
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Wang, Zhanying, Ying Ma, and Yushun Wang. "Effect of V2O5 Additive on Micro-Arc Oxidation Coatings Fabricated on Magnesium Alloys with Different Loading Voltages." Metals 10, no. 9 (August 25, 2020): 1146. http://dx.doi.org/10.3390/met10091146.
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Effect of V2O5 additive in silicate-containing electrolyte on AZ91D magnesium alloys treated by micro-arc oxidation (MAO) technology under different loading voltages was investigated. The results showed that vanadium was well up-taken into the coating chemically. Moreover, a new phase of MgV2O4 with spinel structure was obtained in MAO coatings due to V2O5 added into the electrolyte. The MgV2O4 phase was responsible for the coatings exhibiting brown color and also was beneficial to improving the anti-corrosion property. In spotting tests, the corrosion resistances of coatings prepared under the high voltage are about 6–9 times higher than those of the low voltage because of the thicker coatings of the former. In potentiodynamic polarization tests, the coatings’ corrosion resistances were improved with the addition of V2O5, which was more significant under the low voltage than that under the high voltage. When the concentration of V2O5 was 0.2 g/L, the corrosion current density of the coating was the lowest, which means that the coating’s corrosion resistance under the low voltage is the best. Hence, it is necessary to carry out targeted design of the coating’s microstructure according to the different applications.
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Shen, Xuehui, Hao Peng, Yunna Xue, Baolin Wang, Guosheng Su, Jian Zhu, and Anhai Li. "Microstructure and Properties of WC/Ni-Based Laser-Clad Coatings with Different WC Content Values." Materials 15, no. 18 (September 11, 2022): 6309. http://dx.doi.org/10.3390/ma15186309.
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The purpose of this work is to investigate the effect of the WC content on the surface characteristics and nanoindentation behaviors of WC/Ni-based composite laser-clad coatings. Four NiCrSiBC coatings with WC wt% of 30%, 40%, 50%, and 60%, respectively, were clad on carbon steel substrates using a laser. The morphologies and phase compositions of four clad coatings were comparatively observed. In addition, the hardness and elastic modulus values of the four coatings were measured and quantitatively calculated. As a result, with the increase in WC, the coating grains were more refined. Meanwhile, cracks and WC particle breakage occurred in the 50–60% WC coatings, whereas this was not found in the 30–40% WC coatings. When the WC content increased from 40% up to 50%, the coating hardness and elastic modulus significantly increased. However, a further increase in WC from 50% to 60% did not result in considerable improvement in coating quality but considerably worsened the coating’s cracking behavior instead. Therefore, for WC/Ni-based composite coatings, a threshold exists for the WC content, and this value was 50% within the experimental scope of this study.
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Luzin, Vladimir, ANdrew Vackel, Alfredo Valarezo, and Sanjay Sampath. "Neutron Through-Thickness Stress Measurements in Coatings with High Spatial Resolution." Materials Science Forum 905 (August 2017): 165–73. http://dx.doi.org/10.4028/www.scientific.net/msf.905.165.
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A great variety of techniques are nowadays used to spray coatings with different functionality and properties for the purpose of surface enhancement. Depending on application and design, these can be thermal (plasma or high-velocity oxy-fuel are the most widely used) and warm or cold spraying, which are known to generate considerable residual stresses. This stress is a function of the spaying process as well as the material and thickness of the coating-substrate system. The mechanical integrity of coatings is critical for certain applications, e.g. wear resistant and thermal-barrier coatings, hence residual stress control and mitigation are essential in preventing the coating’s mechanical failure, improving the coating’s performance and the its operational lifetime. Although hole drilling technique or x-ray diffraction combined with layer removal method can be applicable for stress measurements in coatings, the neutron diffraction stress analysis also provides an effective and efficient tool for non-destructive through-thickness stress measurements with a commensurately high resolution, down to 0.1-0.2 mm. The most recent results of neutron diffraction stress measurements in coating systems are presented herein.
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Shu, Xiaoyong, Hao Wang, and Jianping Zhao. "Microstructures and Corrosion Behaviors of Non-Equiatomic Al0.32CrFeTi0.73(Ni1.50−xMox)(x = 0, 0.23) High-Entropy Alloy Coatings Prepared by the High-Velocity Oxygen Fuel Method." Coatings 14, no. 7 (July 20, 2024): 907. http://dx.doi.org/10.3390/coatings14070907.
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The non-equiatomic Al0.32CrFeTi0.73(Ni1.50−xMox) (x = 0, 0.23) high-entropy alloy (HEA) coatings were prepared by the high-velocity oxygen fuel (HVOF) method. The microstructures and corrosion behaviors of the HVOF-prepared coatings were investigated. The corrosion behaviors were characterized by polarization, EIS and Mott-Schottky tests under a 3.5 wt.% sodium chloride aqueous solution open to air at room temperature. The Al0.32CrFeTi0.73Ni1.50 coating is a simple BCC single-phase solid solution structure compared with the corresponding poly-phase composite bulk. The structure of the Al0.32CrFeTi0.73Ni1.27Mo0.23 coating, combined with the introduction of the Mo element, means that the (Cr,Mo)-rich sigma phase precipitates out of the BCC solid solution matrix phase, thus forming Cr-depleted regions around the sigma phases. The solid solution of large atomic-size Mo element causes the lattice expansion of the BCC solid solution matrix phase. Micro-hole and micro-crack defects are formed on the surface of both coatings. The growth of both coatings’ passivation films is spontaneous. Both passivation films are stable and Cr2O3-rich, P-type, single-layer structures. The Al0.32CrFeTi0.73Ni1.50 coating has better corrosion resistance and much less pitting susceptibility than the corresponding bulk. The corrosion type of the Mo-free coating is mainly pitting, occurring in the coating’s surface defects. The Al0.32CrFeTi0.73Ni1.27Mo0.23 coating with the introduction of Mo element increases pitting susceptibility and deteriorates corrosion resistance compared with the Mo-free Al0.32CrFeTi0.73Ni1.50 coating. The corrosion type of the Mo-bearing coating is mainly pitting, occurring in the coating’s surface defects and Cr-depleted regions.
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Li, Ying, Bian Xiao Li, and Wen Jun Zou. "The Relationship between Nanocrystalline Structure and Frictional Properties of Nanodiamond/Ni Composite Coatings by Brush Plating." Applied Mechanics and Materials 80-81 (July 2011): 683–87. http://dx.doi.org/10.4028/www.scientific.net/amm.80-81.683.
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Nanodiamond/Ni and Ni coatings were fabricated via brush plating. Nanocrystalline structure of the composite coating was investigated by SEM and XRD. The results showed that the composite coatings are nanocrystalline structure. The hardness of the nanodiamond/Ni composite coating is higher greatly than that of Ni coating. At same time, the reasons of formation nanocrystalline were discussed, which include the nucleation rate with the increase of a high over-potential, the reciprocating motion between brush and work piece, the heterogeneous nucleation of nanodiamond. The nanodiamonds as second phases make grain finer. The nanodiamonds of core-shell structure play the important role in wear resistance and antifriction. So the wear resistance of the composite coatings is significantly higher than nickel coating’s.
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Chen, Cheng Zhou, Wei Ze Wang, and Kai Di Cheng. "A Comparative Study on the Wear and Corrosion Resistance of Coatings." Applied Mechanics and Materials 853 (September 2016): 441–45. http://dx.doi.org/10.4028/www.scientific.net/amm.853.441.
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The vessel containing sulfur particles has been found failing due to the effect of corrosion and erosion by the sulfur particles. Several coatings, including zinc-aluminum coating, wear-resistance painting and two kinds of polymer, have been provided to resist the negative influence of sulfur in the present study. The wear and corrosion resistance of the selected coatings has been measured to study the performance difference. Impact test has also been done to investigate the bonding condition of coatings under the impact or bending load. The microstructure of coatings before and after wear test is observed by the Optical Microscope (OM) and Scanning Electron Microscope (SEM). The experiment results reveal that one of the polymer coatings shows the best performance in the corrosion resistance, another polymer coating’s wear resistance is better than others. The coatings are bonded well with the substrate except the zinc-aluminum coating. The performance of painting is ordinary in this investigation.
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Kubicki, Grzegorz, Volf Leshchynsky, Ahmed Elseddawy, Maria Wiśniewska, Roman G. Maev, Jarosław Jakubowicz, and Joanna Sulej-Chojnacka. "Microstructure and Properties of Hydroxyapatite Coatings Made by Aerosol Cold Spraying–Sintering Technology." Coatings 12, no. 4 (April 15, 2022): 535. http://dx.doi.org/10.3390/coatings12040535.
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Hydroxyapatite is a widely used material used for the bioactivation of an implant’s surface. A promising hydroxyapatite coating approach is the kinetic deposition of powder particles. The possibility of solid-state deposition improvement through the merging of Aerosol Deposition and Low Pressure Cold Spraying techniques is a promising prospect for improving the deposition efficiency and the quality of coatings. The objective of the paper is to study the possibilities of hydroxyapatite coating structure modification through changes in the coating process and post-heat treatment. The novel Aerosol Cold Spraying system joining Low Pressure Cold Spraying and Aerosol Deposition was used for the deposition of coatings. The coating’s post-processing was conducted using two techniques: Spark Plasma Sintering and Pressureless Sintering. The coating’s structure was examined using scanning, transmission, and light microscopy, and X-ray diffraction. Substrate–coating bond strength was assessed using a tensile test. Homogenous buildup using Aerosol Cold Spraying of hydroxyapatite was achieved. Various pores and microcracks were visible in the sprayed coatings. The deposition process and the thermal post-processing did not lead to significant degradation of the hydroxyapatite phase. As a result of the Spark Plasma Sintering and Pressureless Sintering at 800 °C, an increase in tensile adhesion bond strength and crystal size was obtained.
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Pawłowski, Łukasz, Michał Bartmański, Aleksandra Mielewczyk-Gryń, and Andrzej Zieliński. "Effects of Surface Pretreatment of Titanium Substrates on Properties of Electrophoretically Deposited Biopolymer Chitosan/Eudragit E 100 Coatings." Coatings 11, no. 9 (September 15, 2021): 1120. http://dx.doi.org/10.3390/coatings11091120.
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The preparation of the metal surface before coating application is fundamental in determining the properties of the coatings, particularly the roughness, adhesion, and corrosion resistance. In this work, chitosan/Eudragit E 100 (chit/EE100) were fabricated by electrophoretic deposition (EPD) and both their microstructure and properties were investigated. The present research is aimed at characterizing the effects of the surface pretreatment of titanium substrate, applied deposition voltage, and time on physical, mechanical, and electrochemical properties of coatings. The coating’s microstructure, topography, thickness, wettability, adhesion, and corrosion behavior were examined. The applied process parameters influenced the morphology of the coatings, which affected their properties. Coatings with the best properties, i.e., uniformity, proper thickness and roughness, hydrophilicity, highest adhesion to the substrate, and corrosion resistance, were obtained after deposition of chit/EE100 coating on nanotubular oxide layers produced by previous electrochemical oxidation.
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Poza, Pedro, Paloma Sirvent, Álvaro Rico, Claudio J. Múnez, and Miguel Ángel Garrido. "Oscillating Contact Wear in Cold Sprayed Ti6Al4V Coatings for Aeronautical Repairs." Materials Science Forum 941 (December 2018): 1686–91. http://dx.doi.org/10.4028/www.scientific.net/msf.941.1686.
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Ti6Al4V coatings were cold sprayed onto the same bulk alloy using standard conditions and a set of parameters developed to improve the coating’s performance. In addition, the enhanced coating was heat treated to improve coating adhesion and reduce porosity. Wear tests were performed, onto the coatings and the substrate, in oscillating conditions, which simulate wear induced by the contact with bearing parts during vibration. Wear behaviour at room temperature is dominated by a mixed mechanism, which involves plastic deformation and transference from the counterbody forming mechanically mixed layers. As temperature is increased, the formation of mechanically mixed layers dominates wear. The wear resistance of the enhanced coatings is similar to the bulk alloy, or even better in some conditions. Consequently, cold sprayed improved coatings could be used for repairing titanium components from the contact wear point of view.
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Han, Yan, Xiaoxing Yan, and Yu Tao. "Effect of Transparent, Purple, and Yellow Shellac Microcapsules on Properties of the Coating on Paraberlinia bifoliolata Surface." Polymers 14, no. 16 (August 13, 2022): 3304. http://dx.doi.org/10.3390/polym14163304.
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In order to explore the applicability of the waterborne coating with self-repairing microcapsules based on the surface of wood boards and specify the optimal range of microcapsule content in the coating, three different kinds of shellac microcapsules (transparent shellac, purple shellac, and yellow shellac) were embedded in a waterborne acrylic coating at 0, 1.5 wt.%, 3.0 wt.%, 4.5 wt.%, 6.0 wt.%, and 7.5 wt.%. The Beli wood (Paraberlinia bifoliolata) boards were then covered with self-repairing coatings to investigate the self-repairing coating’s physical and chemical properties, aging resistance, and scratch repair abilities. The findings demonstrated that the chromatic difference and gloss of surface coatings on Beli wood boards were significantly influenced by the content of microcapsules. The optical characteristics and cold liquid resistance performance of the coating on Beli wood were enhanced when the microcapsule content was 3.0 wt.%. Additionally, the mechanical qualities of the coating with 3.0 wt.% transparent shellac microcapsules on Beli wood surface were better, with an H hardness, grade 2 adhesion, and 8 kg·cm of impact strength. The studies on scratch repairing and aging resistance indicated that microcapsules helped to slow down the coating’s damage and retard aging. After a microcrack appeared, the waterborne coating with microcapsules on Beli wood’s surface had the capacity to repair itself. After aging, the coating with 3.0 wt.% transparent shellac microcapsule on Beli wood boards had a better performance on the comprehensive properties, with a 28.9% light loss rate and a 6 kg·cm impact resistance. It also had a 25.0% repairing rate in scratch width after being damaged for 5 d. This study advances the development of self-healing waterborne coatings on the wood board with shellac microcapsules by examining the effects of shellac in various colors and shellac microcapsule content in waterborne coatings.
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Gao, Jin, Wen Juan Yuan, Xiao Gang Li, Ying Chao Li, and Wei Zhu. "Electrochemical Analysis of the Fluorocarbon Anticorrosion Coating after Accelerated Weathering Environment Aging." Advanced Materials Research 239-242 (May 2011): 563–66. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.563.
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Fluorocarbon coating was exposed to artificial weathering environment produced by the xenon lamp/condensation weathering equipment for different time periods. The degradation process was studied by electrochemical impedance spectroscopy (EIS), Fourier Transform Infrared Spectrometry (FTIR) and optical microscope. The results show that the resistance of the coatings decrease ，while the capacitance and soakage become larger with the increase of the aging time. This demonstrates that the early aging of the coating influences its protective properties for the corrosion medium. The reason is the changes of the coating’s surface state and chemical structure accelerate the penetration of medium into the coatings, and therefore accelerate the corrosion of metal occurs under the coating.
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Jensen, Rielle, Zoheir Farhat, Md Aminul Islam, and George Jarjoura. "Effect of Coating Thickness on Wear Behaviour of Monolithic Ni-P and Ni-P-NiTi Composite Coatings." Solids 3, no. 4 (November 1, 2022): 620–42. http://dx.doi.org/10.3390/solids3040039.
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Protective coatings can prolong the lifespan of engineering components. Electroless Ni-P coating is a very hard coating with high corrosion resistance, but low toughness. The addition of NiTi nanoparticles into the coating has shown the potential to increase the toughness of electroless Ni-P and could expand its usability as a protective coating for more applications. However, the study of the tribological behaviour and wear mechanisms of Ni-P-NiTi composite coating has been minimal. Furthermore, there is no studies on the effect of coating thickness on monolithic and composite electroless Ni-P coating wear behaviour. The wear rates of each coating were found by measuring the volume loss form multi-pass wear tests. The wear tracks were examine using a confocal microscope to observe the wear mechanisms. Each sample was tested using a spherical indenter and sharp indenter. It was found that the NiTi nanoparticle addition displayed toughening mechanisms and did improve the coating’s wear resistance. The 9 μm thick Ni-P-NiTi coating had less cracking and more uniform wear than the 9 μm thick Ni-P coating. For both the monolithic and composite coatings, their thicker version had higher wear resistance than their thinner counterpart. This was explained by the often observed trend in coatings where it has higher tensile stress near the substrate interface, which decreases and becomes compressive as thickness increases. Overall, the 9 μm thick Ni-P-NiTi coating had the highest wear resistance out of all the coatings tested.
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Yao, Ying Xue, Li Qun Li, and Jian Jun Xi. "Preparation and Performance of Ceramic Coatings Formed by Micro Arc Oxidation on Titanium Alloy." Key Engineering Materials 375-376 (March 2008): 323–27. http://dx.doi.org/10.4028/www.scientific.net/kem.375-376.323.
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The effect of technological parameters on MAO ceramic coating were investigated through the technique of micro-arc oxidation (MAO) on TC4 titanium alloy and. Microstructure and morphology of coatings were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The result shows that electric parameters and compositions of the electrolyte have notable effects on the growth of MAO ceramic coatings. The cathodic and anodic voltage rise gradually with the oxidation time increasing. The growth rate of ceramic coating is fast at the beginning, and then turns slowly. The ceramic coatings can be divided into three layers from interior to exterior, such as the transition layer, the dense layer and the porous layer. The coating is mainly composed of rutile and anatase and combined with the substrate firmly. The ceramic coating’s composition in inner and outer layers appears quite different. The ceramic coating on titanium alloy is of excellent performance on anti-attrition and anti-corrosion.
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Mingying, Xiao, Xiu Qiang, and Jiang Fengchun. "Effect of Copper Addition on the Phase Composition and Microstructure Evolution of Fe-Based Amorphous Alloy Coatings Prepared by Laser Cladding." Advances in Materials Science and Engineering 2022 (April 25, 2022): 1–7. http://dx.doi.org/10.1155/2022/3511432.
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Laser clad coating’s susceptibility to cracking is extremely high due to the brittleness of the material itself and the enormous residual stress caused by rapid heating and cooling. In order to relieve the residual stress, a series of Fe-based amorphous-Cu composite coatings were fabricated on 20 steel using laser processing. The effects of copper addition on the phase composition and microstructure evolution of the coatings were then investigated. The as-prepared coatings, which are mainly composed of Fe-based amorphous, Cu, and (Fe, Cr)23 (C, B)6 have a network microstructure. A large amount of spherical-shaped copper metal is present in the coating and is evenly dispersed within the amorphous matrix. The copper in the coating has little effect on the crystallisation of Fe-based amorphous alloys due to the negligible solubility of solid copper and the Fe-based amorphous alloy. The coating average hardness reduces considerably and shows a significant difference, improving the coating stress distribution.
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Mingying, Xiao, Xiu Qiang, and Jiang Fengchun. "Effect of Copper Addition on the Phase Composition and Microstructure Evolution of Fe-Based Amorphous Alloy Coatings Prepared by Laser Cladding." Advances in Materials Science and Engineering 2022 (April 25, 2022): 1–7. http://dx.doi.org/10.1155/2022/3511432.
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Laser clad coating’s susceptibility to cracking is extremely high due to the brittleness of the material itself and the enormous residual stress caused by rapid heating and cooling. In order to relieve the residual stress, a series of Fe-based amorphous-Cu composite coatings were fabricated on 20 steel using laser processing. The effects of copper addition on the phase composition and microstructure evolution of the coatings were then investigated. The as-prepared coatings, which are mainly composed of Fe-based amorphous, Cu, and (Fe, Cr)23 (C, B)6 have a network microstructure. A large amount of spherical-shaped copper metal is present in the coating and is evenly dispersed within the amorphous matrix. The copper in the coating has little effect on the crystallisation of Fe-based amorphous alloys due to the negligible solubility of solid copper and the Fe-based amorphous alloy. The coating average hardness reduces considerably and shows a significant difference, improving the coating stress distribution.
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Abakah, Randy, Feng Huang, Qian Hu, Yicong Wang, and Jing Liu. "Comparative Study of Corrosion Properties of Different Graphene Nanoplate/Epoxy Composite Coatings for Enhanced Surface Barrier Protection." Coatings 11, no. 3 (March 1, 2021): 285. http://dx.doi.org/10.3390/coatings11030285.
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Loading of graphene to polymeric materials has proven a widespread increase in the corrosion properties of nanocomposites. In this study, graphene nanoplatelets (Gnps)/epoxy composite coatings were prepared by incorporating three commercial graphene nanoparticles (C750, M15, and X50 Gnps) into epoxy resin. The morphological impact of the Gnps on the surface barrier protection were evaluated in terms of coating’s adhesion to the substate, hydrophobicity and water uptake performance. Salt spray resistance and Electrochemical Impedance Spectroscopy (EIS) authenticated that the coating integrated with C750 Gnp remarkably improved the anti-corrosion performance of neat epoxy composite coatings. A robust passive layer and surface barrier characteristics formed by the composite coatings incorporated with C750 nanoparticle should be the main reason for better protection properties offered by C750 Gnp/epoxy nanocomposites. At the same time, homogeneous dispersion and lesser agglomerates in C750 Gnp/epoxy composite coatings mainly contributed to the coating’s excessive corrosion resistance.
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Dodaran, Mohammad S., Jian Wang, Nima Shamsaei, and Shuai Shao. "Investigating the Interaction between Persistent Slip Bands and Surface Hard Coatings via Crystal Plasticity Simulations." Crystals 10, no. 11 (November 6, 2020): 1012. http://dx.doi.org/10.3390/cryst10111012.
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Fatigue cracks often initiate from the surface extrusion/intrusions formed due to the operation of persistent slip bands (PSBs). Suppression of these surface topographical features by hard surface coatings can significantly extend fatigue lives under lower stress amplitudes (i.e., high cycle fatigue), while cracks initiate early in the coating or in the coating–substrate interface under higher stress amplitudes (i.e., low cycle fatigue), deteriorating the fatigue performance. However, both beneficial and detrimental effects of the coatings appear to be affected by the coating–substrate material combination and coating thickness. A quantitative understanding of the role of these factors in the fatigue performance of materials is still lacking. In this study, crystal plasticity simulations were employed to elucidate the dependence of the coating’s effects on two factors—i.e., the coating thickness and loading amplitudes. The results revealed that the thicker coatings more effectively suppress the operation of the PSBs, but generate higher tensile and shear stresses, normal and parallel to the interfaces, respectively, promoting interfacial delamination. The tensile stresses parallel to the interface within the coating, which favors coating fracture, are not sensitive to the coating thickness.
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Jensen, Rielle, Zoheir Farhat, Md Aminul Islam, and George Jarjoura. "Erosion–Corrosion of Novel Electroless Ni-P-NiTi Composite Coating." Corrosion and Materials Degradation 4, no. 1 (February 8, 2023): 120–41. http://dx.doi.org/10.3390/cmd4010008.
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The lifespan of low-carbon steel petroleum pipelines can often be shortened by the erosion–corrosion damage caused by their service conditions. Applying electroless Ni-P coating is a promising option to protect the steel from the environment due to its high hardness and corrosion resistance. However, electroless Ni-P has a low toughness but can be increased by the addition of NiTi ductile particles. This work produced electroless Ni-P and Ni-P-NiTi coatings of different thicknesses on AISI 1018 substrates and compared their erosion, corrosion, and erosion–corrosion behaviors. The methodology involved conducting slurry pot erosion–corrosion tests on AISI 1018 steel substrate, the monolithic Ni-P coatings, and the composite Ni-P-NiTi coatings. Erosion resistance was highly influenced by coating thickness, presumably because of the relationship between the erosion-induced compressive stresses and the coating’s as-plated internal stresses. The NiTi nanoparticle addition was highly effective at improving the erosion–corrosion resistance of the coating. Pitting corrosion and cracking were present after erosion–corrosion on the monolithic Ni-P coatings. However, the Ni-P-NiTi composite coating had a relatively uniform material loss. Overall, the AISI 1018 steel substrate had the worst erosion–corrosion resistance and 25 μm thick Ni-P-NiTi coating had the best.
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Zhao, Daming, Kaifeng Cheng, Baiyang Chen, Peihu Gao, Qiaoqin Guo, Hao Cheng, Anton Naumov, Qiao Li, and Wenjie Kang. "Investigation of Impact of C/Si Ratio on the Friction and Wear Behavior of Si/SiC Coatings Prepared on C/C-SiC Composites by Slurry Reaction Sintering and Chemical Vapor Infiltration." Coatings 14, no. 1 (January 13, 2024): 108. http://dx.doi.org/10.3390/coatings14010108.
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Carbon/carbon (C/C)-SiC composite materials have a series of outstanding advantages, such as a light weight, resistance to thermal degradation, excellent friction performance, and good stability in complex environments. In order to improve the wear resistance of the C/C-SiC composite matrix, Si/SiC coatings were prepared by a combination of chemical vapor infiltration and reactive sintering. The wear performance of Si/SiC coatings with different amounts of silicon carbide was investigated. When the carbon silicon ratio in the slurry was 1:3, the SiC particle content in the coating was 93.0 wt.%; the prepared Si/SiC coating exhibited the lowest wear rate of 3.2 × 10−3 mg·N−1·m−1 among the four coatings; and its frictional coefficient was 0.95, which was higher than that of the substrate. As the residual Si content in the coating decreased, the continuity between SiC particles in the coating was improved. Both the high hardness of SiC and the dense coating contributed significantly to enhancing the coating’s wear resistance.
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Yuan, Xue Tao, Zhi Qiang Hua, Lei Wang, Dong Bai Sun, and Song Lin Chen. "Effect of Nano-Al2O3 Particles on the NiP/nano-Al2O3 Coatings’ Properties." Applied Mechanics and Materials 66-68 (July 2011): 1668–75. http://dx.doi.org/10.4028/www.scientific.net/amm.66-68.1668.
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Composite coatings were prepared using electroless nickel bath containing different concentrations of Al2O3nano-particles. The analyses of coating compositions, carried out by EDS, showed that there is marginal difference between phosphorus contents of NiP and NiP/nano-Al2O3deposits. The structure of the coatings was examined by scanning electron microscopy (SEM), and X-ray diffraction (XRD). It has been found that the co-deposition of nano-Al2O3particles with Ni disturbs the NiP coating’s regular surface structure and increases its surface roughness. DC and AC electrochemical tests were carried out on such coatings in a 3.5wt.% solution of NaCl in order to evaluate their corrosion resistance. The potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests both showed that, the corrosion resistance of NiP-Al2O3coatings firstly increases and then decreases when Al2O3concentration in electroless bath is increasing, but the corrosion resistance of NiP-Al2O3composite coating is better than that of amorphous NiP coating.
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Szparaga, Łukasz, Przemysław Bartosik, Adam Gilewicz, Katarzyna Mydłowska, and Jerzy Ratajski. "Optimisation of Mechanical Properties of Gradient Zr–C Coatings." Materials 14, no. 2 (January 8, 2021): 296. http://dx.doi.org/10.3390/ma14020296.
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One of the key components of the designing procedure of a structure of hard anti-wear coatings deposited via Physical Vapour Deposition (PVD) is the analysis of the stress and strain distributions in the substrate/coating systems, initiated during the deposition process and by external mechanical loads. Knowledge of residual stress development is crucial due to their significant influence on the mechanical and tribological properties of such layer systems. The main goal of the work is to find the optimal functionally graded material (FGM) coating’s structure, composed of three functional layers: (1) adhesive layer, providing high adhesion of the coating to the substrate, (2) gradient load support and crack deflection layer, improving hardness and enhancing fracture toughness, (3) wear-resistant top layer, reducing wear. In the optimisation procedure of the coating’s structure, seven decision criteria basing on the state of residual stresses and strains in the substrate/coating system were proposed. Using finite element simulations and postulated criteria, the thickness and composition gradients of the transition layer in FGM coating were determined. In order to verify the proposed optimisation procedure, Zr-C coatings with different spatial distribution of carbon concentration were produced by the Reactive Magnetron Sputtering PVD (RMS PVD) method and their anti-wear properties were assessed by scratch test and ball-on-disc tribological test.
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Szparaga, Łukasz, Przemysław Bartosik, Adam Gilewicz, Katarzyna Mydłowska, and Jerzy Ratajski. "Optimisation of Mechanical Properties of Gradient Zr–C Coatings." Materials 14, no. 2 (January 8, 2021): 296. http://dx.doi.org/10.3390/ma14020296.
Full textAbstract:
One of the key components of the designing procedure of a structure of hard anti-wear coatings deposited via Physical Vapour Deposition (PVD) is the analysis of the stress and strain distributions in the substrate/coating systems, initiated during the deposition process and by external mechanical loads. Knowledge of residual stress development is crucial due to their significant influence on the mechanical and tribological properties of such layer systems. The main goal of the work is to find the optimal functionally graded material (FGM) coating’s structure, composed of three functional layers: (1) adhesive layer, providing high adhesion of the coating to the substrate, (2) gradient load support and crack deflection layer, improving hardness and enhancing fracture toughness, (3) wear-resistant top layer, reducing wear. In the optimisation procedure of the coating’s structure, seven decision criteria basing on the state of residual stresses and strains in the substrate/coating system were proposed. Using finite element simulations and postulated criteria, the thickness and composition gradients of the transition layer in FGM coating were determined. In order to verify the proposed optimisation procedure, Zr-C coatings with different spatial distribution of carbon concentration were produced by the Reactive Magnetron Sputtering PVD (RMS PVD) method and their anti-wear properties were assessed by scratch test and ball-on-disc tribological test.
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Li, Weiming, Ping Wang, Shaoqing Wang, Zhihong Duan, Lele Liu, Yimeng Wang, and Min Xu. "In Situ Synthesis of Graphene Oxide-Sealed LDHs Coatings: A Novel Approach to Enhancing Corrosion Resistance and Tribological Performance on Magnesium Alloys." Coatings 13, no. 9 (September 4, 2023): 1544. http://dx.doi.org/10.3390/coatings13091544.
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This study introduces an innovative approach to enhancing the corrosion resistance and tribological performance of magnesium alloys by in situ growing zinc-aluminum layered double hydroxide (ZnAl-LDHs) with graphene oxide (GO) sealing. Traditional LDHs coatings exhibit limitations in corrosion protection due to their porous structure. This paper advances the LDHs coating technology by integrating GO, forming a composite LDHs/GO coating on magnesium alloys. The novel incorporation of GO provides a unique two-layered defense system against corrosion: the GO layer serves as a high-resistance barrier to corrosive agents, while the LDHs layer absorbs NO3− ions, offering a secondary protection. The coating’s properties were meticulously characterized using techniques such as scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared (FTIR) Raman spectroscopy, electrochemical assays, and friction-wear tests. Experimental findings reveal that the synergistic action between LDHs and GO results in significant improvements in corrosion resistance and friction reduction. Specifically, GO’s adherence to the LDHs coating’s pores and its ability to transfer into the friction layer during wear significantly enhances the coating’s integrity and stability. The successful in situ synthesis of LDHs /GO coatings opens new horizons for composite coatings, with potential implications across various industrial applications.
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Kim, Sumin, Clare Chisu Byeon, and Sung Yeol Kim. "Electrochemical Response of Clay/Polyelectrolyte Composite Barrier Coatings." Coatings 10, no. 12 (November 30, 2020): 1173. http://dx.doi.org/10.3390/coatings10121173.
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Composite materials made of polymer and clay are effective at blocking mass transport. In this study, the blocking efficacy of layer-by-layer (LbL) coatings of exfoliated montmorillonite (MMT) and polyethylenimine (PEI) was studied using cyclic voltammetry and a redox couple, indigo carmine (IC). The pH of the MMT solution was varied from 4 to 10 to prepare LbL coatings of different surface roughness on metal substrates. It was found that the coated electrode had a lower redox peak current value than without the coating, demonstrating the reduction of the mass transport of IC to the metal surface. The peak values decreased with decreasing the coating’s roughness and increasing the number of layers, indicating that the blocking capability can be controlled by changing the deposition conditions. Smooth LbL coatings deposited with MMT at pH 4 showed the highest blocking efficacy up to 97.5%. The IC adsorbed at the interface between the coating and the metal substrate was found to cause the peak current measured for the coated electrode. It was also confirmed that the same coating on the copper substrate reduced the corrosion of the copper during the electrochemical potential cycling.
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Прохоров, В. М., Е. В. Гладких, Л. А. Иванов, В. В. Аксененков, and А. Н. Кириченко. "Состав, структура и механические свойства (Ti-Hf)N-покрытий на титановом сплаве." Журнал технической физики 89, no. 5 (2019): 704. http://dx.doi.org/10.21883/jtf.2019.05.47472.173-18.
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AbstractVariations of the composition, structure, and mechanical properties (hardness, elastic modulus) of (Ti–Hf)N coatings with increasing Hf content (Ti : Hf ratio) are reported. As test samples, VT6 titanium alloy plates covered by a magnetron-sputtered titanium hafnium nitride coating have been taken. To see how the coating characteristics depend on Hf content, samples with rated compositions (Ti_0.9Hf_0.1)N, (Ti_0.85Hf_0.15)N, (Ti_0.8Hf_0.2)N, and (Ti_0.7Hf_0.3)N have been studied. The surface and depth element distributions have been found, and the phase composition and the dependence of the titanium nitride lattice parameter on Hf content in the coating have been determined. The depth profiling of a coating’s hardness and elastic modulus has been conducted by instrumental indentation. Hardness and elastic modulus have been found to be maximal (~35 and ~500 GPa, respectively) in (Ti_0.85Hf_0.15)N and (Ti_0.8Hf_0.2)N coatings. In addition, the depth distribution of Hf in these coatings has turned out to be most uniform.
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Koochaki, Mohammad Sadegh, Gelareh Momen, Serge Lavoie, and Reza Jafari. "Enhancing Icephobic Coatings: Exploring the Potential of Dopamine-Modified Epoxy Resin Inspired by Mussel Catechol Groups." Biomimetics 9, no. 6 (June 8, 2024): 349. http://dx.doi.org/10.3390/biomimetics9060349.
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A nature-inspired approach was employed through the development of dopamine-modified epoxy coating for anti-icing applications. The strong affinity of dopamine’s catechol groups for hydrogen bonding with water molecules at the ice/coating interface was utilized to induce an aqueous quasi-liquid layer (QLL) on the surface of the icephobic coatings, thereby reducing their ice adhesion strength. Epoxy resin modification was studied by attenuated total reflectance infrared spectroscopy (ATR-FTIR) and nuclear magnetic resonance spectroscopy (NMR). The surface and mechanical properties of the prepared coatings were studied by different characterization techniques. Low-temperature ATR-FTIR was employed to study the presence of QLL on the coating’s surface. Moreover, the freezing delay time and temperature of water droplets on the coatings were evaluated along with push-off and centrifuge ice adhesion strength to evaluate their icephobic properties. The surface of dopamine-modified epoxy coating presented enhanced hydrophilicity and QLL formation, addressed as the main reason for its remarkable icephobicity. The results demonstrated the potential of dopamine-modified epoxy resin as an effective binder for icephobic coatings, offering notable ice nucleation delay time (1316 s) and temperature (−19.7 °C), reduced ice adhesion strength (less than 40 kPa), and an ice adhesion reduction factor of 7.2 compared to the unmodified coating.
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Kucharska, Barbara, and Mariola Spalik. "The Effect of Al and Si Additions on the Resistance Properties of Magnetron-Deposited FeCrNi Coatings." Solid State Phenomena 223 (November 2014): 137–45. http://dx.doi.org/10.4028/www.scientific.net/ssp.223.137.
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The PVD magnetron sputtering method is one of the most efficient methods enabling the spraying of the multi-component materials and almost unlimited setting of the chemical composition of coatings. The micro-and nanocrystalline coating structure favours the selective diffusion of chromium and other alloy additions that form compact oxide layers. The paper presents the study of coatings made in the process of magnetron sputtering of AISI310S grade chromium-nickel steel. The study covered coatings of the steel's composition with additions of 2-5% Si and of 2-5% Al. The resistance of the coatings at temperatures induced by electric current flow was assessed. The coatings provided a resistance element in the electric circuit, and the measurementof their temperature was made by the voltage drop indirect method. It was found that the steel coatings had a resistance of 0.176 Ω within the entire range of testing temperature, and their failure occurred at a temperature of 350°C due to cracking and delamination from the substrate. Introducing the Si or Al addition to the coatings resulted in an increase in coating resistance and temperature stability, respectively, to 450 and 400°C. Changes of coating’s phase composition and texture were not found. The resistance of the coatings with the Al and Si additions decreased with temperature due to their oxidation.
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Zhou, Hong, and Cheng Peng. "Effect of Shroud in Plasma Spraying on Chemical Composition and Thickness of Titanium Coatings." Coatings 11, no. 4 (April 13, 2021): 446. http://dx.doi.org/10.3390/coatings11040446.
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Titanium and its alloys are wildly used in industries. Shrouded plasma spray can be considered as a useful technology to produce low oxide containing titanium coatings. In this paper, the effect of shroud in plasma spraying on chemical composition and thickness of titanium coatings were investigated. Shrouded plasma-sprayed titanium coatings were deposited onto mild steel substrates. Air plasma-sprayed titanium coatings were also deposited for comparison under the same spraying parameters. Those titanium coatings were then studied in terms of microstructure, oxygen and nitrogen contents and coating’s thickness. The titanium coatings were assessed by scanning electron microscopy and quantitative chemical analysis. The results showed that the shroud played a key role in protecting the particles from oxidation in flight. The shrouded titanium coatings exhibited lower oxygen content and an enhanced microstructure. The reduction in air entrainment with the shroud resulted in better heating of the particles and increases in deposition efficiency and coating thickness.
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Yin, Yan Zi, Ji Hui Wang, Han Li, Jiu Xiao Sun, Heng Tian, and Yun Dong Ji. "The Preliminary Research on the Coating of FBG Embedded in Composites used in Large Aircraft." Advanced Materials Research 239-242 (May 2011): 540–43. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.540.
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The optical fibers with epoxy acrylates and urethane acrylates UV-curable coatings were embedded in composites. It’s found that after high-temperature heated, when the coating’s glass transition temperature was higher than the heating temperature, the microstructure of the coating would not change, but when the coating’s glass transition temperature was lower than the heating temperature, the coating would detached from optical fiber. FBG (fiber Bragg grating) sensors with coating and naked FBG (without coating) sensors were embedded in composite materials to monitor impacting damage. It was found that when the coating broke away from the optical fiber which was embedded in the composites, the sensitivity of the FBG sensors would reduce.
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Houdková, Šárka, and Eva Smazalová. "The Influence of High Temperature Exposure on the Wear of Selected HVOF Sprayed Coatings." Defect and Diffusion Forum 368 (July 2016): 55–58. http://dx.doi.org/10.4028/www.scientific.net/ddf.368.55.
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The influence of high temperature exposure on the mechanical and wear properties of selected HVOF sprayed CrC and No/Co – based alloy coatings were tested. Comparison of as-sprayed and 600°C/116 h annealed coatings’ microhardness, cohesive strength, abrasive and adhesive wear resistance showed that the Co-based Stellite 6 coating’s wear properties were deteriorated by heat exlosure despite of the increase of its hardness and cohesive strength. The heat exposure was found to be beneficial for both mechanical and wear properties of NiCrBSi self-fluxing coating. On the contrary, mechanical properties of Cr3C2-NiCr coating slightly decreased, while its wear resistance slightly increased as a result of high temperature exposure.
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Pei, He Zhong, Pan Huang, Qing Nan Shi, Guo Liang Zhang, and Xue Li. "Research to the Corrosion Resistance of the Alkaline Zinc-Nickel Alloy Plates." Advanced Materials Research 616-618 (December 2012): 1756–61. http://dx.doi.org/10.4028/www.scientific.net/amr.616-618.1756.
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The zinc-nickel alloy coatings were electrodeposited by changing the concentration of the NiSO4 • 6H2O in the plating bath. The scanning electron microscopy (SEM) was used to observe the coating’s surface morphology. The EDS was applied to test the coating’s nickel content. The corrosion resistance was studied by using the Tafel curves, AC impedance spectra and the neutral salt spray test. The results showed that: The coating’s nickel content could reach 12.56% when the NiSO4 • 6H2O concentration was 8g/L in the bath and the coating was very smooth, dense and bright. Its corrosion potential was low and its corrosion reaction resistance was best with red rust time up to 46d, so it had good corrosion resistance. But when the NiSO4 • 6H2O concentration was changed, the coatings’ corrosion resistance would be more or less changed.
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Dhakal, Dhani Ram, Young Uk Han, Byung Geon Lee, Tae Ho Kim, Gi Bum Jang, and Sung Youl Cho. "Wear Resistance Behavior of Low-, Mid-, and High-Phosphorus Electroless Ni-P Coatings Heat-Treated in the Air Environment." Coatings 14, no. 5 (May 20, 2024): 648. http://dx.doi.org/10.3390/coatings14050648.
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The high-temperature heat treatment of electroless nickel–phosphorus (Ni-P) coatings in an air environment, and its consequences have scarcely been investigated. This work investigated tribological characteristics of the high-temperature, heat-treated, electroless Ni-P coatings on steel substrates with low-, mid-, and high-phosphorus content for which the average phosphorus content was 2.4 wt.%, 7.1 wt.%, and 10.3 wt.%, respectively. X-ray fluorescence and energy dispersive spectroscopy were implemented to determine the phosphorus content of the coatings. The oxidation of Ni and the formation of the NiO layer on the coating surface was confirmed by the X-ray diffraction technique. A reciprocating sliding method on a ball-on-flat system was utilized to evaluate the coating’s friction and wear behavior. Among the coatings with varying phosphorus content, a high hardness of 1086 HV was found for high-phosphorus coating when heat-treated at 400 °C in an air environment, and that was decreased to 691 HV when heat-treated at 650 °C. The oxidation of nickel in the electroless Ni-P coating occurred when heat-treated at 400 °C in an air environment, and this phenomenon was increased more when the temperature was increased to 650 °C. The characteristics of the NiO layer that formed on the surface of the heat-treated electroless Ni-P coating were influenced by the concentration of phosphorus, which caused different colors of NiO to be seen on the Ni-P coating surface. A greenish black NiO layer on the low-phosphorus and black NiO layer on the mid- and high-phosphorus Ni-P coating was developed during heat treatment at 650 °C in an air atmosphere. The adhesion and tribological characteristics of the Ni-P coatings were affected by the NiO layer developed on the heat-treated Ni-P coating surfaces. The Ni-P coatings with mid- and high-phosphorus content showed enhanced wear-resistance characteristics when they underwent heat treatment in an air atmosphere at the high temperature of 650 °C. The wear volume obtained for as-plated mid-phosphorus and high-phosphorus Ni-P coatings was 0.111 mm3 and 0.128 mm3, respectively, and that was reduced to 0.031 mm3 and 0.051 mm3, respectively, after the high-temperature heat treatment.
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Yu, Youwei, Kunyu Liu, Shaoying Zhang, Liangliang Zhang, Jiaqi Chang, and Ziyu Jing. "Characterizations of Water-Soluble Chitosan/Curdlan Edible Coatings and the Inhibitory Effect on Postharvest Pathogenic Fungi." Foods 13, no. 3 (January 30, 2024): 441. http://dx.doi.org/10.3390/foods13030441.
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This study focused on developing a composite coating comprising water-soluble chitosan (CTS) and curdlan (CUR). Cherry tomatoes served as the test material for assessing the preservative efficacy of these coatings. The incorporation of CUR markedly enhanced the coating’s surface properties, refined its molecular structure, and improved its tensile strength and elongation at break. Additionally, the coating demonstrated enhanced permeability to water vapor, oxygen, and carbon dioxide and improved light transmission. The storage experiment, conducted at 25 ± 1 °C with a relative humidity of approximately 92% over 10 days, revealed that the CTS/CUR composite coating at a 1:1 ratio significantly outperformed the individual CTS or CUR coating and uncoated samples in maintaining the quality of postharvest cherry tomatoes. The 1:1 CTS/CUR composite coating demonstrated superior preservative effects. This study suggested that water-soluble chitosan/curdlan composite coatings have considerable potential for use in the preservation of postharvest fruits and vegetables.
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Han, Yan, Xiaoxing Yan, and Yu Tao. "Effect of Number of Impregnations of Microberlinla sp with Microcapsule Emulsion on the Performance of Self-Repairing Coatings on Wood Surfaces." Coatings 12, no. 7 (July 14, 2022): 989. http://dx.doi.org/10.3390/coatings12070989.
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Embedding melamine-formaldehyde (MF) resin-coated shellac microcapsules in waterborne coatings can extend the service longevity of waterborne coatings on a wood surface to a certain extent. Due to the content limitation of self-repairing microcapsules in waterborne coatings, the effective self-healing performance time is short. With the aim of improving the self-repairing properties of self-repairing coatings on the surface of a Microberlinla sp substrate, a more effective self-healing mechanism was achieved by impregnating the ebony wood substrate several times with an MF resin-coated transparent shellac-rosin microcapsule emulsion. After the impregnation of the ebony boards with microcapsules, a waterborne acrylic resin coating containing 3.0 wt.% transparent shellac microcapsules was applied to the surface of the wood boards. The influence of the number impregnations on the surface coating’s physical properties, chemical properties, and self-repairing properties was explored. The results showed that the hardness of the surface coating on the ebony boards changed little under different numbers of impregnations. With the increasing number of impregnations, the surface coatings’ adhesion and impact strength slowly increased, the chromatic difference value was increased, and the roughness first increased and then decreased. Impregnating ebony boards with the microcapsule emulsion contributes to enhancing the aging resistance and repair performance of surface coatings on the ebony boards. When the number of impregnations was eight, the width change rate of cracks on surface self-healing coatings was 28.4%, which suggested the best repair performance among all samples. By impregnating the wood substrate with the self-healing microcapsule emulsion, the effect of the interaction between microcapsules and wood on the self-repairing properties of the surface coating was studied, contributing to the theory for further improving the self-repairing properties of waterborne coatings on wood surfaces and promoting the application and development of self-healing microcapsules.
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Mohsin, Dhurgham, Haider Lieth, and Murtadha Jabbar. "Effect of Hexagonal Boron Nitride Nanoparticles Additions on Corrosion Resistance for Zinc Coatings of Weathering Steel in Rainwater." Basrah journal for engineering science 23, no. 1 (July 2, 2023): 64–71. http://dx.doi.org/10.33971/bjes.23.1.9.
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Zinc and its alloy coatings are commonly used to provide cathodic protection for weathering steel. However, the steel substrate corrodes faster than the Zinc coating because of the coating's negative corrosion potential. Many studies have examined Zinc and alloy coatings' resistance to corrosion. Hot-dip galvanizing, Electrodeposition, and Zinc-rich coat (ZRC) spray are just some of the methods that can be used to deposit such coatings. Commercially available 99.95 % pure Zinc oxide was used in the electroplating process in this investigation. Steel samples were plated in Zinc sulphate and Zinc oxide solutions and were controlled by different bath parameters such as voltage, current, pH, temperature, and coating time. The addition of hexagonal Boron Nitride (h-BN) nanoparticles has also shown significant improvements in corrosion resistance. However, Zinc-based coating techniques reinforced with h-BN incorporation show the best corrosion current density (Icorr) of Hot dip 2 % wt. (2.1 μA/cm2), ZRC 2.5 % wt., (4.4 μA/cm2), and electroplating 15.75 g/L (0.081 μA/cm2), which is an order of magnitude lower than coatings without h-BNs. The corrosion rates and current densities of Zn/h-BN coated layers were investigated in a controlled laboratory environment that mimicked natural conditions (Rainwater solution) by extrapolating polarization curves.
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Lille, Harri, Jakub Kõo, Andre Gregor, Alexander Ryabchikov, Fjodor Sergejev, Rainer Traksmaa, and Priit Kulu. "Comparison of Curvature and X-Ray Methods for Measuring of Residual Stresses in Hard PVD Coatings." Materials Science Forum 681 (March 2011): 455–60. http://dx.doi.org/10.4028/www.scientific.net/msf.681.455.
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Physical Vapour Deposition and PVD coatings are designed for several applications, from industrial to biomedical. Residual stresses, arising during coating deposition, have important effect on the coating’s service life as their influence to the mechanical and tribological properties. Our aim was to investigate the residual stresses in five different PVD coatings (TiN, TiCN, TiAlN, TiAlN, nc-(AlTi) N/α -Si3N4) (presence of the Ti as adhesion layer) by the layer growing curvature method and the X-ray diffraction techniques using a plate and a strip as the substrate. Residual stresses were compressive and very large (2.98 - 7.24) GPa in all coatings and comparable in TiN, TiAlN, TiAlN coatings in the case of both methods. The magnitude of residual stresses is influenced by intrinsic strain in the case of layer growth rather than by thermal stress.
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Ekaputri, Tyana Solichah, Ayuni Nur Apsari, and Takashi Tanaka. "Visualization of Commercial Coating Penetration into Fagus crenata Blume Wood Using a Non-Destructive X-ray Microtomography." Coatings 11, no. 8 (August 2, 2021): 927. http://dx.doi.org/10.3390/coatings11080927.
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Coatings can be used as a preservative method to protect the wood, especially the wood surface. The different component of the coating’s dependence of the purpose of it. The Japanese beech (Fagus crenata Blume) applied by several Japanese commercials coating materials. The coatings application used were spray type and brush type. X-ray microtomography in Fuji, Japan was used for visualized the coating samples. The X-ray target used were Cu, and Mo with Al filter. The X-ray image analysis in 2D and 3D were conducted using image J and VGStudio Max, respectfully. The coating’s containing materials and the concentration of it strongly affected the image result of X-ray microtomography visualization. The different X-ray target shows the different image results. The larger energy of X-ray (Mo with Al filter) is recommended to use for visualization. The X-ray images shows the penetration phenomena, which can be applied to calculate the penetration depth.
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Queant, Caroline, Pierre Blanchet, Véronic Landry, and Diane Schorr. "Effect of Adding UV Absorbers Embedded in Carbonate Calcium Templates Covered with Light Responsive Polymer into a Clear Wood Coating." Coatings 8, no. 8 (July 28, 2018): 265. http://dx.doi.org/10.3390/coatings8080265.
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The limited durability of clear coatings is a major issue for the coating and wood industry. The addition of organic UV absorbers improves coating resistance by the absorption and the conversion of the UV radiation into harmless heat. Organic UVAs are prone to degradation and can migrate in the binder of coatings. In this study, commercial UVAs and HALS have been entrapped into CaCO3 templates coated with stimuli responsive polymers. Microspheres were incorporated into a clear acrylic water-based coating formulation. The formulation was applied on glass and wood panels and was placed into an artificial UV chamber. This study presents a comparison between the aesthetic behavior of coating formulations with free and encapsulated commercial UVAs and HALS during the accelerated ageing test. Encapsulation of UVAs was confirmed by XPS and TGA analysis. Results have shown that the coating’s aesthetic was slightly improved when using the encapsulated products.
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Mehta, Amrinder, Hitesh Vasudev, Sharanjit Singh, Chander Prakash, Kuldeep K. Saxena, Emanoil Linul, Dharam Buddhi, and Jinyang Xu. "Processing and Advancements in the Development of Thermal Barrier Coatings: A Review." Coatings 12, no. 9 (September 9, 2022): 1318. http://dx.doi.org/10.3390/coatings12091318.
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Thermal barrier coating is critical for thermal insulation technology, making the underlying base metal capable of operating at a melting temperature of 1150 °C. By increasing the temperature of incoming gases, engineers can improve the thermal and mechanical performance of gas turbine blades and the piston cylinder arrangement. Recent developments in the field of thermal barrier coatings (TBCs) have made this material suitable for use in a variety of fields, including the aerospace and diesel engine industries. Changes in the turbine blade microstructure brought on by its operating environment determine how long and reliable it will be. In addition, the effectiveness of multi-layer, composite and functionally graded coatings depends heavily on the deposition procedures used to create them. This research aims to clarify the connection between workplace conditions, coating morphology and application methods. This article presents a high-level overview of the many coating processes and design procedures employed for TBCs to enhance the coating’s surface quality. To that end, this review is primarily concerned with the cultivation, processing and characteristics of engineered TBCs that have aided in the creation of specialized coatings for use in industrial settings.
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Kotnarowska, Danuta. "The Influence of Battery Acid on the Destruction of Acrylic Coatings of Car Bodies." Coatings 11, no. 8 (August 14, 2021): 967. http://dx.doi.org/10.3390/coatings11080967.
Full textAbstract:
Renovation coatings of car bodies undergo destruction under the influence of operational factors. Like ultraviolet radiation, erosion, and aggressive media (among others, battery acid). This article concerns the evaluation of the influence of battery acid on the destruction of acrylic coatings previously non-aged, as well as aged climatically for 2 years. Ageing of the coatings with battery acid contributed to a degradation increase of their chemical structure. It was supported by a considerable increase in the polar component of surface free energy (SFE) of the coatings. In the case of prior climate ageing, the increase in the polar component was even higher. Moreover, the coating’s ability to absorb battery acid increased, which induced blistering. The DSC method revealed that the action of battery acid caused more intense oxidation of coating material, and as a result, the brittleness increased, leading to chipping of the coating surface layers. This led to the increase in surface roughness, measured using an interferometric method. The coatings previously climatically aged for 2 years presented higher values of surface roughness parameters than the non-aged ones. The increase in the surface roughness contributed to a substantial decrease in the gloss of coatings. A sharp difference in colour escalating with the lengthening of the ageing period was also observed using the spectrophotometric method.
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Mabrouk, Ahmed, and Zoheir Farhat. "Novel Ni-P-Tribaloy Composite Protective Coating." Materials 16, no. 11 (May 25, 2023): 3949. http://dx.doi.org/10.3390/ma16113949.
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Oil and gas pipelines are subject to various forms of damage and degradation during their operation. Electroless Nickel (Ni-P) coatings are widely employed as protective coatings due to their ease of application and unique properties, including high wear and corrosion resistance. However, they are not ideal for protecting pipelines due to their brittleness and low toughness. Composite coatings of higher toughness can be developed through the co-deposition of second-phase particles into the Ni-P matrix. Tribaloy (CoMoCrSi) alloy possesses excellent mechanical and tribological properties making it a potential candidate for a high-toughness composite coating. In this study, Ni-P-Tribaloy composite coating consisting of 15.7 vol.% Tribaloy was successfully deposited on low-carbon steel substrates. Both the monolithic and the composite coatings were studied to evaluate the effect of the addition of Tribaloy particles. The micro-hardness of the composite coating was measured to be 6.00 GPa, 12% greater than that of the monolithic coating. Hertzian-type indentation testing was carried out to investigate the coating’s fracture toughness and toughening mechanisms. The 15.7 vol.% Tribaloy coating exhibited remarkably less severe cracking and higher toughness. The following toughening mechanisms were observed: micro-cracking, crack bridging, crack arrest, and crack deflection. The addition of the Tribaloy particles was also estimated to quadruple the fracture toughness. Scratch testing was performed to evaluate the sliding wear resistance under a constant load and a varying number of passes. The Ni-P-Tribaloy coating exhibited more ductile behavior and higher toughness, as the dominant wear mechanism was identified as material removal, as opposed to brittle fracture in the Ni-P coating.
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Han, Yan, and Xiaoxing Yan. "Effect of Silane Coupling Agent Modification on Properties of Brass Powder-Water-Based Acrylic Coating on Tilia europaea." Polymers 15, no. 6 (March 10, 2023): 1396. http://dx.doi.org/10.3390/polym15061396.
Full textAbstract:
Fine art coating is usually created by the combination of metal filler and water-based coatings, decorated to the surface of wood structures, furniture, and crafts. However, the durability of the fine art coating is limited by its weak mechanical qualities. In contrast, the metal filler’s dispersion and the coating’s mechanical properties can be significantly improved by the coupling agent molecule’s ability to bind the resin matrix with the metal filler. In this study, a brass powder-water-based acrylic coating was prepared, and three different silane coupling agents, 3-aminopropyltriethoxysilane (KH550), γ-(2,3-epoxypropoxy)propytrimethoxysilane (KH560), and γ-methacryloxypropyltrimethoxysilane (KH570), were used to modify the brass powder filler in orthogonal tests. The artistic effect and optical properties of the modified art coating induced by different proportions of brass powder, silane coupling agents, and pH were compared. The result demonstrated that the amount of brass powder and the kind of coupling agent used had a substantial impact on the coating’s optical characteristics. Our results also determined how three different coupling agents affected the water-based coating with varying brass powder contents. The findings indicated that 6% KH570 concentration and pH 5.0 were the ideal conditions for brass powder modification. Better overall performance of the art coating applied to the surface of the Basswood substrates was provided by adding 10% of the modified brass powder into the finish. It had a gloss of 20.0 GU, a color difference of 3.12, a color main wavelength of 590 nm, a hardness of HB, an impact resistance of 4 kg·cm, an adhesion of grade 1, and better liquid resistance and aging resistance. This technical foundation for the creation of wood art coatings promotes the application of art coatings on wood.
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Ctibor, Pavel, Micheala Kašparová, Jeremy Bellin, Emmanuel Le Guen, and František Zahálka. "Plasma Spraying and Characterization of Tungsten Carbide-Cobalt Coatings by the Water-Stabilized System WSP." Advances in Materials Science and Engineering 2009 (2009): 1–11. http://dx.doi.org/10.1155/2009/254848.
Full textAbstract:
Tungsten carbide-cobalt powders (WC-17wt% Co) were plasma sprayed by a water-stabilized system WSP. Experiments with variable feeding distances and spray distances were carried out. Thinner coatings were deposited on carbon steel substrates and thicker coatings on stainless steel substrates to compare different cooling conditions. Basic characterization of coatings was done by XRD, SEM, and light microscopy plus image analysis. Microhardness was measured on polished cross-sections. The main focus of investigation was resistance against wear in dry as well as wet conditions. The appropriate tests were performed with set-ups based on ASTM G65 and G75, respectively. The influence of spray parameters onto coating wear performance was observed. The results of mechanical tests were discussed in connection with changes of phase composition and with the quality of the coating's microstructure. The results show that for obtaining the best possible WC-17Co coating with WSP process, from the viewpoint of wear resistance, the desired parameters combination is long feeding distance combined with short spray distance.
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Wang, Xinsheng, and Zhiguo Xing. "Preparation and Properties of Composite Nanoceramic NiCrBSi-TiO2/WC(Co) Coatings." Coatings 10, no. 9 (September 8, 2020): 868. http://dx.doi.org/10.3390/coatings10090868.
Full textAbstract:
Using the supersonic plasma spraying (SPS) technique, the preparation of a NiCrBSi (Ni60) coating was achieved by adding nano TiO2 in Ni60 coating with WC ceramic particles. Ni60-TiO2 (Ni60T) and Ni60-TiO2/WC coating (Ni60TW) were successfully prepared. Results show that of the three, Ni60T had the best densification, the porosity of the Ni60T coating exhibited the best value of 1.3%, and also has a stronger hardness value of 890 HV. At the same time, the coating corrosion resistance, wear coefficient, and the wear morphology of Ni60T are superior to Ni60 and Ni60TW coatings. It is added TiO2 and ceramic WC(Co) in Ni-based spraying powder. The main purpose is for the nanoparticles to achieve the effect of refining the grain, which can greatly improve the coating’s hardness and toughness.