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1
Xu, Zhong Ping, Wen Li Han, Ying Ying Zhang e Bei Bei Xie. "Study on Epoxy Coating which Could Be Applied on High Temperature (70°C) Steel Surface". Applied Mechanics and Materials 159 (marzo 2012): 311–16. http://dx.doi.org/10.4028/www.scientific.net/amm.159.311.
Testo completoAbstract (sommario):
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
2
Renner, Peter, Ajinkya Raut e Hong Liang. "High-Performance Ni-SiC Coatings Fabricated by Flash Heating". Lubricants 10, n. 3 (14 marzo 2022): 42. http://dx.doi.org/10.3390/lubricants10030042.
Testo completoAbstract (sommario):
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
Jensen, Rielle, Zoheir Farhat, Md Aminul Islam e George Jarjoura. "Effect of Coating Thickness on Wear Behaviour of Monolithic Ni-P and Ni-P-NiTi Composite Coatings". Solids 3, n. 4 (1 novembre 2022): 620–42. http://dx.doi.org/10.3390/solids3040039.
Testo completoAbstract (sommario):
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.
4
Thunaipragasam, Selvakumaran, Aniket Bhanudas Kolekar, Koli Gajanan Chandrashekhar, Rohit Pandey, Mohammad Shahid, K. Rajesh, P. Ragupathi, Asheesh Kumar e 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 (20 aprile 2023): 1–11. http://dx.doi.org/10.1155/2023/7267093.
Testo completoAbstract (sommario):
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.
5
Dunčková, Lucia, Tatiana Durmeková e Renáta Adamcová. "Factors Affecting the Efficiency of Hydrophobic Coatings—Experience from Application on Sandstone". Applied Sciences 14, n. 11 (25 maggio 2024): 4541. http://dx.doi.org/10.3390/app14114541.
Testo completoAbstract (sommario):
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.
6
Dodaran, Mohammad S., Jian Wang, Nima Shamsaei e Shuai Shao. "Investigating the Interaction between Persistent Slip Bands and Surface Hard Coatings via Crystal Plasticity Simulations". Crystals 10, n. 11 (6 novembre 2020): 1012. http://dx.doi.org/10.3390/cryst10111012.
Testo completoAbstract (sommario):
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.
7
Yin, Yan Zi, Ji Hui Wang, Han Li, Jiu Xiao Sun, Heng Tian e Yun Dong Ji. "The Preliminary Research on the Coating of FBG Embedded in Composites used in Large Aircraft". Advanced Materials Research 239-242 (maggio 2011): 540–43. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.540.
Testo completoAbstract (sommario):
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.
8
Zhu, Li Qun, Yan Bin Du, Zhen Xue e Ying Xu Li. "Structure and Anti-Corrosion of Tri-Layer Ni-P Amorphous Alloy Coating Prepared in the Same Bath". Materials Science Forum 546-549 (maggio 2007): 1805–8. http://dx.doi.org/10.4028/www.scientific.net/msf.546-549.1805.
Testo completoAbstract (sommario):
A tri-layer amorphous Ni-P alloy coating was prepared in the same bath by changing the temperatures and currents, followed by heat treament. We studied the behavior of corrosion-resistance of the tri-layer coating before and after heat-treatment at 360°C for different time in the 5% NaCl solution. The result showed that: the tri-layer amorphous Ni-P coating has the excellent performance of anti-corrosion compare with single electroless or electrodeposited Ni-P amorphous coating. The performance of anti-corrosion of the coating was improved by controlling the coating’s structure and the role of electrochemical protection. After being heat-treated at 360°C for 1 hour ,the coating’s structure changed from amorphous to crystalloid and the corrosion resistance of the heat-treated coatings was higher than as-plated tri-layer Ni-P coating.
9
Han, Yan, Xiaoxing Yan e Yu Tao. "Effect of Transparent, Purple, and Yellow Shellac Microcapsules on Properties of the Coating on Paraberlinia bifoliolata Surface". Polymers 14, n. 16 (13 agosto 2022): 3304. http://dx.doi.org/10.3390/polym14163304.
Testo completoAbstract (sommario):
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.
10
Zhao, Daming, Kaifeng Cheng, Baiyang Chen, Peihu Gao, Qiaoqin Guo, Hao Cheng, Anton Naumov, Qiao Li e 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, n. 1 (13 gennaio 2024): 108. http://dx.doi.org/10.3390/coatings14010108.
Testo completoAbstract (sommario):
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.
11
Li, Ying, Bian Xiao Li e 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 (luglio 2011): 683–87. http://dx.doi.org/10.4028/www.scientific.net/amm.80-81.683.
Testo completoAbstract (sommario):
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.
12
Gao, Jin, Wen Juan Yuan, Xiao Gang Li, Ying Chao Li e Wei Zhu. "Electrochemical Analysis of the Fluorocarbon Anticorrosion Coating after Accelerated Weathering Environment Aging". Advanced Materials Research 239-242 (maggio 2011): 563–66. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.563.
Testo completoAbstract (sommario):
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.
13
Yao, Ying Xue, Li Qun Li e Jian Jun Xi. "Preparation and Performance of Ceramic Coatings Formed by Micro Arc Oxidation on Titanium Alloy". Key Engineering Materials 375-376 (marzo 2008): 323–27. http://dx.doi.org/10.4028/www.scientific.net/kem.375-376.323.
Testo completoAbstract (sommario):
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.
14
Mingying, Xiao, Xiu Qiang e 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 (25 aprile 2022): 1–7. http://dx.doi.org/10.1155/2022/3511432.
Testo completoAbstract (sommario):
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.
15
Mingying, Xiao, Xiu Qiang e 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 (25 aprile 2022): 1–7. http://dx.doi.org/10.1155/2022/3511432.
Testo completoAbstract (sommario):
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.
16
Chen, Xuanyu, Hao Wang, Cancan Liu, Wenqiang Wang e Bo Chen. "Influence of Additives on the Macroscopic Color and Corrosion Resistance of 6061 Aluminum Alloy Micro-Arc Oxidation Coatings". Materials 17, n. 11 (29 maggio 2024): 2621. http://dx.doi.org/10.3390/ma17112621.
Testo completoAbstract (sommario):
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.
17
Yu, Youwei, Kunyu Liu, Shaoying Zhang, Liangliang Zhang, Jiaqi Chang e Ziyu Jing. "Characterizations of Water-Soluble Chitosan/Curdlan Edible Coatings and the Inhibitory Effect on Postharvest Pathogenic Fungi". Foods 13, n. 3 (30 gennaio 2024): 441. http://dx.doi.org/10.3390/foods13030441.
Testo completoAbstract (sommario):
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.
18
Kubicki, Grzegorz, Volf Leshchynsky, Ahmed Elseddawy, Maria Wiśniewska, Roman G. Maev, Jarosław Jakubowicz e Joanna Sulej-Chojnacka. "Microstructure and Properties of Hydroxyapatite Coatings Made by Aerosol Cold Spraying–Sintering Technology". Coatings 12, n. 4 (15 aprile 2022): 535. http://dx.doi.org/10.3390/coatings12040535.
Testo completoAbstract (sommario):
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.
19
Jensen, Rielle, Zoheir Farhat, Md Aminul Islam e George Jarjoura. "Erosion–Corrosion of Novel Electroless Ni-P-NiTi Composite Coating". Corrosion and Materials Degradation 4, n. 1 (8 febbraio 2023): 120–41. http://dx.doi.org/10.3390/cmd4010008.
Testo completoAbstract (sommario):
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.
20
Moroz, A. V., A. M. Sipatdinov e V. E. Filimonov. "A TECHNIQUE FOR MONITORING THE INTEGRITY OF THE COATING AND DEVICE FOR ITS IMPLEMENTATION". Kontrol'. Diagnostika, n. 265 (luglio 2020): 36–41. http://dx.doi.org/10.14489/td.2020.07.pp.036-041.
Testo completoAbstract (sommario):
The developed methodology for monitoring the integrity of the protective coating is designed to control dielectric and high-resistance coatings. The control technique consists in measuring the resistance of the signal conductor located between the base of the part that is dielectric insulated from each other and the protective coating. By changing the resistance of the signal conductor, the integrity of the protective coating is judged. A friction machine that implements this technique allows testing the wear resistance of a coating according to GOST 30480–97 with simultaneous monitoring of coating integrity. The results of a joint test of a friction machine and methods during testing for wear of different coatinges are also demonstrated.
21
Moroz, A. V., A. M. Sipatdinov e V. E. Filimonov. "A TECHNIQUE FOR MONITORING THE INTEGRITY OF THE COATING AND DEVICE FOR ITS IMPLEMENTATION". Kontrol'. Diagnostika, n. 265 (luglio 2020): 36–41. http://dx.doi.org/10.14489/td.2020.07.pp.036-041.
Testo completoAbstract (sommario):
The developed methodology for monitoring the integrity of the protective coating is designed to control dielectric and high-resistance coatings. The control technique consists in measuring the resistance of the signal conductor located between the base of the part that is dielectric insulated from each other and the protective coating. By changing the resistance of the signal conductor, the integrity of the protective coating is judged. A friction machine that implements this technique allows testing the wear resistance of a coating according to GOST 30480–97 with simultaneous monitoring of coating integrity. The results of a joint test of a friction machine and methods during testing for wear of different coatinges are also demonstrated.
22
Zhang, Dawei, Haiyang Li, Xiaoli Chen, Hongchang Qian e 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.
Testo completoAbstract (sommario):
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.
23
Queant, Caroline, Pierre Blanchet, Véronic Landry e Diane Schorr. "Effect of Adding UV Absorbers Embedded in Carbonate Calcium Templates Covered with Light Responsive Polymer into a Clear Wood Coating". Coatings 8, n. 8 (28 luglio 2018): 265. http://dx.doi.org/10.3390/coatings8080265.
Testo completoAbstract (sommario):
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.
24
Tu, Chaohui, Xuanyu Chen, Cancan Liu e Deye Li. "Plasma Electrolytic Oxidation Coatings of a 6061 Al Alloy in an Electrolyte with the Addition of K2ZrF6". Materials 16, n. 11 (1 giugno 2023): 4142. http://dx.doi.org/10.3390/ma16114142.
Testo completoAbstract (sommario):
In this study, white thermal control coatings were produced on a 6061 Al alloy using plasma electrolytic oxidation (PEO). The coatings were mainly formed by incorporating K2ZrF6. The phase composition, microstructure, thickness, and roughness of the coatings were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), a surface roughness tester, and an eddy current thickness meter, respectively. The solar absorbance and infrared emissivity of the PEO coatings were measured using a UV–Vis–NIR spectrophotometer and FTIR spectrometer, respectively. The addition of K2ZrF6 to the trisodium phosphate electrolyte was found to significantly enhance the thickness of the white PEO coating on the Al alloy, with the coating thickness increasing in proportion to the concentration of K2ZrF6. Meanwhile, the surface roughness was observed to stabilize at a certain level as the K2ZrF6 concentration increased. At the same time, the addition of K2ZrF6 altered the growth mechanism of the coating. In the absence of K2ZrF6 in the electrolyte, the PEO coating on the Al alloy surface predominantly developed outwards. However, with the introduction of K2ZrF6, the coating’s growth mode transitioned to a combination of outward and inward growth, with the proportion of inward growth progressively increasing in proportion to the concentration of K2ZrF6. The addition of K2ZrF6 substantially enhanced the adhesion of the coating to the substrate and endowed it with exceptional thermal shock resistance, as the inward growth of the coating was facilitated by the presence of K2ZrF6. In addition, the phase composition of the aluminum alloy PEO coating in the electrolyte containing K2ZrF6 was dominated by tetragonal zirconia (t-ZrO2) and monoclinic zirconia (m-ZrO2). With the increase in K2ZrF6 concentration, the L* value of the coating increased from 71.69 to 90.53. Moreover, the coating absorbance α decreased, while the emissivity ε increased. Notably, at a K2ZrF6 concentration of 15 g/L, the coating exhibited the lowest absorbance (0.16) and the highest emissivity (0.72), which are attributed to the enhanced roughness resulting from the substantial increase in coating thickness caused by the addition of K2ZrF6, as well as the presence of ZrO2 with higher emissivity within the coating.
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Macías-Naranjo, Mariana, Margarita Sánchez-Domínguez, J. F. Rubio-Valle, Ciro A. Rodríguez, J. E. Martín-Alfonso, Erika García-López e Elisa Vazquez-Lepe. "A Study of PLA Thin Film on SS 316L Coronary Stents Using a Dip Coating Technique". Polymers 16, n. 2 (19 gennaio 2024): 284. http://dx.doi.org/10.3390/polym16020284.
Testo completoAbstract (sommario):
The dip coating process is one of the recognized techniques used to generate polymeric coatings on stents in an easy and low-cost way. However, there is a lack of information about the influence of the process parameters of this technique on complex geometries such as stents. This paper studies the dip coating process parameters used to provide a uniform coating of PLA with a 4–10 µm thickness. A stainless-steel tube (AISI 316L) was laser-cut, electropolished, and dip-coated in a polylactic acid (PLA) solution whilst changing the process parameters. The samples were characterized to examine the coating’s uniformity, thickness, surface roughness, weight, and chemical composition. FTIR and Raman investigations indicated the presence of PLA on the stent’s surface, the chemical stability of PLA during the coating process, and the absence of residual chloroform in the coatings. Additionally, the water contact angle was measured to determine the hydrophilicity of the coating. Our results indicate that, when using entry and withdrawal speeds of 500 mm min−1 and a 15 s immersion time, a uniform coating thickness was achieved throughout the tube and in the stent with an average thickness of 7.8 µm.
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Jiang, Wei, Xin Shen, Zhiyuan Wang, Yang Liu, Xiaohua Zhang, Enhao Wang e Junxin Zhang. "Effect of Al2O3 on Microstructure and Corrosion Characteristics of Al/Al2O3 Composite Coatings Prepared by Cold Spraying". Metals 14, n. 2 (1 febbraio 2024): 179. http://dx.doi.org/10.3390/met14020179.
Testo completoAbstract (sommario):
Cold spraying was used to prepare Al/Al2O3 composite coatings. The Al2O3 content was controlled to increase the mechanical property and corrosion resistance of the composite coating. The inclusion of Al2O3 particles results in considerable plastic deformation of Al particles and grain size refinement in the coating. Additionally, the coating’s surface roughness decreased from 24.63 μm to 9.02 μm, and the porosity decreased from 6.34% to 2.07%. The increase in microhardness of the composite coatings was attributed to the combined effect of residual compressive stress, second phase strengthening of Al2O3, and plastic hardening of Al particles. The electrochemical test results indicate that the mass fractions of Al2O3 significantly affected the corrosion resistance of the Al/Al2O3 composite coating. Compared to the Al coating, the composite coating exhibited improved corrosion resistance, with a reduction in corrosion current density from 1.09 × 10−3 A/cm2 to 2.67 × 10−6 A/cm2 and an increase in corrosion potential from −1.57 V to −1.14 V. However, when the alumina particle content exceeded 17.7%, it led to more Al2O3 particle breakage, increasing the weak bonding interfaces in the composite coating, and consequently reducing its corrosion resistance.
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Mabrouk, Ahmed, e Zoheir Farhat. "Novel Ni-P-Tribaloy Composite Protective Coating". Materials 16, n. 11 (25 maggio 2023): 3949. http://dx.doi.org/10.3390/ma16113949.
Testo completoAbstract (sommario):
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, e Xiaoxing Yan. "Effect of Silane Coupling Agent Modification on Properties of Brass Powder-Water-Based Acrylic Coating on Tilia europaea". Polymers 15, n. 6 (10 marzo 2023): 1396. http://dx.doi.org/10.3390/polym15061396.
Testo completoAbstract (sommario):
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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Fox-Rabinovitch, Guerman, Goulnara Dosbaeva, Anatoly Kovalev, Iosif Gershman, Kenji Yamamoto, Edinei Locks, Jose Paiva, Egor Konovalov e Stephen Veldhuis. "Enhancement of Multi-Scale Self-Organization Processes during Inconel DA 718 Machining through the Optimization of TiAlCrSiN/TiAlCrN Bi-Nano-Multilayer Coating Characteristics". Materials 15, n. 4 (11 febbraio 2022): 1329. http://dx.doi.org/10.3390/ma15041329.
Testo completoAbstract (sommario):
Optimization of the composition of a new generation of bi-nano-multilayered TiAlCrSiN/TiAlCrN-based coatings is outlined in this study for the machining of direct aged (DA) Inconel 718 alloy. Three types of TiAlCrSiN/TiAlCrN-based bi-nano-multi-layer coatings with varying chemical compositions were investigated: (1) a previous state-of-the-art Ti0.2Al0.55Cr0.2Si0.03Y0.02N/Ti0.25Al0.65Cr0.1N (coating A); (2) Ti0.2Al0.52Cr0.2Si0.08N/Ti0.25Al0.65Cr0.1N with increased amount of Si (up to 8 at.%; coating B); (3) a new Ti0.18Al0.55Cr0.17Si0.05Y0.05N/Ti0.25Al0.65Cr0.1N coating (coating C) with an increased amount of both Si and Y (up to 5 at.% each). The structure of each coating was evaluated by XRD analysis. Micro-mechanical characteristics were investigated using a MicroMaterials NanoTest system and an Anton Paar-RST3 tester. The wear performance of nano-multilayered TiAlCrSiN/TiAlCrN-based coatings was evaluated during the finish turning of direct aged (DA) Inconel 718 alloy. The wear patterns were assessed using optical microscopy imaging. The tribological performance was evaluated through (a) a detailed chip characteristic study and (b) XPS studies of the worn surface of the coated cutting tool. The difference in tribological performance was found to correspond with the type and amount of tribo-films formed on the friction surface under operation. Simultaneous formation of various thermal barrier tribo-films, such as sapphire, mullite, and garnet, was observed. The overall amount of beneficial tribo-films was found to be greater in the new Ti0.18Al0.55Cr0.17Si 0.05Y0.05N/Ti0.25Al0.65Cr0.1N nano-bi-multilayer coating (coating C) than in the previous state-of-the-art coatings (A and B). This resulted in over two-fold improvement of this coating’s tool life compared with those of the commercial benchmark AlTiN coating and coating B, as well as a 40% improvement of the tool life of the previous state-of-the-art coating A. Multi-scale self-organization processes were observed: nano-scale tribo-film formation on the cutting tool surface combined with micro-scale generation of strain-induced martensite zones as a result of intensive metal flow during chip formation. Both of these processes are strongly enhanced in the newly developed coating C.
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Belhamra, Nadjette, Abd Raouf Boulebtina, Khadidja Belassadi, Abdelouahed Chala e Malika Diafi. "Effect of Doping of Nanoparticles on the Properties of Zn-Ni Composite Coatings". Diffusion Foundations 18 (settembre 2018): 19–26. http://dx.doi.org/10.4028/www.scientific.net/df.18.19.
Testo completoAbstract (sommario):
The purpose of this paper was to investigate the effect of Al2O3 and TiO2 nanoparticles contents on structural proporties, microhardness and corrosion resistance of Zn-Ni alloy coationg. Zn-Ni, Zn-Ni-Al2O3 and Zn-Ni-TiO2 composite coatings were electrodeposited on steel substrate by direct current in sulphate bath.The structure of the coatings was studied by X-ray diffration and by scaning electron miroscopy. The results showed the appearance of Ni5Zn21 phases and that the incrorporation of Al2O3 and TiO2 in the Zn-Ni coating refined the crystal grain size.The corrosion performance of coating in the 0.6M NaCl as a corrisive solution was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy EIS methods. It was found that the incorporation of nanoparticules in Zn-Ni alloy coating have better corrosion resistance and the values of Rct and Zw increase, while the values of Cdl decrease with increasing of nanoparticules.
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Yuan, Xue Tao, Zhi Qiang Hua, Lei Wang, Dong Bai Sun e Song Lin Chen. "Effect of Nano-Al2O3 Particles on the NiP/nano-Al2O3 Coatings’ Properties". Applied Mechanics and Materials 66-68 (luglio 2011): 1668–75. http://dx.doi.org/10.4028/www.scientific.net/amm.66-68.1668.
Testo completoAbstract (sommario):
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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Wang, Xinsheng, e Zhiguo Xing. "Preparation and Properties of Composite Nanoceramic NiCrBSi-TiO2/WC(Co) Coatings". Coatings 10, n. 9 (8 settembre 2020): 868. http://dx.doi.org/10.3390/coatings10090868.
Testo completoAbstract (sommario):
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.
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Liu, Li Ping, Xue Feng Yan, Zhi Ming Zhang e Liang Min Yu. "Novel Functional Coating: Luminescent Coating". Advanced Materials Research 337 (settembre 2011): 37–40. http://dx.doi.org/10.4028/www.scientific.net/amr.337.37.
Testo completoAbstract (sommario):
The luminescent coating as one of the special functional coatings of the 21st century has attracted a great deal of attention recently. Luminescent coating is divided into three categories: fluorescent coating, self-luminous coating, energy storage luminescent coating. The article briefly summarizes their principles and luminous characteristics. And mainly reviews the present research situation, the future development tendency and their widely applications both at home and abroad.
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Shen, Xuehui, Hao Peng, Yunna Xue, Baolin Wang, Guosheng Su, Jian Zhu e Anhai Li. "Microstructure and Properties of WC/Ni-Based Laser-Clad Coatings with Different WC Content Values". Materials 15, n. 18 (11 settembre 2022): 6309. http://dx.doi.org/10.3390/ma15186309.
Testo completoAbstract (sommario):
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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Dong, Tianxin, Xingyu Wang, Fei Li, Yifan Zhu e Xiuqing Fu. "Study on the Wear Resistance of Ni-Co-ZrO2 Composite Coatings with Different ZrO2 Nanoparticle Concentrations Prepared Using Electrodeposition on the Micro-Surface of Spindle Hook Teeth". Metals 13, n. 7 (9 luglio 2023): 1251. http://dx.doi.org/10.3390/met13071251.
Testo completoAbstract (sommario):
To improve the wear resistance of the surface of the cotton picker spindle, a Ni-Co-ZrO2 composite coating with different ZrO2 nanoparticle concentrations was prepared using electrodeposition technology on the micro surface of spindle hook teeth, and the morphologies of the surface and cross-section, element contents, grain sizes, microhardness and friction coefficients of the Ni-Co-ZrO2 composite coating were obtained; a simulated wear test was conducted based on the independently developed spindle hook tooth wear device, and the morphologies and elemental distributions of the composite coating before and after wear were obtained; the effects of different ZrO2 nanoparticle concentrations (0, 2, 4, 6, 8 g/L) on the morphology, element content, grain size, microhardness, friction coefficient and wear resistance of the coating were discussed. The test results indicated that compared with Ni-Co coatings, Ni-Co-ZrO2 composite coatings featured a more compact coating structure, a greater coating thickness, and a smaller grain size. The presence of ZrO2 nanoparticles led to further improvement of the coating’s microhardness, friction coefficient and wear resistance. When the mass concentration of ZrO2 nanoparticles reached 4 g/L, the microhardness of Ni-Co-ZrO2 composite coating reached the maximum value, 545.4 Hv0.1, and the friction coefficient decreased to 0.06. At the same time, in the simulated wear test, the composite coating with this concentration had the smallest wear area and the highest wear resistance.
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Koochaki, Mohammad Sadegh, Gelareh Momen, Serge Lavoie e Reza Jafari. "Enhancing Icephobic Coatings: Exploring the Potential of Dopamine-Modified Epoxy Resin Inspired by Mussel Catechol Groups". Biomimetics 9, n. 6 (8 giugno 2024): 349. http://dx.doi.org/10.3390/biomimetics9060349.
Testo completoAbstract (sommario):
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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Liu, Xiao Zhen, Qin Wei Shen, Yi Fan Luo, Xiao Zhou Liu, Jie Chen e Qian Wei Shu. "Effect of Preparation Conditions on the Performance of Electrodeposited Mo-Ni Coating". Applied Mechanics and Materials 577 (luglio 2014): 15–18. http://dx.doi.org/10.4028/www.scientific.net/amm.577.15.
Testo completoAbstract (sommario):
Mo-Ni coatings were prepared on Ni alloy by electrodeposition method. The effects of electrodeposition temperature, current density, stir speed and electrodeposition time on deposition rate and microhardness of Mo-Ni coating were researched, respectively. Deposition rate of Mo-Ni coating decreases with the increase of electrodeposition temperature in 35 °C ~ 60 °C. Deposition rate and microhardness of Mo-Ni coating increases with the increase of current density respectively in 15 A/dm2 ~ 17.5 A/dm2. Deposition rate and microhardness of Mo-Ni coating decreases with the increase of stir speed respectively in 200 r/min to 400 r/min. Deposition rate and microhardness of Mo-Ni coating decreases with the increase of electrodeposition time respectively in 30 min ~ 40 min. When electrodeposition parameters: temperature 35 °C, current density 17.5 A/dm2, stir speed 200 r/mi, pH 5 and time 30 min, deposition rate and microhardness of Mo-Ni coatin are as high as 0.269 mg/ cm2·min and 502.4 HV respectively.
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Sunil Kumar Chaudhary, Vineeta Chauhan, Sunil Kumar Gupta, Babita Jain, Ashish Raj,. "Numerical Exploration and Statistical Analysis of Mathematical Parameters of Anti Reflecting Coating on Operational Parameters Improvement of Solar Cell". Communications on Applied Nonlinear Analysis 31, n. 1 (1 marzo 2024): 266–86. http://dx.doi.org/10.52783/cana.v31.430.
Testo completoAbstract (sommario):
In this research, a detailed abacus adventure and statistic obsession are made to survey the relation of fractions of materials of the anti-reflective coating to effectiveness of a solar cell. Emphasis on the study of whether single or double-layer layers of coatings save energy reflection and improve absorption is done leading to energy conservation. The anti-reflective coating is a familiar term in the solar technology, as it is less realistic without the coating that minimizes the light reflection losses. By way of single or double coating, light transmission increased is by limiting reflection therefore making the surfaces of solar cells to receive more light improving efficiency. These finer details of the coating's power over the solar cells' light absorption depth and output effectiveness are thoughtfully and minutely deliberated. A great deal of numerical methods are used to model light and sunlight impinging on the coated solar cell environments. Light waves' behaviour, when meet an antireflection layer, is a very important aspect in explaining, to some extent, about the thickness of the layer and its materials composition. That is a great role, namely, statistical techniques in this study whose purpose is used to main performance gain in the solar cells. Through simulation and experimental data, correlations are established between solar cell performance and the coating’s parameters. The patterns found will be taken into consideration to further improve the coating. This research, not just performed steps by step analysis of reflection, absorption and power conversion features in solar cells coated; rather, guidelines to excellent anti-reflective coating were offered too. The clarification of complex connections between the performance of coating construction and solar cells performance is enabled in this research and its results significantly contribute towards the development of renewable energy engineering, hence giving the research a certain weight in the field of solar energy.
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Прохоров, В. М., Е. В. Гладких, Л. А. Иванов, В. В. Аксененков e А. Н. Кириченко. "Состав, структура и механические свойства (Ti-Hf)N-покрытий на титановом сплаве". Журнал технической физики 89, n. 5 (2019): 704. http://dx.doi.org/10.21883/jtf.2019.05.47472.173-18.
Testo completoAbstract (sommario):
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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Gu, Jiangdong, Qiufeng An, Meng-chen Huang, Ping Ge e Chao-hua Xue. "Self-Cleaning Antibacterial Composite Coating of Fluorinated Acrylic Resin and Ag/SiO2 Nanoparticles with Quaternary Ammonium". Polymers 16, n. 13 (1 luglio 2024): 1885. http://dx.doi.org/10.3390/polym16131885.
Testo completoAbstract (sommario):
With improvements in living standards, the demand for antibacterial self-cleaning coatings has significantly increased. In this work, self-cleaning coatings with antibacterial properties were fabricated by spray-coating a composite of fluorinated acrylic resin and Ag/SiO2 nanoparticles with quaternary ammonium salts. The synergistic action of the quaternary ammonium salts and silver nanostructures caused the coating to show a dual antibacterial effect. The Ag/SiO2 nanoparticles roughened the coating’s surface and, in combination with the fluorinated chains, provided the surface a superhydrophobic self-cleaning property with a contact angle of 156° and a sliding angle of less than 2°. Notably, the composite coating withstood 100 abrasion cycles without losing its superhydrophobicity and the contact angle is still exceeded 150° after 60 h of immersion solutions with different pH values, demonstrating outstanding wear resistance and acid/alkali stability. The incorporation of nanostructured antibacterial agents was effective in improving the roughness and antibacterial properties of the low-surface-energy resin, resulting in a self-cleaning antibacterial composite coating. This method may pave a new route for the design of functional coating materials with excellent overall performance.
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Buchtík, Martin, Matěj Březina, Ondřej Vyklický, Jan Filipenský e Jaromír Wasserbauer. "Failure Mechanism and Mechanical Characteristics of NiCrBSi Coating". Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 67, n. 3 (2019): 649–57. http://dx.doi.org/10.11118/actaun201967030649.
Testo completoAbstract (sommario):
Mechanical properties of NiCrBSi coatings on plain carbon steel substrate prepared by HVOF (High velocity flame spraying) were studied in this work. Sprayed coatings with average thicknesses of 0.25 mm, 0.5 mm and 1 mm were prepared on preheated steel strips and steel strips without preheating. Chemical analysis of the coatings cross‑section offered information about material structure and distribution of chemical elements within the coating. Hardness of the coating was measured with the aim to reveal the influence of coating thickness and coated substrate preheating on coating hardness. Similar hardness was observed regardless coating preparation conditions and thickness. Bend test was used for characterization of failure character of NiCrBSi thermally sprayed coatings under different thermal conditions. Higher coating thickness was beside cracking, accompanied also by coating delamination from the substrate, while also some influence of testing temperature (laboratory temperature vs. ‑50 °C) on coating failure characteristics were observed. No influence of the coating preparation conditions on the coating pull‑off strength was observed.
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Dhakal, Dhani Ram, Young Uk Han, Byung Geon Lee, Tae Ho Kim, Gi Bum Jang e Sung Youl Cho. "Wear Resistance Behavior of Low-, Mid-, and High-Phosphorus Electroless Ni-P Coatings Heat-Treated in the Air Environment". Coatings 14, n. 5 (20 maggio 2024): 648. http://dx.doi.org/10.3390/coatings14050648.
Testo completoAbstract (sommario):
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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Ma, Pengfei, Jiaoli Li, Ying Zhuo, Pu Jiao e Genda Chen. "Coating Condition Detection and Assessment on the Steel Girder of a Bridge through Hyperspectral Imaging". Coatings 13, n. 6 (29 maggio 2023): 1008. http://dx.doi.org/10.3390/coatings13061008.
Testo completoAbstract (sommario):
The organic coating of bridge steel girders is subjected to physical scratches, corrosion, and aging in natural weathering. The breakdown of the coating may cause serviceability and safety problems if left unnoticed. Conventional coating inspection is time-consuming and lacks information about the coating’s chemical integrity. A hyperspectral imaging method is proposed to detect the condition of steel coatings based on coating-responsive features in reflectance spectra. A field test was conducted on the real-world bridge, which shows obvious signs of degradation. The hyperspectral signature enables an assessment of the coating’s health and defect severity. The results indicated that the coating scratch can be effectively located in the domain of a hyperspectral image and the scratch depth can be determined by mapping a scratch depth indicator (SDI = R532 nm/R641 nm). Rust sources and products in steel girders can be identified by the unique spectral signatures in the VNIR range, and the rust stains (and thus stain areas) scattered on the coating can be pinpointed at pixel level by the chloride rust (CR) indicators >1.11 (CR = R733 nm/R841 nm). The chemical integrity of a topcoat is demonstrated by the short-wave infrared spectroscopy and the topcoat degradation can be evaluated by the decreased absorption at 8000 cm−1 and 5850 cm−1. Hyperspectral imaging enables faster and more reliable coating condition detection by the spectral features and provides an alternative for multi-object coating detection.
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Zhang, Jiannan, Younho Cho, Jeongnam Kim, Azamatjon Kakhramon ugli Malikov, Young H. Kim, Jin-Hak Yi e Weibin Li. "Non-Destructive Evaluation of Coating Thickness Using Water Immersion Ultrasonic Testing". Coatings 11, n. 11 (20 novembre 2021): 1421. http://dx.doi.org/10.3390/coatings11111421.
Testo completoAbstract (sommario):
The coating is applied to prevent corrosion on the surface of ships or marine structures, and the thickness of the coating affects its anti-corrosion effect. As a result, non-destructive testing (NDT) is required to measure coating thickness, and ultrasonic NDT is a convenient and quick way to measure the thickness of underwater coatings. However, the offshore coating’s energy attenuation and absorption rates are high, the ultrasonic pulse echo test is difficult, and the testing environment is harsh. Because of the coating’s high attenuation, the distance of the optimal water delay line designed based on the reflection coefficient of the vertically incident wave is used. To accurately measure the thickness of the coating material, TOF of the reflected echo on the time-domain waveform was evaluated. The experimental results show that, when compared to caliper measurements, the coating thickness measured by the proposed method has a lower error and can be used for accurate measurement. The use of ultrasonic water immersion measurement is almost limitless in terms of size, location, and material of the object to be measured, and it is expected to be used to measure the thickness of the surface coating of ships or marine structures in the water.
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Sun, Haifeng, Weilun Zhang, Yongjun Feng, Suying Hu, Hua Tian e Zhiwen Xie. "Exploring the Effect of Pt Addition on the Fracture Behavior of CrN Coatings by Finite Element Simulation". Coatings 12, n. 8 (5 agosto 2022): 1131. http://dx.doi.org/10.3390/coatings12081131.
Testo completoAbstract (sommario):
Previous research confirmed that Pt addition induced a prominent refinement effect of CrN coating, resulting in an enhanced conductivity and corrosion resistance. In this work, a detailed finite element simulation and scratch test were employed to calculate and characterize the fracture failure behaviors (stress distribution, crack damage process, critical coating load, and coating–substrate adhesion energy) of CrN coatings with different Pt contents. Simulation results showed that the synergistic action of dynamic scratch load and extrusion load induced the fracture of the coatings. S11 and S22 caused transverse cracks in the CrN coating, S11 caused longitudinal cracks in the CrN-Pt coating and CrN-3Pt coatings, S22 led to the inclined propagation of cracks in these coatings, and S11 and S22 jointly induced the separation of the coating from the substrate. The doping Pt element in the CrN coating will make the coating easier to fracture and reduce the adhesion strength between the coating and substrate. Scratch test results revealed that adding Pt into the CrN coating will make this coating easier to fracture and cause more serious damage; the simulation results are in good accordance with the scratch test characterizations. The current founding provided a comprehensive understanding for the fracture damage mechanism of Pt-doped nitride coatings.
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HUANG, ZHONGJIA, e DANGSHENG XIONG. "MoS2 PARTICLES MODIFIED WITH POLYSTYRENE FOR PRODUCING Ni–PS/MoS2 COATINGS". Surface Review and Letters 15, n. 06 (dicembre 2008): 793–97. http://dx.doi.org/10.1142/s0218625x08012050.
Testo completoAbstract (sommario):
The MoS 2 particles were coated with polystyrene and can be written as PS / MoS 2 hereinafter. Ni – PS / MoS 2 coatings and Ni – MoS 2 coatings were produced by PC electrodeposition technique. The surface morphology of Ni – PS / MoS 2 coating was examined and compared with those of Ni – MoS 2 coating. The effect of particle concentrations on the volume percent of particles incorporated in the coatings was investigated. And the microhardness of coatings was also investigated. Results show that the surface morphology of Ni – PS / MoS 2 coating is regular and the thickness of coating is uniform. The introduction of MoS 2 to coatings caused dendritic growth. The surface morphology of Ni – MoS 2 coating is irregular. With the same particles concentration in bath, the volume percent of PS / MoS 2 particles incorporated in the composite coatings was higher than those of MoS 2 particles; and the microhardness of Ni – PS / MoS 2 coating was higher than those of Ni – MoS 2 coating.
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Jaimini, Manish, Arpit Jain, Sanjay K. Sharma e Shailender Mohan. "Solventless coating for Tablets: An alternative to conventional coating technique". Indian Journal of Pharmaceutical and Biological Research 2, n. 02 (30 giugno 2014): 108–14. http://dx.doi.org/10.30750/ijpbr.2.2.18.
Testo completoAbstract (sommario):
There are many ways to coat tablets. Coatings are a very important part in the formulation of pharmaceutical dosage form to achieve excellent formulation quality (e.g., color, texture, mouth feel, and taste masking), physical and chemical protection for the drugs in the dosage forms, and modification of drug release characteristics. Most film coatings are applied as aqueous or organic-based polymer solutions. Such film coating brings their own disadvantages. Solventless coatings are alternative technique of coating. Solventless coating technologies can overcome many of the disadvantages associated with the use of solvents (e.g., solvent exposure, solvent disposal, and residual solvent in product) in pharmaceutical coating. Solventless processing reduces the overall cost by eliminating the tedious and expensive processes of solvent disposal/treatment. In addition, it can significantly reduce the processing time due to reduction of step of drying/evaporation. These environment-friendly processes are performed without any heat in most cases (except hot-melt coating) and thus can provide an alternative technology to coat temperature-sensitive drugs. This review includes various solventless coating methods like magnetic assisted impaction coating , hotmelt coating, supercritical fluid spray coating, electrostatic coating, dry powder coating, and photocurable coating that can be used to coat the pharmaceutical dosage forms.
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Reolon, Luca W., Myriam H. Aguirre, Kenji Yamamoto, Qinfu Zhao, Igor Zhitomirsky, German Fox-Rabinovich e Stephen Clarence Veldhuis. "A Comprehensive Study of Al0.6Ti0.4N Coatings Deposited by Cathodic Arc and HiPIMS PVD Methods in Relation to Their Cutting Performance during the Machining of an Inconel 718 Alloy". Coatings 11, n. 6 (16 giugno 2021): 723. http://dx.doi.org/10.3390/coatings11060723.
Testo completoAbstract (sommario):
The structural, physical–chemical, and micromechanical characteristics of Al0.6Ti0.4N coatings deposited by different physical vapor deposition (PVD) methods, such as cathodic arc deposition (CAD), as well as advanced HiPIMS techniques were investigated in terms of their cutting performance during the machining of an Inconel 718 alloy. XRD studies had revealed that the HiPIMS coating featured lower residual stresses and more fine-grained structure. Electrochemical characterization with the potentiostat-impendence method shows that the HiPIMS coating has a significantly lower porosity than CAD. SEM and AFM studies of the surface morphology demonstrate that the HiPIMS coating has a smoother surface and an absence of droplet phases, in contrast with CAD. XRD, combined with FIB/TEM studies, shows a difference in the crystal structure of both coatings. The micromechanical characteristics of each coating, such as hardness, elastic modulus, fracture toughness, and adhesion to the substrate, were evaluated. The HiPIMS coating was found to possess a more beneficial combination of micromechanical properties compared to CAD. The beneficial characteristics of the HiPIMS coating alleviated the damage of the coated layer under operation. Combined with grain size refinement, this results in the improved adaptive performance of the HiPIMS coating through the formation of a greater amount of thermal barrier sapphire tribo-films on the friction surface. All of these characteristics contribute to the reduction of flank and crater wear intensity, as well as notching, leading to an improvement of the HiPIMS coating’s tool life.
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Ma, Yiheng, Shouliang Deng, Ye Wang, Zehua Li, Xun Gong, Hui Zhao, Haojie Chen e Mei Li. "Microstructure and properties of laser-melted FeCoCrNiSiMox high-entropy alloy coatings". Journal of Physics: Conference Series 2760, n. 1 (1 maggio 2024): 012063. http://dx.doi.org/10.1088/1742-6596/2760/1/012063.
Testo completoAbstract (sommario):
Abstract In this research, FeCoCrNiSiMox high-entropy alloy coatings were created using laser cladding technology on 45 steel surfaces in order to provide a coating with high hardness and strong abrasion resistance. The present study aims to evaluate the effects of including Mo elements on the tissue, structure, and mechanical characteristics of FeCoCrNiSiMox high mercury alloy coatings under optimal laser melting process conditions. Through the regulation of Mo element incorporation, it has been observed that for values of x less than or equal to 0.2, the coating exhibits a singular FCC structure. However, for values of x greater than 0.2, a phase transition occurs in the coating’s structure, resulting in the appearance of a second phase. Consequently, the alloy primarily comprises a solid solution phase combined with the FCC phase and the Mo-rich phase. The introduction of the Mo element results in a steady reduction in the microstructure of the coating, which predominantly consists of dendritic structures. Additionally, the average hardness of the coating exhibits an increase, accompanied by an enhancement in its wear resistance.
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Hu, Qingyuan, Xingming Li, Gai Zhao, Yuling Ruan, Guoqing Wang e Qingjun Ding. "Effects of Graphene Oxide on Tribological Properties of Micro-Arc Oxidation Coatings on Ti-6Al-4V". Coatings 13, n. 11 (19 novembre 2023): 1967. http://dx.doi.org/10.3390/coatings13111967.
Testo completoAbstract (sommario):
This paper investigates the effect of graphene oxide (GO) particles on the friction reduction and wear resistance of coatings on a Ti-6Al-4V alloy generated using the micro-arc oxidation (MAO) technique. Different concentrations of GO were added in aluminate–phosphate electrolyte. The composition of the MAO coatings was investigated using X-ray diffraction and the energy dispersive spectrum. Measurements of the coating’s thickness, hardness, and roughness have also been conducted. Ball-on-disk friction tests under dry conditions were carried out to reveal the tribological behavior of the MAO coating. The results showed that the coating consisted of Al2TiO5 and γ-Al2O3. The addition of GO greatly reduced the friction coefficient by 25%. The coating with 5 g/L of GO particles exhibited the lowest friction coefficient (reduced from 0.47 to 0.35). Moreover, the coating thickness become thicker (from 10 to 20 μm) with an increase in GO concentration from 0 to 10 g/L. The wear mechanism was revealed via worn surface analysis. This study provides a helpful way to improve the surface wear resistance of titanium alloys.