Journal articles: 'Spray coatings'

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Krishna, L. Rama, D. Sen, Y. Srinivasa Rao, G. V. Narasimha Rao, and G. Sundararajan. "Thermal spray coating of aluminum nitride utilizing the detonation spray technique." Journal of Materials Research 17, no. 10 (October 2002): 2514–23. http://dx.doi.org/10.1557/jmr.2002.0366.

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The main objective of this work is to examine the feasibility of depositing aluminum nitride (AlN) powders, synthesized using self-propagating high-temperature synthesis, on a mild steel substrate using the detonation spray coating technique. Thick coatings produced by utilizing the AlN powder were obtained at four different oxygen–acetylene ratios and analyzed for microstructure, microhardness, porosity, indentation fracture toughness, and phase distribution. The AlN powder particles were found to be undergoing oxidation during the deposition process. The interrelationship between the spray parameters and the extent of oxidation of AlN during the coating process was investigated. Tribological performance of the coatings was evaluated using a dry sand abrasion test and a pin-on-disc sliding wear test. The mechanical and tribological properties of the above four coatings were compared with pure alumina (Al2O3) coatings. The correlation between the structure of the coatings and their tribological performance was also established.

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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.

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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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Yin, Shuo, Chaoyue Chen, Xinkun Suo, and Rocco Lupoi. "Cold-Sprayed Metal Coatings with Nanostructure." Advances in Materials Science and Engineering 2018 (2018): 1–19. http://dx.doi.org/10.1155/2018/2804576.

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Cold spray is a solid-state coating deposition technology developed in the 1980s. In comparison with conventional thermal spray processes, cold spray can retain the original properties of feedstock, prevent the adverse influence on the underlying substrate materials, and produce very thick coatings. Coatings with nanostructure offer the potential for significant improvements in physical and mechanical properties as compared with conventional non-nanostructured coatings. Cold spray has also demonstrated great capability to produce coatings with nanostructure. This paper is aimed at providing a comprehensive overview of cold-sprayed metal coatings with nanostructure. A brief introduction of the cold spray technology is provided first. The nanocrystallization phenomenon in the conventional cold-sprayed metal coatings is then addressed. Thereafter, focus is switched to the microstructure and properties of the cold-sprayed nanocrystalline metal coatings, and the cold-sprayed nanomaterial-reinforced metal matrix composite (MMC) coatings. At the end, summary and future perspectives of the cold spray technology in producing metal coatings with nanostructure are concluded.

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Deng, Chun Ming, Min Liu, Chang Guang Deng, Hong Liang Dai, and Ke Song Zhou. "Preparation and Characterizations of NiTi Intermetallic Coatings." Advanced Materials Research 291-294 (July 2011): 80–83. http://dx.doi.org/10.4028/www.scientific.net/amr.291-294.80.

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Much attention has been paid to NiTi intermetallic coating for enhancing cavitation erosion resistance property due to its shape memory effect. In this paper two processes were used to deposit NiTi intermetallic coatings. Process 1 was the deposition of NiTi intermetallic coating using warm spray process with NiTi intermetallic powder as feedstock, and solution treatment was subsequently performed. Process 2 was a mixture process of warm spray and laser treatment. Ni-Ti coating was first deposited via warm spray process with Ni-cladding Ti as feedstock, and laser-treatment was performed to realize the alloying of Ni-Ti. The microstructure and phase compositions for NiTi intermetallic coatings were characterized by means of SEM and XRD. The fundamental properties for NiTi intermetallic coatings were also analyzed.

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Dinh, Văn Chien, Tuan Hai Nguyen, and Khac Linh Nguyen. "Studying Adhesion between a 67Ni18Cr5Si4B Alloy Powder Coating Produced with the High Velocity Oxygen Fuel Thermal Spray Method HVOF and a Substrate Surface of a Worn C45 Steel Shaft." Key Engineering Materials 854 (July 2020): 117–25. http://dx.doi.org/10.4028/www.scientific.net/kem.854.117.

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Nowadays, thermal spray coatings are used to enhance mechanical properties of the material. One of the technologies used to produce thermal spray coating is HVOF spray technology. This is the most advanced and modern technology which has been widely used in the industry due to its flexibility and ability to create coatings with better adhesion in comparison with other thermal spray methods. This article presents some empirical findings from applying the 67Ni18Cr5Si4B alloy powder coating onto C 45 steel shaft by HVOF spray technology. It also analyzes the influence of some technological parameters on the adhesion of the coating. As a result, the parameters of HVOF spray technology are obtained suitable for recovering worn axis-sized workpieces.

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Ni, Weiliang, Peng Li, Yajun Zhu, Zhigang Di, Liangliang Guo, and Yunqi Liu. "Comparative Study of Anti-Corrosion Properties and Lifespan Prediction Model for Inorganic Zinc-Rich Coating and Thermal-Spray Zinc Coating." Coatings 12, no. 4 (April 8, 2022): 505. http://dx.doi.org/10.3390/coatings12040505.

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On the basis of guaranteeing the reliability of the coating, thermal-spray zinc coating has been verified by the industry to have a lifespan of more than 20 years. It is an anti-corrosion coating with excellent performance. Inorganic zinc-rich coating being a new coating technology has a certain degree of influence on its popularization and application in the field of anti-corrosion; this is due to the lack of relevant comparison data on its anti-corrosion performance and service life. It is necessary to compare and analyze the service life and corrosion resistance of the two coatings, so as to obtain the best application scenarios for the two coatings and provide a reference for the selection of the most economical coating. Based on coating reliability, 7500 h of accelerated salt-spray tests of inorganic zinc-rich coating and of the thermal-spray coating of steel structures were carried out. Electrochemical and salt-spray tests on inorganic zinc-rich coating and thermal-spray zinc coating were carried out. The micro-corrosion morphology, corrosion rate and corrosion mechanism of the two coatings and the factors affecting the corrosion rate were obtained. An interfacial corrosion-thinning and weight-loss equation was established to predict the service life of inorganic zinc-rich coating by comparing it with that of the thermal-spray zinc coating salt-spray test; they suggested that inorganic zinc-rich coating has a longer service life. The results are of practical guiding significance for the selection of a zinc coating and the rapid selection and design of a supporting scheme, and can also provide a reference for the service-life prediction of other types of coatings.

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Naidu, S. V., Carlos Green, Christopher Maxie, James D. Garber, and Gary A. Glass. "Surface Analysis of Shear Strength Tested Tungsten Carbide Thermal Spray Coatings+." Microscopy and Microanalysis 3, S2 (August 1997): 791–92. http://dx.doi.org/10.1017/s1431927600010849.

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Thermal spray processing has become an important powder-consolidation technique to yield new materials for extremes of temperature, radiation, wear, corrosion and mechanical stresses. High Velocity Oxy-Fuel (HVOF) spray coating process gives higher deposition densities and coating hardness; lower oxide content and porosity. The adhesive strength of thermal spray coatings is greatly effected by the interfacial impurities. The ring shear test method shown in Fig. 1 appears to give the most accurate results on shear adhesive strength. A typical ring shear test result of 88WC12Co 1/4" ring HVOF thermal spray coating on 4140 steel rod using a Jet kote thermal spray gun is shown in Fig. 2. Repeated ring shear tests on similar samples prepared under same spray and test conditions resulted in different shear bond strength and coating ring displacement before break off. We examined the ring shear tested coatings using a Zeiss DMS942 Scanning Electron Microscope (SEM) and Kevex Energy Dispersive X-ray Spectrometer (EDXS) with LPX1 Quantum Si(Li) Detector.

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Faisal, N. H., R. Ahmed, A. K. Prathuru, A. Paradowska, and T. L. Lee. "Measuring Residual Strain and Stress in Thermal Spray Coatings Using Neutron Diffractometers." Experimental Mechanics 62, no. 3 (November 10, 2021): 369–92. http://dx.doi.org/10.1007/s11340-021-00803-9.

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Abstract Background During thermal spray coating, residual strain is formed within the coating and substrates due to thermo-mechanical processes and microstructural phase changes. Objective This paper provides a comprehensive guide to researchers planning to use neutron diffraction technique for thermal spray coatings, and reviews some of these studies. Methods ENGIN-X at the ISIS spallation source is a neutron diffractometer (time-of-flight) dedicated to materials science and engineering with high resolution testing. The focus is on the procedure of using ENGIN-X diffractometer for thermal spray coatings with a view that it can potentially be translated to other diffractometers. Results Number of studies involving neutron diffraction analysis in thermal spray coatings remain limited, partly due to limited number of such strain measurement facilities globally, and partly due to difficulty is applying neutron diffraction analysis to measure residual strain in the thermal spray coating microstructure. Conclusions This technique can provide a non-destructive through-thickness residual strain analysis in thermally sprayed components with a level of detail not normally achievable by other techniques. Neutron sources have been used to measure strains in thermal spray coatings, and here, we present examples where such coatings have been characterised at various neutron sources worldwide, to study residual strains and microstructures. Graphic Abstract

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Gulizia, Stefan, A. Trentin, S. Vezzù, Silvano Rech, Peter King, Mahnaz Z. Jahedi, and Mario Guagliano. "Characterisation of Cold Spray Titanium Coatings." Materials Science Forum 654-656 (June 2010): 898–901. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.898.

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Cold spray is a solid state spray deposition process utilizing a supersonic De Laval nozzle to accelerate fine particles to high velocities. Particles plastically deform on impact to the substrate and to each other to create dense well adhered structures. In this study, the microstructure and mechanical properties of cold spray Titanium coatings deposited using nitrogen gas at different gas temperature and pressure were examined. In general, it was found that gas-atomised CP-titanium powder is capable of producing dense coating structures on aluminium alloy (Al6061) substrates. The micro-hardness, oxygen and nitrogen content of the coatings were found to be slightly higher than powder in the as-received condition. It was also found the coating residual stress was purely compressive when cold spray is conducted at high gas pressure and temperature.

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Bartuli, C., T. Valente, F. Casadei, and M. Tului. "Advanced thermal spray coatings for tribological applications." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 221, no. 3 (July 1, 2007): 175–85. http://dx.doi.org/10.1243/14644207jmda135.

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Thermal spray coating is one of the most common procedures to improve the tribological properties of materials. Ceramic and cermet coatings, especially those based on oxides (alumina, chromium oxide, etc.) and carbides, are widely used for wear protection. Improvements under investigations are related to the possible use of nanostructured coatings and to the potential application of hybrid techniques. As a possible alternative, solid lubrication is proposed as integration or replacement of the traditional liquid lubrication in the case of severe operative conditions when there is the possibility of a lack of lubricant or when environmental problems can arise from waste disposal. In the present paper, results from experimental activities on different types of abrasion-resistant thermal spray coatings are presented: graded coating systems, specifically designed for titanium-based alloys, obtained by reactive plasma spraying and physical vapour deposition of titanium nitrides; nanostructured WC-Co coatings deposited by high velocity oxy-fuel; plasma-sprayed ceramic coatings based on oxides containing nanophases either from nanostructured precursors or postprecipitated by purposely designed thermal treatments; self-lubricant coatings deposited by plasma spray with the inclusion of graphite.

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Zhu, Qing Jun, and Kai Wang. "Microstructure and Anti-Corrosion Properties of Arc-Sprayed Aluminum Coating in Splash Zone." Advanced Materials Research 199-200 (February 2011): 1949–53. http://dx.doi.org/10.4028/www.scientific.net/amr.199-200.1949.

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Aluminum coatings were developed by arc spray on mild carbon steel Q235. Scanning electron microscopy detection shows that the coatings have good bonding with the substrate and have low porosity. The corrosion behaviors of the coatings in splash zone were studied. The results show that free corrosion potentials of aluminum coatings are much lower than that of Q235. Potentiodynamic polarization measurements reveal that the curves of aluminum coatings have activity anodic dissolution zone, passivation zone and super-passivation zone. Corrosion morphology and energy dispersive spectrometers show that Cl- can penetrate into the coatings and some of the substrate has been corroded. The arc spray Al-coating develops a film of corrosion products on the coating surface, which tend to seal the pores in the coatings. Arc spray aluminum coatings can protect the substrate from corrosion in splash zone.

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Jeandin, Michel, Dimitris Christoulis, Francois Borit, Marie Helene Berger, S. Guetta, G. Rolland, Vincent Guipont, et al. "Lasers and Thermal Spray." Materials Science Forum 638-642 (January 2010): 174–81. http://dx.doi.org/10.4028/www.scientific.net/msf.638-642.174.

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Basically, thermal spray and laser processing can be considered as half brothers since they show many common features due to the use of a (more or less) high-energy source for both. Their combination can therefore be very fruitful and prominent to achieve coatings, which results in their most recent and advanced applications. In the materials processing development story, the laser will thus have moved from cutting to coating. This keynote presentation focuses on the recently-developed coupling of laser processing to cold spray). In this dual process, a cold spray gun is combined to a laser head in a single device, e.g. on a robot. Series of coating experiments using various laser irradiation conditions, primarily pulse frequency, were carried out for Al-based and Ni-based alloys. Laser pre-treatment of the substrate just prior to cold spray, was shown to be beneficial for adhesion of cold-sprayed coatings. Adhesion improvement was exhibited and studied from LASATesting (LASAT for “LAser Shock Adhesion Test”). Incidentally, through LASAT also, the role of lasers in the development of thermally-sprayed coatings can be considered as major. Results are discussed in the light of a TEM (Transmission Electron Microscope) study of the coating-substrate interface with and without laser pre-treatment.

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Raza, Ali, Faiz Ahmad, Thar M. Badri, M. R. Raza, and Khurshid Malik. "An Influence of Oxygen Flow Rate and Spray Distance on the Porosity of HVOF Coating and Its Effects on Corrosion—A Review." Materials 15, no. 18 (September 12, 2022): 6329. http://dx.doi.org/10.3390/ma15186329.

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Thermal spray coating, exceptionally high-velocity oxyfuel (HVOF), improves the corrosion resistance and wear of metal. Coating parameters play a vital role in the properties of the coating. The quality of coating can be increased by selecting appropriate coating parameters. In the case of HVOF, the oxygen flow rate and spray distance are the most significant parameters that directly influence the porosity and corrosion resistance of the coating. Porosity is essential in thermal barrier coatings for low thermal conductivity, but there is a limit of porosity beyond which it can cause failure. Hence, understanding the effects of these parameters is essential to evaluate and further minimize the porosity in order to improve the corrosion resistance and durability of the thermal barrier coating. This article reviews hot corrosion in thermal barrier coatings, the stages of corrosion, the importance of spray parameters, and the effect of the oxygen flow rate and spray distance on the corrosion resistance of HVOF-sprayed coatings. Afterwards, the coating materials, the substrate, the flow rate of oxygen, the spray distance, and the fuel used during the HVOF spraying process from recent articles are summarized. In summary, this review compares the flow rate of oxygen and the spray distance with the corrosion capacity of the coating under different corrosive environments and materials to optimize these parameters for high-quality coating, which would sustain under high temperatures for future applications.

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Tailor, S., RM Mohanty, and PR Soni. "A Review on Plasma Sprayed Al-SiC Composite Coatings." Journal of Materials Science and Surface Engineering 1, no. 1 (2013): 15–22. http://dx.doi.org/10.52687/2348-8956/115.

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This review is done essentially to study results in the field of synthesis and characterization of SiC reinforced Al-SiC composite coatings using thermal spray process. SiC reinforced composite coatings produced by thermal spray process are being developed for a wide variety of applications, e.g. aerospace, automotive, structural and industrial. It is anticipated that, if properly deposited, Al-ceramic coatings could also provide improved properties like wear resistance and thermal barrier coatings. These results clearly demonstrate that the significant improvement in coating performance can be achieved by utilizing proper thermal spray conditions and SiC % in composite coatings. This paper presents a critical review on SiC reinforced Al-SiC composite coatings using thermal spray by various researchers in past years. The researcher’s findings with necessary parameters for achieve good Al-SiC composite coatings are given.

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Yang, De Ming, and Bo Han Tian. "Microstructure and Mechanical Properties of FeAl Coating Deposited by Low Pressure Plasma Spray." Applied Mechanics and Materials 333-335 (July 2013): 1916–20. http://dx.doi.org/10.4028/www.scientific.net/amm.333-335.1916.

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The FeAl intermetallic compound coatings were deposited by low pressure plasma spray, air plasma spray and high velocity oxy-fuel spray. The influence of three kinds of thermal spraying processes on the microstructure, microhardness, elastic modulus and fracture toughness of coatings was investigated. The results show that the FeAl coating deposited by low pressure plasma spray presents special mechanical properties such as higher microhardness and elastic modulus as well as lower fracture toughness, when compared with those by atmospheric plasma spray or high velocity oxy-fuel spray.

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Wielage, Bernhard, Thomas Lampke, and Thomas Grund. "Thermal Spraying of Wear and Corrosion Resistant Surfaces." Key Engineering Materials 384 (June 2008): 75–98. http://dx.doi.org/10.4028/www.scientific.net/kem.384.75.

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Thermal spraying is one of the most variable and diverse surface coating techniques concerning materials to be processed as well as possible geometries to be coated. The group of thermal spray processes covers a large parameter field to combine nearly each coating with each base material. Thermally sprayed coatings can be applied very evenly and therefore allow to be applied on final-shaped components. Otherwise, if further treatment or finishing is necessary, thermal spray coatings can be processed by grinding or even milling. Masking during the coating process permits the selective coating of specific surface parts or the application of required geometrically structures, e. q. conductor structures. The main application field of thermal spray coatings is the (combined) wear and corrosion protection of selected component parts.

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Cavaliere, Pasquale Daniele, Antonella Rizzo, Daniele Valerini, and Laura Capodieci. "Wear and Fretting Behavior of Cold Sprayed IN625 Superalloy." Metals 11, no. 1 (December 28, 2020): 49. http://dx.doi.org/10.3390/met11010049.

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The wear and fretting behaviour of IN625 cold spray coatings was analysed and the results are presented. The cold spray conditions were selected in order to obtain coatings with minimum porosity and maximum particles splat. This leads to compact and hard deposited material able to resist wear damaging and to dissipate energy during fretting. The coating’s strength was evaluated through nanoindentation that revealed an increased hardness from the surface toward the substrate. This different hardening behaviour from the coating surface toward the substrate leads to increased resistance to fretting and wear as the maximum stresses increase. This was revealed by scratch tests performed at linearly increasing loads that allowed identifying of the damage mechanisms acting on the coating as the triaxial stresses increase. The hardening behaviour of the coating also influenced the fretting behaviour revealed by the weight loss experienced by varying the fretting maximum load.

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Kong, Lingyan, Rifei Han, Yang Yang, Jiayi LI, Tianying Xiong, and Tiefan Li. "Fabrication Of Y2O3 Coatings By Cold-Spray." Advanced Materials Letters 10, no. 3 (December 31, 2018): 189–92. http://dx.doi.org/10.5185/amlett.2019.2188.

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KOECH, Pius Kibet, and Chaur Jeng WANG. "Performance Characteristics of Hot-dip and Plasma Spray Aluminide Coated Nickel-Based Superalloy 718 under Cyclic Oxidation in Water Vapour." Materials Science 25, no. 4 (June 27, 2019): 413–21. http://dx.doi.org/10.5755/j01.ms.25.4.21334.

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Aluminium coating due to its ability to form stable alumina oxide scale are commonly used to protect materials such as inconel 718 superalloys at high operational temperatures. Relevant properties of the oxide scale formed; growth rate and coating adherence is not only determined by the composition of the coating material used but is also influenced by the coating manufacturing process and the test condition. In the present work, effect of water vapour and thermocycling commonly prevailing on the morphology and composition of the alumina scales formed during high temperature oxidation was studied using hot-dip and plasma spray aluminium coatings. The coatings highly improved oxidation resistance of the alloy substrate with hot dip coating showing the lowest mass change compared to plasma spray. The results also show that the hot-dip coating has an inherently different morphology and growth rate compared to those formed on the plasma spray coating. High rate of oxidation, spallation and large voids with little protective alumina oxide layer were observed in moist condition test especially in plasma spray coatings.

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Li, Wen Sheng, and Yi Liu. "Effect of Ce on Wear Behavior of Plasma Spray Welded Novel Aluminum Bronze Coatings." Advanced Materials Research 418-420 (December 2011): 831–34. http://dx.doi.org/10.4028/www.scientific.net/amr.418-420.831.

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Aluminum bronze powders with free and 0.1wt%Ce were plasma spray welded on 45# carbon steel substrate, Effects of rare earth Ce on the microstructure and wear resistance of plasma spray welded novel aluminum bronze coatings were investigated. Tribological properties of coatings were tested on reciprocating sliding tester. Results showed that a small amount of Ce (0.1wt %) in novel aluminum bronze coating can refine the coating microstructure and the coating with 0.1wt%Ce process higher wear resistance compared to the Ce-free coating. Both of the coatings have different wear mechanisms.

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Shibe, Vineet, and Vikas Chawla. "Combating Wear of ASTM A36 Steel by Surface Modification Using Thermally Sprayed Cermet Coatings." Advances in Materials Science and Engineering 2016 (2016): 1–10. http://dx.doi.org/10.1155/2016/3894145.

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Thermal spray coatings can be applied economically on machine parts to enhance their requisite surface properties like wear, corrosion, erosion resistance, and so forth. Detonation gun (D-Gun) thermal spray coatings can be applied on the surface of carbon steels to improve their wear resistance. In the present study, alloy powder cermet coatings WC-12% Co and Cr3C2-25% NiCr have been deposited on ASTM A36 steel with D-Gun thermal spray technique. Sliding wear behavior of uncoated ASTM A36 steel and D-Gun sprayed WC-12% Co and Cr3C2-25% NiCr coatings on base material is observed on a Pin-On-Disc Wear Tester. Sliding wear performance of WC-12% Co coating is found to be better than the Cr3C2-25% NiCr coating. Wear performance of both these cermet coatings is found to be better than uncoated ASTM A36 steel. Thermally sprayed WC-12% Co and Cr3C2-25% NiCr cermet coatings using D-Gun thermal spray technique is found to be very useful in improving the sliding wear resistance of ASTM A36 steel.

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MORITA, Nobuyoshi. "Air Spray and Airless Spray Coatings." Journal of the Japan Society of Colour Material 85, no. 3 (2012): 122–29. http://dx.doi.org/10.4011/shikizai.85.122.

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Meekhanthong, K., and S. Wirojanupatump. "Characterization and Comparison of Thermally Sprayed Hard Coatings as Alternative to Hard Chrome Plating." Advanced Materials Research 974 (June 2014): 183–87. http://dx.doi.org/10.4028/www.scientific.net/amr.974.183.

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Thermal spray coatings have become one of the most potential for hard chrome replacement, particularly for wear and corrosion applications. In this study four types of hard coating materials were selected and thermally sprayed by suitable processes as the following designated codes (material/spray technique): Cr-Fe/HVOF, Cr-Ni/HVOF, WC-Ni/SF and Cr-Fe/AS. All of starting materials were characterized in order to create a correlation between spray materials and coating characteristics. SEM was employed for morphology and microstructure investigation. Particle size analysis was investigated by SEM and laser particle size analyzer. Coating characterization included surface roughness measurment by profilometer, porosity evaluation by image analysis and hardness test by Vicker microhardness tester. Microstructure of coatings was also revealed by SEM. Wear performance was evaluated by pin on disc test and dry sand rubber wheel abrasion test. Corrosion resistance was tested by potentiodynamic method. The results showed that particle size and morphology of starting powders were various depending on manufacturing method. Chemical compositions of starting materials showed great effect on coating properties and performance. Coatings deposited by HVOF and spray & fuse (SF) method showed typically dense and homogeneous structure than arc sprayed coating. WC-Ni/SF coating showed lowest abrasive wear rate compared to other thermally sprayed coatings. All Ni base coatings had significantly lower corrosion rates while Cr-Ni/HVOF coating had lowest corrosion rate. Although Cr-Ni/HVOF and WC-Ni/SF could be applicable for both wear and corrosion applications, for heat sensitive parts, Cr-Ni/HVOF coating could be a better alternative to spray and fuse.

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OGAWA, Kazuhiro. "Cold Spray Coatings." Journal of the Vacuum Society of Japan 60, no. 5 (2017): 187–92. http://dx.doi.org/10.3131/jvsj2.60.187.

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Van Steenkiste, T. H., J. R. Smith, R. E. Teets, J. J. Moleski, D. W. Gorkiewicz, R. P. Tison, D. R. Marantz, et al. "Kinetic spray coatings." Surface and Coatings Technology 111, no. 1 (January 1999): 62–71. http://dx.doi.org/10.1016/s0257-8972(98)00709-9.

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Jech, David, Ladislav Čelko, Lenka Klakurková, Karel Slámečka, Miroslava Horynová, and Jiří Švejcar. "Formation of Thermally Sprayed Coatings on Grid-Like Structure Substrate." Solid State Phenomena 258 (December 2016): 387–90. http://dx.doi.org/10.4028/www.scientific.net/ssp.258.387.

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The main goal of this contribution is to investigate the influence of the substrate morphology on the resulting thermally sprayed coatings microstructure. Therefore, three different representative coating systems and/or thermal spray techniques were utilized to produce the coatings on grid-like structure substrates: (i) CoNiCrAlY bond coat (BC) sprayed by high velocity oxygen fuel (HVOF) technique and yttria stabilized zirconia (YSZ) top coat (TC) sprayed by means of atmospheric plasma spray (APS) technique, (ii) YSZ coating sprayed by means of APS and (iii) YSZ coating sprayed by means of nanoparticle colloid suspension plasma spraying (SPS). The shadowing effect of thermal spray coatings in relation with the grid-like substrate structure was investigated in detail. Resulting microstructure of sprayed samples was studied utilizing light microscopy, digital image analysis, scanning electron microscopy, energy-dispersive spectrometer and X-ray diffraction techniques.

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Judd, Kiran G., Mala M. Sharma, and Timothy J. Eden. "Multifunctional Bioceramic Composite Coatings Deposited by Cold Spray." Key Engineering Materials 813 (July 2019): 228–33. http://dx.doi.org/10.4028/www.scientific.net/kem.813.228.

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Bioactive coatings have predominately been explored through plasma spray; but this technique has associated heat and melting of the feedstock materials thereby degrading the novel bioactive properties of hydroxyapatite (HA), as well as deteriorating the adhesion of the coating to the implant. The current study discusses a novel approach to producing biocompatible coatings that have been deposited at temperatures well below their melting point. The cold spray process was used to deposit 100 wt.% titanium (Ti) and composite powders with 80 wt% titanium (Ti) and 20 wt% hydroxyapatite (HA) onto Al6061, 316SS and Ti-6Al-4V substrates with the aim of achieving well-bonded homogeneous coatings; the effect of process parameters and substrate material was investigated. Preliminary results indicate the phase composition of the HA remained the same before and after synthesis of coating. Dense composite coatings were obtained with thicker coatings yielding the least amount of total porosity.

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Shafigullin, Lenar N., A. R. Ibragimov, and A. I. Saifutdinov. "Investigation into the Effects of High Temperature on Mechanical Properties of Thermal Spray Coatings Applied by Plasma Spraying." Solid State Phenomena 284 (October 2018): 1151–56. http://dx.doi.org/10.4028/www.scientific.net/ssp.284.1151.

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C. C. Berndt advanced investigations of mechanical properties of thermal spray coatings under 4-point bending. He found that this investigation method is sensitive to the mechanical properties of thermal spray coatings.This paper contains the detailed investigation results for thermal spray coatings of zirconium dioxide under 4-point bending, i.e. tests of the specimens subjected to spraying at varying conditions and pre-test soaking with the various duration at 1100 °С.It was established how the mechanical properties of thermal spray coatings changed depending on the spraying mode and high temperature soaking. The test results show that the double heat treatment of coatings is more preferable than one-time heat treatment as it make the properties change linearly. It is more easily controllable during operation of the components with thermal spray coating.

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Akinci, A., and F. Yilmaz. "The effect of epoxy‐polyester sealing of sprayed metal coatings for additional corrosion protection." Anti-Corrosion Methods and Materials 58, no. 1 (January 11, 2011): 26–30. http://dx.doi.org/10.1108/00035591111097675.

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PurposeThe purpose of this paper is to report salt spray testing of epoxy‐polyester top‐coating applied on Zn‐sprayed, Al‐sprayed and 85Zn‐15Al‐sprayed steel samples.Design/methodology/approachIn these tests, steel substrates sprayed with Zn, Al and 85Zn‐15Al coatings of different average thicknesses ranging from 120 to 210 μm were top‐coated with an epoxy‐polyester sealing layer. The corrosion test was performed with salt solution for over 2,000‐h. The degree of damage to the samples was evaluated quantitatively in terms of ratio of scribed to unscribed area of coating.FindingsIt was evident that the corrosion resistance of Al‐sprayed top‐coated surfaces was better than coated Zn‐spray or coated 85Zn‐15Al‐spray systems. As a result, when Al‐coated surfaces were top‐coated with polymeric layer, it was found that their surfaces were remarkably unaffected by the salt spray environment.Originality/valueThe salt spray measurements indicated that the Al‐spray epoxy‐polyester polymer double system was more durable than the other two systems (polymeric top‐coated Zn‐spay, and polymeric top‐coated 85Zn‐15Al‐spray), so far as protection from the chloride salt spray environment was concerned.

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Chen, Wen Long, Min Liu, Xiao Ling Xiao, and Xin Zhang. "Effect of Spray Distance on the Microstructure and High Temperature Oxidation Resistance of Plasma Spray-Physical Vapor Deposition 7YSZ Thermal Barrier Coating." Materials Science Forum 1035 (June 22, 2021): 511–20. http://dx.doi.org/10.4028/www.scientific.net/msf.1035.511.

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In order to study the effect of spray distance on the structure and high temperature oxidation resistance of feather-columnar thermal barrier coatings, the feather-columnar ZrO2-7wt. % Y2O3 (7YSZ) thermal barrier coatings were prepared at spray distances of 650 mm, 950 mm, 1100 mm, 1250 mm, and 1400 mm by plasma spray-physical vapor deposition (PS-PVD) technology. The surface roughness, micro morphology, and porosity of the sprayed 7YSZ coating were analyzed by 3D surface profiler, SEM, XRD, etc., and the impedance spectrum characteristics of the 7YSZ coating were characterized by electrochemical alternating current (AC) impedance technology. In addition, the high temperature oxidation resistance test of 7YSZ coating under different spray distances was carried out at a temperature of 1000 °C to study the influence of spray distance on the high temperature oxidation resistance of 7YSZ coating. The research results show that the surface roughness and porosity of feather-columnar 7YSZ coating increased sequentially with the increase of spray distance. At the same time, The YSZ grain boundary resistance value increased exponentially as the porosity of the coating increases. Where the spray distance was in the range of 650 mm and 1250 mm, the high temperature oxidation rate constant of the coating increased with the spray distance. However, the spray distance was greater than 1250 mm, and the spray distance had no significant effect on the high temperature oxidation resistance of the coating.

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Tahari, M., B. Luo, J. Geng, D. Jing, and M. Hatami. "Optimization of Thermal Spray Parameters of NiAl/Cr2C3 Coating by Taguchi Method." Solid State Phenomena 295 (August 2019): 9–14. http://dx.doi.org/10.4028/www.scientific.net/ssp.295.9.

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In this study the effect of thermal spray process on wear resistance of NiAl/Cr2C3 thermal spray coating has been investigated. For this purpose the NiAl power mixed with 10 %wt. Cr2C3 powder and milled for 1 hrs at argon atmosphere. The APS parameters such as voltage (V), current (A), spray distance (mm), powder feed rate (gr/min), were optimize using a response surface methodology. For investigation effect of spray parameters on quality of coatings, the porosity and wear resistance of coatings analyzed with SEM and pin on disk wear test. Results show that increase of voltage and current are more effective other parameters. Increasing of powder feed rate and spray distance raised porosity of coatings intensively.

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Thirumalaikumarasamy, D., V. Balasubramanian, S. Sree Sabari, R. Rajesh, and Medha R. Elayidom. "Predicting the Deposition Efficiency of Plasma Sprayed Alumina Coatings on AZ31B Magnesium Alloy by Response Surface Methodology." Applied Mechanics and Materials 877 (February 2018): 66–81. http://dx.doi.org/10.4028/www.scientific.net/amm.877.66.

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Plasma sprayed ceramic coatings are successfully employed in many industrial applications, where high wear and corrosion resistance with thermal insulation are needed. Plasma spray parameters such as power, stand-off distance and powder feed rate have significant influence on coating characteristics like deposition efficiency. This paper presents the use of statistical techniques specially response surface methodology (RSM), analysis of variance, and regression analysis to develop empirical relationships to predict deposition efficiency of plasma sprayed alumina coatings on AZ31B magnesium alloy. The developed empirical relationships can be efficiently used to predict deposition efficiency of plasma sprayed alumina coatings at 95% confidence level. Response graphs and contour plots were constructed to identify the optimum plasma spray parameters to attain maximum deposition efficiency in alumina coatings. Further, correlating the spray parameters with coating properties permits the identification of characteristics regime to achieve desired quality of coatings.

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Knudsen, Ole Øystein, Håkon Matre, Cato Dørum, and Martin Gagné. "Experiences with Thermal Spray Zinc Duplex Coatings on Road Bridges." Coatings 9, no. 6 (June 8, 2019): 371. http://dx.doi.org/10.3390/coatings9060371.

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Road bridges are typically designed with a 100-year lifetime, so protective coatings with very long durability are desired. Thermal spray zinc (TSZ) duplex coatings have proven to be very durable. The Norwegian Public Roads Administration (NPRA) has specified TSZ duplex coatings for protection of steel bridges since 1965. In this study, the performance of TSZ duplex coatings on 61 steel bridges has been analyzed. Based on corrosivity measurements on five bridges, a corrosivity category was estimated for each bridge in the study. Coating performance was evaluated from pictures taken by the NPRA during routine inspections of the bridges. The results show that very long lifetimes can be achieved with TSZ duplex coatings. There are examples of 50-year old bridges with duplex coatings in good condition. Even in very corrosive environments, more than 40-year old coatings are still in good condition. While there are a few bridges in this study where the coating failed after only about 20 years, the typical coating failures are due to application errors, low paint film thickness and saponification of the paint. Modern bridge designs and improved coating systems are assumed to increase the duplex coating lifetime on bridges even further.

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Xu, Yan, Yinfeng Wang, Yi Xu, Mingyong Li, and Zheng Hu. "Microscopic Characteristics and Properties of Fe-Based Amorphous Alloy Compound Reinforced WC-Co-Based Coating via Plasma Spray Welding." Processes 9, no. 1 (December 22, 2020): 6. http://dx.doi.org/10.3390/pr9010006.

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Plasma spray welding, as one of the material surface strengthening techniques, has the advantages of low alloy material consumption, high mechanical properties and good coating compactness. Here, the Co alloy, WC and Fe-based amorphous alloy composite coating is prepared by the plasma spray welding method, and the coating characteristics are investigated. The results indicate that the coatings have a full metallurgical bond in the coating/substrate interface, and the powder composition influences the microstructures and properties of the coating. The hardness of coatings increases with the mass fraction of the Fe-based amorphous alloy. The spray welding layer has a much higher wear resistance compared with the carbon steel, and the Fe-20 exhibits a superior wear resistance when compared to others. The results indicate that the amorphous alloy powders are an effective additive to prepare the coating by plasma spray welding for improving the wear resistance of the coating.

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Liu, An Qiang, Kui Xiao, Chao Fang Dong, and Xiao Gang Li. "Corrosion Behaviour of Zn-Al Pseudo-Alloy Coating on Carbon Steel in Chloride Environments." Advanced Materials Research 567 (September 2012): 45–48. http://dx.doi.org/10.4028/www.scientific.net/amr.567.45.

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In this work, Zn-Al alloy and Zn-Al pseudo-alloy coatings are deposited on carbon steel by arc spray technology. The corrosion behaviour of the coatings has been studied by salt spray test and electrochemical experiment. The morphology of the coatings exposed to salt spray test for 400 h was analyzed using SEM and EDS. Results show that corrosion rate of Zn-Al alloy coating is faster than that of Zn-Al pseudo-alloy coating and the steel substrate is attacked. The corrosion products formed on the surface of Zn-Al alloy coating were loose, with a large number of cracks and holes, but the Zn-Al pseudo-alloy coating is converted into a stable Al-rich oxide layer, which protects the steel substrate against corrosive attacks and enhances the corrosion resistance of the Zn-Al pseudo-alloy coating. Electrochemical tests show the Zn-Al pseudo-alloy coating as a sacrificial protection coating has the capability of providing sacrificial protection for the steel substrate.

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Zhu, Qing Jun, Kai Wang, and Xin Hong Wang. "Corrosion Behavior of Cold-Spray Aluminum Coating in Marine Environment." Advanced Materials Research 160-162 (November 2010): 364–68. http://dx.doi.org/10.4028/www.scientific.net/amr.160-162.364.

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Aluminum coatings were prepared by cold spray on mild carbon steel Q235. Scanning electron microscopy shows that the bond zone has good bonding between the substrate and the coating and the coatings consist of interlocked particles. The corrosion behaviors of the coatings in marine environment were studied by electrochemical methods. Free corrosion potentials of aluminum coatings are much lower than that of Q235. Potentiodynamic polarization measurements show that the curves of aluminum coatings have activity anodic dissolution zone, passivation zone and super-passivation zone. Corrosion morphology and energy dispersive spectrometers show that Cl- can penetrate into the coating and some of the substrate has been corroded. Corrosion only can happen on the coating surface and specific deeper sites, where Cl- can penetrate through pores. Cold spray aluminum coatings can protect the substrate from corrosion in marine environment.

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Spencer, Kevin, Vladimir Luzin, and Ming Xing Zhang. "Structure and Properties of Cold Spray Coatings." Materials Science Forum 654-656 (June 2010): 1880–83. http://dx.doi.org/10.4028/www.scientific.net/msf.654-656.1880.

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Cold spray coatings are considered promising for surface protection of light metal substrates but the mechanisms of bonding and coating build-up are still poorly understood and are the subject of continuing debate. A variety of coating/substrate combinations have been characterised in detail using electron microscopy to examine the nature of the interparticle and particle/substrate interfaces. Through-thickness residual stress profiles obtained via neutron diffraction show that the internal stress varies significantly depending on the coating materials. The work will present a picture of the cold spray deposition process using different material examples.

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Rafiq, Nafisah Mohd, and Shijie Wang. "Thermal Barrier Coatings: An Insight into Conventional Plasma Spray and Water-Stabilized Plasma Spray." Coatings 12, no. 12 (December 7, 2022): 1916. http://dx.doi.org/10.3390/coatings12121916.

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Thermal barrier coating (TBC) systems have presented an ongoing design issue in bids to improve the lifespan of coatings. A TBC can support an extended lifespan by repairing cracks between interfacial layers during high thermal exposure while at the same time increasing coating thickness. Two deposition techniques, atmospheric plasma spray and water-stabilized plasma spray (WSP), have been distinguished to understand mechanical and thermal performance based on their contrasting torch systems and microstructural characterization. This insight paper will underline the superiority of WSP coating and the need to leverage existing technology by optimizing better deposition parameters for future fatigue-resistant TBC production.

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Alshmri, F. "Metallic Coatings: Al-Zn Alloys." Advanced Materials Research 915-916 (April 2014): 608–11. http://dx.doi.org/10.4028/www.scientific.net/amr.915-916.608.

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Steel sheet has one major drawback, it is attacked by moisture at low temperatures and oxygen at high temperatures. Fortunately, coatings can provide protection to steel sheet from corrosion. Aluminum and aluminum zinc coatings can be applied by different methods. These are chemical vapor deposition coating (CVD), slurry coating, vacuum coating, spray coating, cladding, electroplating, electrophoresis, diffusion coatings, cementation, calorizing and hot dipping. This paper aims at providing a survey of these processes.

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Wu, Wei Qin, Qiang Li, Zhen Yi Wei, and Hui Ye. "Microstructure and Abrasive Wear Properties of Plasma Sprayed Nanostructured Al₂O₃-TiO₂-ZrO₂-CeO₂ Coatings." Advanced Materials Research 291-294 (July 2011): 117–24. http://dx.doi.org/10.4028/www.scientific.net/amr.291-294.117.

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Al2O3-TiO2-ZrO2-CeO2 coatings formed via a plasma spray approach. The optimal spray parameters of plasma sprayed nano-structured coating were determined by orthogonal experimental design, based on porosity, bond strength of the coatings and the partly melted(PM) zone percentage. Microstructure of the plasma sprayed nanostructured Al2O3-TiO2-ZrO2-CeO2 coating sprayed on the optimal spray parameters was analyzed. Wear map was established by wear experiments. The results show, nanostructured coating contains fully melted (FM) zone and PM zone, the increasing of the critical plasma spray parameter (CPSP) promote the decreasing of the PM zone percentage and the increasing of the bond strength of the coatings. The composition phases of the powder reacted to each other during the plasma spraying process. FM and PM zone resulted from fully melted droplets and partly melted particles respectively. Nanosized crystals and amorphous particles exist in the PM zone, liquid phase sintering is taken place in the PM zone. The main wear mechanism of plasma spraying coatings are plastic deformation and microplow, microfracture and grain spalling, fracture and delamination at different normal load and sliding speed in dry friction.

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Kim, Yeon Wook, Hee Jung Kim, and Hyun Myung Shin. "Microstructures and Tribological Properties of Plasma Arc Sprayed Al-Fe-Cr-Ti Quasicrystalline Coatings." Solid State Phenomena 124-126 (June 2007): 1601–4. http://dx.doi.org/10.4028/www.scientific.net/ssp.124-126.1601.

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One of the most important use of thermal spray coatings is for wear resistance. In this work, the tribological properties of plasma prayed Al83.7Fe7Cr6.3Ti3 quasicrystalline coatings have been studied. The quasicrystal powders of Al-base alloys were produced by gas atomization unit in vacuum. The plasma spray process was used to produce quasicrystalline coatings. Then, friction experiments were carried out on a pin-on-disc-type tribometer. The results indicated that the friction coefficient of Al83.7Fe7Cr6.3Ti3 quasicrystalline coating is about 50% lower than that of Al70Fe13Cu10Cr7 quasicrystalline coating.

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Goyal, Rakesh, Buta Singh Sidhu, and Vikas Chawla. "Multi-Walled CNT Reinforcement to Thermal Spray Coatings." Asian Journal of Engineering and Applied Technology 7, no. 2 (October 5, 2018): 93–98. http://dx.doi.org/10.51983/ajeat-2018.7.2.948.

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Thermal spraying coating techniques have emerged as very effective surface protection technology to apply protective coatings for corrosion and wear resistance applications. These coatings have gained more importance in recent past. Advances in powder and wire production have resulted in development of various types of surface coatings with excellent wear and corrosion resistance properties. Because of excellent mechanical, thermal and electrical properties of Carbon Nanotubes, CNTs reinforced composite coatings are being developed for various applications, e.g. automotive, aerospace and sports equipment industry. It is observed that if properly deposited, these CNTs ceramic composite coatings can provide improved properties like wear and corrosion resistance. It has been found that CNTs composite coatings can be successfully deposited by thermal spraying techniques, and these coatings provide better performance than conventional coatings. This paper reviews the performance of such coatings developed by various researchers.

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Wang, Jian Jiang, Xin Kang Du, Hong Wei Liu, and Jun Yan. "Al₂O₃ Multiphase Ceramics Coatings Sprayed by SHS-RFS Based on the Cladding Powders." Key Engineering Materials 280-283 (February 2007): 1111–14. http://dx.doi.org/10.4028/www.scientific.net/kem.280-283.1111.

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Based on SHS reactive flame spray technology, Al2O3 multiphase ceramics coatings were produced. Chemical copper-plating technology was used to produce the Al-CuO powders of copper cladding, which became individual SHS reactive units respectively. The phenomena and principles of the SHS reactive flame spray of the Al-CuO powders of copper cladding forming Al2O3 multiphase ceramics coatings were investigated. It was found that copper cladding of Al-CuO powders were necessary for the SHS reaction during the spray process. The better the cladding was, the more sufficient the SHS reaction, and the higher the transformation rate was. The Cu and Al2O3 fine molten drops produced by the SHS reaction bumped the substrate and flatted to form layer-shaped Al2O3-based multiphase ceramics coatings. The binding strength between the coating and substrate was as high as 19.8MPa, and the micro-hardness of the coatings was Hv712. The overall properties of the coatings were better than those of the ceramics coatings sprayed by the traditional flame spray.

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Molak, Rafał Maksymilian, Bartosz Morończyk, Ewa Ura-Bińczyk, Zbigniew Pakieła, Wojciech Żórawski, Krzysztof Jan Kurzydłowski, and Seiji Kuroda. "A Comparative Study of Aluminium and Titanium Warm Sprayed Coatings on AZ91E Magnesium Alloy." Materials 15, no. 6 (March 8, 2022): 2005. http://dx.doi.org/10.3390/ma15062005.

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Aluminium (Al) and titanium (Ti) coatings were applied on AZ91E magnesium alloy using a low-pressure warm spray (WS) method. The deposition was completed using three different nitrogen flow rates (NFR) for both coatings. NFR effects on coating microstructure and other physical properties were systematically studied. Microstructural characterization was performed using scanning electron microscopy (SEM), and the porosity was estimated using two methods—image analysis and X-ray microtomography. The coating adhesion strength, wear resistance, and hardness were examined. The protective properties of the coatings were verified via a salt spray test. Decreasing NFR during coating deposition produced more dense and compact coatings. However, these conditions increased the oxidation of the powder. Al coatings showed lower hardness and wear resistance than Ti coatings, although they are more suitable for corrosion protection due to their low porosity and high compactness.

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Szczucka-Lasota, B., and J. Piwnik. "New Technological Concept for Thermal Spray Protective Coatings." Archives of Metallurgy and Materials 62, no. 3 (September 26, 2017): 1499–504. http://dx.doi.org/10.1515/amm-2017-0232.

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Abstract Thermally spraying with micro-jet cooling is an innovate technology. It is possible to get fine dispersive structure of coatings during the shorter time in comparable to the classical high velocity oxygen fuel process (HVOF). It corresponds with good corrosion-erosion properties of structure. In the paper the parameters of the spraying with micro-jet cooling process are presented. The selected properties of coatings obtained by hybrid method are presented. The results of wear tests for hybrid and HVOF coating are compared. Results of investigation are very optimistic. The presented technology should be adapted to the actual production of protective coating for machines and construction working in wear conditions.

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Granata, Marco, Giovanna Gautier di Confiengo, and Francesco Bellucci. "High-Pressure Cold Spray Coatings for Aircraft Brakes Application." Metals 12, no. 10 (September 20, 2022): 1558. http://dx.doi.org/10.3390/met12101558.

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This paper addresses the potential use of high-pressure cold spray (HP-CS) technology to produce a film of friction material onto a low-carbon steel substrate to allow its use as potential composite material for the stators and rotors of aircraft brake units. Namely, WC-Cr3C2-Ni, WC-Ni, WC-Co-Cr, Cr3C2-NiCr and WC-Co coatings were deposited by using HP-CS, for the purpose of creating high friction and wear resistance composite coatings onto a low-carbon steel substrate. Tribological (friction coefficient and wear rate) and thermal properties as well as coating hardness and adhesion to the low-carbon steel substrate were evaluated to assess the potential use of the coatings as brake surface materials. The tribological and adhesion properties were evaluated by using a pin-on-disk high-temperature tribometer at 450 °C and a scratch test, respectively, whereas coatings hardness was evaluated with a Rockwell C hardness tester. Results obtained show that all coatings exhibit high friction coefficients and low wear rates compared to the low-carbon steel substrate, good adhesion, and elevated microhardness. Furthermore, the WC-Co coating shows better microhardness and thermal properties, while the WC-Co-Cr coating exhibited a better friction coefficient. Unfortunately, it was not possible to quantify the wear resistance due to the elevated roughness of the coatings, but from the analysis carried out on the alumina counterpart of the tribometer, it can be concluded that all the coatings exhibited a very low wear rate. In fact, after the tribological tests, it emerged that the alumina counterpart was more abraded than the investigated coatings.

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Spencer, Kevin, Daniel Fabijanic, and Ming Xing Zhang. "Cold Spray of Al-MMC Coatings on Magnesium Alloys for Improved Corrosion and Wear Resistance." Materials Science Forum 618-619 (April 2009): 377–80. http://dx.doi.org/10.4028/www.scientific.net/msf.618-619.377.

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Cold spray coatings are considered promising for surface protection of Mg alloys from wear and corrosion since the process temperature is low enough to avoid oxidation of the Mg or any adverse affects on artificial ageing heat treatments. A special version of cold spray known as Kinetic Metallization has been used to produce pure Al and Al alloy metal matrix composite (MMC) coatings on AZ91 Mg alloy substrates in the present work. This surface treatment produces dense coatings with high adhesive and cohesive strength, which have substantially higher hardness and wear resistance than the AZ91 substrate material. The influence of coating composition and subsequent heat treatment on wear and corrosion performance have been investigated, using pin-on-disc wear tests, salt spray testing and electrochemical polarisation techniques. The heat treatment of the cold spray coatings is compatible with the solutionising and T6 ageing heat treatment of AZ91Mg. The results show that cold spray deposition of MMC coatings is a simple and effective technique for improving the surface properties of Mg alloys, both in the as-cast and in the heat treated condition

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Bu, Ai Ming, Yong Fu Zhang, Yan Xiang, Yun Jie Yang, Wei Wei Chen, Huan Wu Cheng, and Lu Wang. "Deposition of SiO₂/SiC Coating on Carbon Fiber to Enhance the Oxidation Resistance." Materials Science Forum 999 (June 2020): 100–105. http://dx.doi.org/10.4028/www.scientific.net/msf.999.100.

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The objective of the present investigation is to study the oxidation resistance of SiO2/SiC coating on carbon fiber by electrolytic plasma spraying. The SiO2/SiC coating can be easily prepared within several tens seconds through this approach. The effect of spraying parameters (fixed point 5s and spray 5 times at the speed of 20mm/s) on the microstructure and oxidation resistance properties of coatings was discussed in this paper. Scanning electronmicroscopy (SEM), energy dispersive spectroscopy (EDS), x-ray photoelectron spectroscopy (XPS), thermogravimetric (TG) and DTG have been used to characterize the SiO2/SiC coatings. It was demonstrated that fixed-point spray 5s has better density and oxidation resistance coating, and the oxidation resistance increased by 12% compared with spray 5 times at the speed of 20mm/s. The fixed-point spray 5s coating was mainly composed of SiO2 and SiC. The SiO2 relative content was 72.6% and the SiC relative content was 27.4%.

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Drewien, C. A., R. G. Buchheit, K. R. Zavadil, and T. E. Neil. "Copper enrichment on Al 2024 surface after de-oxidizing treatment." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 860–61. http://dx.doi.org/10.1017/s0424820100150137.

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Coatings of lithium-aluminum-carbonate-hydroxide are being developed for corrosion protection of aluminum alloys against atmospheric and saline environments. Coating is performed by immersion of the aluminum part into a lithium carbonate-lithium hydroxide solution of pH=11.5. Before coating, the aluminum alloy is degreased in trichloroethylene, cleaned in a sodium carbonate-sodium silicate bath, and de-oxidized in nitric acid containing ammonium biflouride. Coating of most aluminum alloys is easily accomplished, and the coatings pass the ASTM B117 salt spray test. However, aluminum alloys that contain copper, specifically 2024-T3 and 7075-T6, yield coatings that fail the salt spray test, i.e. pitting and general corrosion is observed. Photographs of coatings after 168 hr salt spray exposure are shown in Figure 1 for Al 1100 and 2024-T3 alloys. A study has been undertaken to determine the influence of copper upon the corrosion properties of the coating.The surface of 2024-T3 was analyzed after each processing step in order to determine if copper enrichment at the specimen surface was occurring.

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Jiang, Qiong, Qiang Miao, Wen Ping Liang, Bei Lei Ren, Yi Xu, and Zheng Jun Yao. "Characterization of Microstructure, Phase Composition and Corrosion Resistance of Al-Zn-Si-RE Waterborne Coatings." Advanced Materials Research 887-888 (February 2014): 1076–79. http://dx.doi.org/10.4028/www.scientific.net/amr.887-888.1076.

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New waterborne Al-Zn-Si-RE coatings with improved corrosion resistance were introduced in this study. The corrosion resistance of Al-Zn-Si-RE coatings was evaluated by electrochemical measurements and salt spray test. Evolution of microstructure and phase composition at different exposure time in salt spray test was investigated by scanning electron microscopy and X-ray diffraction technique. The results indicate that Al-Zn-Si-RE coatings provide effective sacrificial protection to the steel substrate but exhibit lower corrosion rate and higher corrosion resistance compared to zinc aluminum coatings. The dense continuous corrosion layer formed on Al-Zn-Si-RE coating acts as a barrier layer, limiting the transport of aggressive species towards the coating-substrate interface and the corrosion rate of the coating; Zinc aluminum hydroxy carbonates are the dominant components in the corrosion layer of Al-Zn-Si-RE coatings.

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Journal articles on the topic 'Spray coatings'

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