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2578 |
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Wednesday, September 28, 2011, Saal B2.1 2:50 PM Cold Spraying 4 |
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Effects of particle strength of feedstock powders on properties of warm-sprayed WC-Co coatings |
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Seiji Kuroda* / National Institute for Materials Science, Japan Pornthep Chivavibul / National Institute for Materials Science, Japan Makoto Watanabe/ National Institute for Materials Science, Japan Jin Kawakita/ National Institute for Materials Science, Japan Masayuki Komatsu/ National Institute for Materials Science, Japan Kazuto Sato/ Fujimi Incorporated, Japan Junya Kitamura/ Fujimi Incorporated, Japan |
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Warm Spray (WS) process, which is capable to control flame temperature, has been successfully applied to deposit WC-Co coatings in attempt to suppress detrimental reactions resulting from dissolution of WC into Co binder and decarburization by keeping particles temperature lower than their melting point. In this study, three nano-structured WC-12Co powders with different particle strength were used to deposit WC-Co coatings on stainless steel substrate by WS process. The deposition characteristics and coating properties were investigated. The results show that particle strength has substantial effects on the properties of the coatings. The deposition efficiency and porosity of the coating decreased with increasing particle strength. The coating deposited from the powder with low particle strength showed W2C and W phases and an increase in Co contents, while those deposited from the medium and high particle strength showed the phase composition essentially same as the feedstock powder. Consequently, the hardness and wear properties of the former coating were inferior to those of the others, whereas these properties of the coatings deposited from the powders with medium and high particle strength were essentially the same. The results indicate that particle strength in feedstock powder is an important factor to control the coatings properties and deposition efficiency for warm spraying. |