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Vol.56, No.2, 113 ~ 121, 2018
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| Title |
| Effects of Feedstock Powder Characteristics on the Microstructural Features and Erosion Resistance of WC-12Co Coatings |
| 강소영 So-yeong Kang , 백경호 Kyeong-ho Baik , 윤상훈 Sang-hoon Yoon , 김형준 Hyung-jun Kim |
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| Abstract |
| WC-Co coatings manufactured by high velocity oxy-fuel (HVOF) spraying have a superior hardness and wear resistance. In this study, HVOF-sprayed WC-12Co coatings from three different feedstock powders were evaluated in terms of microstructural features, carbide decomposition and erosion resistance. The fusedcrushed and the sintered-crushed WC-12Co powders had an angular shape, a dense internal structure and a high apparent density, whereas the agglomerated-sintered powder was found to have a spherical morphology with a porous internal structure and a relatively low apparent density. These differences in powder characteristics significantly affected porosity, carbide decomposition, microhardness and erosion resistance in the WC-Co coating. The fused-crushed coating contained a large amount of intersplat pores and a low fraction of carbide, resulting in the lowest microhardness. The erosion wear rate of the fused-crushed coating increased sharply with increasing impact angle, due to the brittle damage mechanism. The agglomerated-sintered coatings had a low porosity and a high microhardness, and consequently exhibited superior erosion wear resistance with no dependency on impact angle. (Received October 11, 2017; Accepted November 14, 2017) |
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| Key Words |
| WC-Co, HVOF coating, powder processing, porosity, erosion |
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