| Title |
Effects of Feedstock Powder Characteristics on the Microstructural Features and Erosion Resistance of WC-12Co Coatings |
| Authors |
강소영(So-yeong Kang); 백경호(Kyeong-ho Baik); 윤상훈(Sang-hoon Yoon); 김형준(Hyung-jun Kim) |
| DOI |
https://doi.org/10.3365/KJMM.2018.56.2.113 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
WC-Co; HVOF coating; powder processing; porosity; erosion |
| 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) |