금속분말사출성형법으로 제조된 WC-10Co계 초경합금 소결체의 탄소첨가량에 따른 특성변화

초록

In order to investigate the microstructure and mechanical properties of WC-10 wt% Co insert tool alloy fabricated by PIM (Powder Injection Molding) process, the feedstock of WC-10 wt% and wax used as a kind of binder were mixed together by two blade mixer. After injection molding, the debinding process was carried out by two-steps. First, solvent extraction, in which the binder was eliminated by putting the specimen into normal hexane for 24 hrs at 60℃, and subsequently thermal debinding which was conducted at 260℃ and 480℃ for 6 hrs in the mixed gas of H_2/N_2, respectively. Meantime, in order to compensate the decarburization due to hydrogen,1.2~1.8% of carbon was added to ensure the integrity of the phase. Finally, the specimens were sintered in vacuum under different temperatures, and the relative density of 99.8% and hardness of 2100 Hv can be achieved when sintered at 1380℃, even the TRS is lower than the conventional sintering process.

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