Effect of Grain Growth Inhibitor on Sintering of Nanophase WC-10wt%Co

초미립 WC-l0wt%Co 초경 분말의 소결시 입자 성장 억제제 첨가 효과 연구

A radically new approach to the in situ synthesis of the consituent phases of a composite structure has enabled the production of a new WC/Co materials with an ultrafine microstructure. The process for synthesizing nanophase WC/Co powders consists of spray drying from solution to form a homogeneous precursor powder, and thermochemical conversion of the precursor powder to the nanophase WC/Co powder. Near theoretical density of pure nanophase WC-10 wt%Co has been obtained in only 30 sec at 140$0^{\circ}C$. But WC particles were grown up very rapidly with longer sintering time to get full density. To overcome coarsening of WC particle during sintering, VC, TaC and VC/TaC were used as the grain growth inhibitor with different amount respectively. VC/TaC doped WC-10 wt%Co was shown superior hardness and TRS and microstructure was maintained ultrafine scale (average WC size is less than 0.1 ${\mu}{\textrm}{m}$).