Microwave sintering of TiCN-based cermets prepared from electroless Co-coated(Ti,W,Mo,V)CN powders

摘要

In this study,the densification and microstructure evolution of microwave sintered(Ti,W,Mo,V)CN-30 wt%Co cermets,which was prepared from electroless cobalt-coated submicron(Ti,W,Mo,V)CN powders,were investigated.The microwave sintering of mechanical milled powders as well as the conventional sintering of mechanical milled powders and Co-coated(Ti,M)CN powders was conducted as a comparison.Experimental results indicate that a slight densification is observed at sintering temperature of≤1100℃followed by a sharp shrinkage at the temperature range of 1200-1350℃due to the substantial formation of liquid phase at 1200℃.The 98.5%densification is obtained at 1375℃.Moreover,the samples sintered at 1375℃for 10 min have the micro structure with fine and homogeneous grains of about 700 nm.Compared to mechanical milling,electroless cobalt plating suppresses coalescence of neighboring grain at the solid-state sintering stage,thereby inhibiting grain growth.The mechanical properties of samples sintered at different temperatures for varied holding time were also discussed.