The effect of WC, Mo_2C, TaC content on the micro structure and properties of ultra-fine TiC_(0.7)N_(0.3) cermet

摘要

The effect of Mo_2C, WC and TaC on the micro structure and properties of ultra-fine TiC_(0.7)N_(0.3) cermet is studied. A series of cermets of varying nominal composition are prepared with ultra-fine powders, following normal powder metallurgical procedures. The results show that the addition of Mo_2C leads to the appearance of black cores in the ultra-fine cermet, which cannot be seen in medium particle cermet. However, excessive addition will result in the thickening of the rim, and the property goes down; the addition of WC makes the microstructure of TiCo.7No.3-10 wt%Mo_2C-14.5%NiCo cermet more complex, and many white cores appear in it; excessive addition will be detrimental for the hardness and strength of the cermet, and in ultra-fine TiC_(0.7)N_(0.3)-14.5%NiCo cermet, the optimum addition level of Mo_2C, WC and TaC is 10, 15 and 7 wt%, respectively.