Microstructure and Abrasive Wear Resistance of Tic-WC-Co-Ni-Cr Cermets Obtained by Liquid Phase Sintering

摘要

This paper analyses the sinterability, microstructural characteristics and abrasive wear behaviour of TiC-WC-Cr_3C_2- (Co,Ni) cermets. Shrinkage is enhanced by increasing the binder phase content and is shifted to higher temperatures as the Ni content increases. WC additions are fully dissolved after sintering producing a typical core-rim structure with thick (Ti,W)C shells on Ti-rich cores. The (Ti,W)C shell growth kinetics are higher for the Co-based binder phase. Hardness values range from 940 to 1225 kg/mm~2 (HV10) for 32.3 and 25 wt.% binder contents respectively. The toughness of these materials is still lower than that of a reference hardmetal (WC-11wt.%Co, WC grain size:6 μm, 18 vol.% binder phase). Abrasion resistance is mainly affected by hardness, but toughness also plays a significant role. Wear mechanisms change from carbide microcracking and pullout to carbide attrition as toughness decreases.