Microstructure of hot pressed Ti(C, N)-based Cermets

Starting from commercial nanosize TiN and carbon black powders, this study set up a synthesis of fine and pure Ti(C,N) powders. The best experimental conditions were found using a mixture TiN+10 wt.% of C processed at 1430 C for 3 h under flowing Argon. The as-produced Ti(C,N) powder showed regularly shaped particles (100-300 nm), little agglomeration and a C/(C+N) atomic ratio ranging from 0.4 to 0.6. A mixture of Ti(C,N) +15.3 wt% of WC and 9.1 wt% of Ni+Co was prepared and hot pressed at 1620 C for 30 min (5 MPa of applied pressure). Microstructure and some properties of the sintered ceramic-metal composite (cermet) was investigated by SEM-EDX and XRD. The material exhibited a refined microstructure, but also the presence of textured flaws of several tenths of microns, attributed to not-optimized sintering conditions. The results were compared with those obtained from a cermet manufactured with the same nominal formulation but with commercial TiC0.5N0.5 raw powder.