Preparation of ultra-fine TiC_(0.7)N_(0.3)-based cermet

摘要

Since ultra-fine Ti(C,N) has large surface and high activity, preparation of high performance cermets using ultra-fine Ti(C,N) powders is very difficult at the present. In the paper, deoxidation process of ultra-fine TiC_(0.7)N_(0.3) powder is carried out firstly, and the oxygen content of ultra-fine TiC_(0.7)N_(0.3) powder can be decreased from more than 1 wt percent to 0.06 wt percent; milling technology of ultra-fine TiC_(0.7)N_(0.3)-based cermet is studied in the paper, the results show that the optimum milling time is 45 h and the ball to powder weight ratio is 15 is to 1, and the dispersant helps to achieve a homogeneous distribution of the ultra-fine powder; during vacuum sintering of ultra-fine cermet. pores tend to form, hence NT6B shows relatively lower properties than NT6A. After HIP process (1350 deg C, 90 min, 70 MPa), the porosity can be largely decreased. The prepared ultra-fine cermet has typical core-rim microstructure, finer grain size and enhanced properties.