Preparation of Ti(N, C) Based Nanosized Powders and Their Densification

Abstract

The nanosized powders of titanium carbonitride find application in manufacture hard corrosion resistant materials, cutting tools and metal matrix composites. The aim of present work was preparation of nanosized titanium carbonitride powders and manufacture dense bodies. The nanosized powders were prepared by evaporation of titanium or titanium hydride in an inductively coupled nitrogen plasma. The formation and growth of product particles were controlled by introducing cold nitrogen, hydrocarbon or their mixture with ammonia into the vapour region. Presence of ammonia in the plasma flow promotes formation of titanium carbonitride with high content of carbon and eliminates decomposition of hydrocarbons. Particle size of the produced powders is in the range of 20 – 100 nm depending on the process parameters. Ti(N, C) particles have a characteristic cubic shape. The nanosized particles of Ti(N, C) with the specific surface area in the range of 33 – 43 m2/g are stable in air at room temperature but depending on the specific surface they absorb 1.8 – 3.2 wt.% of oxygen. The Ti(N, C) based bodies were prepared by hot pressing and sintering at 1600 – 1800 °C. The density of ceramics depends on sintering temperature, particle size, and composition of powders and strongly on content of carbon.