Sintering behavior of titanium-titanium nitride nanocomposite powders

Abstract

The sintering behavior of titanium-titanium nitride nanocomposite powders has been investigated by dilatometry. Micron-sized titanium powders of average particle size of similar to 12 mu m and nano sized titanium nitride powders of average particle size of similar to 50 nm were used to produce two compositions of Ti-8 wt%TiN and Ti-15 wt%TiN by physical mixing and ultrasonification. Dilatometry was carried out by constant rate of heating (10 degrees C/min) to various temperatures in the range of 650-1250 degrees C followed by isothermal holding for I h. The effect of nano TiN dispersion on the sintering onset temperature, linear shrinkage, shrinkage rate, activation energy, and microstructure of titanium was investigated. The sintering of titanium-titanium nitride nanocomposites was found to be influenced by the sintering between the Ti-Ti contacts (self diffusion), Ti-TiN contacts (diffusion of N into Ti), TiN-TiN contacts, the role of oxygen as well as the alpha-beta transformation in titanium. (C) 2006