Structural and Phase Transformations in Compact Titanium Nitride-Based Ceramics during High-Temperature Heating in Gaseous Media

— We have studied structural and phase transformations in the surface layer of compact titanium nitride-based ceramics during high-temperature annealing in vacuum, nitrogen, and air. The formation of an oxide phase during heat treatment of TiN x ceramics in air is controlled by bulk oxygen diffusion from the gas phase across an initially forming dense rutile TiO 2 layer. Annealing in vacuum or nitrogen in the range 400–800°C changes neither the phase composition nor the grain structure of the ceramics.