Synthesis of t-ZrO₂-TiN composite nanopowders by selective nitridation

A novel composite powder preparation technology based on selective reaction in solid solution was studied. The principle of thermodynamics was utilized to calculate the selective nitridation conditions with ammonia in a t-ZrO₂-TiO₂ solid solution system. The influence of reaction temperature on the phase structure was investigated. Titanium nitride was synthesized by ammonia reduction and nitridation under flowing ammonia atmosphere while the content and tetragonal phase structure of zirconia was unchanged. The average particle size and morphology of nanopowders before and after nitridation were characterized by specific surface area measurement and transmission electron microscopy. The particle size of t-ZrO₂ is about 50-70 nm in the composite powders after nitridation. Elemental quantitative analysis indicates that the nitridation ratio reaches 98%.