Effect of TiO₂ Sintering Assistant Addition and Sintering System on Sintering Densification Behavior of Chromium Oxide

Cr₂O₃ material was prepared under different temperatures (1 000–1 500 °C) and different protective atmospheres (argon, nitrogen) by using Cr₂O₃ powder as raw material and TiO₂ powder as sintering assistant. The effect of TiO₂ addition (0, 1%, 3%, 5%, 5%, mass fraction), sintering temperature and sintering atmosphere on sintering densification behavior of Cr₂O₃  was analyzed. The results show that with the increase of TiO₂ addition, the linear shrinkage rate and relative density of the sample increased, and the densification degree increased. When the TiO₂ addition was 5%, the linear shrinkage rate and relative density reached the maximum, which were 16.25% and 92.51%, respectively. After adding TiO₂, (Cr_0.88Ti_0.12)₂O₃ replacement solid solution was formed to improve the diffusion mass transfer rate and promote sintering densification. With the increase of sintering temperature, the sintering densification degree of Cr₂O₃ first increased and then decreased, and reached the maximum at 1 300 °C. After sintering in nitrogen atmosphere, the Cr₂N film was formed on the surface of Cr₂O₃ particles after sintering in nitrogen, which could play a similar role to the liquid phase and improve the sintering speed, the Cr₂O₃ prepared was denser than that prepared in argon atmosphere.