Preparation Of AlON Ceramics By Solid-State Reaction And Carbothermal Reduction And Nitridation Processing

The spinel aluminum oxynitride(Al ON) is an important single-phase, stable solid solution ceramic of Al2O3-Al N system. Al ON transparent ceramic has similar excellent optical and mechanical properties as the sapphire single crystal, which is a new functional and structural material. Al ON transparent ceramic can be used in the area of window, dome, armor, infrared detection and many other aspects that becomes the focus in the study of transparent ceramic.In this work, Al ON ceramics were fabricated by the solid-state reaction method using commercial Al2O3 and Al N as starting powders. The influence of different proportion of Al2O3/Al N on the phase of the obtained ceramics was investigated. The results show that the composition for single-phase Al ON is 28-32 mol% Al N. In addition, Al ON ceramics were fabricated with Y2O3, Mg O and La2O3 as sintering aids. The effect of different contents of sintering aids on the densification behavior and microstructure of the obtained ceramics were investigated. The addition of Mg O is not only benefit to the ceramic densification but also inhibiting grain growth.In addition, Al ON powders were synthetized by carbothermal reduction and nitridation process using commercial γ-Al2O3 and nanometer Carbon as starting powders. The influence of different proportion of γ-Al2O3/C on the phase, partical size and specific surface area of the synthetized powders were investigated. Al ON ceramics were also sintered at different temperatures using as-synthesized Al ON powder. The composition of synthesized powder is single-phase Al ON when the content of carbon powder ranges from 5.4wt% to 6.0wt%.