Effect of raw materials on carbothermal reduction synthesis of γ-aluminum oxynitride spinel powder

摘要

The effect of starting Al2O3 materials on synthesisof γ-aluminum oxynitride spinel (γ-AlON) powder bycarbothermal reduction has been investigated. Whether usingAl(OH)3, boehmite, dried gel, or calcined alumina as an aluminasource, the reaction rate is faster than that using α-Al2O3. Thatis because the oxygen distribution in γ-Al2O3 is cubic closepacked as the non-metal arrangement in AlON spinel is whereasthat in α-Al2O3 is hexagonal close packed. When hydratedaluminas used lose structural water and transform into γ-Al2O3in heating cycle, γ-Al2O3 is easily reduced and nitrided intoAlON spinel after a slight adjustment in the cation positions andproportions is made in the reduction process of alumina. Theparticle morphology of the product after carbothermal reductionwas strongly influenced by the type of alumina source employed.