Novel synthesis of fine γ-AlON powders from the hydrolysis of Al metal
Jian Yang, Weijie Han, Huibing Li, Qiming Chen, Wentao Xu, Youfu Zhou, Maochun Hong
Abstract
In this study, fine aluminum oxynitride (γ-AlON) powder was synthesized by solid-state hydrolysis byproduct for the first time, through the in-depth research of the hydrolysis of metal Al powder. It was found that hydrolysis begins on the surface of the Al particles, the initial solid-state hydrolysis byproduct is AlOOH and then Al(OH)<sub>3</sub>, and during the reaction stage, a unique core-shell structure with hollow outer core composite precursor is formed. Pure phase AlON powder can be synthesized by utilizing a composite precursor with an appropriate Al<sub>2</sub>O<sub>3</sub>/Al ratio (Al<sub>2</sub>O<sub>3</sub>/Al=10.27) under a flowing N<sub>2</sub> atmosphere. The core-shell structure shortens the diffusion distance between raw materials and reduces the nitridation temperature (1700°C). Furthermore, the unique hollow structure composite precursor makes some of the synthesized AlON powders also have a hollow structure, which is conducive to powder crushing, and fine nanoscale (D<sub>50</sub>=292 nm) powders can be obtained only grinding process. The combination of Al-H<sub>2</sub>O reaction and direct nitridation method has developed a new synthesis method of AlON powder, and also provides a new way for the recovery of solid-state hydrolysis byproduct of metal Al powder.