流化床化学气相沉积法制备近化学计量比的TiN粉体

Preparation of nearly-stoichiometric TiN powder by chemical vapor deposition in fluidized-bed

传统气-固反应工艺制备TiN粉体存在难以逾越的内扩散控制过程,导致制备高纯、正化学计量比的TiN粉体至今存在巨大困难。提出了流态化化学气相沉积工艺(FBCVD)制备高质量TiN粉体,即基于TiCl4-N2-H2体系,在往复运动的TiN种子粉体上沉积新生高质量TiN粉体的新方法。实验发现,当TiN种子粉体粒径大于52.95μm时,即使在1000℃沉积2 h也不会失流,同时在TiN种子粉体上获得了亚微米级的结节状新生TiN颗粒。通过氧氮分析仪和XRD分析发现,新方法显著提升了粉体的氮含量,获得了近化学计量比的TiN0.96,且氧含量下降了约40%。此外,流化床中气相沉积TiN的生长模式为岛状生长模式,为工业中制备高质量TiN粉体提供了一种新的方法。

The traditional gas-solid reaction process for preparing TiN powder has an insurmountable internal diffusion control process,which has caused great difficulties in preparing high-purity,positive stoichiometric ratio TiN powder.Herein,to address the issue,a fluidized bed chemical vapor deposition(FBCVD)process was developed to fabricate high quality TiN powders based on TiCl4-N2-H2 system.The results showed that when the average particle size of TiN seeds was larger than 52.95μm,they can realize long-term stable fluidization at 1000℃ even for 2h and the obtained powders was nearly stoichiometric ratio TiN0.96.In addition,the oxygen content of obtained TiN powders decreased about 40% compared with raw TiN seeds.Moreover,the growth of TiN was controlled by the Volmer-Weber growth mode,which provides a new horizon for preparing high quality TiN powder in industry.