低温反应制备高纯度纳米BN包覆Al_2O_3和ZrO_2粉体

Preparation of Highly Pure Nano-sized t-BN Coating Al_2O_3 and ZrO_2 Composite Powders by a Low-temperature Chemical Reaction

硼酸和尿素在氮气中于 6 5 0℃反应 ,生成 t-BN-Al2 O3 和 t-BN-Zr O2 纳米包覆粉 .IR分析表明 ,反应产物中含 CH2 和 CN基团的杂质属尿素缩聚的复杂产物 ,经 4 5 0℃煅烧即可除去 .硼酸和尿素完全反应 ,得到纯净的纳米复合粉体 .BN产率大于 99% ,在复合粉中的含量与计算值吻合 .

Al 2O 3 and m-ZrO 2 powders with nanometers turbostratic-BN(t-BN) coating were prepared through chemical reaction in nitrogen with boric acid and urea as B source and N source, respectively. t-BN was obtained at 650 ℃ and turned into h-BN by heating the nanocomposite powder at 1 600 ℃ in argon. After being calcined in air at 450 ℃ for 5 h, the semi-finished compounds containing CH 2 and CN groups in the reaction products decomposed and the powders were purified. The yield of BN in the composite powders is more than 99%.