用爆燃法制备纳米氧化锆及其机理

Preparation of zirconia nanocrystalite via deflagration method and mechanism research

采用复合燃料爆燃法制备具有不同晶形的纳米氧化锆粉末,研究了燃料的组分和用量对纳米氧化锆晶相的影响,以及用爆燃法制备氧化锆纳米粉体的机理.结果表明:借助在不同温度段硝铵、尿素和高氯酸铵等铵盐的渐次分解所释放出的气体的膨胀效应,实现了微晶间的气相阻聚;复合铵盐的爆燃产生的热量为氧化锆的瞬间转相提供了能量;调节复合燃料各组分的配比,可以制备出四方相、单斜相以及四方相/单斜相混相的纳米二氧化锆(粒径10-50 nm).

Nanometer powders with different crystal phases were synthesized via deflagration method using composite fuels. XRD, SEM and TEM were used to characterize the as-synthesized product respectively. The effects of fuel components and its dosage on the crystal phases of the as--synthesized powder were mainly investigated. The reaction mechanism was researched through DTA/TG analysis of the precursor and the reaction model was set up. The results show that the agglomeration of nanocrystatlites at high temperature is controlled effectively through expanding domino offect of gas, which is released gradually by composite fuels decomposing in different temperature range. The energy needed for phase transfering is afforded by composite fuels deflagrating. The different crystal phases with diameter of 10-50 nm are attained through adjusting the ratio of composite fuels.