氢氧化铝热分解制备α-Al_2O_3纳米粉体

Preparation of α-Al_2O_3 nanopowder by thermal decomposition of aluminum hydroxide

以工业氢氧化铝为原料,采用引入添加剂的直接煅烧分解法制备出α-Al2O3纳米粉。制粉过程中,在氢氧化铝粉料中加入不同量的相变添加剂ZnF2、AlF3和纳米α-Al2O3晶种,在球磨罐中球磨3h,所得粉料分别于800℃、900℃、950℃、1000℃煅烧1h、1.5h、2h,并将制得的α-Al2O3粉体配制成固相体积分数为15%的悬浮液,加入分散剂并调节pH值=8进行分散处理,再将该悬浮液进行离心分离,使纳米粉被逐步地分级与分离出来。结果表明:向Al(OH)3粉料中加入1%ZnF2+1%晶种或3%AlF3+1%晶种,降低了相变温度,从而在950℃煅烧1h后即可得到晶粒度分别为32nm和37nm的α-Al2O3纳米粉。所制粉体经分散、离心处理后,二次粒度为168nm;TEM观察表明α-Al2O3颗粒呈分散良好的不规则形貌。

α-Al2O3 nanopowder was prepared with direct calcination -decomposition method, using industrial aluminum hydroxide as starting materials. Different amounts of phase-transition additives ZnF2,AIF3 and nano α-Al2O3 crystal seed were added into aluminum hydroxide powder,milled for 3 h in a ball mill,then fired at 800 ℃,990 ℃.950℃,1000℃ for 1 h, 1. 5 h,2 h respectively. The suspension solution with 15% vol of the solid phase was prepared by the α-Al2O3 powder. Dispersant was added and pH value was adjusted to 8. Then the solution was centrifugally separated,until the nanopowder was graded and separated gradually. The results show that adding 3% AIF3 ＋i% hand α-Al2O3 crystal seed or 1% ZnF2 ＋1% nano α-Al2O3 crystal seed decreases the phase transition temperature,and α-Al2O3 nanopowder with grain size of 37 nm or 32 nm are obtained after firing at 950℃ for 1 h. After being dispersed and centrifugal separated,the secondary particle size is 168 nm. TEM micrograph analysis shows well dispersed α-Al2O3 and irregular morphology.