碳酸氢铵沉淀法制备纳米氧化铝粉体的性能与表征

Properties and Characterization of Nano-alumina Powders Precipitated by Ammonium Bicarbonate

以Al(NO3)3.9H2O、NH4HCO3为原料,采用化学沉淀法制备了NH4Al(OH)2CO3和AlO(OH)前驱体。通过X射线衍射、透射电镜和热膨胀仪研究发现:由NH4Al(OH)2CO3热处理得到的Al2O3粉体具有较高的结晶温度和α相变温度;其粒径较小,分散良好,具有较好的烧结活性;非晶态、亚稳相和稳定的α相氧化铝的烧结曲线上分别具有不同数量的拐点,亚稳相氧化铝烧结过程中的α相变产生大量的气孔,阻碍了烧结体的致密化。

NH4Al （OH）2CO3 and AlO （OH） precursors were prepared using Al（NO3 ）3 and NH4 HCO3 as raw materials. The phase and grain size of the powders calcined at different temperatures were investigated by XRD, TEM. The sintering properties were studied using automatic high temperature dilatometer. The results show that the crystallization temperature and α phase transformation temperature of the alumina powder obtained from NH4 Al（OH）2CO3 are higher than those of alumina from AlO （ OH）, respeαively. The powder from NH4Al （OH）2CO3 is superfine and homogeneously dispersed. The sintering property is better than that of the powder from AlO （OH）. There are different inflexion points on the sintering curves of amorphous, metastable phase and stable α phase alumina. When metastable phase transforms into α-alumina, a lot of pores generate, which hinders the densification of sintering.