pH对化学沉淀法制备纳米Al_2O_3粉体的影响

以硫酸铝铵、碳酸氢铵为原料,采用化学沉淀法,在不同pH条件下制备Al2O3的前驱体NH4Al(OH)2CO3,再经不同温度焙烧得到Al2O3粉体;利用扫描电镜、X射线衍射等分析手段对Al2O3粉体进行表征。结果表明,反应溶液pH的增大能降低Al2O3的相转变温度,但pH越大,所得到的Al2O3粉体越容易团聚;控制反应溶液的pH为9¹0,焙烧温度为800℃左右,可得到结晶度高的γ-Al2O3粉体,其平均晶粒径约为12 nm。

Effect of pH on Preparation of Al2O3 Nano-particles by Chemical Precipitation Method

Ammonium aluminum carbonate hydroxide was synthesized as the precursor of Al2O3 by precipitation reaction using ammonium aluminum sulfate and ammonium bicarbonate under different pH values.The precursor was agglomerated to obtain Al2O3 powders.XRD and SEM were used to characterize Al2O3 powders.The results show that the phase transformation temperature of Al2O3 can be reduced when the precursor is synthesized under high pH value.The larger pH values of the solution are,the more likely to be reunited alumina powders.Good crystallinity of γ-Al2O3 powders are gotten when the pH value is between 9 and 10 and the calcination temperature is 800 ℃.Its average grain size is about 12 nm.