高温高表面氧化铝新材料的制备化学研究Ⅲ.硅组分对硫酸铝铵法制高表面Al_2O_3的影响

Study on preparation chemistry of high surface area alumina resisting high temperature Ⅲ.Effect of silicon addition on the high surface area slumina prepared by aluminum ammonium sulface decomposition

采用硫酸铝铵法制得γ Al2 O3 超细粉末。使用XRD、BET、TEM和XPS等表征手段考察了Si的添加对所得γ Al2 O3 超细粉末热稳定性的影响。结果表明 ,经 110 0℃煅烧 32h后 ,未添加Si的γ Al2 O3 超细粉末BET表面积降为17 6m2 / g ,而添加Si的样品仍保持较高比表面 ,含Si 4 0 % (mass)的样品可达 12 3 5m2 / g。添加适量的Si可抑制过渡型氧化铝的高温烧结和向γ Al2 O3 的转变 ,使所得氧化铝具有较好的孔结构 ,从而提高了氧化铝的热稳定性。

Ultrafine gamma alumina was prepared by aluminum ammonium sulfate decomposition The effect of silicon addition on the thermal stability of the ultrafine gamma alumina were studied by XRD,BET,TEM and XPS Silicon was introduced in the gamma alumina using tetraethoxy silicon as precursor The surface area decreased from about 168m 2/g to 17 6m 2/g for the si free sample calcined at 1100℃ for 32h In contrast samples modified with silicon maintained high surface area after calcination at 1100℃ for 32h The surfacte area of sample containing 4 0% Si(mass) was about 123 5m 2/g The studies show that the addition of silicon can inhibit the sintering of micropores of alumina and suppress the transition to alpha phase Consequently,doping silicon in alumina improves the surface area and thermal stability at high temperature