Abstract:

Using Al(NO₃)₃·9H₂O, Cu(NO₃)₂·3H₂O and Ti(OC₄H₉)₄ as raw materials, Al₂O₃ submicron powders were synthesized at a low temperature by the sol-gel process, and the phase and microstructure of powders were investigated.By doping Cu(NO₃)₂·3H₂O and Ti(OC₄H₉)₄ into alumina sol, a blue gel was obtained through placing the sol at 80℃ for a long time.Calcining the blue gel at 950℃ for 2 h produced amorphous Al2O3 powder with only a little γ-Al₂O₃ crystal phase, while α-Al₂O₃ nanopowders with a diameter of 80—100 nm were formed at the calcining temperature of 1000℃.As the calcining temperature increased to 1050℃, the grains grew to 200—400 nm.These results indicated that the synthesis temperature of α以硝酸铝、硝酸铜、钛酸丁酯为原料，采用溶胶-凝胶法低温合成亚微米氧化铝粉体，并对不同温度煅烧后粉体的物相与形貌进行表征。通过在硝酸铝的无水乙醇溶胶中引入少量CuO-TiO₂氧化物助剂前驱体，在80℃水浴中长时间静置后获得浅蓝色凝胶，在不同温度下煅烧该凝胶，结果发现：煅烧温度低于950℃时，所获得的粉体主要为无定形态，仅含有少量的γ-Al₂O₃;将凝胶在1000℃煅烧2 h后，全部变成粒径在80～100 nm之间、粉体颗粒呈球形的α-Al₂O₃;当煅烧温度升高到1050℃时，α-Al₂O₃的颗粒直径长大到