TiO_(2)与SiO_(2)掺杂对Al_(2)O_(3)相转变的研究

Investigation on Phase Transition of Al_(2)O_(3)Doped with TiO_(2)and SiO_(2)

通过球磨混合法,制备TiO_(2)、SiO_(2)和TiO_(2)+SiO_(2)掺杂的Al_(2)O_(3)粉体,经不同温度煅烧后进行X射线衍射(XRD)测试,比较研究这三种掺杂对Al_(2)O_(3)粉体相转变温度的影响。研究结果表明,TiO_(2)、SiO_(2)掺杂对γ-Al_(2)O_(3)向α-Al_(2)O_(3)的相转变均有促进作用。在掺杂质量分数为0.5%的情况下,二者可分别使γ-Al_(2)O_(3)完全转变为α-Al_(2)O_(3)的温度降低100℃和125℃。而TiO_(2)+SiO_(2)复合掺杂对γ-Al_(2)O_(3)向α-Al_(2)O_(3)相转变的促进作用优于TiO_(2)、SiO_(2)单独掺杂。TiO_(2)、SiO_(2)的质量分数均为0.3%时,复合掺杂可使γ-Al_(2)O_(3)完全转变为α-Al_(2)O_(3)的温度降低150℃。此外,还对TiO_(2)、SiO_(2)和TiO_(2)+SiO_(2)掺杂促进Al_(2)O_(3)粉体相转变的机理作了简单分析。

TiO_(2),SiO_(2)and TiO_(2)+SiO_(2)doped Al_(2)O_(3)powders were prepared by ball milling.After calcination at different temperatures,X-ray diffraction(XRD)tests were carried out,and the effects of these three kinds of doping on the phase transition temperature of Al_(2)O_(3)powder were compared.The results show that TiO_(2)and SiO_(2)doping promote the phase transition fromγ-Al_(2)O_(3)toα-Al_(2)O_(3)effectively.In the case of doping mass fraction of 0.5%,temperatures ofγ-Al_(2)O_(3)toα-Al_(2)O_(3)are reduced by 100℃and 125℃respectively.The effect of TiO_(2)+SiO_(2)co-doping on the phase transition of Al_(2)O_(3)is better than that of TiO_(2)and SiO_(2)alone.The doping of 0.3%(mass fraction)TiO_(2)and 0.3%(mass fraction)SiO_(2)reduces the temperature ofγ-Al_(2)O_(3)toα-Al_(2)O_(3)by 150℃.In addition,the mechanism of TiO_(2),SiO_(2)and TiO_(2)+SiO_(2)doping to promote the phase transformation of Al_(2)O_(3)powder was analyzed.