TiO2与SiO2掺杂对Al2O3相转变的研究

通过球磨混合法,制备TiO₂、SiO₂和TiO₂+SiO₂掺杂的Al₂O₃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Al₂O₃粉体相转变温度的影响。研究结果表明,TiO₂、SiO₂掺杂对γ-Al₂O₃向α-Al₂O₃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-Al₂O₃完全转变为α-Al₂O₃的温度降低100 ℃和125 ℃。而TiO₂+SiO₂复合掺杂对γ-Al₂O₃向α-Al₂O₃相转变的促进作用优于TiO₂、SiO₂单独掺杂。TiO₂、SiO₂的质量分数均为0.3%时,复合掺杂可使γ-Al₂O₃完全转变为α-Al₂O₃的温度降低150 ℃。此外,还对TiO₂、SiO₂和TiO₂+SiO₂掺杂促进Al₂O₃粉体相转变的机理作了简单分析。

Investigation on Phase Transition of Al2O3 Doped with TiO2 and SiO2

TiO₂, SiO₂ and TiO₂ + SiO₂ doped Al₂O₃ 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 Al₂O₃ powder were compared. The results show that TiO₂ and SiO₂ doping promote the phase transition from γ-Al₂O₃ to α-Al₂O₃ effectively. In the case of doping mass fraction of 0.5%, temperatures of γ-Al₂O₃ to α-Al₂O₃ are reduced by 100 ℃ and 125 ℃ respectively. The effect of TiO₂+ SiO₂ co-doping on the phase transition of Al₂O₃ is better than that of TiO₂ and SiO₂ alone. The doping of 0.3% (mass fraction) TiO₂ and 0.3% (mass fraction) SiO₂ reduces the temperature of γ-Al₂O₃ to α-Al₂O₃ by 150 ℃. In addition, the mechanism of TiO₂, SiO₂ and TiO₂+SiO₂ doping to promote the phase transformation of Al₂O₃ powder was analyzed.