Al-TiO_2系XD合成的动力学分析

KINETIC ANALYSISON Al- Ti O2 SYSTEM BY XD SYNTHESISTECHNOLOGY

通过 XD(Exotherm ic Dispersion)法原位反应生成 Al2 O3与 Al3Ti增强的铝基复合材料 ,对反应过程动力学机理进行了探讨。结果表明 Al/ Ti O2 经充分混合、挤压成坯后 ,在真空炉中以一定的升温速率加热至 80 0℃左右时发生剧烈的化学反应。 SEM、XRD及能谱分析可知 :生成物 Al2 O3呈等轴颗粒状 ,Al3Ti呈棒状 ,并进一步说明了升温速率、铝含量。

Al2O3 and Al3Ti/Al in situ aluminum matrix composite material was prepared by means of XD (exothermic dispersion) synthesis technique. Its kinetic mechanism was also discussed. The results show that Al-TiO2 system can react in a very short time. The reaction is propagated in the combustion wave. It was also shown that aluminum initially reacted with TiO2 to form Al2O3 and reduced Ti. The Al2O3 and Al3Ti take the shape of equal axial particle and block respectively. A certain heating rate and a certain content of aluminum are needed, if thermal explosion occurs commonly in the Al-TiO2 system. The bulk shrinkage will become higher under the condition of lower heating rate, higher aluminum content and lower green density.