以铝为助剂通过机械合金化和热处理制备Ti_3SiC_2

Preparation of Ti_3SiC_2 by mechanical alloying and heat treatment with Al as aidant agent

采用Ti、Si、C单质粉末为原料,添加少量Al元素粉末为助剂,通过机械合金化和热处理制备高纯Ti3SiC2材料。采用XRD和SEM研究该材料的物相组成和显微结构。研究结果表明,机械合金化Ti、Si、C单质混合粉末,会诱发自蔓延反应,生成组成相为TiC、Ti3SiC2、TiSi2和Ti5Si3的粉末与颗粒产物。添加适量的Al元素可消除硅化物,明显促进Ti3SiC2的反应合成。采用Ti、Si、C、Al单质粉末进行机械合金化,可制备出主相为TiC与Ti3SiC2的粉末与颗粒产物。对掺Al机械合金化粉末产物压制后,在900~1 100℃热处理2 h,可制备出纯度大于95%（质量分数）的Ti3SiC2材料,而颗粒产物在900~1 200℃进行热处理,亦可获得纯度为96%的Ti3SiC2材料。但在1 300℃,热处理产物中的Ti3SiC2会发生严重分解,部分分解为TiC和少量硅化物,使产物纯度降低。

Using Ti,Si and C powders as raw materials,Ti3SiC2 materials were synthesized by mechanical alloying method with the aid of small amount of Al,and subsequently heat-treated.The phase composition and microstructure were measured by XRD and SEM.The results show that mechanical alloying of Ti,Si and C powders may induce self-propagation reaction.The phase analysis reveals the resultant powders and granules contain TiC,Ti3SiC2,TiSi2 and Ti5Si3 phases.However,addition of Al may restrain the formation silicide,which obviously promoted the synthesis of Ti3SiC2.When the initial materials are Ti,Si,C and Al powders,the main phases of the mechanically alloyed powders and granules are Ti3SiC2 and TiC.The as-milled powders contained Al were pressed to compacts and heat-treated at 900~1 300 ℃ and as-milled granules heat-treated at 900~1 200 ℃ for 2 h.The results indicate that both as-milled powders and granules samples can obtain products containing Ti3SiC2 with purity above 95%（mass fraction） after heat-treatment.But,at 1 300 ℃,Ti3SiC2 may decompose seriously,and be partially decomposed to TiC as well as small amounts of silicides,which result in the purity of Ti3SiC2 materials decrease.