掺Si对热压合成Ti_2AlC/Ti_3AlC_2的影响及理论分析  

Effects on synthesis of Ti_2AlC/Ti_3AlC_2 doped with Si from elemental powders by hot pressing and theoretical analysis

作　　者：王苹[1] 梅炳初[2] 闵新民[1] 洪小林[2] 周卫兵[2] 

机构地区：[1]武汉理工大学理学院,湖北武汉430070 [2]武汉理工大学材料复合新技术国家重点实验室,湖北武汉430070

出　　处：《功能材料》2007年第6期1037-1040,共4页Journal of Functional Materials

基　　金：国家自然科学基金资助项目(50572080)

摘　　要：采用热压工艺以Ti、Al、Si元素粉和活性炭为原料,分别以2.0Ti/1.1Al/1.0C(摩尔比)及以0.1和0.2mol的Si取代Al,合成了Ti2AlC/Ti3AlC2块体材料。通过建立Ti2AlC、Ti3AlC2和掺Si的计算模型,计算了平均原子净电荷和平均共价键键级。结果表明:以元素粉2.0Ti/1.1Al/1.0C为原料在1450℃热压60min合成只含有非常少量Ti3AlC2的Ti2AlC材料;当Si取代Al达到0.2mol时,作用非常明显,表现为使同一温度下Ti3AlC2含量增加而Ti2AlC含量减少。另外,应用掺Si后对原子净电荷和共价键键级的影响解释了实验结果。Ti2AlC/Ti3 AlC2 bulk material were synthesized by hot pressing using elemental powder mixture of Ti, Al,Si and active carbon whose molar ratios were 2.0Ti/1.1Al/1.0C,0. 1mol Al replaced by Si and 0. 2mol Al replaced by Si. Through calculating according to models of Ti2AlC, Ti3AlC2 and Si-doped, even net charge of the atoms and even covalent bond orders were calculated respectively. Results show that Ti2AlC material with little Ti3AlC2 could be synthesized by hot pressing elemental powder mixture of 2.0Ti/1. 1Al/1.0C at 1450 ℃ for 60min. On the other hand,the effect of Si was very obvious when 0.2mol Al replaced by Si and it did not improve the synthesis of Ti2AlC but Ti3AlC2 at the same temperature. Moreover, experimental results were explained by the effect of Si doped on net charge of the atoms and covalent bond orders.

关 键 词：Si掺杂 热压 Ti2AlC/Ti3AlC2 理论分析 

分 类 号：TQ174[化学工程—陶瓷工业]