基于Ti/Al/TiC体系的热爆反应低温快速合成Ti_2AlC陶瓷  

Rapid synthesis of Ti_2AlC ceramic through thermal explosion reactions of Ti/Al/TiC powder mixtures

作　　者：刘毅[1] 李莹欣 张梨梨 崔晗[1] 李樊 

机构地区：[1]陕西科技大学材料科学与工程学院,陕西西安710021

出　　处：《陕西科技大学学报》2017年第5期61-64,76,共5页Journal of Shaanxi University of Science & Technology

基　　金：国家自然科学基金项目(51602184);高等学校博士学科点专项科研基金新教师类资助课题(20136125120003);陕西科技大学博士科研启动基金项目(BJ12-10)

摘　　要：为低温快速制备出纯度高、晶粒尺寸小的Ti2Al C陶瓷,以Ti、Al和Ti C粉为原料,按一定比例混合均匀,压片成型后直接放入一定预加热温度的空气炉中进行热爆反应.利用扫面电子显微镜、X射线衍射仪对热爆反应产物的物相和微观结构进行了表征,分别研究了起始原料配比、预加热温度、压片厚度对合成Ti2Al C纯度的影响,并提出了热爆反应过程中Ti2Al C的生成机制.结果表明:(1)当Ti∶Al∶Ti C的摩尔比为1.05∶1.1∶1,预加热温度为600℃~750℃,压片厚度为2~6 mm时,热爆反应产物中Ti2Al C的纯度较高,晶粒形态为片层状结构,径向尺寸小于2μm.(2)当预加热温度大于600℃时,Ti、Al间热爆反应启动,并在坯体局部形成Ti-Al金属间化合物熔体,Ti C颗粒通过在Ti-Al熔体中的溶解-析出机制生成Ti2Al C陶瓷.热爆反应后Ti2Al C为多孔相对致密的陶瓷块体,经过破碎可以被磨成粉体.In order to prepare Ti2 Al C ceramic with high purity and fine grains at low temperatures,Titanium,Aluminum and Titanium Carbide powders were used as raw materials.The powder mixtures with different molar ratios were pressed first and then put into a preheated air furnace to conduct thermal explosion reactions.The phase composition and microstructure of reaction products were characterized by X-ray diffraction（XRD） and scanning electron microscope（SEM）.The effects of molar ratio of starting materials,preheated temperature and the thickness of compacts on the purity of Ti2 Al C were investigated. Ultimately,the formation mechanism of Ti2 Al C during thermal explosion process was proposed according to the adiabatic analysis.It is revealed that Ti2 Al C ceramic with high purity and grains less than 2 μm can be obtained when the molar ratio is 1.05 ∶ 1.1 ∶ 1（Ti ∶ Al ∶Ti C） and the thickness of compact is 2 - 6 mm at temperatures ranging from 600 ℃ to 750 ℃. It is also suggested that Ti-Al intermetallics are firstly formed when the thermal explosion reactions is initiated as the preheated temperature is higher than 600 ℃ and then Ti2 Al C is produced due to the dissolution-precipitation process of Ti C particles in the local Ti-Al melts.

关 键 词：TI2ALC 陶瓷 热爆反应 低温 

分 类 号：TM286[一般工业技术—材料科学与工程]