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在Ti-B体系中引入PTFE作为反应促进剂,实现了Ti B_2-Ti C粉体的低温固相合成。分别采用热分析仪、X射线衍射仪和场发射扫描电子显微镜,测定了体系的反应温度,表征了生成物的物相和微观形貌,并对其反应过程和反应机理进行了分析。合成实验在氩气炉中进行,结果表明:当添加10wt%PTFE时,能够在550℃通过固相反应制备出平均粒径小于400 nm的Ti B_2-Ti C复合陶瓷粉体。DTA测试表明固相反应合成过程主要包括两步:首先,在低温下PTFE和Ti发生反应并释放出大量的热,然后,诱发Ti和B的固相反应生成Ti B_2。
In the Ti-B system, PTFE was introduced as a reaction promoter to achieve low temperature solid state synthesis of TiB_2-TiC powder. The reaction temperature, the phase and the morphology of the product were characterized by means of thermal analyzer, X-ray diffraction and field emission scanning electron microscope respectively. The reaction process and reaction mechanism were also analyzed. The synthesis experiment was carried out in argon gas furnace. The results show that TiB 2 -TiC composite ceramic powder with average particle size less than 400 nm can be prepared by solid-state reaction at 550 ℃ when 10wt% PTFE is added. The DTA test shows that the synthesis of solid-phase reaction mainly consists of two steps: first, PTFE and Ti react at low temperature to release a large amount of heat; then, the solid-state reaction between Ti and B is induced to produce TiB_2.