在Ti-B体系中引入PTFE作为反应促进剂,实现了TiB2-TiC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TiB2-TiC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TiB2.
TiB2-TiC composite powders were prepared at low temperature in the Ti-B system with the PTFE polytetra-fluoroethylene (polytetrafluoroethylene) as a chemical activator. Reaction temperature, phase composition and mor-phology were measuredvia differential thermal analysis, X-ray diffraction and field emission scanning electron mi-croscopy (FESEM) in order to explore the reaction mechanism, respectively. Actual solid-state reaction synthesis ex-periments were carried out for the same composition in an argon atmosphere furnace. It was found that TiB2-TiC composite powder could be synthesized successfully at 550℃ by adding 10wt% PTFE into the initial reactant Ti-B mixture. The FESEM image showed that the average size of the product was smaller than 400 nm. According to dif-ferential thermal analysis results, the combustion synthesis mainly includes two reaction processes: firstly, the initial reaction between titanium and PTFE particles resulting in great amounts of heat release; subsequently, the released en-ergy triggers the solid-state reaction between titanium and boron particles to form TiB2.
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