低温固相反应合成纳米级TiB2-TiC复合粉体

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。

Low-temperature Solid-state Synthesis of Nanometer TiB2-TiC Composite Powder

TiB₂-TiC composite powders were prepared at low temperature in the Ti-B system with the PTFE polytetrafluoroethylene (polytetrafluoroethylene) as a chemical activator. Reaction temperature, phase composition and morphology were measured via differential thermal analysis, X-ray diffraction and field emission scanning electron microscopy (FESEM) in order to explore the reaction mechanism, respectively. Actual solid-state reaction synthesis experiments 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 differential 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 energy triggers the solid-state reaction between titanium and boron particles to form TiB₂.