将球磨工艺引入超重力反应合成,制备TiB2-TiC复相陶瓷。研究发现,随着球磨时间的延长,反应原料尺寸显著细化,其粒度最小可达2.2μm。机械球磨虽未能直接诱发合成反应,但有效地降低反应原料的点火温度及反应激活能,提高了实际反应温度,促使反应呈现“热爆”模式。XRD、FESEM与EDS结果表明,反应制备的陶瓷基体主要由T画片晶、不规则的TiC相、Cr基金属合金相及Al2O3夹杂组成。延长球磨时间,不仅加速Al2O3液滴与陶瓷熔体液相分离,减少Al2O3夹杂及缩孔、缩松的含量,更促使陶瓷基体显微组织细化,提高其均质化水平。
TiB2-TiC multiphase ceramics were prepared by reaction synthesis in ultra-high gravity field after the reactants were treated by ball milling. It's found that the grain size of reactant becomes smaller and smaller with the increasing time of hall milling treatment, the minimum value of which is 2. 2 μm Ball milling doesn't directly induce the combustion reaction, but makes the ignition temperature and reaction activation energy of reactants decrease and the temperature of liquid ceramic increase, which greatly improves the propagation rate of combustion reaction. The XRD, RESEM and EDS results show that TiB2-TiC multiphase ceramics are consisted of a number of TiB2 primary platelets, irregular TiC phases, Cr basic alloy phases and Al2O3 phases. The increasing time of ball milling not only accelerates liquid-liquid separation of TiB2-TiC liquid and Al2O3 droplets, which reduces the number of Al2O3 inclusions and cavities, but also makes the microstructure of ceramic matrix refined and homogenous.