高能球磨对堇青石基陶瓷的相组成和相变机理的影响

Influence of high-energy ball milling on phase components and transformation mechanism of cordierite ceramics

采用X射线衍射 (XRD)和扫描电镜 (SEM )研究了由氧化物粉末制备堇青石陶瓷时 ,高能球磨及其后续热处理对堇青石陶瓷相组成和相变过程的影响 ,分析了高能球磨的作用机理 ;探明了经高能球磨的样品在低温烧成 (90 0℃ )时 ,首先出现了新的中间相镁铝尖晶石 (MgAl2 O4) ,110 0℃中间相消失。与未球磨的样品比较表明 :高能球磨不仅能够降低堇青石的相转变温度 ,而且可以大幅加快中间相和原料相向α 堇青石转变的速度 ,同时发现提高烧成温度有利于中间相向堇青石的转变。研究了粉末状态对堇青石陶瓷相组成的影响 ,结果表明 :加压成型易于使Si4+ 、Mg2 + 和Al3 + 离子扩散 ,促进早期的固相烧结和后期的液相烧结 ,并影响各相的相对含量 ,有利于主晶相α 堇青石的合成 ,但对相的组成没有太大影响。

The effects of high-energy ball milling and subsequent heat-treatment on the phase components and the transformation process of cordierite ceramics prepared with oxide powder were studied using XRD and SEM .The mechanism of high-energy ball milling is also discussed. It is verified that a new immediacy phase(spinel MgAl_2O_4 )for all the milled samples begins to be formed at 900 ℃ and to be dissolved and disappeared at 1 100 ℃. Compared with the non-milled samples, the high-energy ball milling decreases the transformation temperature and accelerates the conversion rate towards α-cordierite .The rising temperature also accelerates the conversion rate of spinel into cordierite. In addition, the effect of powder state on the phase components of cordierite ceramics was also investigated. The results show that the press-shape promotes the solid-sintering and liquid-sintering and the synthesis of α-cordierite at low temperature sintering, but has little effect on the phase components.