工艺条件对莫来石陶瓷相组成和显微结构的影响

Effect of processing conditions on the phase constituent and microstructure of mullite ceramics

以α-Al2O3微粉、高纯石英粉、煤矸石、碳酸钡为原料,采用常压烧结法制备莫来石陶瓷材料。对试样进行XRD和SEM分析,研究烧成温度和保温时间对材料的相组成和显微结构的影响。结果表明:由α-Al2O3微粉、高纯石英粉、BaCO3和煤矸石粉料通过常压烧结可以合成由主晶相莫来石、次晶相单斜钡长石、六方钡长石、少量刚玉和石英5种物相组成的莫来石陶瓷材料;随烧成温度的升高,莫来石的生成量相对较高,刚玉相较少。通过烧成制度的控制可以实现对一次莫来石、二次莫来石生成量和晶体发育情况的控制,达到对莫来石陶瓷显微结构控制。

Mullite ceramics were fabricated by non-pressure sintering using alumina micro fine powder, high purity SiO2 powder, coal gangue, barium carbonate and calcium carbonate as starting materials. Influence of sintering temperature, holding time on the phase constituent and microstructure of samples was investigated by XRD and SEM. The results showed that： mullite ceramics in which the major phase was mullite and minor phases were corundum,monocline celsian,hexagonal celsian and cristobalite could be prepared by non-pressure sintering with alumina micro fine powder, high purity SiO2 powder, coal gangue, barium carbonate and calcium carbonate as starting materials. When the sintering temperature was increased, the content of mullite in mullite ceramics increased, while the content of corundum decreased. The microstructure of mullite ceramics could be controlled by controlling the forming amount of the primary mullite and the secondary mullite and the developing of crystals through controlling sintering condition.