摘要
研究了矾土为原料,部分配以适量煤矸石及加入少量Al2O3,制备矾土基莫来石均质料的加热过程线收缩率、显气孔率、相组成和显微结构的变化。结果表明,其加热过程一般分为三个阶段:(1)1000℃~1200℃,一次莫来石已经形成,试样收缩、气孔率降低。(2)1200℃~1500℃,二次莫来石化阶段,液相已经出现。其中,1300℃~1400℃,二次莫来石大量生成,试样膨胀、气孔率增加。(3)1500℃~1700℃,液相烧结阶段,试样收缩和气孔率下降较快。根据XRD图谱可判断低温阶段(<1400℃)形成的莫来石的结晶度,而对高温阶段则较困难,原因为高温形成的莫来石衍射峰变化很小;显微结构观察表明,随温度升高,莫来石晶体发育不断完善,从片状晶体(1200℃)到发育较差的柱状(1500℃),直至发育完善长大柱状晶体(1700℃),并由其构成交错连续的网络结构。
The changes of linear shrinkage, apparent porosity, phase composition and microstructure of bauxit-based homogenized mullite grogs prepared by homogenization process and high temperature sintering using bauxite as starting material incorporated with appropriate amount of coal gangue and addition of a small quantity of Al2O3 during heating process have been investigated. The results show that changes of heating process are consistent and can be divided three stages: (1) primary mullite have formed at 1000℃-1200℃, specimen shrinkage and apparent decrease. (2) secondary mullitization stage at 1200℃-1500℃ ,liquid phase have appeared, specimen expanding and apparent decrease at 1300℃-1400℃, owing to formation of a great deal second mullite. (3) liquid phase sintering stage at 1500℃-1700℃, specimen shrinkage and apparent decrease obviously. According to XRD patterns, mullite crystal degree formed at below 1400℃ can be estimated, but will be very difficult at above 1400℃due to little change of diffaction patterns of mullite at high temperature. Mullite crystals growth perfectly with temperature increase, from flake piece at 1200℃ to poor prisimatic at 1500℃ and up to well-developed mullite at 1700℃, by observing microstructure of specimens, and form the continuous interlocking network structure of well-developed prisimatic mullite crystals.
出处
《中国陶瓷》
CAS
CSCD
北大核心
2007年第10期46-49,55,共5页
China Ceramics
关键词
莫来石均质料
加热过程
变化
mullite homogenized grogs, heating process, change