摘要
为提高粉煤灰基莫来石的力学性能,以透辉石为烧结助剂,低温条件下采用无压烧结法制得了致密高强的莫来石。通过对莫来石线收缩率、体积密度、抗折强度、孔结构的测试,并借助X射线衍射、显微镜观察、扫描电镜微观分析等方法,研究了不同烧结温度时透辉石掺量对莫来石性能和结构的影响。结果表明:烧结温度为1400℃、透辉石掺量为8%时制得的莫来石性能最佳。此时,莫来石试样的线收缩率、体积密度和抗折强度最大,分别为13.3%、2.88 g/cm3和160.6 MPa;试样的显气孔率仅为2.5%,莫来石试样致密程度高。透辉石在高温(≥1250℃)下熔融成液相,不但可填补莫来石烧结形成的孔洞,提高了试样结构的致密性,且有利于莫来石液相烧结,促进莫来石晶相的形成,莫来石晶相由细针状发育成短柱状,晶粒交叉生长,形成致密高强的粉煤灰基莫来石。
In order to improve the performance of the fly ash based mullite, compact mullite was fabricated at relatively low sintering temperature by pressureless sintering with diopside addition. The influence of diopside content and sintering temperature on the densification of mullite was studied by linear shrinkage, bulk density, flexural strength, mercury intrusion porosimetry, X-ray diffraction and scanning election microscopy. The results showed that the densification effect of mullite was the best when the diopside content was 8 wt% at 1400 ℃, the linear shrinkage, bulk density and flexural strength were 13.3%, 2.88 g,/cm3 and 160.6 MPa respectively, and the open porosity was the lowest （2.5%）. The diopside melted and produced abundant liquid phase at high sintering temperature （ ≥ 1250 ℃ ）, which filled open holes and accelerated the grain growth of mullite while the fine needle-like grains gradually converted to the short columnar ones.
出处
《人工晶体学报》
EI
CAS
CSCD
北大核心
2013年第10期2092-2098,共7页
Journal of Synthetic Crystals
基金
国家自然科学基金项目(51072080)
江苏省自然科学基金项目(BK20130428)
江苏省高校自然科学基金项目(12KJB430014)
江苏省新型环保重点实验室开放课题项目(AE201113)
江苏省生态环境材料重点建设实验室开放课题项目(EML201209)
关键词
粉煤灰
莫来石
透辉石
烧结温度
fly ash
mullite
diopside
sintering temperature
