不同原料固相合成堇青石的显微结构和性能

摘要

With the synthesized spinel and mullite,MgO,Al2 O3 and SiO2 powders as raw materials,the cordierites were synthesized by solid state reaction at 900-1 350 ℃ for 3 h with different raw material composition. The effects of raw material composition on the phase composition,density and microstructure of the synthesized cordierites were studied.The results show that the cordierites were all produced at 1 250 ℃,showing little influence of the raw material composition on the formation temperature.Meanwhile the spinel phase appeared invariably during the phase evolution process at 1 250 ℃ and above.The cordierites prepared using spinel or mullite as raw materials had a higher density than that with pure oxides as raw materials,moreover the grain growth was more complete and the grain size was larger.%以合成的镁铝尖晶石、莫来石以及 MgO、Al2 O3和 SiO2粉为原料，通过改变原料组成在900~1350℃下固相反应3 h制备了堇青石，研究了不同原料对堇青石物相组成、密度和显微结构的影响。结果表明：堇青石相基本都在1250℃时生成，原料组成对其开始形成温度影响较小，同时在该温度及以上的相演变过程中均出现了镁铝尖晶石相；以镁铝尖晶石或莫来石为原料合成的堇青石比采用纯氧化物合成的密度高，且晶粒发育更完整，晶粒尺寸更大。