煅烧气氛对Al_2O_3-Si材料组成、结构和性能的影响  

Effects of firing atmospheres on phase composition,microstructure and properties of Al_2O_3-Si material

作　　者：刘新红[1] 张磊[1] 冯隆[1] 叶方保[1] 

机构地区：[1]郑州大学高温材料研究所,河南郑州450052

出　　处：《耐火材料》2012年第6期410-413,共4页Refractories

基　　金：河南省科技创新杰出青年基金资助(124100510019);河南省重点科技攻关项目(112102210095)资助;河南省教育厅自然科学基金资助(2011A430024)

摘　　要：以电熔白刚玉、α-Al2O3微粉和Si粉为主要原料,以酚醛树脂为结合剂,制备Al2O3-Si复合材料试样。研究了煅烧气氛对1 500℃烧后试样性能、组成和显微结构的影响。结果表明:1)在氧化气氛和弱氧化气氛中煅烧后,试样表面生成含莫来石的玻璃膜,保护了试样内部的单质Si;由于单质Si的液相助烧结作用,试样的致密度和常温强度较高,但其高温抗折强度和抗热震性较低。2)在弱还原气氛和还原气氛中煅烧后,试样中的单质Si完全与Al2O3和通过气孔进入的CO、N2反应,生成晶须状SiC、粒状Si2N2O(或絮状O’-SiAlON),试样的致密度和常温强度减小,高温强度和抗热震性提高。3)在氮气气氛中煅烧后,Si完全反应生成短柱状β-SiAlON和晶须状SiC,试样的高温强度和抗热震性明显提高。Al2O3-Si composite specimens were prepared using white fused corundum, ultrafine α-Al2O3 and Si powder as main starting materials and resin as binder. Effects of firing atmospheres on phase composition,microstructure and properties of specimens after firing at 1500℃ were investigated. The results show that,（1）after firing at oxidative and weak oxidative atmospheres, a glass film containing mullite is formed on specimen surface protecting Si in the specimens;because of the sintering aiding of Si liquid phase,the density and cold strength are relatively high, but hot modulus of rupture and thermal shock resistance are poor;（2） after firing at weak reductive and reductive atmospheres, Si reacts completely with Al2O3, and the entered CO and N2 through the pores forming whisker-like SiC, granular Si2N2O or flocculent O＇-SiAION, the density and cold strength decrease,and hot strength and thermal shock resistance increase; （3）after firing in nitrogen atmosphere,Si reacts completely forming whisker-like SiC and columnar 13-SiAION crystals, the hot strength and thermal shock resistance of the specimens increase noticeably.

关 键 词：Al2O3-Si材料 单质硅 煅烧气氛 物相组成 显微结构 

分 类 号：TQ175.65[化学工程—硅酸盐工业]