利用工业废弃微硅粉制备多孔莫来石陶瓷

Preparation of Porous Mullite Ceramics Using Industrial Wasted Silica Fume

以微硅粉和氧化铝粉为主要原料,采用凝胶注模工艺和无压烧结法制备了多孔莫来石陶瓷材料。研究了原料配比和烧结温度对莫来石形成、多孔莫来石陶瓷显微结构和性能的影响。通过X射线衍射(XRD)、扫描电镜(SEM)和力学性能测定等手段表征了制备的多孔莫来石陶瓷。结果表明:烧结温度和Al2O3/SiO2配比是影响莫来石合成的主要因素;从1300℃开始,微硅粉中的SiO2就与Al2O3发生反应,生成莫来石晶相,到1450℃时样品中莫来石含量达到最高;微硅粉适当过量有利于提高莫来石相的纯度,当Al2O3/SiO2物质的量比为3∶2.5时,合成的莫来石纯度高达90%,密度为2.51g/cm3,气孔率为20.56%,抗压强度为260.93MPa。

The porous mullite ceramics were prepared using silica fume and alumina powders by gel-casting and pressureless sintering process.The effects of composition and sintering temperature on formation of mullite,microstructure and mechanical properties of porous mullite ceramics were investigated.XRD,SEM and strength testing were used to characterize the porous mullite materials.The results showed that,sintering temperature andAl2 O3/SiC2 ratio have important influences on the formation of mullite.The formation of mullite derived from the reaction between SiO2 in the silica fume and Al2O3 takes place at 1300 ℃,while mullite content reaches maximum when temperature raised to 1450 ℃.Meanwhile,the proper over-dose of silica fume is propitious to synthesize mullite with higher purity.When the Al2O3/SiO2 molar ratio was 3：2.5,the mullite content,bulk density,porosity and compressive strength of porous mullite ceramics were 90%,2.51 g/cm3,20.56% and 260.93 MPa,respectively.