热处理温度对免烧SiC砖相组成和显微结构的影响

Effect of heat-treatment temperature on phase composition and microstructure of non-fired SiC bricks

以工业SiC为主要原料,添加少量Si粉和Al粉,以酚醛树脂为结合剂,经120℃烘干制备免烧SiC试样,分别在500、800和1 000℃埋炭热处理12 h,借助XRD和SEM研究其相组成和显微结构变化。结果表明:借助酚醛树脂炭化营造的低氧分压及Al-Si合金的动力学优势,500℃时结合相主要为Al-Si合金熔化产生的塑性相及部分Al4C3,800℃时结合相主要为Al4C3,1 000℃时形成了SiC、SiO2、Al4C3和Al2O3等结合相,赋予了材料良好的结构和性能。

Non-fired SiC specimens were prepared using industrial SiC as the main starting material,and phenolic resin as the binder,adding a small amount of Si powder and Al powder,and drying at 120℃.The specimens were carbon embedded firing at 500,800 and 1 000℃for 12 h,respectively,and the change of the phase composition and microstructure was studied by XRD and SEM.The results show that by virtue of low oxygen partial pressure generated by carbonization of phenolic resin and kinetic advantages of Al-Si alloy,at 500℃,the bonding phases are mainly plastic phases produced from the melting of Al-Si alloy and some Al4C3;at 800℃,the bonding phases are mainly Al4C3;and at 1 000℃,bonding phases such as SiC,SiO 2,Al4C3 and Al2O3 form,which provide excellent structure and performance to non-fired SiC materials.