加入β-SiAlON对铝碳质材料性能的影响

Effects of β-SiAlON addition on properties of alumina-carbon refractories

以白刚玉、熔融石英(≤0.5mm)为骨料,鳞片石墨(≤0.15mm)、白刚玉(≤0.088mm和≤0.045mm)、矾土基β-SiAlON(≤0.088mm)以及添加剂为基质料,酚醛树脂作结合剂,在骨料与基质的质量比为35∶65的基础上,分别用0、7%、14%、21%、28%的矾土基β-SiAlON取代铝碳质材料中的石墨,经等静压成型后,试样于180℃固化24h,并在埋炭条件下于930℃热处理,研究了β-SiAlON加入量对处理后试样常温物理性能、抗氧化性、高温机械性能和抗热震性的影响。结果表明:(1)随着β-SiAlON加入量的增加,试样的显气孔率显著上升,体积密度降低,常温和高温抗折强度下降,抗氧化能力变差;(2)与原铝碳材料相比,加β-SiAlON的试样抗热震性均有所降低,但仍保持了良好的抗热震性,在1100℃热震温差下水冷3次和5次后的强度保持率均在90%和75%以上;(3)从降低C含量的角度考虑,在不显著降低铝碳材料性能的情况下,β-SiAlON加入量以7%左右较为适宜,此时试样仍具有较好的抗氧化性和高温抗折强度。

The specimens were prepared by using white alumina and fused silica（ ≤0..5 mm） as aggregate, flake graphite（ ≤0.1.5 mm） ,white alumina（ ≤0. 088 mm and ≤0. 045 mm）, bauxite-based β-SiAlON （ ≤0.088 mm） and additives as matrix, phenolic resin as binder. Based on fixed mass ratio of aggregate to matrix of 3.5：6.5 ,graphite was substituted by β-SiAlON with additions of 0,7% ,14% ,21% and 28% respectively. The specimens were cured at 180 ℃ for 24 h after isostatic press moulding,then were treated at 930 ℃（ carbon embedded）. The influence of β-SiAlON on the mechanical properties at room and high temperature,oxidation resistance,thermal shock resistance were investigated. The results show that： （1） with the increase of β-SiAlON addition,the apparent porosity increases remarkably,the bulk density and the modulus of rupture （room temperature and high temperature）,and oxide resistance decrease. （2）compared with aluminacarbon materials without β-SiAlON,the thermal shock resistance of the specimens containing β-SiAlON decreases slightly, but maintains well. The residual strength ratios are more than 90% and 7.5% respectively after cooling by water at 1100 ℃ for 3 and .5 times. （3）based on reducing carbon content and maintaining the properties of alumina- carbon materials,the optimum addition of β-SiAlON is 7%.