工艺参数对镁铝尖晶石保温材料物相与性能的影响

Influence of Process Parameters on Phase and Properties of MA Spinel Heat Insulating Material

以α-Al_2O_3微粉、电熔镁砂和ρ-Al_2O_3为原料,采用泡沫胶凝法制备了体积密度0.9~1.1 g/cm3镁铝尖晶石保温材料,考察了ρ-Al_2O_3、电熔镁砂加入量、烧成温度和保温时间对镁铝尖晶石保温材料物相与性能的影响。研究结果表明,随着ρ-Al_2O_3加入量增加试样常温耐压强度与烧成线变化率增大,物相组成均为＂刚玉＋镁铝尖晶石＂;增加Mg O加入量试样先收缩后膨胀,加入量为20wt%时常温耐压强度达最大值,物相组成由＂刚玉＋镁铝尖晶石＂变为＂镁铝尖晶石＂再变为＂镁铝尖晶石＋方镁石＂;提高烧成温度能明显促进试样烧结,延长保温时间可提高试样常温耐压强度。

The magnesium aluminium spinel heat insulating materials of 0.9-1.0 g/cm3 bulk density was prepared by using α-Al_2O_3 fine powder,fused magnesia and ρ-Al_2O_3 as raw materials though foam gelation method.The effect of amounts of ρ-Al_2O_3 and fused magnesia,sintering temperature and holding time on phase and properties of the heat insulating material was investigated.It has been showed that the cold crushing strength and the firing line change rate increased with the increase of amount of ρ-Al_2O_3,and all samples have the same phase composition of ＂ corundum ＋ spinel＂.With the increase of amount of fused magnesia,the firing line change rate gradually changed from shrinkage to expansion,the cold crushing strength attained its maximum at 20wt% fused magnesia,phase composition changed from ＂ corundum ＋spinel＂ to ＂ spinel＂ and then to ＂ spinel ＋ periclase＂.Higher sintering temperature can obviously promote sintering and the cold crushing strength can be enhanced when prolonging holding time.