添加Al2O3-MA复合微粉对铝镁质浇注料性能的影响

摘要

为了探究Al2O3-MA复合微粉的加入对铝镁质浇注料性能的影响,对比加入不同量的(加入质量分数分别为2.5%和5%)Al2O3-MA复合微粉(Al2O3与MA的质量比为32,d50=2.49 μm)的试样与不加复合微粉的参比试样在不同温度(1150~1450 ℃)热处理后的性能,并分析试样的物相组成和显微结构.结果表明:加入Al2O3-MA复合微粉有利于CA6的形成,降低了CA6的初始形成温度.从显微结构看,随着Al2O3-MA复合微粉加入量的增大,片状CA6的生长受到了限制.镁铝尖晶石(220)、(400)与(440)晶面衍射峰强度比值随试样处理温度的变化表明,Al2O3-MA复合微粉的加入能够促进尖晶石的反转.另外,Al2O3-MA复合微粉会导致试样加热永久线变化率和显气孔率增大,但烧后试样的强度呈现非单调变化.%In order to investigate the influence of Al2O3-MA composite micropowder addition on properties of alumina-magnesia castables,the properties of specimens heated at different temperatures(1 150 -1 450 ℃)with 2.5 mass% or 5 mass% of Al2O3-MA composite micropowder(the mass ratio of Al2O3to MA is 3:2,d50=2.49 μm)were compared with the specimens without composite micropowder.The phase composition and microstructure of the specimens were analyzed.The results show that the Al2O3-MA com-posite micropowder addition is beneficial to the formation of CA6,and the initial formation temperature of CA6decreases.As for the microstructure,the growth of platelet CA6is limited with the increase of the com-posite micropowder addition.The intensity ratios of diffraction peaks of crystal faces(220),(400)and (440)of magnesium aluminate spinel vary with the heating temperature,which indicates that the addition of the composite micropowder can promote the inversion of spinel.In addition,the composite micropowder in-creases the permanent linear change rate and apparent porosity of the specimens,but the strength change of the specimens after heating is non-monotonic.