以特级铝矾土和轻质氧化镁为主要原料，按m（Al2 O3）m（MgO）＝2．54配料，采用一步烧结法制备尖晶石材料，研究了成型压力（分别为25、50、75、100、125、150 MPa）和热处理温度（分别为1250、1300、1350、1400、1450、1500、1550℃）对合成材料的物相组成、显微结构、体积密度、显气孔率、荷重软化温度的影响。结果表明：1）以50 MPa压力成型的试样在1450℃保温4 h热处理后显气孔率最小，以100、125和150 MPa成型的试样在1450℃保温4 h热处理后存在开裂或扭曲现象；2）1250～1550℃热处理后试样的主晶相均为MgAl2 O4，MgAl2 O4晶粒随热处理温度的升高逐渐发育完整并长大；3）随着热处理温度的升高，试样的致密度逐渐升高，但以1400℃为转折点，致密度升高速率前高后低；4）随着热处理温度的升高，试样的荷重软化温度逐渐升高。
Magnesium-aluminate spinel materials were prepared by one-step sintering process with special grade bauxite and light weight magnesia as main starting materials with the ratio of m(Al2 O3 )m(MgO)=2.54.Effects of molding pressure (25,50,75,100,125,and 150 MPa)and heat treatment temperature (1 250,1 300,1 350,1 400,1 450,1 500,and 1 550 ℃)on phase compositions,microstructure,bulk density, apparent porosity,and refractoriness under load of specimens were studied.The results show that:(1 )the specimen pressed under 50 MPa and fired at 1 450 ℃ for 4 h has the lowest apparent porosity,while the specimens pressed under 100,125,and 150 MPa fired at 1 450 ℃for 4 h crack or distort;(2)the specimens fired at 1 250-1 550 ℃ have main crystal phase of MgAl2O4,and the MgAl2O4 crystals develop and grow as heat treatment temperature rises;(3)as heat treatment temperature rises,the bulk density of specimens increases,and the increasing rate slows down after 1 400 ℃;(4)as heat treatment temperature rises,the refractoriness under load increases gradually.
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