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研究S i3N4多孔预制体的表面氧化程度对无压浸渗制备S i3N4/A l复合材料界面反应以及复合材料性能的影响是复合材料优化设计的基础。不同氧化程度的S i3N4多孔预制体在相同的浸渗工艺下无压浸渗制得S i3N4/A l复合材料,利用EDS,XRD和洛氏硬度计分别测定陶瓷多孔预制体的成份,复合材料的相组成和硬度。结果表明:S i3N4/A l复合材料组成相包括A l,S i3N4,A lN以及少量的S i,Mg2S i,MgO,MgA l2O4;随着氧化程度增加,复合材料内A lN相减少,MgO含量增加,并逐渐出现MgA l2O4相;复合材料的硬度随预制体的氧化程度增加而线性下降;预制体的氧化造成S i3N4和A l之间的反应减弱是硬度下降的重要原因。
The effect of the surface oxidation of Si 3 N 4 porous preform on the interfacial reaction and composite properties of S i3N4 / Al composites prepared by pressureless infiltration is the basis for the optimal design of composites. S i3N4 porous preform with different oxidation degree was impregnated with S i3N4 / Al composite under the same infiltration process without any pressure, and the composition of ceramic porous preform was determined by EDS, XRD and Rockwell hardness tester respectively. The phase composition and hardness. The results show that the phase composition of S i3N4 / Al composite includes A l, S i3N4, AlN and a small amount of Si, Mg2Si, MgO and MgAl2O4. With the increase of the degree of oxidation, the AlN phase in the composite decreases, The hardness of the composites decreases linearly with the increase of the oxidation degree of the preform; the decrease of the reaction between S i3N4 and Al due to the preoxidation of the preform decreases the hardness.