以低压铸造用升液管为研究目的，以Y2O3-Al2O3-Fe3O3为复合烧结助剂，磨切单晶硅废料Si粉和SiC为主料，反应烧结法制备Si3N4／SiC复相陶瓷。研究了Y2O3含量对复合材料结构和力学性能的影响，采用XRD、SEM对复合材料的相组成、微观形貌进行分析。结果表明，反应烧结后试样生成Si3N4结合SiC晶粒为主相的烧结体，并含有少量Sialon晶须及未反应的Si。Y2O3含量对复相陶瓷力学性能影响很大，在分析稀土Y2O3作用机理的基础上，得到2．5％Y2O3优化试样的力学性能优良，相对密度达到88％，维氏硬度达到1．1GPa，常温抗弯强度50MPa。
In order to meet the requirements of lift tube in aluminium alloy low-pressure die-casting, Si3N4 bonded SiC multi-phase ceramics were fabricated by reaction-sintering from Si and SiC powders, usingY2O3-Al2O3-FeEO3 as sintering additives. The effect of Y2O3 content on mierostructure and mechanical properties of the ceramics was studied. The phase components and surface morphology of the ceramics were observed and analyzed by XRD and SEM. The results show that the sintered materials mainly consist of SiaN4 and SiC with a small amount of Sialon and residual Si particles. Significant effect of Y2O3 content on mechanical properties of the multi-phase ceramics is observed. Based on the experiments, optimum mechanical properties of sample with 2.5% Y2O3are obtained, which are the relative density of 88% , Vicker＇s hardness of 1. 1 GPa and room temperature flexural strength of 50 MPa.
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