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研究了不同粒度的Si3N4粉体对制备的逆反应烧结Si3N4-SiC复合材料性能的影响。结果表明:同一升温制度下,Si3N4粒度从0.074 mm减小到0.045 mm,Si3N4-SiC复合材料体积密度增大,显气孔率变低,抗折强度降低。随着Si3N4粒度减小,材料中的Si3N4含量降低;中温保温从900℃升到1200℃,Si3N4含量升高;高温保温温度从1350℃到1500℃,材料内部氧化程度增高,Si3N4含量降低,SiO2含量升高;Si3N4-SiC复合材料玻璃相增多,玻璃相中有SiO2晶体析出,使得孔隙被生成的玻璃相和发育的SiO2晶粒填充,材料的气孔减少。
The effect of Si3N4 powder with different particle size on the properties of reverse-reaction sintered Si3N4-SiC composites was studied. The results show that the grain size of Si3N4 decreases from 0.074 mm to 0.045 mm under the same temperature increase. The bulk density of Si3N4-SiC composites increases and the porosity decreases, and the flexural strength decreases. With the decrease of Si3N4 particle size, the content of Si3N4 in the material decreases. The temperature increases from 900 ℃ to 1200 ℃ and the content of Si3N4 increases from 1350 ℃ to 1500 ℃. The internal oxidation degree increases and the content of Si3N4 decreases. The glass content of Si3N4-SiC composites increases, and SiO2 crystals are precipitated in the glass phase, so the pores are filled with the formed glass phase and the developed SiO2 grains, and the pores of the material are reduced.