加入纳米氮化硅对氮化硅陶瓷性能与结构影响

本文以亚微米级氮化硅为起始原料，加入纳米氮化硅来增强基体，添加氧化铝和氧化钇为烧结助剂，等静压成型，采用无压烧结的方式来制备具有优良性能的氮化硅陶瓷。主要研究了纳米氮化硅的分散；纳米氮化硅的加入量对氮化硅陶瓷力学性能的影响；纳米氮化硅的加入量对氮化硅陶瓷使用性能的影响；纳米氮化硅的加入量对氮化硅陶瓷显微结构的影响。研究结果表明：乙醇作为溶剂在分散介质为聚乙二醇的情况下，超声波震荡40分钟时，纳米氮化硅分散效果最好；随纳米氮化硅加入量的增加，显气孔率增加，吸水率增大；加入3wt％的纳米氮化硅时，试样的体积密度最大，抗弯强度、洛氏硬度、断裂韧性最好，具有较理想的显微结构。

EFFECT OF NANOSIZED SILICON NITRIDE AS ADDITIVE ON PROPERTIES AND MICROSTRUCTURE OF Si3N4 CERAMICS

Silicon nitride ceramic was fabricated using Si3N4 powder of micron and nano-Si3N4, adding Al2O3 and Y2O3 to reinforce sintering, by isostatic pressing and sintered silicon nitride (SSN). So, Si3N4 ceramic have good properties to improve properties Si3N4 ceramic. In the paper, the dispersion of nano-Si3N4 powder, the influence of different nano-Si3N4 concentration on silicon nitride mechanical properties, the influence of the different nano-Si3N4 concentration on silicon nitride ceramic using properties, the influence of different nano-Si3N4 concentration on silicon nitride ceramic microstructure are studied. The experiments results indicated dispersion effect was better than others when PVA as disperser in ethanol solvent and time was 40 minutes through supersonic instrument; AP and hygroscopic coefficient increased with content of nano-Si3N4.BD?bending strength?Rockwell hardnessand? fracture tougness of specimens was maximum and microstucture was perfect when content of nano-Si3N4 was 3wt%.