固相含量对多孔Si3N4显微结构及性能的影响

Effects of Solid Loading on Microstructure and Properties of Porous Si3N4

以氮化硅为原料,以叔丁醇为溶剂,采用凝胶注模成型工艺,在无压烧结温度1 780℃、保温时间1.5 h、流动氮气气氛下,成功制备出具有高强度和高气孔率的多孔氮化硅陶瓷透波材料。通过对材料的密度、孔隙率、压缩强度和介电性能测试及显微组织观察,系统分析了固相含量对透波多孔陶瓷性能的影响。研究结果表明:随着固相含量的提高,孔隙率与介电性能呈下降趋势而抗压强度呈上升趋势。当固相体积分数为15%时,制备出孔隙率达到63.1%、压缩强度达到(329.4±1.6)MPa、介电常数在10 MHz频率下达到3.99的高性能多孔透波氮化硅陶瓷。

The wave-transparent porous Si3N4 ceramics with higher strength/porosity were prepared via tert-butyl alcohol（TBA）-based gel-casting process and pressureless sintering in nitrogen at 1 780 ℃ for 1.5 h.The density,porosity,compressive strength and dielectric constant and loss were investigated,and the microstructure was analyzed.The effect of solid loading in initial slurry on the properties of wave-transparent porous Si3N4 ceramics was discussed.The results show that the porosity and dielectric prop-erties decrease and the compression strength increases with increasing the solid loading.The wave-transparent silicon nitride ce-ramics with the porosity of 63.1%,compressive strength of（329.4±1.6） MPa and dielectric constant of 3.99 at 10 MHz were ob-tained when the solid loading was 15% in the initial slurry.