【摘要】 以氮化硅为原料,以叔丁醇为溶剂,采用凝胶注模成型工艺和无压烧结工艺(1 750℃、保温1.5h、流动氮气气氛),制备出具有高强度和高气孔率的多孔氮化硅。在浆料中初始固相含量固定为15%体积分数的基础上,研究了烧结助剂含量对多孔氮化硅的气孔率、孔径尺寸分布、物相组成及显微结构的影响,分析了弯曲强度与结构之间的关系。结果表明,通过改变烧结助剂含量,所制备的多孔氮化硅的气孔率为52%-65%;气孔尺寸呈单峰分布,均匀性好,平均孔径为0.82-1.05μm;弯曲强度为64.4-193.5 MPa,且随烧结助剂含量增加呈先增大后减少,在烧结助剂含量为7.5%质量分数时达到最大值(193.5±10.1)MPa。更多还原

【Abstract】 High strength and high porosity porous silicon nitride ceramics were prepared by tert-butyl alcohol(TBA)-based gel-casting process and pressureless sintering at 1 750 ℃ for 1.5 h in flowing nitrogen.At a fixed solid loading of 15 vol% of the initial slurry,the influence of the content of sintering aids on the porosity,pore size distribution,phase and microstructure was discussed.The relationship between flexural strength and microstructure was also discussed.The results showed that porous silicon nitride ceramics with high porosity ranging from 52% to 65% were prepared by adjusting the content of sintering aids.A uniform pore size distribution was observed,and the mean pore size ranged from 0.82 to 1.05 μm.The flexural strength of porous Si3N4 ceramics was between 64.4 and 193.5 MPa,which showed a first increasing and then decreasing trend with the content of sintering aids increasing and reached(193.5±10.1) MPa at the 7.5wt% sintering aids.更多还原