BN含量对多孔BN／Si3N4陶瓷结构和性能的影响  

Effect of BN content on microstructure and properties of porous BN/Si_3N_4 ceramics

作　　者：董薇[1,2] 汪长安[2] 尉磊[2,3] 欧阳世翕[1] 

机构地区：[1]中国建筑材料科学研究总院,北京100024 [2]清华大学材料科学与工程系,新型陶瓷与精细工艺国家重点实验室,北京100084 [3]北京科技大学材料科学与工程学院,北京100083

出　　处：《复合材料学报》2013年第1期125-129,共5页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金(90916025,90816019,51172119);纤维材料改性国家重点实验室(东华大学)资助课题

摘　　要：以氮化硅(Si3N4)为基体,氮化硼(BN)为添加剂,叔丁醇为溶剂,采用凝胶注模成型与无压烧结工艺(温度为1750℃、保温时间为1.5h、流动N2气氛),成功制备出具有一定强度和低介电常数的多孔BN/Si3N4陶瓷。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BN含量对多孔Si3N4陶瓷材料的气孔率、物相组成及显微结构的影响,分析了抗弯强度、介电常数与结构之间的关系。结果表明,通过改变BN含量可制备出气孔率为55.1%～66.2%的多孔Si3N4陶瓷;多孔BN/Si3N4复合陶瓷的介电常数随着BN含量的增加而减小,为3.39～2.25;抗弯强度随BN含量提高而有所下降,BN质量分数为2.5%时,抗弯强度最高,为(74.8±4.25)MPa。Porous BN/Sis N4 ceramics with high strength and low dielectric constant were prepared by tert-butyl alcohol （TBA） based gel-casting method and pressureless sintering process at 1750 C for 1.5 h in flowing nitrogen. At a fixed solid loading （15%, volume fraction） of the initial slurry, the influence of boron nitride content on the porosity, phase and microstructure was discussed. The relationships among flexural strength, dielectric constant and microstructure were also discussed. The results show that porous BN/Sis N4 composite ceramics with high porosity ranging from 55.1% to 66.2o/00 are prepared by adjusting the content of BN. Dielectric constant of porous BN/Si2 N4 composite ceramics is between 3.39 and 2.25, which shows a decreased trend with the content of BN increasing. Flexural strength decreases with BN content increasing, flexural strength reaches the maximum value （74.8±4.25） MPa, when the mass fraction of BN is 2.5%.

关 键 词：BN SI3N4 多孔陶瓷 气孔率 介电常数 抗弯强度 

分 类 号：TQ174[化学工程—陶瓷工业]