烧结助剂对Si_3N_4/BN层状复合陶瓷结构与性能的影响  

Effects of Additives to Si_3N_4 Matrix on Microstructure and Properties of Laminated Si_3N_4/BN Ceramics

作　　者：李翠伟[1] 黄勇[1] 汪长安[1] 昝青峰[1] 赵世柯[1] 

机构地区：[1]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

出　　处：《无机材料学报》2003年第5期1091-1096,共6页Journal of Inorganic Materials

基　　金：国家自然科学基金(51072023)

摘　　要：研究了MgO-Y2O3-Al2O3体系(相应的层状复合陶瓷试样记为A)、Y2O3-Al2O3体系(相应的层状复合陶瓷试样记为B)及La2O3-Y2O3-Al2O3体系(相应的层状复合陶瓷试样记为C)烧结助剂对Si3N4/BN层状复合陶瓷结构与性能的影响.研究表明:在相同的烧结工艺下,试样A、B、C的抗弯强度分别为700、630、610MPa,断裂功分别为2100、1600、3100J/m2.试样A、B以脆性断裂为主,裂纹偏转现象不明显,而试样C的载荷-位移曲线显示了明显的“伪塑性”特征,裂纹的偏转与扩展现象明显.试样A中Si3N4晶粒大小不均且长径比较小,而试样C中长柱状Si3N4晶粒发育完善,有较大的长径比.The effects of additives to Si3N4 matrix layers on microstructure and properties of laminated Si3N4/BN ceramics were studied. Laminated Si3N4/BN ceramics with La2O3-Y2O3-Al2O3 (denoted as C), Y2O3-Al2O3 (denoted as B), MgO-Y2O3-Al2O3 (denoted as A) added as sintering aids to the Si3N4 matrix layers were prepared and tested separately. The results obtained show that WOF (work of fracture) of sample C is 3100J/m(2), which is higher than that of 2100 and 1600J/m(2) of sample A and B. Bending strength of sample C is 610MPa, which is lower than that of 700 and 620MPa of sample A and B. In sample C, crack deflection and propagation occur, which result in high-energy absorption and high toughness. And in sample C, elongated beta-Si3N4 grains grow very well, which is caused by the addition of La2O3.

关 键 词：层状复合陶瓷 烧结助剂 Β-SI3N4 

分 类 号：TQ174[化学工程—陶瓷工业]