Yb_2O_3-Al_2O_3烧结助剂对气压烧结氮化硅陶瓷性能的影响  

Effect of Yb_2O_3-Al_2O_3 Sintering Aids on the Properties of Silicon Nitride Ceramics Prepared by Gas Pressure Sintering

作　　者：杨亮亮[1] 谢志鹏[1,2] 宋明[1] 

机构地区：[1]景德镇陶瓷学院,景德镇333000 [2]清华大学材料学院,北京100084

出　　处：《人工晶体学报》2016年第1期104-109,共6页Journal of Synthetic Crystals

基　　金：国家自然科学基金(51232004)

摘　　要：以Yb_2O_3-Al_2O_3体系为烧结助剂,采用气压烧结法制备了氮化硅陶瓷。研究了烧结温度对气压烧结氮化硅陶瓷的致密度、失重率、物相、力学性能与显微结构的影响及材料的烧结机理。结果表明:随着烧结温度的升高,氮化硅的致密度、抗弯强度、断裂韧性和硬度均呈现先增加后降低的趋势,而失重率呈现一直升高的趋势;当烧结温度为1780℃、烧结气压为6 MPa时,所得氮化硅烧结体的体积密度(3.31 g·cm^(-3))、抗弯强度(967.2)、断裂韧性(8.9MPa·m^(1/2))和硬度(17.1 GPa)达最大值,晶粒以长柱状的β相为主;烧结温度高于或等于1700℃时,材料中的α相可完全转化为β相,β-Si_3N_4晶粒的平均长径比达12.31。Silicon nitride ceramics were prepared by gas pressure sintering with Yb_2O_3-Al_2O_3 systems as sintering aids.In this study,the influences of sintering temperature on the densification,weight loss rate,phase composition,microstructure and mechanical properties of silicon nitride ceramics were investigated.The sintering mechanisms under Yb_2O_3-Al_2O_3 aids were also discussed.The results show that the relative density,bending strength,fracture toughness of the samples increase firstly and then decrease with the increase of sintering temperature;while,the rate of weight loss increases with the increase of sintering temperature.When sintered at 1780 ℃ and sintering pressure was 6 MPa,the silicon nitride ceramics show the maximum bulk density of 3.31 g · cm^(-3),the bending strength of 967.2 MPa,the fracture toughness of8.9 MPa· m^(1/2) and the hardness of 17.1 GPa.The starting α-Si_3N_4 phase transforms completely into β-Si_3N_4 phase when the materials were sintered at 1700 ℃ or a higher temperature,by this time the elongatedβ-Si_3N_4 grain presents an average aspect ratio of 12.31.

关 键 词：氮化硅 烧结温度 力学性能 显微结构 

分 类 号：TQ174.1[化学工程—陶瓷工业]