采用Li2O-Al2O3助烧剂低温埋碳制备Si3N4陶瓷  

Preparation of Si3N4 ceramics by Li2O-Al2O3 sintering aid at low temperature with carbon embedded

作　　者：李凌锋 王战民[1] 赵世贤[1] 郭昂 Li Lingfeng;Wang Zhanmin;Zhao Shixian;Guo Ang

机构地区：[1]中钢集团洛阳耐火材料研究院有限公司先进耐火材料国家重点实验室

出　　处：《耐火材料》2019年第6期405-408,413,共5页Refractories

基　　金：国家重点研发计划项目(2017YFB0310300)

摘　　要：为了制备致密的Si3N4陶瓷,在Si3N4粉末中加入15%(w)的助烧剂(Li2O-Al2O3),经过球磨、造粒、烘干成型后,在传统电炉中埋碳和Si3N4粉,于1550、1600、1650℃保温2 h后无压烧结制备Si3N4陶瓷,研究了烧结助剂配比和烧结温度对试样致密化、线收缩率、质量损失率、相转变以及微观结构的影响。结果表明:1)随着助烧剂中Li 2O比例的增加,Si3N4陶瓷的致密度先增加后降低。随着温度的升高,Si3N4陶瓷的密度不断提高,当达到1600和1650℃时,试样的相对密度分别达到93%和95%以上;2)在1600℃时,所有试样物相中都已经生成β-Si3N4,并随着烧结温度的升高其转化率逐渐增加,显微结构照片可以看到明显的棒状β-Si3N4;3)采用低温埋碳和Si3N4粉的烧结工艺为低成本Si3N4陶瓷的制备提出了可行的方法。The dense Si 3N 4 ceramics were prepared by adding 15 mass%additives(Li 2O-Al 2O3)in Si 3N 4 powder,ball-milling,pelleting,drying,molding and pressureless sintering in an electric furnace at 1550,1600,or 1650℃for 2 h with Si 3N 4 and carbon powders embedded.The effects of the sintering aid proportion and the sintering temperature on the densification,linear shrinkage,mass change,phase transformation,and microstructure were researched.The results reveal that:(1)the densification of Si 3N 4 ceramics increases first and then decreases with the increasing ratio of Li 2O in the additives;with the increase of the temperature,the density of Si 3N 4 ceramics increases continuously;when the temperature reaches 1600 and 1650℃,the relative density of the specimens is over 93%and 95%,respectively;(2)at 1600℃,β-Si 3N 4 forms in all specimens and the conversion rate increases gradually with the increase of the sintering temperature;elongatedβ-Si 3N 4 can be seen from the SEM images;(3)the low-temperature sintering of silicon nitride ceramics with Si 3N 4 and carbon powder embedded provides a feasible method for the preparation of low-cost Si 3N 4 ceramics.

关 键 词：氮化硅 空气 低温 Li2O助烧剂 无压烧结 

分 类 号：TQ174[化学工程—陶瓷工业]