摘要
在非均相沉淀法制备的Fe-Mo包覆Si3N4金属陶瓷粉末中添加助剂MgO-Y2O3进行常压烧结,采用X线衍射仪(XRD)、电子能谱(EDS)、电镜扫描(SEM)等方法研究了不同烧结温度下该金属陶瓷相组成和显微结构等方面的演化趋势。结果表明:温度升高有利于金属相的转变和液相的生成,在复合粉末还原过程中,Si3N4的强还原性将Mo、Fe依次直接还原出来并反应生成Fe3Mo化合物,随着还原温度的升高,该金属间化合物与Si3N4反应生成Fe3Mo3N;同时Mg、Y氧化物与基体反应生成的MgSiO3、Fe17Y2加速了Fe3Mo3N的形成。1 600℃烧结时,Fe3Mo3N仍能稳定存在,但在1 700℃烧结时发生分解,材料组织中出现大量长径比较高的晶须状物质生成,同时表面粘附一层小颗粒物质.烧结温度为1 750℃时,金属小颗粒相仍得以保留,材料基体中晶须状物质消失。
Fe-Mo/SiaN4 ceramics were prepared by normal pressure sintering, using MgO-Y2Oa as additives. The effects of sintering temperature on the phase composition microstructure formation and evolution of Fe-Mo/Si3N4 phase were discussed, using XRD, EDS and SEM. Results indicate that the rise of sintering temperature is beneficial to the formation of liquid phase and the generation of fl-Si3N4 whisker. In the process of reduction, MgsiO3 and FelTY2 are founded, which accelerates Mo, Fe and Si3N4 reaction to generate Fe3Mo3N. At the temperature of 1 600 ℃, Fe3lo3N still exists, but at 1 700 ℃ the organization decomposes. A large number of whisker materials with high length to diameter ratio are formed in the microstructure, with a layer of small particles adhering to the surface of them. When the sintering temperature is up to 1 750 ℃, the metal particles are still preserved, and the whisker is disappeared.
出处
《硬质合金》
CAS
2013年第2期66-72,共7页
Cemented Carbides
基金
国家自然科学基金(51174085
51274093)资助项目
湖南省工业科技支撑计划基金(2012GK2020)重点项目
关键词
烧结温度
金属陶瓷
反应烧结
显微结构
sintering temperature
metal ceramics
reactive sintefing
microstructure
