成型压力对原位氮化生成Si3N4结合MgO-C材料性能影响  

Effects of Briquetting Pressure on the Microstructure and Performance of In-situ Formed Si_3N_4 Bonding Mg O-C Material

作　　者：彭耐[1] 邓承继[1] 祝洪喜[1] 王少华[1] 员文杰[1] 

机构地区：[1]武汉科技大学,省部共建耐火材料与冶金国家重点实验室,武汉430081

出　　处：《硅酸盐通报》2015年第10期2930-2933,共4页Bulletin of the Chinese Ceramic Society

基　　金：国家自然科学基金(51274156);湖北省自然科学基金(2012FFA103)

摘　　要：以电熔镁砂、单质Si粉和鳞片石墨为主要原料,木质磺酸钙溶液(1.25g/mL)为结合剂,氮气气氛下分别于低温段1350℃氮化2h和高温段1500℃氮化3h制备成MgO-C材料。通过X射线衍射(XRD)和扫描电子显微镜(SEM)分别分析试样的物相组成和显微结构,显气孔率、体积密度和耐压强度被用来表征试样的物理性能。结果表明:除500 MPa成型压力下试样内部生成少量的MgSiN2相外,不同成型压力氮化后试样的物相组成并无明显变化,主要生成α-Si3N4、β-Si3N4和少量的SiC相。试样内部原位氮化合成的β-Si3N4晶体主要呈现长柱状形貌。当成型压力为400MPa时,β-Si3N4晶体的尺寸最大,试样显气孔率最低,耐压强度最大。In-situ formed Si3N4 bonding Mg O-C materials were prepared by using high quality fused magnesia,silicon powder,and flake graphite as raw materials,liquid calcium lignosulfonate with a concentration of 1.25 g/m L as binder.Then the prepared materials were sintered under N2 atmosphere via two-stage sintered process that low-temperature stage with 1350 ℃ for 2h and high-temperature stage with 1500 ℃ for 3 h,respectively.The phase compositions and microstructure of the Mg O-C materials were investigated by X-ray diffraction（ XRD） and scanning electron microscope（ SEM）,the physical properties including apparent porosity,bulk density and cold crushing strength were also investigated.A large number of α-Si3N4,β-Si3N4 and a small number of Si C phases were formed in the nitriding process,and the composition was hardly affected with the briquetting pressure,whereas a specific MgSiN2 phase formed at the briquetting pressure of 500MPa.The β-Si3N4 crystals presented a columnar morphology.When the briquetting pressure is 400 MPa,the sizes of β-Si3N4 crystals possessed the maximum,and the specimen possessed the lowest apparent porosity and highest cold crushing strength at this briquetting pressure.

关 键 词：原位 成型压力 SI3N4 MGO-C 氮化 

分 类 号：TQ175.7[化学工程—硅酸盐工业]