氮化烧结制备Si_3N_4-SiC复相陶瓷  

Preparation of Si_3N_4-SiC multiphase ceramics by nitridation sintering method

作　　者：陈超[1] 徐永东[1] 张立同[1] 成来飞[1] 范尚武[1] 刘小瀛[1] 夏卿[1] 

机构地区：[1]西北工业大学超高温结构复合材料国防科技重点实验室,西安710072

出　　处：《耐火材料》2006年第2期96-99,共4页Refractories

基　　金：陕西省科技攻关项目资助(2002K07-G5)

摘　　要：以酚醛树脂作为结合剂,以冷等静压方法成型制备氮化烧结Si3N4-SiC复相陶瓷,研究了结合剂对坯体强度和生成材料物相组成的影响。坯体强度随酚醛树脂含量增加而提高,最高强度达到23MPa,实现坯体可直接机械加工。经过氮化烧结,生成材料物相中含有SiC,含量达到7.1%～15.7%,并观察到细小的等轴颗粒αSi3N4、棒状晶粒βSi3N4以及少量针状和晶须状Si3N4。SiC颗粒与Si3N4结合在一起,被Si3N4包裹。Si3N4-SiC复相材料的生成机理:300～600℃,酚醛树脂发生裂解,形成单质C,残碳率为50%;1000～1100℃,C开始与Si发生固相反应,形成SiC;1100℃后,Si开始发生氮化反应,生成Si3N4。The influence of phenolic resin binder on bending strength of green body and phase compositions of nitridation sintered silicon nitride was studied by cold isostatic pressing and nitridation sintering method. With the increase of the phenolic resin, the bending strength of green body also increases and comes to the maximum 23 MPa. Moreover, the green body can be directly mechanically processed. SiC is generated with content ranging from 7.1% to 1.5.7%. The equiaxed grains of α-Si3N4,rodlike crystals of β-Si3N4,acicular crystals of Si3N4,and some little whisker like Si3N4 can be observed in SEM photographs. SiC grains are found bonding with Si3N4. The generation mechanism is discussed：at 300 -600 ℃,the phenolic resin decomposes to C with residual C rate about .50% ;at 1000 - 1100 ℃,the residual C begins to react with Si to generate SiC;and after 1100 ℃,the Si begins to react with N2 and generate Si3N4.

关 键 词：SI3N4-SIC 酚醛树脂 氮化烧结 复相陶瓷 

分 类 号：TQ124.758[化学工程—无机化工] TF341.6[冶金工程—冶金机械及自动化]