仿生制备多孔氮化硅陶瓷  

Biomimetic Synthesis of Porous Si_3N_4 Ceramics

作　　者：罗民[1] 程佳[1] 马晶[1] 陈小虎[1] 王斌鉴[1] 杨建锋[2] 

机构地区：[1]宁夏大学化学化工学院,银川750021 [2]西安交通大学金属材料强度国家重点实验室,西安710049

出　　处：《无机材料学报》2008年第4期763-768,共6页Journal of Inorganic Materials

基　　金：教育部科学技术研究重点项目(203143);973前期研究专项(2007CB216400，2008CB617613);宁夏高等学校科研项目(2007)

摘　　要：以松木炭化后形成的多孔木炭为模板,经Y_2O_3/SiO_2混合溶胶浸渍生物碳模板形成Y_2O_3/SiO_2/C复合体,在高压氮气氛下(0.6MPa),1600℃碳热还原氮化制备出生物形态多孔氮化硅陶瓷.借助XRD、SEM研究了烧结助剂、烧结温度、反应时间和烧结气氛对烧结产物显微结构和晶相的影响,探讨了多孔Si_3N_4陶瓷的反应过程和机理.结果表明,多孔Si_3N_4陶瓷是由主晶相β-Si_3N_4和少量晶间玻璃相Y_sSi_4N_4O_(14)组成;多孔Si_3N_4不仅保留了松木的管胞结构,还在孔道中生长出纤维状形貌的β-Si_3N_4颗粒;Si_3N_4的反应烧结过程包括α-Si_3N_4的形成、晶形转变(α-β相变)和晶粒生长三个阶段.在1450℃烧结的机理是气-固和气-气反应机理,在1600℃通过液相烧结的溶解-沉淀机理形成纤维状的多孔Si_3N_4陶瓷.Porous silicon nitride ceramics with a biomorphic microstructure were manufactured by carbothermal reduction and nitridation of Y203/SiO2/charcoal composites in high concentration nitrogen atmospheres（0.6MPa） at 1600℃. These composites were prepared from pine-derived charcoal impregnated with yttrium-incorporated silica mixed sol by vacuum/pressure infiltration process. The influences of sintering temperature, reaction time, additive and sintering atmosphere on microstructure and phase composition were studied by XRD, SEM. The formation mechanism of Si3N4 was analyzed. XRD analysis shows that mainly β-Si3N4 and minor glass component of YsSi4N4O14 are detected. SEM observation reveals that the resulting porous Si3N4 retains the microcellular morphology of original pinewood tissue, and the remarkable rod-like β-Si3N4 grains grow from the internal walls of macroscopic pores. The sin- tering process of porous 2-Si3N4 consists of three stages, namely, formation of α-Si3N4, transformation of α-β and grain growth, respectively. Nitridation is based on gas-solid and gas-gas reaction among SiO（g）, N2（g）, C（s） or CO（g） for the samples treated at 1450℃. Porous ceramics with elongated fibrous 3-Si3N4 grain is developed by solution-reprecipitation mechanism at 1600℃.

关 键 词：仿生合成 多孔Si3N4陶瓷 纤维状颗粒 碳热还原氮化反应 

分 类 号：TB39[一般工业技术—材料科学与工程]