氮化硅结合碳化硅多孔陶瓷支撑体的制备与表征

Preparation and Characterization of Porous Ceramic Supports of Silicon Nitride-Bonded Silicon Carbide

以碳化硅、硅粉为主要原料,以氧化铝和氧化钇为烧结助剂,通过添加不同质量分数的淀粉为造孔剂,采用反应烧结方式制备了系列氮化硅结合碳化硅多孔陶瓷支撑体,并对烧成样品的物相、显微结构、孔隙率、抗折强度、孔径分布、纯水通量和耐酸碱性能进行了分析和表征.结果表明,样品的主晶相为碳化硅和氮化硅,还有少量的焦硅酸钇和塞隆;随着淀粉质量分数的增加,样品的孔隙率随之增大,样品的抗折强度随之减小,同时样品的平均孔径和纯水通量随淀粉质量分数的增加均呈现先增大后减小的趋势;样品有良好的耐酸碱性能,在标准酸性和碱性条件下的质量损失率分别为1.96%~2.04%、3.96%~4.13%;当淀粉的质量分数为3%时,烧成样品的孔隙率为41.8%,抗折强度为18.1 MPa,孔径主要分布在0.7μm^2.5μm之间,纯水通量最高,可达9.2 m^3/(m^2·h),综合性能较佳.

A series of porous ceramic supports of silicon nitride-bonded silicon carbide（SNBSC）were preparedby reactive sintering, using silicon carbon powder and silicon powder as raw materials, alumina and yttriumoxide as sintering additives and different mass fractions of starch as pore-forming agent. The crystal phase, micro-structure, porosity, flexural strength, pore size distribution and acid and alkali resistance of the samples werecharacterized. The results show that the main crystal phases of the samples are silicon carbide and siliconnitride, and the minor phases are yttrium pyrosilicate and sialon. The porosity of the samples increases while theflexural strength decreases with the mass fraction of starch increasing, respectively. Simultaneously, the meanpore diameter and the pure water flux of the samples both increase and then decrease with the increase of themass fraction of starch. The porous ceramic supports of SNBSC exhibit good acid and alkali resistance, and themass loss rates are 1.96%-2.04% in standard acidic conditions and 3.95%-4.13% in standard alkaline condi-tions, respectively. They also show better comprehensive properties with porosity of 41.8%, flexural strength of18.1 MPa, pore diameters in the range of 0.7 μm and 2.5 μm, and the maximum value of pure water flux of9.2 m^3/（m^2·h）when the mass fraction of the starch is 3%.