碳化硅-堇青石多孔陶瓷的制备及其性能

以碳化硅粉末、高岭土和滑石等为原料,按堇青石的化学计量比设计原料配比,制备了堇青石理论生成量分别为0、10%、15%、20%、100%的碳化硅-堇青石多孔陶瓷,测定了试样的抗折强度、显气孔率和热膨胀系数,并分别用XRD和SEM分析了试样的晶相组成和断面形貌。结果表明:与碳化硅多孔陶瓷相比,碳化硅-堇青石多孔陶瓷的抗折强度显著提高,热膨胀系数明显降低,但显气孔率有所降低。SEM分析结果表明:碳化硅-堇青石多孔陶瓷中碳化硅颗粒排列较紧密,断面呈“网格状”结构;而在多孔碳化硅陶瓷中,晶粒形貌清晰且排列较疏松,气孔平均孔径较大。

Preparation and properties of porous SiC-cordierite ceramics

Porous SiC-cordierite ceramics with cordierite theoretical contents of 0,10%,15%,20% and 100% respectively were prepared using silicon carbide power,Kaolin clay and talc as starting materials according to stoichiometric composition for cordierite.Modulus of rupture(MOR),apparent porosity and thermal expansion coefficient (TEC)of the specimens were determined.The crystal phases and microstructure of the section surface were analyzed by XRD and SEM.Results showed that compared with porous SiC ceramics,the MOR of SiC-cordierite was improved significantly,and the TEC decreased remarkably,and the apparent porosity also decreased.SEM analysis results revealed that the SiC grains in porous SiC-cordierite ceramics distributed more closely and the section surface appeared as reticular structure.However,porous SiC ceramic had the loosen structure of SiC grains,distinct crystal shape and larger average pore size.