陶瓷纤维增强堇青石质陶瓷材料的研究

Ceramic fiber reinforced cordierite-based ceramics

为了制得热膨胀系数小、力学性能好的优质堇青石质陶瓷材料,以粒径≤0.074 mm的黏土、d_(50)=1μm的SiO_2微粉和≤0.074 mm的轻烧MgO为原料,按照堇青石的理论组成进行配料,外加质量分数10%的硅酸铝陶瓷纤维或多晶莫来石纤维,采用挤出方式成型,分别于1 250、1 300和1 350℃保温3 h制得堇青石质陶瓷材料。采用国标检测了试样的常温物理性能和热膨胀系数,采用X射线衍射仪和扫描电镜对试样的物相组成和显微结构进行了分析。结果表明:1 350℃保温3 h制得的堇青石质陶瓷材料的热膨胀系数较低,力学性能较好;试样以堇青石相为主晶相,堇青石相在引入的硅酸铝陶瓷纤维表面生成且基本呈定向分布。

In order toobtain highquality cordierite-basedceramics with lowthermal expansion coefficient and good mechanical properties,cordierite-based cereimics were prepared through the extrusion molding methodandfired at 1 250°C,1 300°C,1 350°C for 3 h,respectively.The formulation was based on the theo-retical composition of cordierite using clay(≤0.074 mm),silica micropowder(d5t)=1 nm)and light-burned MgO(≤0.074 mm)as the starting materials and extra-adding 10 mass%aluminum-silicate ceramic fiber or polycryste^lline mullite fit)er.The cold physical properties and thermal expansion coefficif^nt of the synthe-sized cordierite-based cereimics were determined according to national standards.The phase composition and microstructure were analyzed by an X-reiy diffreictometer and a scanning electron microscope.The re-sults show that cordierite-based cereimics synthesized at 1 350°C for 3 h have low thermal expansion coeffi-cient and good mechanical properties.The main crystalline phase is cordierite,which grows on the surfeice of the introducedaluminum-silicate ceramic fibers andmainly directionally distributes inthe specimens.