以黏土和粉煤灰为主要原料制备低热膨胀系数堇青石基陶瓷

Cordierite-based Ceramics with Low Thermal Expansion Coefficient from Clay and Coal Fly Ash

低成本合成堇青石陶瓷材料一直受到研究者们的广泛关注。以黏土、粉煤灰、滑石和铝矾土为主要原料制备低膨胀堇青石质陶瓷,研究了四种原料的配比及烧成制度对陶瓷物相、显微形貌、热膨胀系数、孔隙率的影响规律。结果表明:滑石添加量的改变显著影响堇青石陶瓷的相组成,当滑石添加量为33.14wt.%时可以获得纯堇青石相的陶瓷,过量滑石将导致尖晶橄榄石的生成;烧成温度的升高和保温时间的延长有助于试样中堇青石的合成,在1300℃保温3.5 h的烧成条件下,可得到热膨胀系数值最低为2.21×10^(-6)℃^(-1)、强度为36.17 MPa的纯相堇青石质陶瓷材料。

Low-cost synthesis of cordierite ceramic materials has been widely concerned.In this study,clay,fly ash,talc and bauxite were used as the main raw materials to prepare low-expansion cordierite ceramics.The effects of composition of the raw materials and sintering condition on structural characteristics of the ceramics,such as phase content,micromorphology,thermal expansion coefficient,porosity and so on,were systematically studied.It is found that the content of talc had a significant effect on phase composition of the cordierite ceramics.When the content of talc was 33.14 wt.%,single phase cordierite ceramics can be obtained.Excessive talc would lead to the formation of spinel olivine phase.The increase in sintering temperature and time is helpful for the phase formation of cordierite.After sintering at 1300℃for 3.5 h,the cordierite ceramics had a minimum thermal expansion coefficient of 2.21×10^(-6)℃^(-1)and a strength of 36.17 MPa.