溶胶-凝胶过程影响堇青石结晶行为的因素

Factors affecting crystallization behavior of cordierite by Sol-gel

为了研究影响堇青石结晶行为的因素,以Mg(NO3)2.6H2O、Al(NO3)3.9H2O、正硅酸乙酯为原料,根据堇青石的化学式2MgO.Al2O3.5SiO2,按照配比制成溶胶,利用溶胶-凝胶法制备堇青石粉末,并利用X射线衍射、差示扫描热量法等测试手段对堇青石粉末进行表征.测试结果表明,煅烧温度和凝胶预处理温度对堇青石的结晶行为有直接的影响,当干凝胶的预处理为500℃,煅烧温度为1 200℃时,出现明显的α-堇青石晶相.

Cordierite is widely used with its low thermal expansion coefficient, dielectric constant and high ther- mal shock resistance. In order to study the factors affecting the cordierite crystallization behavior, cordierite crystalline powder was prepared according to the cordierite chemical formula （2MgO·2Al2O3·5SiO2 ）, and Mg（ NO3 ）2·6H2 O, Al（ NO3 ）3·9H2O, tetraethyl orthosilicate （TEOS） were used as the raw materials to get the sol- gel, then the gel was calcined at different temperature to obtain the cordierite powder. The structure and the composition of the cordierite power were characterized with the X - ray diffraction （XRD） and differen- tial scanning calorimetry （DSC） techniques. The results show that the pretreatment and calcination temperature has a direct influence on the cordierite crystallization behavior. When the pretreatment temperature is 500 ℃ and the calcination temperature is 1 200 ℃, alpha- cordierite phase is obtained.