溶胶-凝胶法制备堇青石粉体的固相反应过程和烧结性的研究

Solid Phase Reaction Process of Cordierite Powders Prepared by Sol-Gel Method and Its Sintering

将TEOS,镁铝硝酸盐以及一定量的尿素溶于乙醇-水溶液。100℃水浴加热形成凝胶。凝胶干燥后,高温煅烧可得到一种镁铝硅复合氧化物粉体。对在不同温度下煅烧的粉体和1350℃烧结的样品进行X射线衍射分析,发现在煅烧过程中,基体形态经历了从无定形态向晶态α-堇青石的转化过程,并伴随有μ-堇青石相,镁铝尖晶石相和β-石英固溶体的出现和消失。1350℃烧结的样品全部为α-堇青石相,烧结致密度最高达99.5％。以扫描电镜观察该样品的表面形貌,可看出其晶粒呈薄片状。并对纯堇青石的致密化烧结过程进行了探讨。

The TEOS, stoichiometric magnesium nitrate and aluminum nitrate, and some carbamide were dissolved in the solution of CH3CH2OH-H2O. The solution was heated at 100degreesC and then transformed into gelatinate. The dried gelatinate calcined at high temperature and a compound of MgO, Al2O3 and SiO2 could be obtained. The powder calcined at different temperatures and the sample sintered at 1350degreesC for 2h were examined by using XRD. The X-Ray diffraction studies indicate that the forms of the matrix when heat-treated come through a progress from amorphous compound to alpha-cordierite, with the appearance and disappearance of mu-cordierite, spinel and beta-SiO2. The whole sample sintered at 1350degreesC is made of a-cordierite. The highest density of the samples is 99.5%. The SEM micrograph of the sample shows that the grain is flake. The densification process of pure cordierite ceramics was investigated.