大比表面积高牢固度堇青石蜂窝涂层的制备

以拟薄水铝石粉为原料,分别采用铝溶胶法、活性Al_2O_3浆料法和混合浆液法,对堇青石蜂窝基体进行涂层处理。通过黏度、SEM、BET和超声振荡等分析测试手段,着重考察了涂层浆液固含量和黏度对蜂窝涂层量、比表面积和牢固度的影响,比较了采用不同方法进行涂层的效果。结果表明,铝溶胶的涂层具有牢固度高的特点,缺点是比表面积小;Al_2O_3浆料的涂层比表面积较大,但牢固度较差。而混合浆液法利用铝溶胶作为Al_2O_3浆料的胶联剂,结合上述两种涂层方法的优势,涂层后的蜂窝既具备大的比表面积(达59m~2·g~(-1)),又保持了较高的涂层牢固度,而且涂层工艺简单可控,有利于工业化应用。

Preparation of cordierite honeycomb coating with large surface area and high adhesive capacity

Cordierite honeycomb was coated with three different liquid coating precursors, i. e. , alumina sol, alumina slurry and mixed slurry prepared from pseudoboehmite powders. Effects of solid content in the precursor and viscosity of the liquid precursor on loading percentage, surface area and adhesive capacity of the coatings on the cordierite substrate were investigated by viscosity measurement, SEM, BET and ultrasonic surging techniques, and coating behaviors of the three precursors compared. The results showed that coating derived from alumina sol exhibited high adhesive capacity but low surface area; coating derived from alumina slurry had high loading percentage and specific surfaee area, but low adhesive capacity. The mixed slurry containing alumina sol as the binder combined the merits of both and exhibited large surface area （59 m^2·g^-1 ） and high adhesive capacity of the coating. The coating process was simple and controllable, which facilitated its commercialization.