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采用溶胶-凝胶法制备了化学组成为CaZr4P6O24(CZP)的溶胶态前驱物,用其涂覆薄壁蜂窝堇青石陶瓷,经过700℃焙烧2h转化为具有低热膨胀特性的结晶态CZP涂层。用X射线衍射和BET(Brunauer-Emmett-Teller)氮吸附法表征了涂层的物相和孔结构,用扫描电镜观察了涂层表面及涂层与基体的界面结合处的形貌,用能量色散光谱仪分析了涂层中的元素分布及含量。结果表明:在蜂窝堇青石陶瓷基体上形成的涂层组成为CZP;表面沉积了19.5%(质量分数)CZP的蜂窝堇青石陶瓷的BET比表面积、孔体积和平均孔径分别为16.4m2/g,0.0225mL/g和2.74nm。CZP涂层与蜂窝堇青石基体的界面结合良好。发动机台架性能试验结果表明:“CZP-蜂窝堇青石”复合载体负载的单钯催化剂表现出与“γ-Al2O3-蜂窝堇青石”负载的单钯催化剂相近的三效转化活性。
A sol precursor with a chemical composition of CaZr4P6O24 (CZP) was prepared by sol-gel method. The thin-walled honeycomb cordierite ceramic was coated on it and calcined at 700 ℃ for 2h to form a crystalline CZP coating with low thermal expansion. The phase and pore structure of the coating were characterized by X-ray diffraction and BET (Brunauer-Emmett-Teller) nitrogen adsorption. The morphology of the coating surface and the interface between the coating and the substrate were observed by scanning electron microscopy. Dispersive spectrometer analysis of the coating element distribution and content. The results show that the coating composition of honeycomb cordierite ceramic substrate is CZP. The BET specific surface area, pore volume and average pore diameter of honeycomb cordierite ceramics with 19.5% (mass fraction) CZP deposited on the surface are 16.4 m2 / g, 0.0225 mL / g and 2.74 nm. CZP coating and honeycomb cordierite matrix interface well. The engine bench performance test results show that the single-palladium catalyst supported by “CZP-Cellular cordierite” composite carrier exhibits three-way conversion activity similar to that of “γ-Al2O3-honeycomb cordierite” supported single palladium catalyst.