中文摘要：

以磷酸铝铬溶液和Cr2O3粉末为原料制备了一种封孔剂，并对WC-12Co热喷涂涂层进行封孔处理。利用XRD、SEM、EDS以及TG-DSC分别对磷酸铝铬的物相、封孔前后涂层表面形貌、固化特性和耐热性能进行检测分析。利用动电位极化电化学测试和热震试验分别对封孔前后涂层的抗腐蚀性和固化后的磷酸铝铬层的抗热震性能进行研究。结果表明：磷酸铝铬的固化温度在250℃左右，在700℃内体系无任何热效应发生，材料具有良好的耐热性能。固化后涂层表面致密，磷酸铝铬对涂层孔隙具有良好的填充作用，明显降低了涂层的孔隙率。封孔后的涂层具有较高的自腐蚀电位和较小的腐蚀电流密度，涂层耐蚀性显著提高。在450℃下进行热震试验，当热震次数一定时（热循环100次），添加填料的磷酸铝铬层的剥落面积低于未添加填料的磷酸铝铬层，表现出较高的抗热震性能。

英文摘要：

The sealant was prepared with the chromium-aluminum-phosphate and the Cr203 powder. The chromium- aluminum-phosphate sealants were used to seal the thermal sprayed WC-12Co coatings. XRD, SEM, EDS and TG-DSC were used to examine the phases, surface morphologies, curing characteristics and heat resistance of the WC-12Co coatings with and without chromium-aluminum-phosphate sealant, respectively. Potentiodynamic polarization electrochemical test and thermal shock experiment were also used to examine the corrosion resistance and thermal shock resistance of the WC-12Co coatings with and without chromium-aluminum-phosphate films. The results show that the curing temperature is about 250 ~C and the sealant has excellent heat resistance below 700 ~C. Besides, the chromium-aluminum-phosphate could fill into the pores, reducing the porosity of the coating. The WC-12Co coatings after sealant treatment show higher corrosion potential and smaller corrosion current density, indicating the improved corrosion resistance. After thermal cycling for 100 times under 450℃, the spalling areas of the sealant layer with Cr203 powder were smaller than that of the sealant without Cr203 filler, which showed better thermal shock resistance for the sealant layer with Cr2O3 powder.