封孔处理等离子喷涂Cr_2O_3涂层耐蚀性的电化学表征

ELECTROCHEMICAL CHARACTERIZATION FOR CORROSION RESISTANCE OF PLASMA-SPRAYED Cr_2O_3 COATING WITH SEALING

用等离子喷涂工艺在Q235钢基体上制备Cr_2O_3陶瓷涂层,并采用磷酸铝和环氧树脂对其进行封孔处理。利用图像分析法和电化学方法对封孔前后涂层的孔隙率进行了测试,采用弱极化技术和电化学阻抗谱技术对封孔前后涂层的耐蚀性能进行了研究。结果表明,封孔处理提高了涂层的耐蚀性能,环氧树脂封孔涂层的耐蚀性能更优异;陶瓷涂层在腐蚀介质中耐蚀性能主要取决于涂层的孔隙率。

Cr2O3 coating was deposited on Q235 steel by means of plasma-sprayed technology, which was sealed by aluminum phosphate and epoxy resin respectively. The porosity of the coating was investigated by graph analysis and electrochemical measurement, and the corrosion resistance of the coating was characterized by polarization curve and electrochemical impedance spectroscopy （EIS）. It is found that the sealing treatment can elevate corrosion resistance of the Cr2O3 coating. Compared with the coating sealed with aluminum phosphate, the epoxy resin-sealed coating shows excellent corrosion resistance. The electrochemical behavior of the Cr2O3 coating in the corrosive electrolyte depends mainly on the porosity of the coating.