Electrochemical Corrosion Behaviour of Cerium Chemical Conversion Coatings on 304 Stainless Steel in Alkaline Solutions Containing Chloride Ions

摘要

A chemical conversion coating was successfully prepared on the surface of 304 stainless steel (SS).The morphology and chemical composition of the obtained coating were analysed by scanning electronmicroscopy (SEM) and energy dispersive spectrometry (EDS). The electrochemical corrosionbehaviour was investigated in 3.5 wt.% NaCl with different pH values. The results show that thechemical conversion coating is quite stable in alkaline solutions containing chloride ions. The coated304 SS shows much higher corrosion potential and pitting potential in comparison with the uncoated304 SS. It is suggested that the chemical conversion coating can noticeably improve thepitting corrosion resistance of 304 SS. In addition, the cerium chemical conversion coating shows goodpitting resistance in an alkaline solution with increasing pH values.