Effect of Selective Oxidation of Silicon on Phosphating Performance of Cold-Rolled Steel Plates

Abstract

In order to study the effect of selective oxidation of silicon on phosphating performance of cold-rolled steel plates， phosphating was performed on cold rolled steel plates with different silicon contents. Electrochemical test， X-ray photoelectron spectroscopy， transmission electron microscopy and scanning electron microscopy were used to analyze the corrosion resistance，composition and morphology of the samples before and after grinding. Results showed that the silicon oxide film formed in the annealing process of cold-rolled steel plate was mainly composed of Si， SiC， SiO2 and SixOy. Before grinding， the phosphating performance of the samples with higher silicon contents was obviously worse， and the corrosion resistance of their phosphating films was also poorer. After grinding， the phosphating performance of samples with different silicon contents had no obvious difference. Through an analysis on the surface composition and microstructure of the cold-rolled steel plates， it could be concluded that the silicon oxide film on the surfaces of samples with high silicon contents was not easy to dissolve in the phosphating solution. During the phosphating process， the anode reaction was hindered by the silicon oxide film， and the deposition of phosphate was affected. In general，the selective oxidation of silicon had a significant effect on the phosphating performance of cold-rolled steel plates.

Keywords

• silicon|selective oxidation|phosphating|cold-rolled steel plate|corrosion resistance