Corrosion resistance of zinc diffusion coating on clip
[Introduction] The corrosion resistance of clips treated by sherardizing, sherardizing + silicate sealing, and sherardizing + oil-based painting in neutral salt spray and sulfur dioxide environments is worth studying. [Method] The sherardizing layers with different thicknesses and morphologies were collected by using magnetoresistive thickness gauge and metallographic microscope, and then sealed with silicate and oil-based paint, respectively. The distribution and chemical composition of the sealing layers were examined by scanning electron microscopy and energy-dispersive spectroscopy. The neutral salt spray test and sulfur dioxide test were carried out. [Result] The silicate sealing layer, which was thin, was distributed on the surface of the sherardizing layer in the way of infiltration into the gaps. The oil-based painting layer, which was thick, was covered on the surface of the sherardizing layer in a more uniform and continuous way. After 120 hours of neutral salt spray test or sulfur dioxide test, red rust appeared on the unsealed and silicate-sealed sherardizing specimens, but the red rust area of the latter was less than that of the former. No red rust was formed on the sherardizing specimen sealed with oil-based paint. [Conclusion] The corrosion resistance of sherardizing layer can be improved by silicate sealing or oil-based painting as a post-treatment. Although the anticorrosion performance of oil-based painting is the best, the post treatment for sherardized products should be selected more reasonably in terms of operation, environmental friendliness, safety, cost, and service conditions.
万方数据
维普
