Research on water based coating containing nano-silica for magnesium alloy

摘要

Due to magnesium's active chemical property, a novel environmental protective water based metallic coating was developed, which mainly contains metal flake, nano-silica, silicate and silane. The coating's properties were investigated by neutral salt spray test, micro-hardness testing, adhesion test and electrochemical technique etc. Meanwhile the coating surface and microstructure was observed by scanning electron microscopy (SEM), Furthermore, the effect of nano silica on the coating was also explored. Results showed that an excellent adhesive, heat-resisting, protective coating for AZ91D magnesium alloy could be achieved by this technique. It also indicated that nano silica could greatly improve the properties of coating. In the paper, mechanism of nano silica coating was also discussed.