Curing Process Optimization of Silane Coating on AZ91D Magnesium Alloy

AZ91D Mg alloy was immersed in the KH-550 solution to form the silane coating,and orthogonal experiments combined with single factor experiments were applied to determine the optimal curing process conditions such as curing temperature and curing time.The corrosion resistance of the silane coating based on the optimized parameters was estimated by neutral salt spray test.The surface morphology and composition of the silane coating were characterized by using scanning electron microscopy and energy dispersive spectrometry.Results showed that curing temperature had a significant effect on the corrosion resistance of silane coating.The optimum curing temperature was 120 ℃ and curing time was 60 min.Under the optimized curing process,the contents of C,N,Si,O elements in the silane coating were significantly increased and the silane coating was thicker and appeared to be uniform and compact networks.Resultant silane coating for AZ91 D magnesium alloy had much better protective ability than that formed under natural dry condition.