Electroless Ni-P-TiO_2/Ni-P-SiC Composite Coating's Corrosion Resistances on Mg_2B_2O_5w/AZ91D Magnesium Matrix Composites

摘要

Ni-P, Ni-P-TiO_2 and Ni-P-SiC composite coatings on AZ91D magnesium matrix composite were prepared by the electroless composite depositing. The surface morphology of the coatings was observed by scanning electronic microscopy(SEM) and electron probe X-ray microanalyser(EPMA). The corrosion resistance of coatings were studied by the electrochemical method and the impact of TiO_2 and SiC was analyzed. The results showed that nano-TiO_2 and nano-SiC particles refining the depositing, cause the depositing loose, the corrosion resistance of composite depositing reduced. The corrosion potential is over -0.8V when 2g/L TiO_2 or SiC is added in solution, though the potentials lower than Ni-P coating(lower -0.5V), it still shows a protective effect for magnesium matrix composite.