Mg_2B_2O_5晶须增强AZ91D镁基复合材料表面Ni-P-SiC化学镀层的耐蚀性与SiC含量的关系

Corrosion Resistance of Electroless Ni-P- SiC Composite Coating on AZ91D Magnesium Matrix Composite Reinforced by Mg_2B_2O_5 Whisker

有关Ni-P-Si C复合镀层耐蚀性的研究不多。为此,在Mg2B2O5晶须增强AZ91D镁基复合材料表面化学镀Ni-P-Si C层。采用扫描电镜(SEM)、电子探针(EPMA)、电化学方法研究了镀液中纳米Si C含量对镀层表面形貌、成分、耐蚀性、结合力的影响。结果表明:纳米Si C颗粒的加入细化了镀层晶粒,造成了镀层疏松,随着镀液中Si C浓度的增加,复合镀层的耐蚀性逐渐降低,但对基体仍有保护作用,Si C浓度为2 g/L时耐蚀性较佳,且镀层与基体结合良好。

Electroless Ni-PSiC composite coating was prepared on AZ91 D magnesium matrix composite reinforced by Mg_2B_2O_5 whisker.The surface morphology and composition of as-obtained Ni-P-SiC composite coating were analyzed by scanning electron microscopy and electron probe microanalysis.The corrosion resistance of the composite coating was evaluated by electrochemical method,and the effects of SiC content in the plating bath on the corrosion resistance and adhesion force of the Ni-P-SiC composite coating were investigated.Results indicated that nanometer SiC caused refining of the grains and loosening of the composite coating.The corrosion resistance of the Ni-P-SiC composite coating tended to decline gradually with increasing SiC content in the electroless plating bath,and in particular,the Ni- P- SiC composite coating obtained from the plating bath containing 2 g/L SiC exhibited good corrosion resistance and high adhesion force to the Mg matrix composite substrate.