AZ91镁合金脉冲电沉积Ni-SiC纳米复合涂层的磨损与腐蚀性能

为了改善AZ91镁合金的表面性能，在含0-15g／LSiC纳米颗粒的改进的瓦特槽中，采用脉冲电沉积得到不同SiC含量的Ni-SiC纳米复合涂层。采用扫描电子显微镜（SEM）研究涂层的形貌，采用能谱仪（EDs）测试涂层的SiC含量。从15g／LSiC槽中电沉积得到的样品，其涂层的显微硬度提高了600％。采用动电位极化法研究包覆AZ91镁合金的腐蚀行为。结果表明，样品的耐腐蚀性能明显提高，即腐蚀电流密度从未包覆样品的0．13mA／cm2降低到槽中含15∥LSiC电沉积包覆样品的1．74x101mA／cm2，腐蚀电位从未包覆样品的-1．6V增加到槽中电沉积包覆样品的-0．31V。使用盘销摩擦测试仪评估了包覆和未包覆样品的耐磨性能，包覆样品的磨损量比未包覆的小8倍。

Improvement of wear and corrosion resistance of AZ91 magnesium alloy by applying Ni-SiC nanocomposite coating via pulse electrodeposition

To improve the surface properties of AZ91 magnesium alloy, Ni-SiC nanocomposite coatings with various SiC contents were pulse electrodeposited in modified Watts baths containing SiC nano-particles with the concentration of 0-15 g/L. The morphology of the coatings was studied by scanning electron microscope （SEM）. The SiC content of the coatings was measured by energy dispersive spectroscopy （EDS） analyzer. Microhardness measurement of the coatings showed up to 600% enhancement for the sample produced from the bath with 15 g/L SiC. The corrosion behavior of the coated AZ91 alloy was investigated by potentiodynamic polarization method. The results reveal a significant improvement in the corrosion resistance, that is, the corrosion current density decreases from 0.13 mA/cm2 for uncoated specimen to 1.74x10-6 mA/cm2 for the sample coated from the bath containing 15 g/L SiC and the corrosion potential increases from -1.6 V for uncoated specimen to -0.31 V for the sample coated from the bath. The wear resistance of both coated and uncoated samples was evaluated by pin-on-disc tribotester. The results show that the wear volume loss of coated sample is 8 times less than the bare alloy.