Effects of MgO Nanoparticles on Corrosion and Wear Behavior of Micro-arc Oxide Coatings Formed on AZ31B Magnesium Alloy

To further improve the corrosion and wear resistance of AZ31B magnesium alloy, the oxide ceramic coatings were fabricated through micro-arc oxidation, and MgO nanoparticles (4 g/L) were added into the electrolyte. The surface and cross-sectional morphology were observed by scanning electron microscopy. The phase composition was measured by X-ray diffraction. The corrosion resistance was tested by electrochemical workstation and salt spray test. The abrasion resistance was tested using pin on disk test. The results indicate that with addition of the MgO nanoparticles, the corrosion current density is reduced to 4.28×10-9 A/cm2, due to the micropores are significantly sealed and the MgO, as one of the components of the coatings is increased. The results of neutral salt spray show that the corrosion takes place in the form of pitting and crack, and the deposition of MgO reduces the corrosion point. Under dry friction of 2 N, with the increase of the thickness of the inner dense layer, the friction coefficient and the wear rate decreased to 0.228 and 1.39×10-5 mm3/(N•m), respectively. The corrosion and wear resistance are effectively improved. © 2018, Materials Review Magazine. All right reserved.