Effect of Nanostructured Oxide Coatings on Tensile Properties of Cast Pure Magnesium

Abstract

In this work, nanostructured magnesium oxides were formed by PEO process on cast pure magnesium and the tensile properties of thin (5.8 μm) and thick (11.2 μm) coated samples were evaluated. The results obtained by uniaxial tensile testing show that the thin PEO coating had very little effect on the ultimate tensile strength (UTS) and elongation of the cast pure magnesium, while its yield strength was somewhat decreased. For the thick coated sample, both the yield strength and UTS decreased considerably, but the variation of the elongation was moderate, compared to the uncoated sample. The microstructures characterized by SEM revealed that the high porosity content and the large size of pores in the thick PEO coating should be responsible for the significant reduction in the properties of cast pure magnesium. The relationship between the tensile properties and microstructure of the PEO coated samples suggests that the thin PEO coating should be selected to protect the pure magnesium for biodegradable applications.