Effect of Spark Plasma Sintering on Plasma Electrolytic Oxidation Coatings on Gas-Atomized Mg-Zn-Y Alloy Containing Nano-Sized Powders

摘要

Mg-1.0wt.%Zn-2.0wt.%Y alloy powders were produced by gas atomization, and subsequently sintered by spark plasma sintering (SPS). The SPSed Mg-1.0wt.%Zn-2.0wt.%Y alloy, which showed a microstructure of well-bonded grains containing nano-sized powders of approximately 100 nm in diameter, was coated by a plasma electrolytic oxidation (PEO) method. Microstructure, mechanical properties and corrosion properties of PEO coatings were investigated and compared to those of normally sintered Mg-1.0wt.%Zn-2.0wt.%Y and cast Mg-1.0wt.%Zn alloys. All coatings consisted of MgO and Mg_2SiO_4. The micro-hardness and friction coefficient of coatings on the SPSed Mg-1.0wt.%Zn-2.0wt.%Y alloy were higher than those on normally sintered Mg-1.0wt.%Zn-2.0wt.%Y and cast Mg-1.0wt.%Zn alloys. However, the corrosion resistance in 3.5% NaCl solution for the SPSed Mg-1.0wt.%Zn-2.0wt.%Y alloy was between that for normally sintered Mg-1.0wt.%Zn-2.0wt.%Y alloy and cast Mg-1.0wt.%Zn alloy.