The Influence of PEO Process Parameters on the Mechanical and Sclerometric Properties of Coatings on the Ultralight Magnesium Alloy LA141

This study explores the influence of significant manufacturing parameters, i.e., peak current density and frequency, on the oxide coatings’ micromechanical and sclerometric properties. The parameter levels were determined using a full experimental design with two variables at three levels. Plasma electrolytic oxidation (PEO) was conducted on an ultralight LA141 magnesium alloy in an alkaline ternary electrolyte. Coating performance was characterized by measuring hardness (HIT) and Young’s modulus (EIT), as well as three loads significant to coating failure: Lc1, the initiation of Hertzian tensile cracks; Lc2, the initiation of cohesive coating failure; and Lc3, full delamination of the coating. Scratch testing was complemented by profilographic analysis to provide isometric surface images. Statistical analysis was then employed to ascertain correlations of process parameters with the developed mechanical and sclerometric properties.