Tribological behavior of plasma electrolytic oxidation coating on magnesium alloy with oil lubrication at elevated temperatures

The ceramic coating with micro-pores structure on AM60B magnesium alloy was prepared in silicate electrolyte by plasma electrolytic oxidation (PEO) method. The PEO coating is mainly composed of percales MgO and forsterite Mg2SiO4 phases. The tribological performance of the PEO coatings and uncoated magnesium alloys under oil-lubricated wear conditions at different loads and elevated temperatures (80-120 degrees C) was comparatively investigated. Results shown that the PEO coating exhibited significantly higher wear resistance and relatively lower friction coefficient when compared with Mg alloy under oil-lubricated conditions. The excellent tribological performance can be attributed to the high hardness and micro-pores structure feature of the PEO coating. Such high-performance PEO coating on magnesium alloys under oil-lubricated conditions could be applied as attractive advanced material for a wide range of automobile engine applications. (C) 2009 Elsevier B.V. All rights reserved.