Structure, friction and wear of AlZn5.5MgCu based PEO coatings modified by diamond nanoparticles and silver micropowder

Abstract

Aluminum alloys, in particular AlZn5.5MgCu, are widely used due to low density. Their tribological properties are poor, plasma electrolytic oxidation (PEO) is often used to improve them. This study proposes modification of PEO coatings, during the formation of which nanodiamonds (ND) and micro dispersed silver were added to electrolyte. A comprehensive method for studying coatings included friction and wear tests at room and elevated temperatures, indentation, and calculating stresses in coated bodies. The failure of coatings with and without modifiers takes place through the mechanism of brittle fracture. The higher the test temperature, the more modifiers must be used to avoid the fracture. Samples with the largest volume of modifiers had COF in the range of 0.34–0.37 at all temperatures.