Influence of Electrolysis Time on Fretting Wear Characteristic of Plasma Electrolytic Oxidation Coating upon TC4 Alloys

Abstract TC4 alloy exhibits relatively poor wear resistance and inevitably undergoes fretting wear during practical applications, which can result in the degradation or even failure of critical engineering components. Plasma electrolytic oxidation (PEO) technology offers a promising approach for enhancing the fretting wear performance of TC4 alloy. By tailoring key processing parameters in the PEO process, the properties of the resulting coatings can be precisely optimized. In this study, the fretting wear performance of PEO coatings upon TC4 alloy produced at various electrolytic times were carefully investigated. The results revealed that the electrolytic time significantly affected the fretting behavior, damage characteristics, and wear mechanisms of the PEO coatings. Appropriately extending the electrolytic time reduced the friction coefficient and wear volume of the coatings, which was beneficial for enhancing their overall properties and resistance to fretting wear. The dominant wear mechanism shifted from adhesive wear to abrasive wear and subsequently shifted to slight deformation. However, excessively prolonged electrolytic time led to an increase in both surface and internal defects within the coatings, resulting in severe fatigue wear and ultimately a decrease, rather than an improvement, in the fretting wear resistance of the PEO coating upon TC4 alloy.