Assessment of the morphology, microstructure, stereometric and tribological properties of Al2O3 surface layers produced electrolytically with the alternating current method in the presence of molybdenum disulfide

Abstract

Dry friction tests were performed using a pin-on-plate tribological tester. In this study, Al2O3 and Al2O3 with MoS2 admixture plate with PEEK/BG pin. Plate surfaces were created using the constant current method and the non-periodic alternating current method. The dimension of Al2O3 fibers walls were calculate based on SEM micrographs. SGP measurements of the oxide layers were made by a Taylor Hobson Talysurf 2D pin profilometer. It was found that the gradient structure favors the reduction of the friction coefficient and weight loss of PEEK/BG in the tested friction pairs, and the method of gradually reducing non-periodic alternating current allowed to obtain a more homogeneous microstructure of aluminum oxide. The use of high current densities at the beginning of the process leads to the production of non-gradient coatings characterized by higher SGP amplitude parameters. This property translates directly into higher wear of the sliding PEEK/BG material and higher values of the friction coefficients of the tribological pairs thus obtained. The research also identified a strong correlation between the friction coefficient μ and surface topography parameters before the tribological cooperation of PEEK/BG pairs - Al2O3 oxide coating.