TYPE OF WEAR OF ALUMINIUM OXIDE LAYERS DEPENDING ON MANUFACTURING PARAMETERS

摘要

The article presents the type of wear of Al_2O_3 layers produced on the aluminium alloy EN AW-5251 depending on the production parameters. Oxide layers were produced by using DC anodizing in a ternary electrolyte at variable current density and electrolyte temperature. The layer scratch tests were carried out using a Micron- Gamma microhardness tester. The scratches of oxide layers were tested for the geometric structure of the surface using a Form TalySurf 2 50i contact profilograph. Contact thickness measurements were also made using a Dualscope MP40 device based on the eddy-current method. Using a scanning microscope (SEM), photos of the sample surfaces were taken to show and compare the surface morphology of the anodized layers in various parameters. Based on the research, it can be concluded that changes in the conditions of the production process of Al_2O_3 layers (electrolyte temperature and current density) have an impact on the type of tribological wear and changes in layer thickness. The largest thickness of the oxide layer (19.44 μm) was measured for Sample B produced at a current density of 3A/dm~2 at an electrolyte temperature of 283 K, which was also characterized by the lowest value of the ratio of parameters f1 to f2 (0.584). The smallest thickness (5.32 μm) was measured for the Sample C anodized at 1 A/dm~2 at 303 K, this sample had the largest ratio f1 to f2 (1.068) for the produced Al_2O_3 layers. Thanks to the parameters f1 and f2 and the calculation of their ratio, the wear process for Sample B was determined as scratching and microcutting, while for Sample C as grooving.