Coating of Al 2024 alloy with micro arc oxidation method with additional additives, investigation of tribological properties and corrosion behaviors

In this study, the coating process was carried out by adding graphite, h-BN and ZnO particles to the surface of 2024 Al alloy by micro arc oxidation method. The surface morphology, tribological properties and corrosion behavior of the samples coated were investigated. The added additives influenced the average coating thickness, and the highest average coating thickness (334.71 µm) was observed in the sample coded as ZAC. The surface roughness of the coated samples increased, and the lowest average surface roughness value (Ra=1.79 µm) was obtained in the ZnO doped ZAC coded sample. All samples showed the presence of γ-Al2O3 in the inner layer with a uniform structure. In the different environmental wear experiments, the average coefficient of friction was found to be lower in the nitrogen atmosphere and seawater environment compared to the air environment. The lowest average coefficient of friction value (0.047 µm) was observed in the sample coded as GAC. The effect of additives on the coefficient of friction in the seawater environment was not observed. The lowest wear rate value (4.55x10-3 mm3 /N.m) was observed in the sample with coded as GAC in nitrogen atmosphere. The coating processes had an effect on corrosion, and the best corrosion resistance was observed in the graphite doped GAC coded sample. For the GAC coded sample, the Ecorr and Icorr values were determined as -709.5 V, 1.73x10-7 A/cm2 , respectively.