Micro- and macro-scale characterization of the microstructure and scratch resistance of the 5083-anodic aluminum oxide film

This paper focuses on the thickness, microstructural, and scratch resistance of the sulfuric oxide layer of 5083-aluminum alloy for different anodizing durations/reaction times (RT = 30, 60, and 90 min). The thickness and the microstructure analyses were carried out using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy, and ImageJ post-processing software. The scratch resistance was investigated using macro- and micro-scratch tests. Experimental results revealed that the oxide layer was covered by larger-sized microcavities and a thicker oxide layer for 90 min RT. Moreover, the area, which was covered by microcavities percentage, was decreased for 60 min RT and increased for 90 min RT. Besides, using the macro-scratch test, and when increasing RT, no micro-cracks were detected inside the scratch mark. Nerveless, the increasing of the normal load was shown that the oxide layer was more resistant to scratch. Finally, the 5083-aluminum alloy oxide layer had a high-scratch resistance such as a weak penetration depth and a low friction coefficient.