Microstructural, Adhesion and Tribological behavior Investigation of Porous Anodic Aluminum Oxide Coating on 5083 Aluminum Alloy

In this study, the aluminum oxide coating was applied on 5083 Aluminum alloy by hard anodizing method in sulfuric acid. M icrostructural investigations showed that anodizing process leads to the formation of porous amorphous alumina coating on the surface of 5083 aluminum alloy. The porosity of the coating surface increases by increasing the anodizing voltage, leading to an increment in the surface roughness. In addition, as the voltage increased, the thickness and hardness of the coating increased due to the higher dissolution rate of the 5083 Al alloy substrate. M icroscopic examinations were indicant of appropriate adhesion of the aluminum oxide coatings. The anodizing process significantly improved the tribological behavior (at least more than 20 times) of 5083 aluminum alloy. M icroscopic analysis showed that the main wear mechanisms of 5083 aluminum alloy were abrasion and delamination and the dominant wear mechanisms in aluminum oxide coatings were adhesive and delamination.