Influence of Hard Anodizing on the Mechanical and Corrosion Properties of Different Aluminum Alloys

Hard anodizing of different aluminum alloys 2014-T3, 6061-T6, and 7075-T6 is conducted in sulfuric acid electrolyte at a temperature of - 5 degrees C and current densities of 1.6 to 2.8 A/dm(2) for 30 to 60 min. The effect of substrate microstructure on the mechanical properties, corrosion resistance, and morphology of the hard anodic layers is investigated. Electrochemical technique, thickness, hardness, and abrasion testing devices are used to test the corrosion and mechanical properties of hard anodic layers. The morphology and nanostructure of the anodic film are observed by SEM. The results show that the 7075-T6 (Al-Zn-Mg-Cu) aluminum alloy has the highest hard coat thickness, hardness, and abrasion resistance. The Fe, Si intermetallic phases present in 6061 Al alloy hinder the oxide growth. The oxide layer formed on 2014 Al alloy has the lowest thickness, hardness, abrasion resistance, and corrosion resistance due to the high content of copper.