Structure and Performances of 7075 Aluminum Alloy Surface Subject to Hot-Dip Zinc

The hot-dip galvanized coating was produced on the 7075 aluminum alloy plate by immersion in a pure zinc bath at different temperature from 440°C to 470°C for different modification time (between 1 min and 10 min). The hot-dip galvanized of the treated and un-treated samples were investigated by using scanning electron microscopy (SEM) with EDX analysis, X-ray diffraction (XRD), hardness measurements and potentiodynamic polarization curves. There were three layers fabricated on the 7075 substrate surface, specifically, zinc-rich layer, two-phase mixed layer Al-Zn and interdiffusion layer. Moreover, the 7075 aluminum alloy with the hot-dip galvanized coating exhibit higher hardness and better anti-corrosion properties in comparison with the 7075 substrate.