Influence of surface condition on the corrosion of ultra-high-purity Mg alloy wire

Corrosion of extruded and cold-drawn XHP-ZX00 wire samples was studied using immersion in CO2-bicarbonate buffered Hanks' solution. Six surface conditions were studied: as-extruded, as-drawn, annealed, mechanically cleaned, chemically polished and cleaned with acetic acid. Cold drawing introduced some iron impurity particles onto the wire surface, however the low corrosion rates suggest that the amount of these particles was low. Corrosion was evaluated by mass loss, hydrogen evolution and radius reduction, an adapted corrosion evaluation method. There was good agreement between the corrosion rates evaluated from mass loss and radius reduction. Mechanically cleaning produced the lowest corrosion rate.