Corrosion Propensity of Cold Deformed 5052Aluminium Alloy in Seawater

摘要

Conventional 5052 aluminium alloysare known to exhibit characteristics response to deformation having a rebound effect on their corrosion propensity. This study investigates this phenomenon with a view to establishing the appropriate processing method that confers enhanced corrosion resistance to stem the incidence of facility failure in the food processing industry. Samples of the alloy were produced by casting after proper charge calculation. The cast samples were cold rolled in a two-high mill at ambient temperature to 20%, 40%, 60% and 80% size reduction. Corrosion test coupons were then prepared from the deformed samples on which electrochemical corrosion polarisation in seawater environment for 36 hours at an interval of 6 hours was carried out. Results of the corrosion campaigns show that corrosion rate increases as degree of deformation increases and this is attributed to high energy density in the deformed sample matrix which approximates initiation sites for corrosion.