Corrosion Behaviour of Heat Treated 1060 Aluminium in Dilute Acid Solutions

Abstract

The electrochemical corrosion behaviour of untreated, quenched and annealed cold rolled 1060 aluminium specimens was studied through weight loss measurement, potentiodynamic polarization technique and optical microscopy in 0.5, 1, 1.5 and 2M H 2 SO 4 and HCl solutions. Data obtained from the tests show that the quenched specimens had the highest corrosion resistance as a result of its hardened surface due to retained saturated solid solution. The untreated aluminium specimens exhibited a lower corrosion resistance than the quenched specimens though the corrosion rates from HCl solution are generally higher than values obtained from H 2 SO 4 . Annealed specimens had the highest corrosion rate as its passive protective film resulting from the rearrangement of its microstructural constituents could not sustain the aggressive attack of corrosive anions within the acid solution. Micrographs from optical microscopy showed a severely deteriorated annealed morphology resulting from depletion of the grain boundary. Corrosion pits were observed in the untreated specimens while the quenched specimens showed limited deterioration due to general corrosion.