Effect of methanol on the corrosion behaviour of Al-Cu Alloys in sulphuric acid

Abstract

The effect of Cu additions (1, 3 and 5 at.-%) on the corrosion behaviour of Al in 0.5 M H 2 SO 4 + 2 ppm hydrofluoric acid + methanol at 50 °C, environment found in a direct methanol fuel cell, has been evaluated using electrochemical techniques. Electrochemical techniques included potentiodynamic polarisation curves, electrochemical impedance spectroscopy and electrochemical noise measurements measurements. Methanol concentrations included 1, 5, 10 and 20 M. Results have shown that corrosion resistance increases with increasing the methanol concentration. The addition of Cu to Al increases the corrosion rate of the former by the formation of micro galvanic cells, inducing localised typo of corrosion also.

Corrosion of structural constituents of 2017 aluminium alloy in acidic solutions containing inhibitors

“…They observed a severe attack on the matrix in the vicinity of Al 2 Cu grains and much less severe in the interior of the solid solution grains whereas Al 2 Cu intermetallic remained not corroded. [ 29 ] This is exactly the same mechanism as described above.…”

“…[ 24 ] Unfortunately, the corrosion mechanism of these alloys was rarely studied in acidic solutions. Vergara‐Juarez et al [ 29 ] described the corrosion of Al‐Cu alloys, containing from 1 to 5 wt% of Cu, in 0.5‐M sulphuric acid solutions also containing fluoride ions and a significant amount of methanol. They observed a severe attack on the matrix in the vicinity of Al 2 Cu grains and much less severe in the interior of the solid solution grains whereas Al 2 Cu intermetallic remained not corroded.…”