Effects of heat treatment and quenching regimen on the electrochemical corrosion behaviour of aluminium alloy AA8011 in 0.1M H 2 SO 4 was studied by open circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy measurements. Three different specimens (untreated/ control, air -quenched oven-quenched) were investigated. Polarization results show that all the specimens underwent active dissolution, with no distinctive transition to passivation, heat treatment was observed to shift the corrosion potential towards low anodic values and decreased the rates of anodic partial reactions of the corrosion process. Electrochemical investigations reveal that heat treatment techniques have positive impacts on the alloy as indicated in increase in charge transfer resistance, polarization resistance and decrease in double layer capacitance. These positive effects are attributed to decrease in mean defect size and increase in lattice distortion of the crystallites in the heat treated specimens of the alloy. Studies of X-ray diffraction (XRD) spectra, scanning electron microscopy (SEM) morphologies of control, air and oven quenched samples of AA8011 aluminium alloy indicate decrease in mean defect size of 18.97 % and 40.44 %; increase in the lattice distortion of 11.07 % and 20.04 % for air and oven quenched specimens respectively.

ABSTRACT.A ploycrystaline copper (99.99%) coupons of dimension 1x2x5 cm in which a hole of diameter 0.5cm drilled was used. Before all measurements, the coupons were polished successively with metallographic emery paper between (600 and 1200) grits, then washed with doubly distilled water, degreased with acetone and again washed using distilled water and finally allowed to dry in air at room temperature.Explanation of the effects of magnetic fields on inhibition process using the chemical quantum calculations. The dipole moment is the product of a charge and distance of separation of the charges in an atom or molecule. Any process which can cause change in the alignment of the dipoles on the surface of the corroding metal systems can facilitate an increase in inhibition process. The magnetic field acts on the dipoles such that it aligns the charges on the metal thereby providing the needed charge types at the required point. This explains the graph on figure 1 which shows an increase in inhibition efficiency in the presence of magnetic fields.

A ploycrystaline copper (99.99%) coupons of dimension 1x2x5 cm in which a hole of diameter 0.5cm drilled was used. Before all measurements, the coupons were polished successively with metallographic emery paper between (600 and 1200) grits, then washed with doubly distilled water, degreased with acetone and again washed using distilled water and finally allowed to dry in air at room temperature. Explanation of the effects of magnetic fields on inhibition process using the chemical quantum calculations. The dipole moment is the product of a charge and distance of separation of the charges in an atom or molecule. Any process which can cause change in the alignment of the dipoles on the surface of the corroding metal systems can facilitate an increase in inhibition process. The magnetic field acts on the dipoles such that it aligns the charges on the metal thereby providing the needed charge types at the required point. This explains the graph on figure 1 which shows an increase in inhibition efficiency in the presence of magnetic fields.

Effects of heat treatment and quenching regimen on the electrochemical corrosion behaviour of aluminium alloy AA8011 in 0.1M H2SO4 was studied by open circuit potential, potentiodynamic polarization and electrochemical impedance spectroscopy measurements. Three different specimens (untreated/control, air -quenched oven- quenched) were investigated. Polarization results show that all the specimens underwent active dissolution, with no distinctive transition to passivation, heat treatment was observed to shift the corrosion potential towards low anodic values and decreased the rates of anodic partial reactions of the corrosion process. Electrochemical investigations reveal that heat treatment techniques have positive impacts on the alloy as indicated in increase in charge transfer resistance, polarization resistance and decrease in double layer capacitance. These positive effects are attributed to decrease in mean defect size and increase in lattice distortion of the crystallites in the heat treated specimens of the alloy. Studies of X-ray diffraction (XRD) spectra, scanning electron microscopy (SEM) morphologies of control, air and oven quenched samples of AA8011 aluminium alloy indicate decrease in mean defect size of 18.97% and 40.44%; increase in the lattice distortion of 11.07% and 20.04% for air and oven quenched specimens respectively.