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In order to provide scientific basis for advanced applications of near eutectic Al-Si-Mg alloys as architectural prof iles,a comparative study on the corrosion resistance of an as-extruded near eutectic Al-Si-Mg alloy and AA6063 aluminium alloy was carried out by means of neutral salt spray test.The corroded surfaces of the alloys were examined with optical microscopy and scanning electron microscope(SEM).Results show that the corrosion type of these two alloys is pitting corrosion.The number of corrosion pits in the AA6063 aluminium alloy is more than that in the near eutectic Al-Si-Mg alloy,but the pits in the latter alloy are much larger and deeper.Because the relatively low polarization resistance of the near eutectic alloy leads to poorer repassivation ability,autocatalytic acidif ication occurs once a pit forms.Thus,occluded corrosion cells are developed in this alloy.
In order to provide scientific basis for advanced applications of near eutectic Al-Si-Mg alloys as architectural prof iles, a comparative study on the corrosion resistance of an as-extruded near eutectic Al-Si-Mg alloy and AA6063 aluminum alloy was carried out by means of neutral salt spray test. The corroded surfaces of the alloys were examined with optical microscopy and scanning electron microscope (SEM). Results show that the corrosion type of these two alloys is pitting corrosion. number of corrosion pits in the AA6063 aluminum alloy is more than that in the near eutectic Al-Si-Mg alloy, but the pits in the latter alloy are much larger and deeper.Because the relatively low polarization resistance of the near eutectic alloy leads to poorer repassivation ability, autocatalytic acidification once a pit forms.Thus, occluded corrosion cells are developed in this alloy.