Originally Posted by Andrew Troup
Under free exposure conditions in fresh waters or sea water, aluminium bronzes free from gamma 2 phase do not show selective phase corrosion but, under crevice conditions, beneath deposits or marine growths or under the influence of galvanic corrosion or of electrical leakage corrosion, selective phase attack can occur. In the alphabeta alloys this takes the form of slightly preferential attack on the beta phase.
A lovely writeup Andrew and informative. The crevice corrosion is interesting as is galvanic. Since its galvanic corrosion that to me is the main issue.
I would love to see a study of aluminum
bronze and sea water
effects on it over time (1-4 years). If Aluminum
bronze props didn't require zincs, I would be less concerned with its corrosion resistance. Perhaps its only a minimum loss of material so no real loss of strength.
I find that dealuminification being mentioned at all is interesting as well as
<<It can be very largely prevented under most conditions>> . Since zinc in brass/bronze has been around for well over 200 years, I would expect it to show up more. Aluminum Bronze was not so common.
But in truth, I am not that familiar with the aluminum bronze combinations. But am well aware of aluminum's weaknesses.