On the corrosion behaviour of individual phases present in aluminium bronzes

Abstract

The corrosion properties in NaCl solutions at room temp. of the various phases present in aluminium bronzes are investigated over periods up to 850 h by combination of electrode kinetic, quantitative analytical, electron microscopic and X-ray methods. Experimental results on binary α-phases are fully compatible with the proposed model based on a porous Cu 2O layer doped with Al 3++ ions. In contrast to α and hypoeutectoid martensites, hypereutectoid martensites and Ύ 2-rmphases are not able to develop a sufficiently thick protective layer and show an increasing susceptibility to dealuminization by the dissolution-redeposition mechanism. κ-phases and related intermetallic compounds present in iron and nickel containing aluminium bronzes tend to passivate. Conclusions with respect to the behaviour of complex Cu-Al-Fe-Ni alloys used in practice are drawn.