Cavitation Erosion Corrosion Behaviour of Manganese-nickel-aluminum Bronze in Comparison with Manganese-brass

The cavitation erosion corrosion behaviour of ZQMn12-8-3-2 manganese-nickel-aluminum bronze and ZHMn55-3-1 manganese-brass was investigated by mass loss, electrochemical measurements (polarization curves and electrochemical impedance spectroscopy) and the cavitation damaged surfaces were observed by scanning electron microscopy (SEM). The results showed that ZQMn12-8-3-2 had better cavitation erosion resistance than ZHMn55-3-1. After the cavitation erosion for 6 h, the cumulative mass loss of ZQMn12-8-3-2 was about 1/3 that of ZHMn55-3-1. The corrosion current density of ZQMn12-8-3-2 was less than that of ZHMn55-3-1 under both static and cavitaiton condition. The free-corrosion potentials of ZQMn12-8-3-2 and ZHMn55-3-1 were all shifted in positive direction under cavitation condition compared to static condition. In the total cumulative mass loss under cavitation condition, the pure erosion played a key role for the two tested materials (74% for ZHMn55-3-1 and 60% for ZQMn12-8-3-2), and the total synergism between corrosion and erosion of ZQMn12-8-3-2 (39%) was larger than that of ZHMn55-3-1 (23%). The high cavitation erosion resistance of ZQMn12-8-3-2 was mainly attributed to its lower stacking fault energy (SFE), the higher microhardness and work-hardening ability as well as the favorable propagation of cavitation. cracks for ZQMn12-8-3-2, i.e., parallel to the surface rather than perpendicular to the surface for ZHMn55-3-1.