Cavitation Corrosion Behaviour of Carbon Steel, Al-Bronze and Cobalt-Based Alloy in Seawater

Abstract An ultrasonically induced cavitation facility was used to study the cavitation corrosion behavior of carbon steel (UNS G10200), Al-Bronze (UNS C95300), and cobalt-based alloy (UNS R30006) in seawater. The work included measurements of free corrosion potentials, and mass loss in presence and absence of cavitation. The cavitation tests were made at a frequency of 20 KHz and at temperatures of 250C. Cavitation conditions caused a noble shift in the free corrosion potential for carbon steel and an active one for Al-Bronze and cobalt-based alloys. Cavitation also increased the rate of mass loss of these alloys by several orders of magnitude with respect to stagnant conditions. Cavitation made the surface of these alloys very rough, exhibiting large cavity pits in the middle region of the attacked area as revealed by the scanning electron microscope (SEM). Mechanical factors were determined to be the leading cause of metal loss.