ELECTROCHEMICAL MEASUREMENT OF EROSION FROM INDIVIDUAL CAVITATION EVENTS GENERATED FROM CONTINUOUS ULTRASOUND

Passivated electrode surfaces of aluminium and lead have been employed to investigate individual erosion corrosion events produced by ultras ound. Individual events are recorded with a resolution within the sub- millisecond time scale. The probability of the recorded events was fou nd to fit with the expected physical model of the system. Distance dep endence of the erosion corrosion currents recorded are reported showin g that the active transient cavitation zone of the sound field employe d is within the first err. 5 mm of the sound emitting surface. The ele ctrode material is also shown to have a marked effect on the distance dependence of surface erosion. The extent of surface damage, as the re sult of individual cavitation events, are calculated from the current time transients recorded on passivated lead electrodes.