Name given to a material-damaging process which occurs as a result of vaporous cavitation. "Cavitation" pertains to the occurrence or formation of gas- or vapor- filled pockets in flowing liquids caused by the hydrodynamic generation of low pressure (below atmospheric pressure). This damage results from the hammering action when cavitation bubbles implode in the flow stream. Ultra-high pressures resulting from the collapse of the vapor bubbles produce deformation, material failure and, in the end, erosion of the surfaces.