Cavitation degradation model of hard thin pvd coatings

Abstract

A cavitation degradation process and fatigue phenomenon were described. Similarly to fatigue phenomenon, cavitation pulses division into three fractions was suggested. The action of each fraction was respectively compared to low-cycle fatigue, high-cycle fatigue and low-amplitude fatigue. The action of each fraction was described separately. Detailed analysis of the influence of each fraction on the degradation process shows that besides mechanical loading also thermal loading occurs. The cavitation erosion is assumed to be the sum of degradation of each fraction. Thus, the model of PVD coatings degradation under action of cavitation pulses include variable-amplitude and variable-temperature fatigue.

Studies on resistance to erosion of nickel and its alloys to be used in elements of fluid - flow machines

“…The strike of the cumulative liquid flux onto the surface of a washed metal element leads to its plastic deformation and the increase of its hardness -work-hardening. Microcracks being the result of fatigue appear in the strengthened surface metal layers under further striking of cumulative liquid fluxes [8]. Their subsequent development leads to the formation of erosive pits in the form of craters.…”

Studies of Erosion Resistance of Protective Coats on the Surfaces of Machine Elements Washed with Fluids

“…Corrosive -erosive damage of fluid washed surfaces of hydraulic and thermal machines intensify degradation of their technical condition, at the same time lowering durability of the washed elements. The cause of erosion occurrence is most often due to cavitation in the operating areas of machine or facility [1,2,3]. At present, the corrosive-erosive theory of metal surface damage has been acclaimed.…”