Cavitation

Cavitation wear occurs on surfaces exposed to fluids in which entrained bubbles collapse at or near the surface. The collapse releases a jet of the fluid that impacts the surface, causing severe local ‘hammering’. Cavitation is, at best, combated through component redesign that either stops bubble formation or inhibits bubble collapse near the affected surfaces. However, coatings can provide temporary relief until redesign can be achieved or can be used in applications where redesign is not feasible.

Intense cavitation is combated using tough, usually cobalt based materials that strongly work-harden. These are best applied using processes that lead to metallurgical bonding, such as welding and fusing. Where mild to weak cavitation is present, HVOF coatings and nitriding, particularly carbonitriding, can reduce wear.


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