Cavitation is a well known phenomenon by which materials submerged in a flowing fluid (usually water) are prone to erosion. This type of erosion affects runner blades of Francis turbines, needle and seat rings of Pelton turbines as well as impellers in pumps Depending on the material, different techniques have been tried in the past to overcome this problem. Laser hardening is a promising technique which has the potential to mitigate this problem to a great extent.
