Erosion corrosion is a degradation of material surface due to mechanical action, often by impinging liquid, abrasion by a slurry, particles suspended in fast flowing liquid or gas, bubbles or droplets, cavitation, etc. The mechanism can be described as follows: * mechanical erosion of the material, or protective (or passive) oxide layer on its surface, * enhanced corrosion of the material, if the corrosion rate of the material depends on the thickness of the oxide layer.