Abstract
It was found that potassium dichromate (PDC), a corrosion inhibitor of passivating type, retards the development of cavitation erosion on commercially pure iron. The process was postulated as follows: PDC dissolved in an environmental liquid might adsorb on the metal surface and exert tension on the surface. This tension might retard cavitation erosion. The surface tension of the environmental liquid and the contact angle of the liquid wetting the surface were measured, and it was confirmed that tension certainly works on the surface in the liquid. It was also confirmed that a tensile stress applied mechanically on the metal retards the development of cavitation erosion in the early stage. The process postulated above was accordingly deemed correct.
