Effects of Hard Chromium Plating on Cavitation Erosion

The cavitation erosion of the hard chromium plating on steel was studied by vibratory erosion tests. The mass loss vs. exposure time curves are divided into three stages. The first stage is the process of the erosion of hard chromium in itself. The base metal below the interface begins to be damaged in the second stage. The third stage appears when the plating layer has fallen off in massive particles. The mass loss rates in each stage are larger in 3% NaCl solution than those in ion exchanged water because intercrystalline fracture occurs. The effects of plating thickness on the damage in each stage were also discussed. The life of plating as an erosion resistant coating increases in propotion to the thickness in ion exchanged water. In 3% NaCl solution, however, it is smaller and increases no more than about 50 μm in thickness.