Effect of Surface Roughness on Metastable Pitting of Amorphous Ni Alloy

The effect of surface roughness on nucleation and growth of metastable pitting on amorphous NiCrFeSiB alloy was studied using potentiostatic and potentiodynamic polarization tests.Nucleation of metastable pits on the alloy was significantly facilitated by rougher surface. Both the growth rate parameters and the peak currents of metastable pits follow log-normal distribution. Rougher surface also promoted the growth of metastable pits, and lead to a wider distribution of the growth rates.