Abstract
The effects of additives such as Cu, Mo, and Mn on the corrosion resistance of Ni-Cr alloy were investigated in Ringer's solution by the polarization resistance method.
The corrosion potential became noble and the polarization resistance increased with the addition of Cu or Mo. Anodic polarization measurements showed that these two elements retarded the anodic reaction and enhanced the passivation of Ni-Cr alloy.
Mn also reduced the corrosion rate of Ni-Cr alloy as well as Cu and Mo, although the inhibition mechanisms were different. Electrochemical measurements and microscopic observations showed that the presence of Mn did not contribute to the protectiveness of passive films but decreased the cathodic reaction rate of Ni-Cr alloys.
A good linear relationship was observed between average corrosion rate obtained from the weight loss measurement and average polarization conductance, and could be expressed as
icorr=25(mV)Ycorr.
