Origin and Basis of 100 mV Cathodic Polarization Criterion

The 100 mV cathodic polarization criterion is an important criterion in cathodic protection standards. It has been used more and more in metal structures which have serviced for a long time and with poor anticorrosive coating. However, in standards and literature, there is a lack of introduction and validity demonstration of this cathodic protection criterion. There are doubts and debates in the industry about the effectiveness of this criterion. So, in this paper, the origin of the 100 mV cathode polarization criterion is introduced. The validity of the criterion is expounded through theoretical basis and field verification data. The advantages and disadvantages in practical application of this criterion are compared, and the applicable conditions are clarified.