Effect of barnacle on the cathodic protection of high-strength steel and its potential risk related to hydrogen permeation

The cathodic protection efficiency and hydrogen permeation behaviour of high-strength steel with barnacle adhesion in the tidal zone were studied using field exposure and laboratory simulation tests for 2 years. Because of the shielding effect, barnacles can lead to an uneven calcareous deposition, a flatter morphology and a higher protection efficiency of steel. By contrast, because of the higher hydrogen permeation current at the edge of the barnacle adhesion area (caused by a higher hydrogen evolution rate), barnacle adhesion can promote hydrogen permeation. A mechanism was proposed to explain the observed phenomenon, and its effect on service safety was analysed.