Effect of calcareous deposits on hydrogen permeation in X80 steel under cathodic protection

The effect of calcareous deposits in simulated soil environment on the hydrogen permeation of X80 steel was investigated using electrochemical hydrogen permeation technique in association with hydrogen content tests and cross-section analysis by scanning electron microscopy (SEM). A raising trend of hydrogen permeability with the formation of calcium hydroxide deposits on X80 steel surface was obtained. This can be attributed to many factors, such as the cathodic current density significantly contributed to increase in hydrogen permeation, while the excessive cathodic current density was likely to break the integrity of the calcareous layer. Furthermore, the hydrogen content and thickness of calcareous deposits increased with respect to the charging current density and hydrogen charging duration, which were in accordance with the change trend of hydrogen permeation in presence of calcium hydroxide deposits.