Hydrogen entry and absorption in ZrO2 coated iron studied by electrochemical permeation and desorption techniques

► ZrO2 sol-gel coating against hydrogen absorption by metals. ► ZrO2 partially blocks iron surface to hydrogen evolution and hydrogen entry. ► The coating efficiently prevents iron surface become more active to hydrogen entry. ► The local concentration of hydrogen beneath the ZrO2-free iron sites increases. ► The increase in hydrogen concentration results in more intensive hydrogen trapping.