The inhibition effect of the molybdate on hydrogen permeation of 2205 duplex stainless steel

The inhibition effect of molybdate on the hydrogen permeation of 2205 duplex stainless steel was investigated by using a Devanathan and Stachurski double cell. The mechanism governing this inhibition was determined via potentiodynamic polarization and electrochemical impedance spectroscopy. The results revealed that molybdate adsorbed on the metal surface led to a decrease in the hydrogen permeation current density and, accordingly, the pitting corrosion. This adsorption was described by the Langmuir adsorption isotherm equation and the molybdate formed a barrier layer in the solution. Moreover, Raman spectroscopy revealed the occurrence of physical adsorption, as evidenced by the absence of oxidized molybdate from the metal surface. Molybdate adsorbed on the surface led to a decrease in the pitting corrosion on the surface of the metal and thereby inhibited the hydrogen permeation behavior.