1 Reply Latest reply on May 19, 2011 2:01 PM by Bryan Balazs

    What is the mechanism of hydrogen ion passing through metal sheets.?

    Ahmad Ehsani

      What is the mechanism of hydrogen ion passing through metal sheet walls of pipes and atanks ?

      How we can explaine the phenomenon. in oil and gas industry when the fluid is rich in H2S , a type of metal failure occure in most cases that the material is notselected according to NACE standard.Some call it Hydrogen Blistering,some Hydrogen embrittlement and some hydrogen induced craking  but what is the secret behinde the case?

        • What is the mechanism of hydrogen ion passing through metal sheets.?
          Bryan Balazs

          It's likely that a solid state reaction is occurring between the H2S and the Fe (and other metals present in the pipes and tanks) to form FeS and mixed iron and other metal suflides.  These sulfides are less dense than Fe, so they form a "scale" on the surface which sloughs off.  Hydrogen is also produced in this reaction and migrates through the metal (presumably as hydrogen atoms but perhaps as hydrogen molecules along grain boundaries), leading to hydrogen embrittlement, hydrogen-induced cracking, etc.