THE INHIBITION OF CORROSION AND HYDROGEN EMBRITTLEMENT OF AISI 410 STAINLESS-STEEL

A study was carried out on the inhibition of corrosion and hydrogen embrittlement of AISI 410 stainless steel by two organic inhibitors, namely benzotriazole and benzonitrile. Tensile testing, scanning electron microscopy, weight loss measurements and potentiodynamic polarization were the techniques used for this study. Tensile tests showed that 410 steel is highly susceptible to hydrogen stress cracking. Scanning electron microscopic observations of fracture surfaces showed a brittle quasi-cleavage type of failure when the steel was hydrogen charged from 0.5 M H2SO4. Both inhibitors reduced hydrogen induced ductility loss though the fracture mode was unaltered. They showed increasing inhibition efficiencies for corrosion as well as cathodic hydrogen evolution as their concentration in H2SO4 increased from 3.9 x 10(-5) M to 8.4 x 10(-3) M. Benzonitrile was found to be a more efficient inhibitor than benzotriazole for AISI 410 stainless steel exposed to 0.5 M H2SO4.