Effects of electrolytic zirconium oxide coating on hydrogen permeation of AISI 430 stainless steel

Through Devanathan hydrogen permeation tests and a mathematical analysis, the retarding effect of electrolytic deposition of zirconium oxide (ZrO2) films on the hydrogen-induced blistering or entry was investigated. The permeation test has indicated that the diffusion coefficient in a metal sheet of AISI 430 (UNS S43000) stainless steel (D-m) was 1.73 x 10(-8) cm(2)/s and that in ZrO2 (D-Zr) was 4.74 x 10(-16) cm(2)/s. Also, the subsurface hydrogen concentration on the metal (C-h(m); 2.29 x 10(-5) mol/cm(3)) was reduced to (C-h(m) = 0.64 x 10(-5) mol/cm(3)) caused not only by a high concentration ratio (K; 8.022) of the oxide film to the metal but also by the extremely low value of D-Zr. Blistering was found on the uncoated specimen after the hydrogen permeation test but was not found on the coated specimen. The electrolytic deposition of ZrO2 film on the AISI 430 stainless steel demonstrated the retarding effect on hydrogen entry and the occurrence of blistering.