Graphene Containing Composite Coatings as a Protective Coatings against Hydrogen Embrittlement in Quenching & Partitioning High Strength Steel

Pure Ni and Ni-graphene coatings fabricated by reverse pulse electrodeposition were applied to protect quenching & partitioning (QP) steel as the substrate from hydrogen embrittlement (HE). The inhibitory effects of coatings on HE in steel were assessed by slow strain rate test (SSRT) after electrochemical hydrogen charging and hydrogen permeation test using the Devanathan-Stachurski (D-S) cells. According to the results of the total elongation loss El(loss) and steady state permeation current I-infinity as well as the diffusion coefficient D, it is suggested that the effect of pure Ni coatings on HE in QP steel was slight, whereas Ni-graphene coatings could act as a more effective protecting coatings against HE. Finally, the mechanisms affecting the performance of coatings on HE in QP steel were also discussed. (C) 2016 The Electrochemical Society. All rights reserved.