Preparation and Characterization of Composite Hydrogen Barrier Coatings with (Graphene–Epoxy Resin)/(Silicon Carbide–Epoxy Resin)/(Graphene–Epoxy Resin) Sandwich Structures

How to solve hydrogen embrittlement (HE) is a key issue that urgently needs to be addressed in the hydrogen energy industry. The use of hydrogen barrier coatings can effectively reduce the occurrence of HE. In this article, we utilized the epoxy resin (ER) as the base coating and the graphene (GN) and the silicon carbide (SiC) as the additives to prepare the (GN-ER)/(SiC-ER)/(GN-ER) sandwich structure composite hydrogen barrier coatings by the spin coating method and investigated the effect of coating composite ways on the hydrogen barrier performance. The GN-ER and the SiC-ER are used as the hydrogen barrier layer and the hydrogen capture layer, respectively, in order to improve the hydrogen barrier performances jointly. The XRD and the SEM were used to characterize their phase compositions and microstructures, and the hydrogen barrier performances were analyzed by the electrochemical hydrogen permeation curves. The adhesive strength was characterized through the pull-out method. Compared to the single-layer and the double-layer structures, sandwich structures can effectively enhance the hydrogen barrier performance of the coatings, such as the relatively low electrochemical hydrogen diffusion coefficient (D_t, 3.88 × 10⁻⁸ cm²·s⁻¹), the relatively high permeation reduction factor (PRF, 59) and adhesive strength (10.9 MPa). This research may provide a theoretical basis for improving the hydrogen barrier performance of coatings. The (GN-ER)/(SiC ER)/(GN-ER) sandwich structures composite hydrogen barrier coatings can be expected to be used in the field of safe hydrogen storage and transportation.