Mesoporous Silica Composites for Enhancing Hydrogen Barrier Performance of Electrodeposited Nickel Metal Coatings

Hydrogen embrittlement poses a critical bottleneck for the reliable application of metallic infrastructure in the hydrogen energy sector. The application of hydrogen barrier coatings on metal surfaces can effectively alleviate the penetration and diffusion of hydrogen atoms within metals. In this study, mesoporous silica nanoparticle (MSN) with a large specific surface area and rich pore structure was prepared using the sol–gel method. A composite coating of nickel metal and MSN was prepared on a Q235 substrate using an electrodeposition method. The micromorphology and composition of the composite coating were characterized in detail, and the hydrogen barrier performance and corrosion resistance of the composite coating were evaluated, and the effect of MSN on the microstructure of the composite coatings was analyzed. The synergistic effects of MSN-induced grain refinement, mesoporous hydrogen adsorption, and preferential (111) crystal plane orientation are key to enhancing hydrogen barrier and corrosion protection performance. By replacing direct current with pulsed current, the steady-state hydrogen permeation current density of the coating reaches 4.24 μA/cm 2 at an MSN content of 1.5 g/L, representing an 86% improvement over the pure Ni coating. Simultaneously, the corrosion resistance of the coating progressively improved with increasing MSN content and the application of pulsed current. This work demonstrates the feasibility of incorporating mesoporous materials into Ni-based coatings as an effective strategy for mitigating hydrogen embrittlement and corrosion of structural metals.