Zinc-Nickel (Zn-Ni) alloy coatings are being investigated as a safer alternative to cadmium coatings due to health and environmental concerns. The Zn-Ni coating process generates hydrogen, which can diffuse into ultra-high strength steels (UHSS) and cause hydrogen embrittlement, compromising their structural integrity. Despite outgassing steps to remove hydrogen, residual hydrogen and future ingress pose risks.

This study proposes a numerical model to analyse stress development and hydrogen concentration in Zn-Ni coated UHSS. The model integrates hydrogen transport in both the coating and metal substrate with a continuum damage mechanics framework. The coating's geometry, derived from micrographs, enables examination of morphological effects on the metal-coating structure. The varying hydrogen amounts produced under different coating conditions are addressed by distinct initial conditions in the model. Simulation outcomes are validated through comparison with tensile tests, and the damage model parameters are calibrated accordingly.