Full-link stray light evaluation method for an optical baffling system under a neutral salt spray test

To ensure stable performance of black coatings in a salt spray environment and reliable life-cycle operation of marine optical systems, this paper proposes a full-link stray light evaluation method combining a neutral salt spray test, coating’s surface characterization, stray light simulation, and measurement. The mechanism of degraded coating’s scattering properties on the stray light suppression of the baffle under salt spray conditions is revealed. Results show that the overall coating performance changes slightly but regional inhomogeneities and roughness differences occur. The relative bidirectional reflectance distribution function increases by 20%–40% and absorptivity decreases by up to 1.07%, resulting in more surface scattering. Simulated and measured point source transmittance values of the baffle rise to 1–2 times and 1–3.06 times the original levels, respectively. The coating preliminarily meets the requirements for coastal applications.