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[Display omitted] • The laser activated the crystal modifier to form a cellular structure. • The cellular structure increases the surface potential inhomogeneity. • The electrochemical corrosion rate decreases by approximately 4 times. • Corrosion mechanism changes from stress corrosion to pitting corrosion. • The improvement of corrosion resistance is caused by micro corrosion cells. Laser irradiation was applied to a Ni–P electrolyte containing a crystal modifier. This produced a Ni–P alloy surface prepared via electrodeposition that was composed of numerous three-dimensional microcellular structures. The coating maintained its original amorphous structure while reducing the residual tensile stress. This structure replaced the surface crack structure, thus reducing the corrosion rate by nearly a factor of four. The main corrosion mechanism corresponding to the conventional method was stress corrosion, whereas the proposed method involved pitting corrosion. This was primarily because of the formation of corrosion microcells owing to the electrochemical non-uniformity caused by the structures. [ABSTRACT FROM AUTHOR]