Corrosion and wear performance of tungsten inert gas cladded CoCrNiMo_0.6 multi-principal element alloy coatings via heat-input modulation

For stainless-steel components operating in marine environments, protective coatings with balanced corrosion and wear resistance are highly desirable. In this work, CoCrNiMo_0.6 multi-principal element alloy coatings were deposited on 316 stainless steel by TIG cladding, and the effect of heat-input (401.8–578.2 J/mm) on microstructure, corrosion behavior, and wear performance was investigated. Increasing heat-input induced pronounced microstructural evolution, including grain coarsening, a decrease in σ-phase fraction from 28.2% to 18.3%, and the transformation of σ-rich interdendritic regions from a continuous eutectic network to discontinuous banded morphologies. Corrosion resistance showed a non-monotonic dependence on heat-input, and the coating prepared at 460.6 J/mm exhibited the lowest corrosion current density of 2.29 × 10⁻⁷ A cm⁻². In contrast, hardness and wear resistance deteriorated monotonically with increasing heat-input; the coating produced at 401.8 J/mm showed the highest hardness of 652.4 HV_0.5 and the lowest wear rate of 0.24 × 10⁻⁵ mm³/N m. These results demonstrate that heat-input modulation provides an effective route to tailoring the corrosion-wear trade-off in TIG-cladded CoCrNiMo coatings.