Abstract This study evaluates cobalt addition by electrodeposition on the microstructure and corrosion behavior of pulsed Nd: YAG laser-welded UNS S32750 SDSS. Four conditions Co₁, Co₂, Co₃ and Co₄, containing 3. 3, 5. 0, 7. 5, and 11. 0 wt% Co on the weld surface were analyzed by SEM/EDS, and cyclic polarization was performed in 3. 5 wt% NaCl at 25 °C and 70 °C. Increasing Co promoted austenite formation in the fusion zone, and Co3 (7. 5 wt% Co) showed the phase balance closest to the base metal, whereas the HAZ remained predominantly ferritic in all cases. At 25 °C, the curves exhibited a similar passive plateau and a highly restrictive hysteresis loop, with no measurable differences in localized corrosion resistance within the experimental scatter. At 70 °C, all welded conditions showed poor repassivation, with \: Eₑ₄₀ₒₒ₈ₕ₀ₓ₈₎₍ close to E₂₎ₑₑ, indicating the weld as the critical site for localized corrosion and a secondary Co effect. EDS line scans showed a systematic decrease in the detected Cr and Mo signals with increasing Co, with Co₄ presenting the lowest intensities.
Seloto et al. (Tue,) studied this question.