NiO cathode dissolution is considered as one of the serious problems determining the MCFC life time. In this work, 6 wt% and 12 wt% Co-coated specimens were fabricated by electroplating method and NiO cathode as reference. The aim of this experiment is to investigate Co coating effect by determination solubility at the variable cathode gas partial pressure in Li/K and Li/Na electrolytes. To obtain the suppression factors of NiO dissolution, Atomic Adsorption Spectroscopy (AAS), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) were used.