Abstract: The ZrO2+MgS auxiliary electrode coating was prepared on the surface of the MgO stabilized zirconiabased solid electrolyte by laser cladding. The surface morphology and phase composition were analyzed with the scanning electronic microscope (SEM) and Xray diffractometer (XRD). The factors influenced the stability of ZrO2+MgS coatings were also analyzed. The research results showed that the cladding layer was combined well with the substrate. MgS powder were not fully decomposed and oxidized. From this work， it showed that laser cladding was an effective method to prepare ZrO2+MgS coating on the surface of the MgO stabilized zirconiabased solid electrolyte. At 1600℃， if the sulfur partial pressure was higher than 10-495Pa， MgS phase did not decompose; if the oxygen pressure was 10-5578Pa and sulfur partial pressure was higher than 10-4636Pa， MgS phase did not oxidize.

Key words: zirconia, solid electrolyte, laser cladding, ZrO2+MgS powder, auxiliary electrode