Abstract
The process of cathodic electrolytic formation of molybdenum oxide films from molybdate-citrate bath was investigated using Hull-Cell test, cathodic polarization measurement and UV absorption spectra measurement of the solution. pH, temperature and the concentration ratio of citrate ions to that of molybdate ions were changed. Chemical states of the deposited films were evaluated by XPS (X-ray photoelectron spectroscopy).
The results of Hull-Cell test and cathodic polarization curves showed that molybdenum oxide film was deposited in the presence of citrate ions in the bath and the deposition rate was related to the bath pH and temperature of the solution. UV spectra indicated the formation of citrate-molybdate complexes which induce the deposition of molybdate oxide films. From the XPS analysis, the film was found to be a layered structure of Mo/MoO2/MoO3, in which metallic Mo was detected only on the substrate of Iron family elements, Ni, Fe, and only the second layer of MoO2 grew thicker by electrolysis.
