SURFACE CHARACTERIZATION OF RUO2-IRO2-TIO2 COATED TITANIUM ELECTRODES

RuO2-IrO2-TiO2 coatings on titanium electrodes prepared by thermal dec omposition have been characterized by scanning electron microscopy, x- ray diffraction analysis (XRD), x-ray photoelectron spectroscopy (XPS) , thermal desorption spectrometry (TDS), andy, cyclic voltammetry (CV) . The XRD results indicated that the mixed oxide coatings formed a thr ee-component solid solution. The TDS and the CV were applied for quant itative analysis of surface RuO2 content. The chemical composition exa mined by XPS, TDS, and CV showed that the surface RuO2 Content was low er than the nominal content. The XPS results, however, deviated consid erably from those of TDS and CV The XPS method can detect the elements only at the outer surface of rough textures, whereas the other two me thods can reflect the RUO2 content of both the outer and the inner sur face, including pores and intergrain regions, of the coatings. This me ans that TDS and CV are useful in the investigation of the surface com position of Ru-base mixed oxide electrodes.