SECONDARY-ION MASS-SPECTROMETRY CHARACTERIZATION OF IRO2-TA2O5 THIN-FILMS - EFFECT OF RELATIVE COMPOSITION ON ELECTRODE PROPERTIES

IrO2 and Ta2O5 mixed oxide coatings were deposited on Ti supports in o rder to fabricate dimensionally stable electrodes used in chloro-alkal i technology. Secondary ion mass spectrometry (SIMS) and electrochemic al experiments were carried out in order to characterize these materia ls. Electrochemical tests found the highest electrocatalytic activity for 50% IrO2-50% Ta2O5 electrodes. SIMS analyses are in harmony with t hese results, and it is shown that IrO2 is more diluted on the surface for noble metal oxide concentrations higher than 50%. Finally, it was observed by SIMS that support material migration was favoured at the highest concentrations of Ta2O5 stabilizer. (C) 1998 John Wiley & Sons , Ltd.