Secondary ion mass spectrometry characterization of IrO2-Ta2O5 thin films: Effect of relative composition on electrode properties

IrO and TaO mixed oxide coatings were deposited on Ti supports in order to fabricate dimensionally stable electrodes used in chloro-alkali technology. Secondary ion mass spectrometry (SIMS) and electrochemical experiments were carded out in order to characterize these materials. Electrochemical tests found the highest electrocatalytic activity for 50% IRO-50% TaO electrodes. SIMS analyses are in harmony with these results, and it is shown that IrO 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 TaO stabilizer.