Secondary ion mass spectrometric studies on the formation mechanism of IrO2/TiO2-based coatings

The formation mechanism of an IrO/TiO film electrode has been studied by secondary ion mass spectrometry (SIMS). A coating mixture with the composition 50% Ir+50% Ti prepared on a titanium support from an isopropanolic solution of hydrated iridium chloride and titanium bis-2,4-pentanedionate precursors was heated to specified temperatures and analysed by SIMS. Concentration depth profiles of some selected species (e.g. Cl, O, ClO, TiO, Ir, IrO 2-, TiO 2-, CH n-, CH n-, OH) were used to follow the process of film evolution. Segregation phenomena resulting in the increased dispersity of the noble metal on the surface were identified. The results are in accordance with--and complementary to--those of former measurements by combined thermoanalytical, mass spectrometric and emission Fourier transform infrared (FTIR) techniques. Copyright © 1995 John Wiley & Sons, Ltd.