Preparation and characterisation of platinum and platinum–iridium coated titanium electrodes

Abstract Metallic coatings of Pt and Pt–Ir were prepared by the thermochemical glazing process on titanium substrates for application as electrodes in the electrolytic dissolution of nuclear fuels. Titanium substrates with a RuO 2 –TiO 2 single layer were applied with Pt and Pt–Ir chemical solutions and heat treated in vacuum at different temperatures between 973 and 1473 K for 1 h. The physical characterisation by SEM/EDX, XRD and SIMS indicated the presence of adherent and smooth metallic coatings of Pt–Ti and Pt–Ir containing intermetallic compounds of Ti, Pt and Ir. Electrochemical polarisation studies carried out in 1 M HNO 3 at room temperature showed that the specimen prepared at 1373 K had a better electrochemical performance in comparison with Pt sheet electrodes. Significant changes in the open circuit potential (OCP) and the polarisation behaviour of the electrodes were noticed. The life assessment in a simulated reprocessing test solution of boiling 10 M HNO 3 showed excellent performance of the Pt–Ir layered electrode in comparison with conventional mixed oxide coated titanium (MOCTA) electrodes.