HYDROLYTIC REACTIONS IN HYDRATED IRIDIUM CHLORIDE COATINGS

A hydrolytic side reaction in hydrated iridium chloride films heat-tre ated on titanium supports was discovered by simultaneous thermal analy sis, emission FTIR and SIMS techniques. In the presence of water vapou r the degree of hydrolysis increases significantly in the outermost pa rt of the film leading to the formation of oxidic species at low tempe ratures. In a wet oxygen atmosphere encapsulated hydrogen chloride as a hydrolysis product reacts with the support to form titanium chloride species segregated in the surface region of the coating. In addition to the formation of hydrolysis products, the presence of surface speci es like iridium carbonyl and iridium carboxylate was also confirmed in the coating. (C) 1997 Elsevier Science S.A.