Thermogravimetric investigations of nickel-oxide thin films and powders

Classical TC analysis of films supported on micro-cover glasses was perform ed in order to determine the appropriate processing temperature to achieve electrochemically active NiOxHy thin films. As deposited films made from th ree different precursors (Ni-acetate, nitrate and sulphate) and their corre sponding powders were also investigated. From dynamic TG measurements the o nset decomposition temperature could be determined. It was found out that t he starting temperature of the mass change of thin films is approximately 3 0 degrees lower than that of the powders. A broader decomposition range was also observed for thin films. Furthermore, the isothermal treatment of fil ms deposited on conducting substrate at 270 and 300 degrees C was performed and by cyclic voltametry the importance of temperature and time of heating was proved. Films obtained at higher temperatures (>300 degrees C) are ele ctrochemically inert because of the NiO phase formation.