Electrodeposition of Se on Ti. Impedance and Photoelectrochemical Study of Passivation Phenomena

The passivation phenomena observed during electrodeposition of Se on Ti substrates have been investigated. A high overpotential for hydrogen evolution appears essential to observation of passive and transpassive domains. Impedance analysis suggests that passivation results from the formation of a thin, highly resistive film, detected under all conditions of current density, temperature, illumination and concentration of sodium n-dodecyl sulphate. Electron transport in this film presumably occurs by a high field conduction mechanism. The deposits show photoconductive properties typical of amorphous Se.