Abstract: Highly localized and minute depassivation events are recorded using 50μm diametertitanium microelectrode in Ringer's physiological solution. These transient events are believed to be due to microscopic breakdown of passivity and occur well below the pitting potential of the metal. A mechanism is proposed to explain the observed phenomenon.Possible implications on passivity and the application of metallic biomaterials in vivo are also discussed.

Key words: passivity, titanium, physiological solution, microelectrode