Electrochemical Impedance Studies on Tribocorrosion Behavior of Plasma-Sprayed AlO Coatings.

In this paper, the tribocorrosion of plasma-sprayed AlO coatings in simulated seawater was investigated by electrochemical impedance spectroscopy (EIS) technique, complemented by scanning electron microscopy to observe the morphology of the tribocorrosion attack. Base on EIS of plasma-sprayed AlO coatings undergoing long-time immersion in simulated seawater, the corrosion process of AlO coatings can be divided into the earlier stage of immersion (up to 20 h) and the later stage (beyond 20 h). Then, the wear tests were carried out on the surface of AlO coating undergoing different times of immersion to investigate the influence of wear on corrosion at different stages. The coexistence of wear and corrosion condition had been created by a boron nitride grinding head rotating on the surface of coatings corroded in simulated seawater. The measured EIS and the values of the fitting circuit elements showed that wear accelerated corrosion at the later stage, meanwhile, corrosion accelerated wear with the immersion time increasing. [ABSTRACT FROM AUTHOR]