Tribocorrosion of Stellite 706 and Tribaloy 400 superalloys

Abstract

Co based superalloys such as Stellites and Tribaloys have been extensively used in many engineering applications owing to their inherent superior corrosion and wear resistance and hot hardness property at elevated temperatures. The combined interaction among wear and corrosion which is known as tribocorrosion often results in a significant increase in material loss especially in aqueous environments. In this study tribocorrosion performance of Stellite 706 and Tribaloy T400 was investigated by electrochemical techniques such as potentiodynamic (anodic polarisation) and open circuit potential (OCP) measurement with three electrode electrochemical cell set-up under sliding contact in 3·5% NaCl solution. The effect of friction on anodic polarisation behaviour of superalloys was studied at different loads of 20 and 80 N. During OCP measurements the frequency was increased from 0·5 to 1·5 Hz by an increment of 0·5 Hz. Thus the effect of frequency on tribocorrosion behaviour of superalloys was determined. Tribaloy 400 exhibited greater performance in potentiodynamic polarisation test. On the other hand, Tribaloy 400 was more affected by corrosive wear in OCP measurements as compared to Stellite 706.