Corrosion Behavior of CoCrFeNiTa_x Alloys in 1 M Sodium Chloride Aqueous Solution

This paper investigates the effects of Ta content on the microstructures, hardness and corrosion behavior of as-cast CoCrFeNiTa_x alloys. The results indicate that the addition of Ta can change the microstructures of these alloys to dual-phased structures (FCC + HCP), as well as increasing their hardness. This study uses constant galvanostatic/potentiometric methods to measure the polarization curves of CoCrFeNiTa_0.1, CoCrFeNiTa_0.3 and CoCrFeNiTa_0.5 alloys in deaerated 1 M sodium chloride solution at different temperatures. Electrochemical impedance spectroscopy is also used to analyze these alloys in sodium chloride solution. The results indicate that the CoCrFeNiTa_0.5 alloy has a eutectic structure and the highest hardness. Furthermore, although the CoCrFeNiTa_0.5 alloy has the best corrosion resistance, the CoCrFeNiTa_0.3 alloy has the best pitting resistance among these alloys.