Correlation between grain orientation and corrosion performance of different tantalum crystal facets in 3.5 wt% NaCl aqueous solution

Abstract

To investigate the influence of different crystal orientations of tantalum on corrosion performance, this study explored the diverse corrosion behaviors exhibited by the (110), (200), and (211) crystal planes of monocrystalline tantalum in a 3.5 wt% NaCl aqueous solution. The electrochemical behavior of the three crystal planes was characterized using open circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy tests. The results revealed that the corrosion potential of the (110) crystal plane was slightly higher than that of the other two crystal planes, suggesting that this can be attributed to the influence of surface energy. The corrosion current density and corrosion rate of the (110) crystal plane were measured to be 0.269 μA cm⁻² and 1.911 × 10⁻³ mm/y, respectively, significantly exceeding those of the other two crystal planes. Additionally, the electrochemical impedance spectroscopy results indicated that the modulus impedance and polarization resistance of the (110) crystal plane were much lower compared to the other two crystal planes, suggesting inferior corrosion resistance. A comprehensive analysis indicates that the (110) crystal plane exhibits poorer corrosion resistance compared to the (200) and (211) planes, with the interplanar spacing identified as the primary factor influencing its corrosion resistance.