Comparing Resistances to Pitting Corrosion of Additive Manufactured Ti-6Al-4V Alloys in NaCl and NaBr Aqueous Solutions, NaCl과 NaBr수용액에서 적층가공으로 제조된 Ti-6Al-4V 합금의 공식 저항성 비교

Abstract

Resistances to pitting corrosion of additive manufactured (AM) Ti-6Al-4V alloys in 0.6 M NaBr and 0.6 M NaCl aqueous solutions were compared using micro-droplet cell techniques. With respect to the pitting corrosion resistance, this study focused on two different types of halide anions in aqueous solutions, i.e. Br - and Cl - . The differences between Br - and Cl - halide anions for breakdown on passive films of AM Ti-6Al-4V alloy were explained using Langmuir adsorption model with their equilibrium adsorption coefficients. The results of the analysis showed that the lower resistance to pitting potential of AM Ti-6Al-4V alloy in Br - aqueous solution was attributed to the higher equilibrium adsorption coefficient of Br - . In addition, micro-electrochemical test results showed that the pitting corrosion resistance of dark grains in additive manufactured Ti-6Al-4V alloy was lower as compared to that of bright grains due to the larger volume of α ' phase that caused the susceptibility to pit initiation.