Quasi-In Situ Localized Corrosion of an Additively Manufactured FeCo Alloy in 5 Wt Pct NaCl Solution

Abstract FeCo alloys are important materials used in pumps and motors the offshore oil gas drilling industry. These subjected to marine environments with a high NaCl concentration, therefore, corrosion catastrophic failure anticipated. So, surface dissolution of additively manufactured samples is investigated quasi- situ manner, particular, pitting 5.0 wt pct solution. The local same sample region monitored after 24, 72, 168 hours. Here, formation rectangular circular pits ultra-fine dimensions (less than 0.5 µ m) observed increasing immersion time. In addition, corrosion-inhibiting layer detected on surface. Surface leads change structure, however, no grain shape or size noticed. topography correlated orientation. Quasi- analysis shows preferential high-angle boundaries (HAGBs) leading fraction HAGBs low-angle (LAGBs). For sample, potentiodynamic polarisation test reveals potential (E corr ) − 0.475 V referred standard hydrogen electrode (SHE) exchange current density (i 0.0848 A/m 2 . Furthermore, experiments showed that grains oriented along certain crystallographic directions corroding more compared other significant decrease height. Grains plane normal close $$\langle {1}00\rangle$$ ⟨ 100 ⟩ direction reveal lower higher resistance, whereas planes {11}0\rangle$$ 110 {111}\rangle$$ 111 exhibit dissolution.