Effects of competitive anion adsorption (Br− or Cl−) and semiconducting properties of the passive films on the corrosion behavior of the additively manufactured Ti–6Al–4V alloys

•Corrosion behavior of additively manufactured (AM) Ti–6Al–4V was examined.•Effect of the adsorption of Br− and Cl− ions on pitting corrosion was investigated.•Competitive adsorption of anions on pitting was simulated by Langmuir isotherm.•The relationship between the pitting, the doping densities and α′ phase was established. Herein, the corrosion behavior of the additively manufactured (AM) Ti–6Al–4V is investigated based on the relation between the pitting potentials and equilibrium adsorption of the Br− and Cl− anions using potentiodynamic polarization curves, Mott–Schottky plots, and the Langmuir isotherm model. The Mott–Schottky plots are measured using the microdroplet cell technique based on the capacitance of the passive films on each dark and bright AM Ti–6Al–4V grain. The pitting potential can be attributed to the doping densities as well as α′ phase distribution and predicted using the equilibrium adsorption coefficient of Br− and Cl−.