The　electrochemical　behavior　of　Ni-Cr　alloys,　with　and　without　Mn　addition,　was　investigated　to　understand　the　influence　of　Mn　on　their　passivation　and　corrosion　mechanisms.　The　alloys　were　fabricated　using　vacuum　arc　melting　(VAM)　and　spark　plasma　sintering　(SPS)　methods,　which　also　influenced　the　crystallographic　orientation　of　Ni-based　alloys.　Electrochemical　tests,　including　cyclic　potentiodynamic　test　(CPD),　electrochemical　impedance　spectroscopy　(EIS),　and　Mott-Schottky　(M-S)　analysis,　were　performed　in　0.6　M　NaCl　solution　to　assess　the　corrosion　resistance　of　Ni-Cr　alloys.　Results　show　that　Mn　addition　negatively　affected　corrosion　resistance　due　to　the　dissolution　of　Mn,　which　destabilized　the　passive　film.　The　crystallographic　orientation　played　a　significant　role　in　the　corrosion　behavior,　with　the　(111)　plane　exhibiting　better　corrosion　resistance.　First-principles　calculations　using　density　functional　theory　(DFT)　additionally　demonstrate　that　crystallographic　orientation　modified　the　electronic　characteristics　of　passive　films,　resulting　in　a　higher　oxidation　ability　on　the　(111)　plane.　The　study　highlights　that　Mn　addition　is　generally　believed　to　reduce　corrosion　resistance,　while　the　crystallographic　orientation　may　have　positive　effect　on　the　corrosion　resistance.　This　research　provides　new　insights　into　the　mechanisms　underlying　the　corrosion　of　Mn-containing　Ni-Cr　alloys,　offering　valuable　information　for　their　application　in　chemical,　marine,　and　energy　sectors.　©　2025　Elsevier　B.V.