An electrochemical study on the effect of stabilization and sensitization heat treatments on the intergranular corrosion behaviour of AISI 321H austenitic stainless steel

•DEIS and Mott-Schottky analysis were used to assess intergranular corrosion (IGC).•Sensitized samples have less intact passive films according to Mott-Schottky results.•Prolonged sensitization time led to have IGC even for stabilized specimens.•DEIS results showed different corrosion mechanisms in transpassive potential range.•The more severe the IGC, the lower the inductance values would be.