From Wiley via Jisc Publications RouterHistory: received 2021-03-27, rev-recd 2021-05-16, accepted 2021-05-25, pub-electronic 2021-06-10Article version: VoRPublication status: PublishedFunder: EPSRC Royce@Manchester; Grant(s): EP/R00661X/1Abstract: Bipolar electrochemistry produces a linear potential gradient between two feeder electrodes, providing access to the full spectrum of anodic‐to‐cathodic electrochemical behaviour. A type 420 martensitic stainless steel has been used to investigate microstructure evolution and corrosion behaviour with application of different tempering heat treatments. Tempering treatments at 250°C, 400°C and 700°C revealed the occurrence of pitting corrosion, with treatments at 550°C resulting in general and intergranular corrosion. Cr23C6 was present in all tempering conditions, with Cr7C3 and CrC only observed for tempering at 550°C. The 250°C tempering treatment had the highest corrosion resistance with a hardness value much higher than 500 HV