Nitrided bipolar plates and a scheme for their fabrication are provided. The present invention also contemplates device incorporating bipolar plates according to the present invention. For example, in accordance with one embodiment of the present invention, an electrochemical conversion assembly is provided. The electrochemical conversion cells of the assembly are separated by respective bipolar plates comprising an alloy of Fe and Cr. A surface portion of the bipolar plates comprises a single phase nitrided structure. According to another embodiment of the present invention, a plasma nitriding process is utilized to create a single phase nitrided structure along a surface portion of respective ones of said bipolar plates.