Electrochemical carburization of pure iron in 1Â M Na2SO4 aqueous solution with the presence of supercritical carbon dioxide

Electrochemical carburization (ECC) of pure iron in a 1 M Na2SO4 bath containing supercritical CO2 (sc-CO2) fluids was investigated. The experimental results showed that the carbon-bearing films electrodeposited on iron substrate could be successfully produced under either galvanostatic or potentiostatic modes. The formation of carbon film on metal substrate and the subsequent carburization of iron substrate were analyzed by X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and scanning transmission electron microscopy (STEM) coupled with energy dispersive X-ray spectroscopy (EDS), with the aid of a focused ion beam (FIB).