Impedance Based Characterization of Raw Materials Used in Electrochemical Manufacturing

To be able to understand the extent to which the oxide state (on the surface of the precursor) influences process parameters, appropriate measurement methods are required to probe the relevant properties that would change with oxide coverage. Electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) are excellent methods for this purpose. This article outlines a case study wherein these techniques have been employed to probe the growth of oxide films on a stainless steel sample that represented the precursor, and provides a practical example of how such methods can be beneficially used in practice during electrochemical manufacturing processes. The impedance based screening of raw materials has a tremendous positive impact in an industry where the state of the oxide film on stainless steel strongly influences process and product performance. Process development can be improved because of improved knowledge of how constitutive processes alter the oxide on stainless steel or how they depend on its state. Furthermore, incoming raw materials can be screened rapidly to determine what type of cleaning/pre-processing is necessary and sufficient.