Impedance of steels in new and degraded ester based lubricating oil

The measurement model technique was used to analyze impedance data associated with Cronidur 30 and M50 steel samples in new and degraded jet engine oil. The analysis for the degraded oil included both determining the error structure associated with the data and evaluating the consistency of the data with Kramers–Kronig relations. Voigt measurement model parameters were used to identify characteristic time constants for new and degraded oils. This information was used to differentiate the impedance responses into bulk oil and alloy-oil interfacial contributions. The analysis presented here represents a step toward understanding the physical processes involved.