On the use of instantaneous impedance for post-electrochemical treatment analysis

For many electrochemical treatments, surface modifications and processes occurring during the relatively short post-treatment time are difficult to monitor using traditional surface analysis techniques. Instantaneous impedance, i.e. time-resolved impedance calculated from an in situ odd random phase multisine electrochemical impedance spectroscopy measurement, may allow for monitoring of these surface modifications. In this work, the AC electrograining process is used as a case study to investigate the possibility of post-electrochemical treatment analysis. It is found that the expected surface changes are indeed found in the instantaneous impedance data. The technique described in this paper can be used to monitor a variety of post-electrochemical treatment surface modifications in situ.