Operando Odd Random Phase Electrochemical Impedance Spectroscopy (Orp-Eis) for in Situ Monitoring of the Zr-Based Conversion Coating Growth in the Presence of (In)Organic Additives

Abstract

Operando odd random phase electrochemical impedance spectroscopy (ORP-EIS) is introduced as an in-situ monitoring tool to directly monitor the conversion treatment of a zinc substrate in a hybrid Zr-based solution containing aminosilane and Cu additives. SEM and EDX are applied to investigate the morphology and elemental composition of the oxide film. Results show that the operando ORP-EIS provides an opportunity to investigate the growth of the conversion layer and its surface homogeneity during conversion. Moreover, operando ORP-EIS data reveal that the presence of aminosilane in the Zr solution containing Cu, improves the morphology and barrier properties of the conversion film.

Keywords: Operando ORP-EIS, Conversion treatment, Zinc, Aminosilane, Additives