Plasma Electrolytic Oxidation of Pure Zirconium in Chromium Containing Electrolyte Juan Carlos Sihotang (a,b), Maman Kartaman Ajiriyanto (b), Anawati (a*)
a) Department of Physics, Faculty of Mathematics and Natural Science, Universitas Indonesia, Depok, 16424, Indonesia
*anawati[at]sci.ui.ac.id
b) Research Center for Nuclear Material and Radioactive Waste Technology, National Research and Innovation Agency, Serpong, 15314, Indonesia
Abstract
Plasma Electrolytic Oxidation (PEO) -is an effective surface modification technique for producing oxide coatings on metal substrates. Various types of particle additives are commonly added to the electrolyte to enhance the properties of the resulting coatings. In this study, chromium (Cr) was incorporated into the PEO coating on pure zirconium (Zr) by introducing a dissolved Cr-containing additive into the electrolyte. The PEO treatment was conducted in an electrolyte composed of 30 g/L NaAlO2, 30 g/L KOH, 10 g/L ethanol, and 10 g/L K2CrO4, at a current density of 50 mA/cm2 for durations of 3, 5, and 10 min. The electrolyte temperature was maintained at 10C. The surface morphology and elemental composition of the coatings were analyzed using scanning electron microscopy (SEM). The phase composition was determined through X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Electrochemical performance was evaluated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The coating thicknesses for the samples treated for 3, 5, and 10 min were 3.10, 5.91, and 6.55 micrometer, respectively. XRD analysis revealed that the dominant phase was tetragonal ZrO2. Energy-dispersive X-ray spectroscopy (EDS) confirmed the presence of Cr in the oxide layer, with Cr content increasing with treatment duration, reaching 2.73 atomic percent after 10 min. The presence of Cr was further verified by XPS, which indicated that Cr was likely present in the form of its oxides. Interestingly, the PDP results showed that the coating formed after 5 minutes of treatment exhibited the best corrosion resistance, with a corrosion current density of 2.437 x 10-10 A/cm2. Further detailed results and discussions are presented in the full paper.
