Dmax 3 a type

The microstructural morphologies and cross-sections of the films formed after the various treatments were observed by SEM (JSM-6400, JEOL, Japan). The concentrations of the elements present on the surface and in the cross-section of the film were determined by EDS (7274, Oxford Instruments, England). The phase of the surface layer was analyzed by X-ray diffraction (XRD) analysis (Dmax III-A type, Rigaku, Japan) using a Cu target. The step size was 0.0334°, and the time per step was 50 s.
The electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements were performed to evaluate the corrosion performance of the coating using a potentiostat/galvanostat (2273, AMETEK, USA). A Ag/AgCl/KCl electrode (saturated) was used as the reference electrode, and a platinum electrode was used as the counter electrode; the specimen was connected to the working electrode. The corrosion potential and corrosion current density were measured by a scanning rate of 3 mV/s in a 0.9% NaCl solution. The EIS measurements were made at frequencies of 100 mHz to 100 KHz.

High-resolution field emission scanning electron microscopy (HR FE-SEM in KBSI Jeonju, SU8230, Hitachi, Japan) was used to investigate the topography of the liner-bonded surface, cross-sectional bonded interfaces, and fractured surfaces after etching with a 9.5% hydrofluoric acid gel for 30 s. The liner layer was removed with a 5% hydrofluoric acid solution for 30 min to identify the effects of liner treatment on zirconia ceramic. The distribution of the chemical elements at the bonded interface was analyzed using an energy dispersive X-ray spectrometer (EDS, Bruker, Germany), and the crystal structure on the liner-bonded surface was investigated by X-ray diffraction (XRD, Dmax III-A type, Rigaku, Japan).