Electrophoretic deposited Ni(OH)2-YSZ and NiO-YSZ nanocomposite coatings, microstructural and electrochemical evaluation

In this research, Ni(OH)2-YSZ and NiO-YSZ composite powders were synthesized with the mass ratio of 60%Ni-40%YSZ using the hydrothermal method. The crystalline structure of nanocomposite powders was examined by X-ray diffraction analysis (XRD). Nanocomposite powders were coated on 316L stainless steel by Electrophoretic deposition. The surface morphology of coatings was investigated using scanning electron microscope (SEM). NiO-YSZ coating provided a more uniform particle size distribution. The corrosion behavior of samples in 3.5 wt% NaCl solution was determined by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests. The corrosion resistance of bare 316L stainless steel, 1.01 × 104 Ω cm2, increased by applying Ni(OH)2-YSZ and NiO-YSZ coatings to about 1.88 × 104 Ω cm2 and 1.16 × 105 Ω cm2, respectively. From the Nyquist plots, NiO-YSZ coated 316L SS showed a larger arc compared to Ni(OH)2-YSZ coated SS. Thus, NiO-YSZ coating provided a more appreciable barrier in the corrosive medium and improved the corrosion resistance of 316L stainless steel.