Nano-Grain Ni/ZrO2 Functional Gradient Coating Fabricated by Double Pulses Electrodeposition with Enhanced High Temperature Corrosion Performance

Abstract

Functional gradient materials (FGM) have many excellent properties, and high-performance gradient coating exhibits good prospective application. In this paper, the nano-grain Ni/ZrO2 gradient coating was prepared by double pulse electrodeposition (BP). The surface morphology, crystal structure and electrochemical corrosion resistance of the nano-grain Ni/ZrO2 coating and Ni coating, annealed at different temperatures (400–800 °C), have been compared. In the vertical direction to the substrate surface, the content of ZrO2 increases from 0% to 34.99%. X-ray diffraction (XRD) revealed that the average crystal size of Ni/ZrO2 gradient coating gradually increases from 13.75 to 27.75 nm, and the crystal structure is a face-centered cubic (FCC). The main crystal orientation faces are (111) and (200), while the (200) face exhibited a stronger preferred orientation. Compared with the Ni coating by scanning electron microscopy, the surface morphology of double pulse fabricated Ni/ZrO2 gradient coating was revealed as being smoother, denser, and having fewer pores, and the crystal particle size distribution became narrow. X-ray photoelectron spectroscopy (XPS) shows that the chemical binding states of elements Ni and Zr have been altered. The binding energies of 2p3/2 and 2p1/2 for Ni have been increased, resulting in a higher electron donor state of Ni. The binding energy of 3d5/2 and 3d3/2 of Zr4+ in ZrO2 is decreased, thus becoming better electron acceptors. Chemical bonding has been formed at the Ni/ZrO2 interface. This study demonstrated that double pulse electrodeposition is a promising fabrication method for functional gradient coatings for high temperature applications.

The Effect of Heat Treatment on the Microstructure and Mechanical Properties of 2D Nanostructured Au/NiFe System

“…Probably, the opposite behavior of the mechanical properties is associated with the difference in the processes activated by heat treatment, both in the material volume and on the surface. We concluded that three complex processes significantly affect the mechanical properties of the system after analyzing the investigation results and literature [24][25][26][27]30,35,39,48]:…”

“…Thus, the choice of pulse duration allows for you to select the desired grain size. More detailed control of the microstructure by varying the pulse duration is described in the previous article [ 38 , 39 , 40 ]. Complex electrolyte was used for NiFe electrodeposition.…”

Effect of pulse electroplating parameters on the morphology and corrosion resistance of Ag plating coating

“…The current density of DC electroplating is much lower than the peak current density of pulse electroplating. Pulse electrodeposition not only has an effect on the morphology of the plated layer, but also on the corrosion resistance of the plated coating [23][24][25][26][27][28]. However, the mechanism of the effects of pulse electroplating parameters on the morphology and corrosion resistance of silver coatings have received little attention.…”