Characterization of microstructure and properties of electroless duplex Ni-W-P/Ni-P nano-ZrO2 composite coating

Abstract

In this study, we prepared the Ni-W-P/Ni-P nano-ZrO2 nanocomposite coating by electroless chemical deposition methods. The structures, morphologies, and corrosion behavior of the nanoparticle enhanced duplex coating were evaluated by X-ray diffraction, atomic force microscopy, scanning electron microscopy as well as the electrochemical methods, such as the potentiodynamic polarization curve and electrochemical impedance spectroscopy. The Ni-W-P/Ni-P nano-ZrO2 duplex coatings were amorphous under the as-plated condition and crystallized and produced nickel borides upon heat-treatment. The duplex coatings exhibit the higher microhardness after different heat treatments and also depict the better corrosion resistance than conventional Ni-P coating in the H2S/CO2-containing environment. This novel type of Ni-P coating possesses both excellent mechanical properties and good corrosion resistance, and it would expand their scope of applications in H2S/CO2-containing environment.