Preparation and characterization of electrodeposited Ni–TiC, Ni–TiN, and Ni–TiC–TiN composite coatings on tungsten carbide cutting tool

Abstract

Electrodeposition technique for developing functionally graded composite coatings is an economical and versatile method, used for depositing metal-based coatings. This paper presents a comparison of microstructural and mechanical properties of Ni–TiC, Ni–TiN, and Ni–TiC–TiN composite coatings deposited through electrodeposition technique on tungsten carbide cutting inserts. The variable coatings deposited at optimized current and pH value were analyzed and compared in terms of microhardness and adhesion of electrodeposited specimens. The microstructure analysis of the deposited coatings was carried out using scanning electron microscope, energy dispersive spectroscopy, and X-ray diffraction, while the adhesion strength was analyzed using scratch test. All the three composite coatings showed improved mechanical characteristics and stable microstructure over uncoated tungsten carbide inserts, with Ni–TiC–TiN coating showing maximum microhardness, and Ni–TiN coating showing maximum adhesion among the three types.