Characterization of niobium carbide film deposited on commercially pure titanium by low-temperature plasma glow discharge

Abstract

By using a low-temperature plasma glow discharge with argon gas and C₂H₂ as a carbon source, niobium carbide thin films were applied on a commercially pure titanium substrate. The coatings were deposited in three different deposition times: Group-1 with 2-h deposition time, group-2 with 4-h deposition time and group-3 with 6-h deposition time. The films were analysed for phase composition, microstructure, surface morphology, roughness and wettability as a function of deposition time. The X-ray diffraction (XRD) patterns suggest the formation of various phases (either orthorhombic-Nb₂C or cubic-NbC). It is worth noting that deposition time affects the crystal structure of both phases, with Nb₂C having a more noticeable effect due to a noticeable shift in the related XRD pattern. This might be attributable to changes in carbon content and sputtered niobium ions throughout the deposition process when the chamber gas conditions were verified to form phase pure NbC. The scanning electron microscopy images of the deposited NbC films display a microstructure that shows good regularity and homogeneity; a uniform morphology is revealed with an agglomerating characteristic of the material. Increased deposition time results in less surface roughness, according to atomic force microscope analysis. In contrast, the measurements of the water contact angle revealed only a little improvement in wettability as the deposition period increased.