Ti–Cu Coatings Deposited by a Combination of HiPIMS and DC Magnetron Sputtering: The Role of Vacuum Annealing on Cu Diffusion, Microstructure, and Corrosion Resistance

Abstract

Titanium-copper (Ti–Cu) coatings have attracted extensive attention in the surface modification of industrial and biomedical materials due to their excellent physical and chemical properties and biocompatibility. Here, Ti–Cu coatings are fabricated using a combination of high-power pulsed magnetron sputtering (HPPMS; also known as high power impulse magnetron sputtering (HiPIMS)) and DC magnetron sputtering followed by vacuum annealing at varied temperatures (300, 400, and 500 °C). X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) data showed that Ti, Cu, and CuTi3 are mainly formed in the coatings before annealing, while Ti3O, Cu2O, and CuTi3 are the main compounds present in the annealed coatings. The cross-sectional TEM micrographs and corresponding EDS results provided evidence that Ti is mainly present on the surface and interfaces of the silicon substrate and the Ti–Cu coatings annealed at 500 °C, while the bulk of the coatings is enriched with Cu. The resistivity of the coatings decreased with increasing the annealing temperature from 300 to 500 °C. Based on self-corrosion current density data, the Ti–Cu coating annealed at 300 °C showed similar corrosion performance compared to the as-deposited Ti–Cu coating, while the corrosion rate increased for the Ti–Cu coatings annealed at 400 and 500 °C. Stable release of copper ions in PBS (cumulative released concentration of 0.8–1.0 μM) for up to 30 days was achieved for all the annealed coatings. Altogether, the results demonstrate that vacuum annealing is a simple and viable approach to tune the Cu diffusion and microstructure of the Ti–Cu coatings, thereby modulating their electrical resistivity, corrosion performance, and Cu ion release behavior.

Antibacterial Activity and Cytocompatibility of Electrospun PLGA Scaffolds Surface-Modified by Pulsed DC Magnetron Co-Sputtering of Copper and Titanium

“…The appearance of such compounds was due to the fact that the chemically active plasma-modified surface of PLGA scaffolds can also actively interact with oxygen in the ambient air [ 75 ]. Qin et al demonstrated that Cu-Ti composite thin films fabricated by magnetron sputtering have TiO, Ti 2 O 3 , TiO 2 , Cu 2 O, and CuO compounds [ 53 ]. The formation of metal-oxygen species was most likely caused by the chemical bonding of deposited Cu, Ti atoms with O 2 taken from ambient air for thicker film thicknesses, whereby for the first layer the Cu and Ti atoms are also interacting chemically with the functional groups of the polymer backbone.…”

“…The copper ion release rates (RR) were calculated according the following equation [ 52 ]: with: —concentration of copper ions in deionized water on at time “ t ” in mg∙L −1 , —concentration of copper ions at “ t + ∆ t ”, ∆ t —the difference time for the interaction of the samples with water, at which two different concentrations were observed ( and ) in days (d). Copper ion release rates were calculated in a similar way in other studies [ 53 , 54 ].…”

Antibacterial Ti–Cu implants: A critical review on mechanisms of action

“…Numerous techniques, including ion implantation [ 83 ], oxidation [ 109 ], ion-beam assisted deposition [ 110 ], dip coating [ 111 ], plasma spraying [ 112 , 113 ], electroplating [ 114 ], magnetron sputtering [ 105 , [115] , [116] , [117] , [118] , [119] ], ion-assisted plasma polymerization [ [120] , [121] , [122] , [123] , [124] ] and plasma immersion ion implantation (PIII) [ [125] , [126] , [127] , [128] , [129] ] have been established to fabricate implant coatings and bioactive interfaces. In particular, a large body of works has been devoted to create contact killing surfaces that contain bactericidal agents such as F [ 130 ], Cu [ 83 , 131 ], Ag [ 108 , 109 , 132 ] and Zn [ 133 ].…”

Co-sputtered CuO/TiO2 coatings with varying copper content deposited on Ti6Al4V alloy

“…So far, Ti-Cu alloys and their compounds have found some applications in medicine, electronics and aeronautics [1,2]. For biomedical applications, the exact chemical, phase composition and crystallinity depending on the relative proportion of both metals in such coatings are of prime importance since they modulate Cu ion release behavior and therefore, influence the antimicrobial functionality and cell behavior [3]. Cu is known to be metabolized but exhibits strong cytotoxicity at certain conditions [4].…”