Electrochemical, Tribological and Biocompatible Performance of Electron Beam Modified and Coated Ti6Al4V Alloy

Abstract

Vacuum cathodic arc TiN coatings with overlaying TiO2 film were deposited on polished and surface roughened by electron beam modification (EBM) Ti6Al4V alloy. The substrate microtopography consisted of long grooves formed by the liner scan of the electron beam with appropriate frequencies (500 (AR500) and 850 (AR850) Hz). EBM transformed the α + β Ti6Al4V mixed structure into a single α’-martensite phase. Тhe gradient TiN/TiO2 films deposited on mechanically polished (AR) and EBM (AR500 and AR850) alloys share the same surface chemistry and composition (almost stoichiometric TiN, anatase and rutile in different ratios) but exhibit different topographies (Sa equal to approximately 0.62, 1.73, and 1.08 μm, respectively) over areas of 50 × 50 μm. Although the nanohardness of the coatings on AR500 and AR850 alloy (approximately 10.45 and 9.02 GPa, respectively) was lower than that measured on the film deposited on AR alloy (about 13.05 GPa), the hybrid surface treatment offered improvement in critical adhesive loads, coefficient of friction, and wear-resistance of the surface. In phosphate buffer saline, all coated samples showed low corrosion potentials and passivation current densities, confirming their good corrosion protection. The coated EBM samples cultured with human osteoblast-like MG63 cells demonstrated increased cell attachment, viability, and bone mineralization activity especially for the AR500-coated alloy, compared to uncoated polished alloy. The results underline the synergetic effect between the sub-micron structure and composition of TiN/TiO2 coating and microarchitecture obtained by EBM.

Advances in Multifunctional Bioactive Coatings for Metallic Bone Implants

“…Simultaneously, cells cultured on the grooved surface with a smaller channel spacing (AR500) tended to have a stronger orientation along the groove axis compared to the AR850 surface with greater groove spacing. The results show that the deposited TiN/TiO2 coating on the micro-rough EBM surface stimulates and accelerates cell differentiation [225]. Besides, magnetron-sputtered TiON and ZrON films on SS 316L substrates indicated a drastic reduction of bacterial adhesion (P. aeruginosa) as well as inhibition of biofilm formation at different time durations [229].…”

“…Simultaneously, cells cultured on the grooved surface with a smaller channel spacing (AR500) tended to have a stronger orientation along the groove axis compared to the AR850 surface with greater groove spacing. The results show that the deposited TiN/TiO 2 coating on the micro-rough EBM surface stimulates and accelerates cell differentiation [225].…”

“…Therefore, in addition to the enhanced wear resistance of TiN x O y coatings, they can "isolate" the substrate metal from the bone and accelerate the effect on the growth of bone cells. For that reason, our research group synthesized gradient TiN/TiO 2 coatings by a cathodic arc (for TiN) and glow discharge deposition (for TiO 2 ) on an initial surface treated by electron beam Ti6Al4V alloy [225]. The initial electron beam treatment (EBT) of the alloy not only roughened the surface of the alloy forming regular grooves and heights but also enhanced the hardness of the substrate, thus generating a smooth gradient in stiffness from the substrate to the coating.…”

“…Ion implantation [147] TiN and "soft" Ti 4 N 3−x on Ti6Al4V alloy DC magnetron sputtering [181] TiN coating on Ti20Nb13Zr (TNZ) alloy Cathodic arc PVD [182] Copper-doped TiN (TiCuN) deposited on 316L SS Axial magnetic field enhanced arc ion plating [186] Oxides ZnO and ZnO/Ag on Mg-Ca alloy Electroless deposition [89] TiO 2 layers on Ti sheets and TiO 2 nanotubes Atomic layer deposition [116] Tantalum oxide on Mg alloy Reactive magnetron sputtering [203] Doped-TiO 2 coatings MAO (PEO) [206,208,209,211] TiO 2 nanotubes on pure Ti Anodization [207] TiO 2 layer embedding silver (Ag) and zinc (Zn) nanoparticles 3D printing [212] Ag-doped TiO 2 coatings on Ti Sol-gel [213] Collagen/polydopamine/TiO 2 coatings on Ti implants MAO and hydrothermal treatment [216] Oxynitrides TiN/TiO 2 coatings on Ti6Al4V Cathodic arc deposition (CAD) and glow discharge oxidation [225] TiON and ZrON films on SS 316L Magnetron sputtering [229] Carbon-based Hybrid DLC coatings incorporating TiO 2 nanoparticles on AISI 316 plasma-enhanced CVD [246] Nanocrystalline and microcrystalline diamonds on Mo substrates Hot filament CVD [257] Modified ultra-nanocrystalline diamond coatings on Ti Microwaved plasma-assisted CVD and electron-beam evaporation [253] DLC with Zr-containing interlayers Unbalanced magnetron sputtering [242] Mg-functionalized GO coating on Ti6Al4V Electrophoretic deposition [262] Graphene on pure Ti Liquid-free technique [268] Apatite-nanodiamond coating on SS Electrodeposition [256] GO loaded with interleukin 4 on Ti Spraying [362] Calcium phosphates and hydroxyapatite…”

Formation and characterization of CuO coatings deposited by reactive magnetron sputtering

“…In particular, metal oxides are used to increase the resistance to wear and corrosion and to improve the biocompatibility of materials [7]. For example, TiO2 coatings can be used as protective non-toxic coatings that improve the wear and corrosion resistance of materials, with additional benefits such as self-cleaning and antibacterial effects [8][9][10]. Copper oxide (CuO) in the form of a coating or nanoparticles is used in medical applications [11][12][13].…”