Physical-chemical properties of zirconia thin films deposited by electron beam on Ti6Al4V alloy for biomedical applications

Abstract

The growing need for safer and more effective biomaterials aligns with advancements in medicine, where surface properties are crucial. Surface modifications are key to developing advanced materials, and depositing thin films presents significant advantages for biomedical uses. This study applied a 470 nm thick yttria-stabilized zirconia film to titanium alloy discs through electron beam deposition. The film was found to be amorphous and stoichiometric. Both the microhardness and Reduced Young's modulus of the substrate and film were measured using instrumented microhardness testing with a Berkovich tip, and Vickers hardness was estimated using established mathematical formulas. The results showed an increase in microhardness compared to the substrate, though small cracks did form in the film under a high load (2000 mN). Microabrasive wear resistance was evaluated with a rotating ball test using Calotest equipment with a load cell. The contact angle was tested according to ASTM (American Society for Testing and Materials) D7334–08 to assess the film wettability. The study revealed a 44 % improvement in microabrasive wear resistance, and the contact angle data indicated better osteointegration potential. These improvements indicate that the electron beam deposition technique is highly effective for applying yttria-stabilized zirconia thin films to biomaterials. Biological assays also demonstrated increased biocompatibility of the coated material, as evidenced by the indirect viability test, and showed that L929 fibroblast cells did not adhere to the film surface—an advantageous feature for preventing fibrotic tissue formation in implants.