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Keywords

Ti-6Al-7Nb implant alloy, Electrophonic deposition, Hydroxyapatite, Tantalum oxide, Corrosion behaviour

Document Type

Article

Abstract

The Ti6Al7Nb alloy is widely used as an orthopedic implant in biomedical applications. Despite its excellent corrosion resistance and mechanical properties, metallic wear particles and metal ion release occur over long spans. In order to improve the surface properties of the Ti alloy and develop its clinical use, electrophoretic deposition has been applied to enhance the surface characteristics of the Ti alloy. In this study, a hydroxyapatite-chitosan nanocomposite coating was applied on the Ti6Al7Nb implant alloy surface with varying tantalum oxide contents of 0, 10, 30, and 50 wt.% at a direct current of 60 V for 6 minutes. Hydroxyapatite (HA) is a bioceramic material that provides bioactivity and corrosion resistance, with a chemical composition close to that of the bone, while tantalum oxide (Ta2O5) is a biologically inert material with good mechanical properties, and chitosan (CS) is a biocompatible, biodegradable, and antimicrobial natural polymer widely used in Electrophoretic Deposition (EPD) to create bioactive coatings on implants and medical devices. Characterization of the deposited coating involved optical microscopy, scanning electron microscopy, X-Ray diffraction, contact angle, and adhesion tests. Polarization curves were used to assess the corrosion behavior of the coated and uncoated Ti alloy samples. The results revealed that the presence of Ta2O5 significantly improved the coating layer's properties. The coatings became more uniform and crystalline, leading to better electrochemical performance and stronger adhesion to the substrate. Coating thicknesses increased from 20.14 μ m at 100% HA/CS coating to 28.52 μ m at 50% HA+ 50%Ta2O5. The incorporation of Ta2O5 significantly enhanced the corrosion resistance of the coated samples, decreasing the corrosion rate of the uncoated Ti6Al7Nb substrate from 9.662× 10–3 to 1.403 × 10–4 at a coating composition of 50 % HA+ 50%Ta2O5. This improvement was also reflected in a decrease in the contact angle and an increase in adhesion strength as the Ta2O5 concentration rose.

DOI

10.30684/2412-0758.1561

First Page

129

Last Page

150

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