Titanium implants are commonly used because of several advantages, but their surface modification is necessary to enhance bioactivity. Recently, their surface coatings were developed to induce local antibacterial properties. The aim of this research was to investigate and compare mechanical properties of three coatings: multi-wall carbon nanotubes (MWCNTs), bi-layer composed of an inner MWCNTs layer and an outer TiO2 layer, and dispersion coatings comprised of simultaneously deposited MWCNTs and nanoCu, each electrophoretically deposited on the Ti13Nb13Zr alloy. Optical microscopy, scanning electron microscopy, X-ray electron diffraction spectroscopy, and nanoindentation technique were applied to study topography, chemical composition, hardness, plastic and elastic properties. The results demonstrate that the addition of nanocopper or titanium dioxide to MWCNTs coating increases hardness, lowers Young’s modulus, improves plastic and elastic properties, wear resistance under deflection, and plastic deformation resistance. The results can be attributed to different properties, structure and geometry of applied particles, various deposition techniques, and the possible appearance of porous structures. These innovative coatings of simultaneously high strength and elasticity are promising to apply for deposition on long-term titanium implants.

Carbon nanotubes are proposed for reinforcement of the hydroxyapatite coatings to improve their adhesion, resistance to mechanical loads, biocompatibility, bioactivity, corrosion resistance, and antibacterial protection. So far, research has shown that all these properties are highly susceptible to the composition and microstructure of coatings. The present research is aimed at studies of multi-wall carbon nanotubes in three different combinations: multi-wall carbon nanotubes layer, bilayer coating composed of multi-wall carbon nanotubes deposited on nanohydroxyapatite deposit, and hybrid coating comprised of simultaneously deposited nanohydroxyapatite, multi-wall carbon nanotubes, nanosilver, and nanocopper. The electrophoretic deposition method was applied for the fabrication of the coatings. Atomic force microscopy, scanning electron microscopy and X-ray electron diffraction spectroscopy, and measurements of water contact angle were applied to study the chemical and phase composition, roughness, adhesion strength and wettability of the coatings. The results show that the pure multi-wall carbon nanotubes layer possesses the best adhesion strength, mechanical properties, and biocompatibility. Such behavior may be attributed to the applied deposition method, resulting in the high hardness of the coating and high adhesion of carbon nanotubes to the substrate. On the other hand, bilayer coating, and hybrid coating demonstrated insufficient properties, which could be the reason for the presence of soft porous hydroxyapatite and some agglomerates of nanometals in prepared coatings.

Wpływ stopowania laserowego z użyciem nanorurek węglowych stopu Ti13Nb13Zr do zastosowań biomedycznych na jego wybrane własności mechaniczne The influence of laser alloying with carbon nanotubes of Ti13Nb13Zr on some of its mechanical properties in biomedical application Mgr inż. Dorota Rogala-Wielgus, dr inż. Beata Majkowska-Marzec, mgr inż. Michał Bartmański-Politechnika Gdańska.

Three coatings suitable for biomedical applications, including the dispersion coating composed of multi-wall carbon nanotubes (MWCNTs), MWCNTs/TiO2 bi-layer coating, and MWCNTs-Cu dispersion coating, were fabricated by electrophoretic deposition (EPD) on Ti Grade II substrate. Optical microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and nanoindentation were applied to study topography, chemical, and phase composition, roughness, hardness, Young’s modulus, plastic, and elastic behavior. The results showed that the best mechanical properties in terms of biomedical application were achieved for the MWCNTs coating with titania outer layer. Nevertheless, both the addition of nanocopper and titania improved the mechanical resistance of the base MWCNTs coating. Compared to our previous experiments on Ti13Nb13Zr alloy, a general tendency is observed to form more homogenous coatings on pure metal than on the alloy, in which chemical and phase compositions are more complex.

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