Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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  • Article
    Citation - WoS: 14
    Citation - Scopus: 20
    Influence of Al2o3 Reinforcements and Ti-Al Intermetallics on Corrosion and Tribocorrosion Behavior of Titanium
    (Elsevier, 2023) Sousa, Luis; Antunes, Rui D. M.; Fernandes, Joao C. S.; Alves, Alexandra Cruz; Toptan, Fatih
    Ti-Al2O3 composites have demonstrated favorable characteristics for use in load-bearing biomedical implant applications; however, the influence of Al2O3 reinforcement particles and Ti-Al intermetallics on the electrochemical and tribo-electrochemical responses of Ti are not well-understood. This study explored the corrosion and tribocorrosion characteristics of powder metallurgy-manufactured Ti-Al2O3 composites in a simple physiological saline solution at body temperature. Electrochemical analysis was performed by electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization and tribo-electrochemical mechanisms were explored under open circuit potential (OCP) against a 10 mm diameter alumina ball in a ball-on-plate tribometer with reciprocating configuration. Results revealed that the corrosion behavior of Ti was adversely affected by the development of a heterogeneous oxide film on the Ti matrix and the Ti-Al intermetallic phases formed by the interaction of Ti and Al2O3 particles. However, there was a drastic improvement in tribocorrosion behavior, evidenced by decreased corrosion tendency under sliding and a marked reduction in wear volume, primarily as a result of the decreased wear damage resulting from the load-bearing reinforcements.
  • Article
    Citation - WoS: 20
    Citation - Scopus: 20
    Preliminary Tribo-Electrochemical and Biological Responses of the Ti-Tib In-Situ Composites Intended for Load-Bearing Biomedical Implants
    (Elsevier, 2022) Sousa, Lia; Toptan, Fatih; Alves, Alexandra C.; Costa, N. A.; Gemini Piperni, Sara; Rossi, Andre Linhares; Ribeiro, Ana R.; Simöes, Sönia; Toptan, Fatih
    Poor tribocorrosion resistance of Ti and its alloys remains as a concern for load-bearing biomedical implants. Despite being an effective method to improve tribocorrosion resistance, titanium matrix composites (TMCs) have yet to be used in this type of applications. In-situ TiB (titanium boride) and TiC (titanium carbide) reinforcement phases have been considered as one of the best options to produce TMCs once these phases present high compatibility and strong interfacial bonding with Ti. Although the effect of these phases on the mechanical properties of Ti has been thoroughly researched in the last years, their effect on corrosion, tribocorrosion and biocompatibility of Ti is yet to be fully understood. In this work, in-situ Ti-TiB-TiCx composites obtained by reactive hot pressing showed identical corrosion response compared to the unreinforced Ti but displayed improved tribocorrosion behaviour. Under 0.5 N load, composites presented as average a reduction of 51% in wear volume loss and under 10 N the reduction was up to 93%. Early biological tests showed promising results, as composites were biocompatible and induced osteoblasts spreading and possibly proliferation most probably due to composite chemistry and surface hardness.
  • Article
    Citation - WoS: 26
    Citation - Scopus: 29
    Tribocorrosion-Resistant Biofunctionalized Ti-Al2o3 Composites
    (Elsevier, 2021) Sousa, Luis; Basilio, L.; Alves, Alexandra Cruz; Toptan, Fatih
    Recent studies have shown that titanium matrix composites have potential for load-bearing biomedical implants due to their improved tribocorrosion behaviour compared to Ti and its alloys. However, lack of bioactivity remains as a concern due to bioinert Ti matrix and the fact that most reinforcement phases are also bioinert. In this work, biofunctionalized Ti-Al2O3 composites were produced by performing micro-arc oxidation treatment on the Ti-Al2O3 composites processed by hot-pressing technique. The overall microstructure consisted of Al2O3 particles dispersed within a biofunctionalized Ti matrix having a micro-porous structure rich in Ca and P elements. The corrosion behaviour of the composites was greatly improved after MAO treatment, whereas the tribocorrosion behaviour of the composites was also further improved after MAO treatment.