Materials Science and Engineering / Malzeme Bilimi ve Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4719
Browse
3 results
Search Results
Article Citation - WoS: 14Citation - Scopus: 20Influence 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, FatihTi-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: 10Citation - Scopus: 10Influence of Calcium Acetate Concentration in Electrolyte on Tribocorrosion Behaviour of Mao Treated Titanium(MDPI Multidisciplinary Digital Publishing Institute, 2021) Sousa, Luis; Mendes, Ana Rita; Pinto, Ana Maria Pires; Toptan, Fatih; Alves, Alexandra CruzTi-based materials are widely used for dental and orthopaedic implant applications due to their adequate mechanical properties, corrosion behaviour and biocompatibility. However, these materials are biologically inert and display poor wear resistance. In one of the most studied processes that aims to overcome these drawbacks, Ti surfaces are often covered by anodic oxide films with the incorporation of bioactive agents such as Ca and P. Although there are several works on the tribocorrosion behaviour of MAO-treated Ti surfaces, the influence of electrolyte composition on the corrosion kinetics under sliding is yet to be fully understood. In the present work, anodic oxide films were produced on cp-Ti surfaces with different calcium acetate concentrations in the electrolyte. Tribocorrosion behaviour was investigated by reciprocating sliding tests performed in 8 g/L NaCl solution at body temperature, under potentiostatic conditions. The results showed that higher concentrations of calcium acetate had a detrimental effect on tribocorrosion kinetics, however, they resulted in less mechanical damage due to alterations in the topography and structure of the MAO layer.Article Citation - WoS: 26Citation - Scopus: 29Tribocorrosion-Resistant Biofunctionalized Ti-Al2o3 Composites(Elsevier, 2021) Sousa, Luis; Basilio, L.; Alves, Alexandra Cruz; Toptan, FatihRecent 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.