38 documents found, page 1 of 4
Investigation of the influence of high-pressure torsion and solution treatment ...
Yilmazer, Hakan; Caha, Ihsan; Dikici, Burak; Toptan, Fatih; Isik, Murat; Niinomi, Mitsuo; Nakai, Masaaki; Alves, Alexandra Manuela Vieira Cruz PintoIn this study, the influence of the high-pressure torsion (HPT) processing parameters and solution treatment (ST) on the corrosion and tribocorrosion behavior of CoCrMo (CCM) alloys was investigated for possible usage in biomedical applications. The corrosion behavior of the CCM alloys was investigated by using potentiodynamic scanning (PDS) and electrochemical impedance spectroscopy (EIS) tests. Tribocorrosion...
Improved tribocorrosion behavior obtained by in-situ precipitation of Ti2C in T...
Gonçalves, Vinícius Richieri Manso; Çaha, Ihsan; Alves, Alexandra Manuela Vieira Cruz Pinto; Toptan, Fatih; Rocha, Luís AugustoNovel in-situ Ti-based matrix composites (TMCs) were developed through the reactive hot pressing of Ti + NbC powder blends. Due to the chemical reaction that occurred in the solid-state during processing, the produced samples were composed of an Nb-rich β-Ti phase that formed a metallic matrix along with Ti<sub>2</sub>C as a reinforcing phase. By employing different proportions of Ti:NbC, the phase composition ...
Influence of calcium acetate concentration in electrolyte on tribocorrosion beh...
Sousa, Luís; Mendes, Ana Rita; Pinto, A. M. P.; Toptan, Fatih; Alves, Alexandra Manuela Vieira Cruz PintoTi-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 bioactiv...
Corrosion and tribocorrosion behaviour of Ti-B4C composites processed by conven...
Sousa, L.; Alves, Alexandra Manuela Vieira Cruz Pinto; Guedes, A.; Toptan, FatihIn this work, low volume reinforcement ex-situ Ti-B4C composites were produced using two different routes: conventional powder metallurgy (PM) and hot-pressing (HP). The effect of reinforcement phases and processing method on corrosion and tribocorrosion behaviour were studied. Composites processed by PM lost the typical passive behaviour of Ti matrix, while composites processed by HP presented similar behaviou...
Electrochemical response of Ti joints vacuum brazed with TiCuNi, AgCu, and Ag f...
Marinho, C.; Toptan, Fatih; Guedes, A.; Alves, Alexandra Manuela Vieira Cruz PintoThe properties of the joints are dictated by the nature, distribution, and morphology of the phases formed at the interface. The mechanical properties of brazed joints are well documented in the literature, contrarily to their electrochemical behaviour. Thus, the main objective of this study was to understand the influence of the phases formed at the interface on the corrosion behaviour of commercially pure Ti ...
TiO2 bioactive implant surfaces doped with specific amount of Sr modulate miner...
Costa, A. I.; Gemini-Piperni, S.; Alves, Alexandra Manuela Vieira Cruz Pinto; Costa, N. A.; Checca, N. R.; Leite, P. E.; Rocha, L. A.; Pinto, A. M. P.One of the main problems that remain in the implant industry is poor osseointegration due to bioinertness of implants. In order to promote bioactivity, calcium (Ca), phosphorus (P) and strontium (Sr) were incorporated into a TiO2 porous layer produced by micro-arc oxidation. Ca and P as bioactive elements are already well reported in the literature, however, the knowledge of the effect of Sr is still limited. I...
Interactions between wear and corrosion on cast and sintered Ti-12Nb alloy in c...
Caha, Ihsan; Alves, Alexandra Manuela Vieira Cruz Pinto; Chirico, C.; Tsipas, S. A.; Rodrigues, I. R.; Pinto, A. M. P.; Grandini, C. R.; Rocha, L. A.This work investigates the corrosion and tribocorrosion behavior of alpha + beta Ti-12Nb alloy processed by casting and sintering, in 9 g/l NaCl solution at body temperature, and compares the results with the commercial Ti-6Al-4 V alloy. Different electrochemical techniques were used to access the corrosion behavior. Tribocorrosion behavior was studied at open circuit potential under continuous and intermittent...
Effect of bio-functional MAO layers on the electrochemical behaviour of highly ...
Alves, Alexandra Manuela Vieira Cruz Pinto; Costa, A., I; Toptan, Fatih; Alves, J. L.; Leonor, I. B.; Ribeiro, E.; Reis, R. L.; Pinto, A. M. P.Ti foams are attractive for orthopaedic applications due to reduced Young's modulus and ability of bone ingrowth. However, poor corrosion behaviour and lack of bioactivity are yet to be overcome. In the present work, highly porous Ti samples were processed by powder metallurgy with space holder technique and bio-functionalized by micro-arc oxidation, resulting in nano/micro structured TiO2 surfaces containing b...
Corrosion and tribocorrosion behavior of Ti-40Nb and Ti-25Nb-5Fe alloys process...
Caha, Ihsan; Alves, Alexandra Manuela Vieira Cruz Pinto; Chirico, Caterina; Pinto, A. M. P.; Tsipas, Sophia; Gordo, Elena; Toptan, FatihThe requirement of good mechanical properties, lower Young's modulus, superior corrosion resistance, and excellent biocompatibility makes beta-type titanium alloys attractive materials for orthopedic implants. In this study, Ti-25Nb-5Fe and Ti-40Nb beta-type titanium alloys were designed and produced by powder metallurgy route using titanium hydride, niobium, and iron powders. The effect of sintering conditions...
Degradation behavior of Ti-Nb alloys: Corrosion behavior through 21 days of imm...
Caha, Ihsan; Alves, Alexandra Manuela Vieira Cruz Pinto; Kuroda, P. A. B.; Grandini, C. R.; Pinto, A. M. P.; Rocha, L. A.; Toptan, FatihNon-toxic and allergic free beta-type Ti alloys are attractive metallic implant materials due to their lower Young's modulus and good biocompatibility, but the corrosion and tribocorrosion behavior are yet to be fully understood. In this study, corrosion behavior of Ti-15Nb and Ti-40Nb alloys was investigated and compared with the commercial Ti-6Al-4V alloy through an immersion period of 21 days. The tribocorro...