Browsing by Author "Bütev Öcal, Ezgi"

Now showing 1 - 2 of 2

Citation - WoS: 66
Citation - Scopus: 66
Comparison of the Short and Long-Term Degradation Behaviors of As-Cast Pure Mg, Az91 and We43 Alloys
(Elsevier Science Sa, 2020) Esen, Ziya; Aydinol, Kadri; Dericioglu, Arcan F.; Ocal, Ezgi Butev; Bütev Öcal, Ezgi
The corrosion behaviors of pure magnesium, AZ91, and WE43 alloys have been evaluated by weight loss, hydrogen evolution rate, pH change measurements and potentiodynamic polarization as well as electrochemical impedance spectroscopy (EIS) methods. Main corrosion product formed on the surface of Mg/Mg-alloys after immersion of 24 h was Mg(OH)(2) on the other hand, at the end of the 20 days additional CaCO3 which was found to display a critical role in degradation characteristics of the samples, was found. Examination in the cross section of the polished surfaces revealed that protective layers became thicker and corrosion rate of the samples decreased possibly due to increased protective abilities of the surfaces. Intermetallics in AZ91 and WE43 alloys acted as cathodic centers and induced micro galvanic corrosion. Undermining of intermetallics in WE43 alloy intensified the corrosion rate. AZ91 alloy exhibited the lowest corrosion rate among the samples when tested in simulated body fluid (SBF).
Effect of alkali treatment parameters on surface structure and mechanical properties of porous Ti6A17NB scaffolds
(2014) Bütev Öcal, Ezgi; Yeni, Elif Eda; Yılmaz, Emre; Esen, Ziya; Bor, Şakir
In the present study, highly porous Ti6Al7Nb alloy scaffolds having 70% pore contents with 200-250 µm average pore size were produced through the spacer holder technique as a result of evaporation of Mg powder from the Ti6Al7Nb-Mg powder mixtures. In order to make the manufactured Ti6Al7Nb foam surfaces more suitable for biomedical applications they were exposed to alkali and heat treatment. Porous samples were immersed in 5M NaOH (aq.) solutions at 60°C for 24 hours then subsequent heat treatment was carried out to obtain crystalline sodium titanate layer. Crystallization heat treatments were also conducted in muffle furnaces to investigate the effect of heat treatment environment on titanate formation. Then, the morphology, structure and chemical composition of the formed titanate layers were characterized by using scanning electron microscopy (SEM) and TF-XRD techniques. According to mechanical testing, produced Ti6Al7Nb alloy foams had elastic moduli and yield strength very close to that of bone which makes them suitable for biomedical application because of the lessened stress shielding problem