Mechanical Engineering / Makina Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4129
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Article Citation - WoS: 2Citation - Scopus: 2Staphylococcus Epidermidis Adhesion on Surface-Treated Open-Cell Ti6al4v Foams(Walter de Gruyter GmbH, 2016) Türkan, Uğur; Güden, Mustafa; Sudağıdan, MertThe effect of alkali and nitric acid surface treatments on the adhesion of Staphylococcus epidermidis to the surface of 60% porous open-cell Ti6Al4V foam was investigated. The resultant surface roughness of foam particles was determined from the ground flat surfaces of thin foam specimens. Alkali treatment formed a porous, rough Na2Ti5O11 surface layer on Ti6Al4V particles, while nitric acid treatment increased the number of undulations on foam flat and particle surfaces, leading to the development of finer surface topographical features. Both surface treatments increased the nanometric-scale surface roughness of particles and the number of bacteria adhering to the surface, while the adhesion was found to be significantly higher in alkali-treated foam sample. The significant increase in the number of bacterial attachment on the alkali-treated sample was attributed to the formation of a highly porous and nanorough Na2Ti5O11 surface layer.Other Corrigendum To ‘‘the Effect of Surface Treatment on Cap Deposition of Ti6al4v Open Cell Foams in Sbf Solution.’’ [ceram. Int. 39 (2010) 1805–1816](Elsevier Ltd., 2011) Türkan, Uğur; Güden, MustafaThe authors regret that they accidentally omitted to refer to Prof. A.C. Tas, who originally found the SBF solution used in the experiments. The corrections to the affected sentences are listed below. ‘‘The SBF solution for in vitro tests was prepared by dissolving the following analytical reagents in 1 L of deionized water: 6.547 g of NaCl, 2.268 g of NaHCO3, 0.372 g of KCl, 0.124 g of Na2HPO4, 0.305 g of MgCl2 6H2O, 0.368 g of CaCl2 2H2O, 0.071 g of Na2SO4 and 6.057 g of trishydoxmethylaminomethane (A.C. Tas)’’. A.C. Tas, Synthesis of biomimetic Ca-hydroxyapatite powders at 37 8C in synthetic body fluids, Biomaterials 21 (14) (2000) 1429–1438.Article Citation - WoS: 10Citation - Scopus: 13The Effect of Nitric Acid Surface Treatment on Cap Deposition of Ti6al4v Open-Cell Foams in Sbf Solution(Elsevier Ltd., 2010) Türkan, Uğur; Güden, MustafaThe effect of nitric acid surface treatment on CaP deposition of an open-cell Ti6Al4V foam (60% porous and 300–500 m in pore size), prepared by means of the space holder method using 94 and 66 μm average particle size powders, was investigated in a simulated body fluid (SBF) solution up to 14 days. Although, nitric acid surface treatment did not change the foam flat surface roughness values significantly, it increased surface area difference greatly by introducing nano scale undulations on the surface. The increased surface area difference was found to be more pronounced in smaller particle size foam samples. A continuous relatively thin CaP coating layer formed after 5 and 14 days of SBF immersion in nitric acid surface treated small and larger average particle size foam specimens, respectively. Whereas, the cells of untreated foam specimen were observed to be filled with CaP precipitates and a continuous CaP layer development was found after 14 days of SBF immersion. These results were also confirmed with the grazing incidence XRD and FTIR analysis of SBF immersed specimens.Article Citation - WoS: 16Citation - Scopus: 16The Effect of Surface Treatment on Cap Deposition of Ti6al4v Open Cell Foams in Sbf Solution(Elsevier Ltd., 2010) Türkan, Uğur; Güden, MustafaThe effects of alkali and nitric acid surface treatment and acid etching on the CaP deposition of an open cell Ti6Al4V foam (60% porous and 300–500 μm in pore size) developed for biomedical applications were investigated in a simulated body fluid (SBF) solution for 14-day. The surface roughness of the foam specimens ground flat surfaces was measured in nano-metric scale before and after SBF immersion using an atomic force microscope (AFM). A significant increase in the surface roughness of alkali treated foam specimen after SBF immersion indicated a smaller crystal size CaP deposition, which was also confirmed by the AFM micrographs. The microscopic evaluation clearly showed that alkali treatment and nitric acid treatment induced a continuous, uniform CaP deposition on the cell wall surfaces of the foam (interior of cells). While in untreated foam specimen the cells are filled with CaP precipitates and acid etching did not produce a continuous coating layer on particles interior of the cells. The coating layer thickness was ∼3 μm in alkali treated foam specimens after 14-day of SBF immersion, while nitric acid treatment induced relatively thinner coating layer, 0.6 μm.Article Citation - WoS: 30Citation - Scopus: 33Processing and Compression Testing of Ti6al4v Foams for Biomedical Applications(Springer Verlag, 2009) Dizlek, Mustafa Eren; Güden, Mustafa; Türkan, Uğur; Taşdemirci, AlperOpen cell Ti6Al4V foams (60% porosity) were prepared at sintering temperatures between 1,200 and 1,350 °C using ammonium bicarbonate particles (315–500 μm) as space holder. The resulting cellular structure of the foams showed bimodal pore size distribution, comprising macropores (300–500 μm) and micropores (1–30 μm). Compression tests have shown that increasing sintering temperature increased the elastic modulus, yield and compressive strength, and failure strain of foams. The improvements in the mechanical properties of foams prepared using smaller size Ti64 powder with bimodal particle distribution were attributed to the increased number of sintering necks and contact areas between the particles. Finally, the strength of foams sintered at 1,350 °C was found to satisfy the strength requirement for cancellous bone replacement.