Production and characterization of surface treated biomedical Ti6Al7Nb alloy foams /

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2015
Bütev, Ezgi
The current study was undertaken to investigate the production and surface processing of biomedical Ti6Al7Nb alloy foams. Space holder method was utilized to manufacture foams with varying porosities around 53.0-73.0 vol. % via evaporation of magnesium from compacted Ti6Al7Nb-Mg powder mixtures. Bioactivities of foam surfaces were further enhanced by obtaining sodium rich phases using NaOH alkali-heat treatment method. Moreover, untreated and surface treated foams were tested in simulated body fluid (SBF) in order to investigate the apatite formation and compare the bioactivities of the surfaces. It has been observed that Ti6Al7Nb alloy foams with average pore size of 200 μm can be considered as suitable materials for biomedical applications due to their mostly interconnected open porous structures. Quasi-static compression tests showed that stress-shielding problem may be alleviated by use of foams having porosities in the range 63.0-73.0 vol. % because of their elastic moduli close to that of bone. The relation between mechanical properties and macro porosity contents of foams was observed to obey power law relation in which the proportionality constant and the exponent reflected the structure and properties of micro porous cell walls and macropore character of foams. Heat treatment of foams at 600 oC, subsequent to immersion in 5 M NaOH solution at 60 oC, provided transformation of sodium titanate hydrogel, NaxH2-xTiyO2y+1.nH2O, layer into more stable sodium titanate, Na2TiyO2y+1, phase. NaOH alkali-heat treated surfaces allowed hydroxyapatite, Ca10(PO4)6(OH)2, formation in shorter time and exhibited superior bioactivities during SBF tests.
Citation Formats
E. Bütev, “Production and characterization of surface treated biomedical Ti6Al7Nb alloy foams /,” M.S. - Master of Science, Middle East Technical University, 2015.