Processing and compression testing of Ti6Al4V foams for biomedical applications

2010

Ceramics International

The 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 mm 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 mm in alkali treated foam specimens after 14-day of SBF immersion, while nitric acid treatment induced relatively thinner coating layer, 0.6 mm. #

Section: Foam Preparation and Surface Treatmentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The effect of surface treatment on CaP deposition of Ti6Al4V open cell foams in SBF solution

Türkan

2010

Ceramics International

“…Angular shape ammonium bicarbonate powder (Aldrich) with a particle size range of 315-500 μm was used as a space holder. The details of the Ti6Al4V foam preparation, the microstructure development after sintering and mechanical properties are given elsewhere [3]. Briefly, the green powder compacts, compacted uniaxially at 200 MPa, were heat treated under a high purity (99.998%) Ar flux at 200°C for 2 h to remove the space holder and then at 1300°C for 1 h to sinter Ti6Al4V particles.…”

Section: Foam Preparation and Surface Treatmentmentioning

confidence: 99%

“…The SBF solution for in-vitro tests was prepared according to the protocol given in [19,20] by dissolving the following analytical reagents in 1 L of deionized water: 6.547 g of NaCl, 2.268 g of NaHCO 3 , 0.372 g of KCl, 0.124 g of Na 2 HPO 4 , 0.305 g of MgCl 2 ·6H 2 O, 0.368 g of CaCl 2 ·2H 2 O, 0.071 g of Na 2 SO 4 and 6.057 g of trishydoxmethylaminomethane. The used SBF protocol (1.5 × SBF) was previously shown to coat untreated Ti6Al4V alloy strips with a CaP layer in 7 days [21].…”

Section: Bioactivity and Characterizationmentioning

confidence: 99%

“…In addition, the extent of well-known stress shielding, which causes implant loosening, can be further reduced with the use of a low elastic modulus porous implant structure [2]. Certain implant applications of Ti alloy foams have also been exploited as the spinal inter body fusion cages used in spinal surgery for bone fixation [3,4]. Calcium phosphate (CaP) coating of porous surfaces including Ti mesh [5,6] and the sintered bead surface coatings [7,8] were previously investigated.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The effect of nitric acid surface treatment on CaP deposition of Ti6Al4V open-cell foams in SBF solution

Türkan¹,

Surface and Coatings Technology

2010

Self Cite

The 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.

Open cell lead foams: processing, microstructure, and mechanical properties

Savacı

Yilmaz²,

2012

J Mater Sci

Open cell lead foams with the porosities between 48 and 74 % were prepared by means of powder metallurgical and casting routes, using ammonium bicarbonate particles, silica beads, and sodium chloride salt particles as space holder. The resulting foam samples structure closely resembled open cell foam structure: each cell had few interconnections with neighboring cells. Small-sized lead (II) fluoride precipitates were microscopically observed in the interior of cells in the foam samples prepared using silica beads as space holder, resulting from the reaction between silica and hydrofluoric acid in the space holder dissolution step. The compression stress-strain curve of foam samples prepared by powder metallurgical route showed brittle deformation behavior following the initial elastic deformation region, while the foam samples prepared by casting route showed characteristic foam deformation behavior: cell edge crushing on the bent cell walls, and cell wall tearing. The collapse stresses, densification strains, and elastic moduli of the prepared foams were further fitted with scaling relations.