Shape-memory NiTi foams produced by replication of NaCl space-holders

A. Bansiddhi*, D. C. Dunand

*Corresponding author for this work

Research output: Contribution to journalArticle

145 Scopus citations

Abstract

NiTi foams were created with a structure (32-36% open pores 70-400 μm in size) and mechanical properties (4-25 GPa stiffness, >1000 MPa compressive strength, >42% compressive ductility, and shape-memory strains up to 4%) useful for bone implant applications. A mixture of NiTi and NaCl powders was hot-isostatically pressed at 950 and 1065 °C and the NaCl phase was then dissolved in water. The resulting NiTi foams show interconnected pores that replicate the shape and size of the NaCl powders, indicating that NiTi powders densified significantly before NaCl melted at 801 °C. Densifying NiTi or other metal powders above the melting point of the space-holder permits the use of NaCl, with the following advantages compared with higher-melting, solid space-holders such as oxides and fluorides used to date: (i) no temperature limit for densification; (ii) lower cost; (iii) greater flexibility in powder (and thus pore) shape; (iv) faster dissolution; (v) reduced metal corrosion during dissolution; (vi) lower toxicity if space-holder residues remain in the foam.

Original languageEnglish (US)
Pages (from-to)1996-2007
Number of pages12
JournalActa Biomaterialia
Volume4
Issue number6
DOIs
StatePublished - Nov 1 2008

Keywords

  • Bone replacement
  • Hot isostatic pressing
  • Nitinol
  • Porous
  • Sodium chloride

ASJC Scopus subject areas

  • Biotechnology
  • Biomaterials
  • Biochemistry
  • Biomedical Engineering
  • Molecular Biology

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