Fabrication of titanium scaffolds with porosity and pore size gradients by sequential freeze casting

This paper reports a novel method for producing porous Ti scaffolds with a gradient in porosity and pore size using the freeze casting method, in which TiH2/camphene slurries with various TiH2 contents (40, 25, and 10 vol.%) were cast sequentially into a mold, followed by freeze drying and heat-treatment in a vacuum at 1300 °C for 3 h. This simple sequential freeze casting method produced good bonding between the layers with different porosities of 35, 53, and 75 vol.% obtained using the TiH2 contents of 40, 25 and 10 vol.%, respectively. In addition, the pore size could be increased significantly by increasing the freezing time. The pore sizes obtained in the regions produced using 40, 25, and 10 vol.% TiH2 after freezing for 7 days were 96, 166, and 270 μm, respectively.

[1]  A Tampieri,et al.  Porosity-graded hydroxyapatite ceramics to replace natural bone. , 2001, Biomaterials.

[2]  H. Rack,et al.  Titanium alloys in total joint replacement--a materials science perspective. , 1998, Biomaterials.

[3]  T. J. Kim,et al.  Titanium powder sintering for preparation of a porous functionally graded material destined for orthopaedic implants , 2001, Journal of materials science. Materials in medicine.

[4]  D. Dunand,et al.  Directionally freeze-cast titanium foam with aligned, elongated pores , 2008 .

[5]  Tadashi Kokubo,et al.  Mechanical properties and osteoconductivity of porous bioactive titanium. , 2005, Biomaterials.

[6]  I. G. Turner,et al.  Fabrication of porous bioceramics with porosity gradients similar to the bimodal structure of cortical and cancellous bone , 2007, Journal of materials science. Materials in medicine.

[7]  Maryam Tabrizian,et al.  Three-dimensional growth of differentiating MC3T3-E1 pre-osteoblasts on porous titanium scaffolds. , 2005, Biomaterials.

[8]  Naoyuki Nomura,et al.  Mechanical properties of porous titanium compacts prepared by powder sintering , 2003 .

[9]  Abhay Pandit,et al.  Fabrication methods of porous metals for use in orthopaedic applications. , 2006, Biomaterials.

[10]  Abhay S Pandit,et al.  Porous titanium scaffolds fabricated using a rapid prototyping and powder metallurgy technique. , 2008, Biomaterials.

[11]  Dao-xi Li,et al.  Gradient porosity and large pore size NiTi shape memory alloys , 2007 .

[12]  B. Kieback,et al.  Processing techniques for functionally graded materials , 2003 .

[13]  Clemens A van Blitterswijk,et al.  Bone ingrowth in porous titanium implants produced by 3D fiber deposition. , 2007, Biomaterials.

[14]  Hans Peter Buchkremer,et al.  High-porosity titanium, stainless steel and superalloy parts , 2000 .

[15]  R. Correia,et al.  Titanium scaffolds for osteointegration: mechanical, in vitro and corrosion behaviour , 2008, Journal of materials science. Materials in medicine.

[16]  Hyoun‐Ee Kim,et al.  Aligned porous alumina ceramics with high compressive strengths for bone tissue engineering , 2008 .

[17]  L. Gibson.  Biomechanics of cellular solids. , 2005, Journal of biomechanics.

[18]  Peter Greil,et al.  Mechanical properties and in vitro cell compatibility of hydroxyapatite ceramics with graded pore structure. , 2002, Biomaterials.

[19]  Hyoun‐Ee Kim,et al.  Porous titanium (Ti) scaffolds by freezing TiH2/camphene slurries , 2008 .

[20]  Hyoun‐Ee Kim,et al.  Generation of Large Pore Channels for Bone Tissue Engineering Using Camphene-Based Freeze Casting , 2007 .