This title appears in the Scientific Report :
2009
Please use the identifier:
http://dx.doi.org/10.1002/adem.200900168 in citations.
Powder Metallurgical Near-Net-Shape Fabrication of Porous NiTi Shape Memory Alloys for Use as Long-Term Implants by the Combination of the Metal Injection Molding Process with the Space-Holder Technique
Powder Metallurgical Near-Net-Shape Fabrication of Porous NiTi Shape Memory Alloys for Use as Long-Term Implants by the Combination of the Metal Injection Molding Process with the Space-Holder Technique
A new method was developed for producing highly porous NiTi for use as an implant material. The combination of the space-holder technique with the metal injection molding process allows a net-shape fabrication of geometrically complex samples and the possibility of mass production for porous NiTi. F...
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Personal Name(s): | Köhl, M. |
---|---|
Habijan, T. / Bram, M. / Buchkremer, H. P. / Stöver, D. / Köller, M. | |
Contributing Institute: |
Werkstoffsynthese und Herstellungsverfahren; IEF-1 |
Published in: | Advanced engineering materials (2009) S. 959 - 968 |
Imprint: |
Weinheim
Wiley-VCH Verl.
2009
|
Physical Description: |
959 - 968 |
DOI: |
10.1002/adem.200900168 |
Document Type: |
Journal Article |
Research Program: |
Rationelle Energieumwandlung |
Series Title: |
Advanced Engineering Materials
11 |
Subject (ZB): | |
Publikationsportal JuSER |
A new method was developed for producing highly porous NiTi for use as an implant material. The combination of the space-holder technique with the metal injection molding process allows a net-shape fabrication of geometrically complex samples and the possibility of mass production for porous NiTi. Further, the porosity can be easily adjusted with respect to pore size, pore shape, and total porosity. The influence of the surface properties of powder metallurgical NiTi on the biocompatibility was first examined using human mesenchymal stein cells (hMSCs). It was found that pre-alloyed NiTi powders with an average particle size smaller than 45 mu m led to the surface properties most suitable for the adhesion and proliferation of hMSCs. For the production of highly porous NiTi, different space-holder materials were investigated regarding low C- and O-impurity contents and the reproducibility of the process. NaCl was the most promising space-holder material compared to PMMA and saccharose and was used in subsequent studies. In these studies, the influence of the total porosity on the mechanical properties of NiTi is investigated in detail. As a result, bone-like mechanical properties were achieved by the choice of Ni-rich NiTi powder and a space-holder content of 50 vol% with a particle size fraction of 355-500 mu m. Pseudoelasticity of up to 6% was achieved in compression tests at 37 degrees C as well as a bone-like loading stiffness of 6.5 GPa, a sufficient plateau stress sigma(25) of 261 MPa and a value for sigma(50) Of 415 MPa. The first biological tests of the porous NiTi samples produced by this method showed promising results regarding proliferation and ingrowth of mesenchymal stein cells, also in the pores of the implant material. |