Porous stainless steel for biomedical applications

Porous stainless steel for biomedical applications

Author Mariotto, Sabrina de Fátima Ferreira Google Scholar
Guido, Vanessa Google Scholar
Yao Cho, Liu Google Scholar
Soares, Cristina Pacheco Google Scholar
Cardoso, Kátia Regina Autor UNIFESP Google Scholar
Institution Universidade do Vale do Paraíba Instituto de Pesquisa e Desenvolvimento
Universidade Federal de São Paulo (UNIFESP)
Abstract Porous 316L austenitic stainless steel was synthesized by powder metallurgy with relative density of 0.50 and 0.30 using 15 and 30 wt. (%) respectively of ammonium carbonate and ammonium bicarbonate as foaming agents. The powders were mixed in a planetary ball mill at 60 rpm for 10 minutes. The samples were uniaxially pressed at 287 MPa and subsequently vacuum heat treated in two stages, the first one at 200 ºC for 5 hours to decompose the carbonate and the second one at 1150 ºC for 2 hours to sinter the steel. The sintered samples had a close porous structure and a multimodal pore size distribution that varied with the foaming agent and its concentration. The samples obtained by addition of 30 wt. (%) of foaming agents had a more homogeneous porous structure than that obtained with 15 wt. (%). The MTT cytotoxicity test (3-[4,5-dimethylthiazol]-2,5-diphenyltetrazolium bromide) was used to evaluate the mitochondrial activity of L929 cells with samples for periods of 24, 48, and 72 hours. The cytotoxicity test showed that the steel foams were not toxic to fibroblast culture. The sample with the best cellular growth, therefore the most suitable for biomedical applications among those studied in this work, was produced with 30 wt. (%) ammonium carbonate. In this sample, cell development was observed after 48 hours of incubation, and there was adhesion and spreading on the material after 72 hours. Electrochemical experiments using a chloride-containing medium were performed on steel foams and compared to massive steel. The massive steel had a better corrosion performance than the foams as the porosity contributes to increase the surface area exposed to the corrosive medium.
Keywords stainless steel
cellular solids
powder metallurgy
Language English
Date 2011-01-01
Published in Materials Research. ABM, ABC, ABPol, v. 14, n. 2, p. 146-154, 2011.
ISSN 1516-1439 (Sherpa/Romeo, impact factor)
Publisher ABM, ABC, ABPol
Extent 146-154
Origin http://dx.doi.org/10.1590/S1516-14392011005000021
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000292723200003
SciELO ID S1516-14392011000200003 (statistics in SciELO)
URI http://repositorio.unifesp.br/handle/11600/6195

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