http://www.cnr.it/ontology/cnr/individuo/prodotto/ID120214

Silicon nitride ceramics for bio-structural applications (Comunicazione a convegno)

Type

Prodotto della ricerca (Classe)
Comunicazione a convegno (Classe)

Label

Silicon nitride ceramics for bio-structural applications (Comunicazione a convegno) (literal)

Anno

2009-01-01T00:00:00+01:00 (literal)

Alternative label

Bellosi A. (2009)
Silicon nitride ceramics for bio-structural applications
in 6th International Conference on Nitrides and Related Materials, Karlsruhe, Germany
(literal)

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Bellosi A. (literal)

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In: ISNT 2009 - 6th International Conference on Nitrides and Related Materials (Karlsruhe, Germany, 5-18 March 2009). (literal)

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Notwithstanding the good combination of mechanical and tribological properties, the suitability of silicon nitride for application as prosthesis in bone substitution is still controversial. This study aims to design and produce different silicon nitride-based ceramics. (two monolithics 90.0 vol% Si3N4 + 10.0 vol% bioglass, and 91.3vol%Si3N4 + 8.7vol%MgO, and a composite 65.0 vol% (93wt% Si3N4 + 2 wt%Al2O3+5wt%Y2O3) + 35.0vol%TiN ) and to test the materials. Besides microstructure and mechanical properties, several properties critical to biomedical applications were examined: citotoxicity, wetting behaviour and chemical stability against aqueous media (including SBF), wear performance under conditions simulating the ones typical of the hip joint prosthesis. The main features are the followings: i) the three ceramics exhibit non-toxic behaviour; ii) the contact angles of water, physiological solution and bovine serum are quite low in any case, also compared to oxide ceramics like alumina and zirconia. iii) in water and physiological solutions the surface modification is very low in the two monolithic silicon nitrides. The composite Si3N4-TiN evidence a limited oxidation of TiN and a very scarce dissolution of the grain boundary phases. vi) tribological tests evidence very low and constant friction coefficients for the two monolithic ceramics (about 0.1) while in the Si3N4-TiN composite it increases to about 0.14. The surface modification and wear tracks are not detectable in the monolithic silicon nitrides, while in the Si3 N4-TiN composite a preferential removal of grain boundary phases was observed, associated with a slight oxidation of TiN and material removal by friction. In any case the friction coefficients are lower than results shown in literature and the wear resistance is order of magnitude higher than those reported for other ceramics used for hip joints. Preliminary results of in-vitro tests are presented. Examples of complex shaped components (prostheses (literal)

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