ISSN:
0142-2421
Schlagwort(e):
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Physik
Notizen:
The corrosion behaviour of orthopaedic metal implants was studied in an animal experiment in which 30 rabbits had stainless steel plates implanted after a varization osteotomy of the tibiae of their hind legs for one year. ESCA was used for the investigation of the surfaces of the inplants. The removed plates were covered by an easily destroyable 3-5 nm thick oxidic layer which contained Cr(III), Fe(II), Fe(III), Mo(VI) and Mo(IV), but no Ni. This passive layer (and possibly also the nearest metal layer below it) is strongly enriched in Cr. Additionally, corrosion experiments with radioactivated implants in Ringer's solution demonstrated that the passivation of the stainless steel is accompanied by marked selective solution of the steel constituents. The observed solubilities (Co 〉 Ni 〉 Fe 〉 Mo 〉 Cr) are inversely correlated with the abundance of the respective element in the passive layer. The trace element composition of the tissues was measured by instrumental neutron activation analysis. It turned out that the actual burdening of the tissues surrounding the implants by corrosion products is exhibited by strong enrichments of the elements Cr, Fe, Co, Ni and Mo relative to their normal concentrations. While Cr, Co, Ni and Mo are abundant in fairly constant ratios in the contact tissues, the excess of Fe is influenced by biological regulation mechanisms. The extent to which the distribution patterns of steel-specific elements in animal (and human) tissues can be explained by the dissolution of the steel during the passivation process is discussed.
Zusätzliches Material:
6 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/sia.740030304
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