CORROSION AND LEACHING OF SILVER-DOPED CERAMIC IBAD COATINGS ON SS 316L UNDER SIMULATED PHYSIOLOGICAL CONDITIONS

In order to improve the biomedical applications of stainless steel AIS I 316L, commonly used for medical implants, ceramic coatings in combin ation with a thin (50 nm) silver layer on the outermost part of the ce ramic coating were deposited by IBAD lion beam assisted deposition). T he interference of the bactericidal silver layer with the insulating p roperties of the ceramic coating was of special interest. As corrosion protection coatings for SS 316L, different ceramic materials, Al2O3, TiO2, SiO2 and ZrO2, were deposited by IBAD. They were chosen because of their already known bioinert or bioactive properties. In addition, investigations were performed to determine the most effective minimal thickness of the ceramic coatings. To achieve bactericidal properties, the top layer (50-150 nm) of the ceramic coatings was doped with silv er simultaneously with the deposition of the outermost part of the coa ting. Interesting differences occurred during the corrosion evaluation s of the pure ceramic coating in comparison with the silver doped cera mic coatings. The electrochemical corrosion tests were done by potenti odynamic current density and by chronoamperometric measurements under simulated physiological conditions. Leaching tests of the silver doped ceramic coatings were performed in human plasma to determine the amou nt of dissolved silver. The quantification of the dissolved silver in human plasma was done by using solid sample graphite furnace atomic ab sorption spectroscopy. The amount of doped silver was determined by Au ger depth profiles. During the evaluations, the pure and silver doped ZrO2 coating had the best performance of the investigated coatings, fo llowed by the pure and silver doped TiO2 coatings. (C) 1998 Elsevier S cience S.A.