title: Tantalum as a buffer layer in diamond-like carbon coated artificial hip joints.
abstract: The acid resistance of tantalum coated and uncoated human hip joint prostheses was studied with commercial CrCoMo acetabular cups. The samples were exposed to 10% HCl solution and the quantities of dissolved Cr, Co, and Mo were measured with proton-induced X-ray emission (PIXE). The absolute quantities were obtained with the use of Cr and Se solution standards. Tantalum coatings (thicknesses 4-6 microm) were prepared in vacuum with magnetron sputtering. Tantalum coating decreased the corrosion rate by a factor of 10(6). As a spinoff from recent wear tests on artificial hip joints it was shown that tantalum has excellent mechanical properties as an intermediate layer of diamond-like carbon (DLC) coatings. When tantalum was tested together with DLC on three metal-on-metal hip joint pairs in a hip simulator, no observable defects occurred during 15 million walking cycles with a periodic 50-300-kg load (Paul curve).
authors.affiliation: Department of Physical Sciences, University of Helsinki, P. O. Box 64, FIN-00014, University of Helsinki, Finland. mirjami.kiuru@helsinki.fi
authors.forename: Mirjami
authors.initials: M
authors.lastname: Kiuru
authors.forename: Esa
authors.initials: E
authors.lastname: Alakoski
authors.forename: Veli-Matti
authors.initials: VM
authors.lastname: Tiainen
authors.forename: Reijo
authors.initials: R
authors.lastname: Lappalainen
authors.forename: Asko
authors.initials: A
authors.lastname: Anttila
mesh_terms: D000143:Acids; D001672:Biocompatible Materials; D001696:Biomechanical Phenomena; D002244:Carbon; D003343:Corrosion; D018130:Diamond; D019544:Equipment Failure Analysis; D006622:Hip Prosthesis; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D011474:Prosthesis Design; D012107:Research Design; D013499:Surface Properties; D013635:Tantalum
chemical_list: D000143:Acids; D001672:Biocompatible Materials; D013635:Tantalum; D002244:Carbon; D018130:Diamond