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Preliminary tribological evaluation of nanostructured diamond coatings against ultra‐high molecular weight polyethylene
Author(s) -
Hill Michael R.,
Catledge Shane A.,
Konovalov Valeriy,
Clem William C.,
Chowdhury Shafiul A.,
Etheridge Brandon S.,
Stanishevsky Andrei,
Lemons Jack E.,
Vohra Yogesh K.,
Eberhardt Alan W.
Publication year - 2008
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.30926
Subject(s) - polyethylene , materials science , nanoindentation , composite material , contact angle , diamond , wetting , scanning electron microscope , raman spectroscopy , surface roughness , tribology , optics , physics
Background: Some loss of joint prostheses has been attributed to osteolytic loosening associated with debris from wear of polyethylene articulating against metal alloys. Reduced polyethylene wear has been reported with ceramics serving as an alternative counterface. Methods: Nanostructured Diamond (NSD) coatings were deposited onto Ti6Al4V by microwave plasma‐assisted chemical vapor deposition, with both hydrogen‐rich (H‐NSD) and helium‐rich (He‐NSD) feedgas mixtures. Pin‐on‐disk wear tests of polyethylene against NSD and CoCr were performed in serum lubrication at body temperature. Scanning electron microscopy was used to examine surface morphology, and nanoindentation was used to determine hardness and modulus of the polyethylene wear surfaces. Raman spectroscopy, surface roughness, and wettability analyses of the NSD coatings were performed. Results: Raman spectroscopy confirmed sp 2 and sp 3 bonded carbon in the NSD coatings. No significant differences in wear factors were found between polyethylene on H‐NSD, He‐NSD, and CoCr, despite higher roughness and friction coefficients for the He‐NSD and H‐NSD coatings, compared with CoCr. Contact angles for the diamond coatings were reduced following the wear tests, indicating that these surfaces became more hydrophilic. Numerous small protuberances were observed on pins articulated against CoCr, and a single, large protuberance was observed in polyethylene‐on‐NSD. These features were conjectured to be reconsolidated polyethylene particles. Nanoindentation modulus and hardness of the worn polyethylene surfaces were lower for polyethylene‐on‐diamond than for polyethylene‐on‐CoCr. Conclusions: As a counterface to polyethylene, NSD‐coated Ti6Al4V produced wear factors comparable to CoCr in the present pin‐on‐disk tests, a promising step towards its use in joint replacement bearing applications. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008