On Interlayer Stability and High-Cycle Simulator Performance of Diamond-Like Carbon Layers for ArticulatingJoint Replacements

International Journal of Molecular Sciences

Götz Thorwarth¹  Renato Figi²  Bernhard Weisse²  Michael Stiefel²  Kerstin Thorwarth²  Roland Hauert² 

[1] DePuy Synthes Companies of Johnson & Johnson, Luzernstrasse 21, 4528 Zuchwil, Switzerland;Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland;

关键词: diamond-like carbon;    biomedical implants;    adhesion;    simulator testing;    wear;    coating;    tantalum interlayer;   

DOI  :  10.3390/ijms150610527

来源: DOAJ

【 摘 要 】

Diamond like carbon (DLC) coatings have been proven to be an excellent choice for wear reduction in many technical applications. However, for successful adaption to the orthopaedic field, layer performance, stability and adhesion in physiologically relevant setups are crucial and not consistently investigated. In vitro wear testing as well as adequate corrosion tests of interfaces and interlayers are of great importance to verify the long term stability of DLC coated load bearing implants in the human body. DLC coatings were deposited on articulating lumbar spinal disks made of CoCr28Mo6 biomedical implant alloy using a plasma-activated chemical vapor deposition (PACVD) process. As an adhesion promoting interlayer, tantalum films were deposited by magnetron sputtering. Wear tests of coated and uncoated implants were performed in physiological solution upto a maximum of 101 million articulation cycles with an amplitude of ±2° and −3/+6°in successive intervals at a preload of 1200 N. The implants were characterized by gravimetry, inductively coupled plasma optical emission spectrometry (ICP-OES) and cross section scanning electron microscopy (SEM) analysis. It is shown that DLC coated surfaces with uncontaminated tantalum interlayers perform very well and no corrosive or mechanical failure could be observed. This also holds true in tests featuring overload and third-body wear by cortical bone chips present in the bearing pairs. Regarding the interlayer tolerance towards interlayer contamination (oxygen), limits for initiation of potential failure modes were established. It was found that mechanical failure is the most critical aspect and this mode is hypothetically linked to the α-β tantalum phase switch induced by increasing oxygen levels as observed by X-ray diffraction (XRD). It is concluded that DLC coatings are a feasible candidate for near zero wear articulations on implants, potentially even surpassing the performance of ceramic vs. ceramic.

【 授权许可】

Unknown