Adjustment of wear particle size distribution . of DLC coatings for tribological metal‐on‐metal pairing in artificial hip joints

Abstract

The term DLC (diamond-like carbon) describes a whole class of different biocompatible materials based on amorphous carbon. One possible application for DLC is the coating of artificial hip joints to increase their life expectancy. The life expectancy of artificial hip joints is limited by osteolysis caused by wear particles, especially by wear particles in a range from 0.3 lm to 10 lm. In this study, biocompatible steel substrates are coated with DLC. Coatings with different structure are produced and investigated regarding their wear behavior. The aim is to influence the wear particle size distribution. To improve the adhesion of the coatings on the substrate, metallic interface layers are deposited by cathodic vacuum arc deposition, comparing chromium and titanium as interface layer material. The DLC-coatings are deposited by a vacuum arc that allows a transition from cathodic to anodic operation mode.It is shown, that by varying the deposition process parameters and thus by variation of the film properties, the wear particle size distribution can be adjusted significantly. Es konnte gezeigt werden, dass durch Variation der Parameter beim Abscheiden die Größe der Abriebpartikel gezielt beeinflusst werden kann. Dem Ziel, Abriebpartikel kleiner als 0.3 lm zu erhalten, wurde bedeutend näher gekommen.

In Vitro and In Vivo Evaluation of Toxicity of Structurally Different Diamond-Like Carbon Wear Debris in Joint Replacements

“…It suggests that the DWPs has an irregular shape and a nanosize (around 20−100 nm) after wear or grinding, which is also similar to the size of the DWPs after wear test in the other researchers' results. 36,44 Figure 1 also presents an electron diffraction pattern of the DWPs, revealing their amorphous structure after both preparation methods. These results demonstrate that DWPs after grinding have similar size and shape to the real wear debris in the human body.…”

Bioceramic Materials

“…Such materials could be based, for example, on the quaternary system CaO -P 2 O 5 -TiO 2 -ZrO 2 (Schneider et al ., 2001 ;Heimann, 2006 ; see Section 10.5.2.3 ), in which stoichiometric compositions exist with much -improved mechanical and chemical stabilities compared to the calcium phosphates. Finally, developments are under way to improve the wear resistance of ceramic femoral heads by the application of ultrahard coatings, for example, diamond -like carbon ( DLC ) or TiN coatings that not only improve the mechanical abrasion wear resistance of the ceramic when articulating against the PE -UHMW -lined acetabular cup, but also reduce the coeffi cient of friction (Affatato et al ., 2000 ;Reuter et al , 2006 ;Stamm et al , 2008 ). These are currently being designed to mimic the mechanical and biological performances of natural bone; examples include composites of PLA and HAp, as well as of collagen and HAP.…”

Dose-dependent cytotoxicity evaluation of graphite nanoparticles for diamond-like carbon film application on artificial joints

“…There is a wide size range of DLC debris after wear, from the nanometer to the micrometer scale [14,15]. In vivo or simulated body fluid, DLC wear debris would be generated as μm scale [16,17]. For DLC wear in air conditions, if the DLC coating was firmly adhered on the substrate and there was not any DLC delamination, DLC wear debris were of a nanoscale after wear [15].…”