scholarly journals Amorphous Carbon Coatings for Total Knee Replacements—Part II: Tribological Behavior

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1880 ◽  
Author(s):  
Benedict Rothammer ◽  
Max Marian ◽  
Kevin Neusser ◽  
Marcel Bartz ◽  
Thomas Böhm ◽  
...  
Keyword(s):  
Amorphous Carbon ◽  
Laser Scanning ◽  
Tribological Behavior ◽  
Wear Behavior ◽  
Laser Scanning Microscopy ◽  
Adhesion Properties ◽  
Carbon Coatings ◽  
Knee Replacements ◽  
Total Knee ◽  
Amorphous Carbon Coatings

Diamond-like carbon coatings may decrease implant wear, therefore, they are helping to reduce aseptic loosening and increase service life of total knee arthroplasties (TKAs). This two-part study addresses the development of such coatings for ultrahigh molecular weight polyethylene (UHMWPE) tibial inlays as well as cobalt-chromium-molybdenum (CoCr) and titanium (Ti64) alloy femoral components. While the deposition of a pure (a-C:H) and tungsten-doped hydrogen-containing amorphous carbon coating (a-C:H:W) as well as the detailed characterization of mechanical and adhesion properties were the subject of Part I, the tribological behavior is studied in Part II. Pin-on-disk tests are performed under artificial synovial fluid lubrication. Numerical elastohydrodynamic lubrication modeling is used to show the representability of contact conditions for TKAs and to assess the influence of coatings on lubrication conditions. The wear behavior is characterized by means of light and laser scanning microscopy, Raman spectroscopy, scanning electron microscopy and particle analyses. Although the coating leads to an increase in friction due to the considerably higher roughness, especially the UHMWPE wear is significantly reduced up to a factor of 49% (CoCr) and 77% (Ti64). Thereby, the coating shows continuous wear and no sudden failure or spallation of larger wear particles. This demonstrated the great potential of amorphous carbon coatings for knee replacements.

scholarly journals Amorphous Carbon Coatings for Total Knee Replacements—Part I: Deposition, Cytocompatibility, Chemical and Mechanical Properties

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1952
Author(s):  
Benedict Rothammer ◽  
Kevin Neusser ◽  
Max Marian ◽  
Marcel Bartz ◽  
Sebastian Krauß ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Amorphous Carbon ◽  
Detailed Characterization ◽  
Carbon Coatings ◽  
Dlc Coatings ◽  
Total Knee Replacements ◽  
Knee Replacements ◽  
Total Knee ◽  
Amorphous Carbon Coatings

Diamond-like carbon (DLC) coatings have the potential to reduce implant wear and thus to contribute to avoiding premature failure and increase service life of total knee replacements (TKAs). This two-part study addresses the development of such coatings for ultrahigh molecular weight polyethylene (UHMWPE) tibial inlays as well as cobalt–chromium–molybdenum (CoCr) and titanium (Ti64) alloy femoral components. While a detailed characterization of the tribological behavior is the subject of part II, part I focusses on the deposition of pure (a‑C:H) and tungsten-doped hydrogen-containing amorphous carbon coatings (a‑C:H:W) and the detailed characterization of their chemical, cytological, mechanical and adhesion behavior. The coatings are fabricated by physical vapor deposition (PVD) and display typical DLC morphology and composition, as verified by focused ion beam scanning electron microscopy and Raman spectroscopy. Their roughness is higher than that of the plain substrates. Initial screening with contact angle and surface tension as well as in vitro testing by indirect and direct application indicate favorable cytocompatibility. The DLC coatings feature excellent mechanical properties with a substantial enhancement of indentation hardness and elastic modulus ratios. The adhesion of the coatings as determined in modified scratch tests can be considered as sufficient for the use in TKAs.

Amorphous Carbon Coatings for Locally Adjusted Tribological Properties in Sheet Bulk Metal Forming

2012 ◽  
Vol 504-506 ◽  
pp. 969-974 ◽  
Author(s):  
Harald Hetzner ◽  
Stephan Tremmel ◽  
Sandro Wartzack
Keyword(s):  
Amorphous Carbon ◽  
Tribological Properties ◽  
Metal Forming ◽  
Friction And Wear ◽  
Wear Properties ◽  
Carbon Coatings ◽  
Bulk Metal ◽  
Bulk Metal Forming ◽  
Friction And Wear Properties ◽  
Amorphous Carbon Coatings

In sheet bulk metal forming, locally adapted friction properties of the contact tool/workpiece are an appropriate means for the targeted enhancement of the material flow, enabling an improved form filling and lowered forming forces. However, the implementation of desirable friction conditions is not trivial. And further, friction is inseparably linked to wear and damage of the contacting surfaces. This calls for a methodological approach in order to consider tribology as a whole already in the early phases of process layout, so that tribological measures which allow fulfilling the requirements concerning local friction and wear properties of the tool surfaces, can already be selected during the conceptual design of the forming tools. Thin tribological coatings are an effective way of improving the friction and wear properties of functional surfaces. Metal-modified amorphous carbon coatings, which are still rather new to the field of metal forming, allow tackling friction and wear simultaneously. Unlike many other types of amorphous carbon, they have the mechanical toughness to be used in sheet bulk metal forming, and at the same time their friction properties can be varied over wide ranges by proper choice of the deposition parameters. Based on concrete research results, the mechanical, structural and special tribological properties of tungsten-modified hydrogenated amorphous carbon coatings (a-C:H:W) are presented and discussed against the background of the tribological requirements of a typical sheet bulk metal forming process.

scholarly journals PROPERTIES OF NITROGEN-DOPED AMORPHOUS CARBON COATINGS OBTAINED BY IMPULSE VACUUM-ARC METHOD

2018 ◽  
Vol 59 (9) ◽  
pp. 68 ◽  
Author(s):  
Aleksandr I. Poplavskiy ◽  
Aleksandr Ya. Kolpakov ◽  
Marina E. Galkina ◽  
Igor Yu. Goncharov ◽  
Roman A. Lyubushkin ◽  
...  
Keyword(s):  
Amorphous Carbon ◽  
Carbon Coating ◽  
Vacuum Arc ◽  
Internal Stresses ◽  
Structure And Properties ◽  
Carbon Coatings ◽  
Nitrogen Doped ◽  
Structure Surface ◽  
Amorphous Carbon Coatings ◽  
Carbon Plasma

The paper presents results of the research of the structure and properties of nitrogen-doped amorphous carbon coatings obtained in the vacuum from the flow of pulsed carbon plasma. The doping by nitrogen of carbon coating was determined to lead to increases in electrical conductivity, reductions of internal stresses, reduce of density, hardness and modulus, and to the change in structure, surface morphology and tribological characteristics.

Effects of atomic structure on the frictional properties of amorphous carbon coatings

2015 ◽  
Vol 263 ◽  
pp. 8-14 ◽  
Author(s):  
Longqiu Li ◽  
Wenping Song ◽  
Andrey Ovcharenko ◽  
Ming Xu ◽  
Guangyu Zhang
Keyword(s):  
Amorphous Carbon ◽  
Atomic Structure ◽  
Carbon Coatings ◽  
Frictional Properties ◽  
Amorphous Carbon Coatings

Origin of temperature-induced low friction of sputtered Si-containing amorphous carbon coatings

2015 ◽  
Vol 82 ◽  
pp. 437-446 ◽  
Author(s):  
O. Jantschner ◽  
S.K. Field ◽  
D. Holec ◽  
A. Fian ◽  
D. Music ◽  
...  
Keyword(s):  
Amorphous Carbon ◽  
Low Friction ◽  
Carbon Coatings ◽  
Amorphous Carbon Coatings
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