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- Zocco, A., et al.
(författare)
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Mechanical and tribological properties of CNx films deposited by reactive pulsed laser ablation
- 2002
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Ingår i: Diamond and related materials. - 0925-9635 .- 1879-0062. ; 11:1, s. 98-104
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Tidskriftsartikel (refereegranskat)abstract
- We report the tribological, mechanical, structural and compositional characteristics of CNx films deposited by excimer laser (XeCl, ? = 308 nm, TFWHM = 30 ns) ablation of a graphite target in N2 atmosphere. The influence of growth conditions on structural, morphological, tribological and mechanical properties of the CNx films has been examined by X-ray Photoelectron Spectroscopy (XPS), Transmission and Scanning Electron Microscopy (TEM and SEM, respectively), nanoindentation measurements and ball-on-disk tests. All the as-deposited films have a microstructure consisting of nanometer-sized graphitic clusters in an amorphous matrix. The stresses of the films are tensile or compressive depending on the deposition conditions. Friction coefficients of the films, deduced by high speed steel balls, increase with laser fluence and nitrogen pressure from 0.12 to 0.14. Friction is thus, lower than what has been reported in literature for CNx films. © 2002 Elsevier Science B.V. All rights reserved.
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| 2. |
- Broitman, E., et al.
(författare)
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Carbon nitride films on orthopedic substrates
- 2000
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Ingår i: Diamond and related materials. - 0925-9635 .- 1879-0062. ; 9:12, s. 1984-1991
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Tidskriftsartikel (refereegranskat)abstract
- The mechanical and tribological properties of carbon nitride (CN(X)) films deposited on orthopedic substrates are presented. CN(X) films were prepared by d.c. reactive magnetron sputtering from a graphite target in N2/Ar plasma. Films were grown on Ni and ZrO2 substrates to a thickness of ~1 µm at a total pressure of 3 mtorr and a substrate temperature of 250°C. High-resolution transmission electron microscopy (HRTEM) shows dense and homogeneous films, with 'fullerene-like' micro-structures consisting of curved, frequently intersecting, and highly in-plane oriented basal lattice planes. Nanoindentation measurements revealed a change in the mechanical properties of films treated with three different biological solutions. Spectroscopic analysis confirmed a change in the chemical structure of the treated films. The friction coefficients of CN(X) films against high speed steel (HSS), ZrO2 and Ultra-High Molecular Weight Polyethylene (UHMWPE) balls were evaluated by ball-on-disk tests in dry and lubricated conditions. In the case of dry sliding against a HSS ball, the steady state friction coefficient values are 0.22 for the film on the Ti substrate and 0.26 for the film on the ZrO2 substrate. The friction coefficients under human serum lubrication conditions were below 0.18 for the ZrO2 and UHMWPE balls. An increase in wettability of human plasma on CN(X) films was observed compared to the orthopedic surfaces, which could enhance the retention of synovial fluid on those surfaces, improving the lubrication of the bearings of total joint arthroplasty components during function. (C) 2000 Elsevier Science B.V. All rights reserved.The mechanical and tribological properties of carbon nitride (CNX) films deposited on orthopedic substrates are presented. CNX films were prepared by d.c. reactive magnetron sputtering from a graphite target in N2/Ar plasma. Films were grown on Ni and ZrO2 substrates to a thickness of approximately 1 µm at a total pressure of 3 mtorr and a substrate temperature of 250 °C. High-resolution transmission electron microscopy (HRTEM) shows dense and homogeneous films, with `fullerene-like' microstructures consisting of curved, frequently intersecting, and highly in-plane oriented basal lattice planes. Nanoindentation measurements revealed a change in the mechanical properties of films treated with three different biological solutions. Spectroscopic analysis confirmed a change in the chemical structure of the treated films. The friction coefficients of CNX films against high speed steel (HSS), ZrO2 and Ultra-High Molecular Weight Polyethylene (UHMWPE) balls were evaluated by ball-on-disk tests in dry and lubricated conditions. In the case of dry sliding against a HSS ball, the steady state friction coefficient values are 0.22 for the film on the Ti substrate and 0.26 for the film on the ZrO2 substrate. The friction coefficients under human serum lubrication conditions were below 0.18 for the ZrO2 and UHMWPE balls. An increase in wettability of human plasma on CNX films was observed compared to the orthopedic surfaces, which could enhance the retention of synovial fluid on those surfaces, improving the lubrication of the bearings of total joint arthroplasty components during function.
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