104,742 research outputs found
Influence of Atmospheric Humidity and Grain Size on the Friction and Wear of High Nitrogen Austenitic Stainless Steel
No full textWear resistance of fine-grained high nitrogen austenitic stainless steel coated with amorphous carbon films: The soft X-ray spectroscopy approach
No full textThe wear resistance dependence on grain size of a high-nitrogen-alloyed austenitic stainless steels (HN) is investigated and compared to measurements for the same samples coated with amorphous carbon (a-C : H) and nitrogenated amorphous carbon (a-C : H(N)) films, deposited by means of plasma-enhanced chemical vapour deposition. A synergic effect between the grain re. ning and the film in the case of nitride amorphous carbon overcoats is observed in terms of increased low-friction performance duration. The temperature dependence of the wear resistance of a micro crystalline HN stainless steel coated with carbon films is also investigated. An overall decrease of the films' wear resistance is found with increasing temperature. Furthermore, a higher wear resistance is found in the a-C : H coated steel with respect to the a-C : H: N material. High-lateral-resolution photoemission microscopy reveals that inhomogeneities within the film after wear testing are correlated to an increase of the number of N-sp(2) C-bonded sites. The study of energy-distribution curves and high-lateral-resolution images on the nitrogenated samples shows that a modi. cation of the surface chemistry occurs by mechanical action; in particular this implies that existing N-sp(2) C sites are beginning to cluster as temperature increases. RI Valentini, Luca/D-5238-2011; Kenny, Jose/F-9372-201
Spectroscopic analysis of the structure of amorphous nitrogenated carbon films after wear tests
No full textThe effects of wear tests on the electronic structure of amorphous nitrogenated carbon (a-C:H:N) films prepared in a radiofrequency plasma-enhanced chemical vapor deposition system from a mixture of methane and nitrogen have been investigated. The tribological properties were investigated with a tribometer in a ball-on-disk configuration. For different N-2 fractions, film structure and chemical composition were examined using conventional Raman and X-ray photoelectron spectroscopy, and also by means of high-lateral-resolution soft X-ray photoemission microscopy using synchrotron radiation. Nitrogen incorporation into the as-deposited amorphous carbon network results in an increase in the number of N-sp(2)-C bonded sites with respect to the films grown in a nitrogen-free atmosphere. The wear stability of the films was analyzed as a function of the nitrogen fraction, and a thorough description of the electronic structure was obtained in the as-deposited state and after wear testing. High-lateral-resolution photoemission microscopy reveals for the first time that inhomogeneities within the film after wear testing are correlated to nitrogen incorporation. The study of energy distribution curves and high-lateral-resolution images on the nitrogenated samples shows that a modification of the surface chemistry occurs by mechanical action. (C) 2002 Elsevier Science B.V. All rights reserved. RI Valentini, Luca/D-5238-2011; Kenny, Jose/F-9372-201
Influence of grain size and film composition on wear resistance of ultra fine AISI 304 stainless steel coated with amorphous carbon films
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Microtribological investigations on fluorocarbon thin films deposited in continuous and modulated C2F4 RF glow discharges
No full textWear Resistance of a High Nitrogen Austenitic Stainless Steel Coated with Amorphous Carbon Films: Influence of Grain Size and Film Composition
No full textEffect of load range, relative humidity and grain size on the microfriction behaviour of AISI 304 austenitic stainless steel
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