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- Dalibon, Eugenia L., et al.
(författare)
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Carbon Based Coatings Deposited on Nitrided Stainless Steel: Study of Thermal Degradation
- 2017
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Ingår i: PROCEEDINGS OF THE 3RD PAN AMERICAN MATERIALS CONGRESS. - Cham : SPRINGER INTERNATIONAL PUBLISHING AG. - 9783319521329 - 9783319521312 ; , s. 57-66
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Konferensbidrag (refereegranskat)abstract
- Amorphous hydrogenated carbon (DLC) coatings have a high hardness depending on the relative amount of sp(3)/sp(2) bondings. They also exhibit an extremely low friction coefficient and are chemically inert. However, these coatings have some disadvantages which limit their applications. For instance, adhesion is poor when they are deposited on metallic substrates and they are also unstable at high temperatures, degrading into graphite and loosing hardness. In this work, DLC coatings were deposited on precipitation hardening stainless steel (PH Corrax) which was plasma nitrided before the coating deposition. The samples were submitted to annealing treatments for an hour at different temperatures from 200 to 600 degrees C, together with a control group, which was only coated but not nitrided. After each annealing cycle, Raman Spectroscopy, nanoindentation and microscopy were used to check film properties. It was demonstrated that the nitriding pre treatment improved not only adhesion but also the thermal stability of the DLC, slowing degradation and preventing delamination.
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| 2. |
- Dalibon, Eugenia. L., et al.
(författare)
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Characterization of DLC coatings over nitrided stainless steel with and without nitriding pre-treatment using annealing cycles
- 2019
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Ingår i: JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMRandT. - : ELSEVIER SCIENCE BV. - 2238-7854. ; 8:2, s. 1653-1662
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Tidskriftsartikel (refereegranskat)abstract
- Amorphous hydrogenated diamond-like carbon (DLC) coatings were deposited using plasma assisted chemical vapour deposition (PACVD) on precipitation hardening (PH) stainless steel.Plasma nitriding has been used as pre-treatment to enhance adhesion and mechanical properties. Chemical and mechanical properties of DLC coatings are dependent on the hydrogen content and so on the relation between sp(3)/sp(2) bondings. The bondings and the structure of the DLC film change with temperature. In this work, a study of the thermal degradation and the evolution of the mechanical properties of DLC coatings over PH stainless steel have been carried out, including the effect of an additional nitrided layer. Nitrided and non-nitrided steel samples were subjected to the same coated in the same conditions, and they were submitted to the same thermal cycles, heating from room temperature to 600 degrees C in several steps. After each cycle, Raman spectra and surface topography measurements were performed and analyzed. Nanohardness measurements and tribological tests, using a pin-on-disc machine, were carried out to analyze variations in the friction coefficient and the wear resistance. The duplex sample, with nitriding as pre-treatment showed a better thermal stability. For duplex sample, the coating properties, such as adhesion, and friction coefficient were sustained after annealing at higher temperatures; whereas it was not the case for only coated sample. (C) 2018 Brazilian Metallurgical, Materials and Mining Association. Published by Elsevier Editora Ltda.
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