Oxidation kinetics of hydrogenated amorphous carbon (a-CH(x)) overcoats for magnetic data storage media
The oxidation kinetics of a-CHx overcoats during exposure to oxygen and water vapor have been measured using X-ray photoemission spectroscopy (XPS) in an apparatus that allows oxidation and analysis of freshly deposited a-CHx overcoats without prior exposure of the overcoats to air. The uptake of ox...
| Publié dans: | Langmuir : the ACS journal of surfaces and colloids. - 1991. - 23(2007), 10 vom: 08. Mai, Seite 5485-90 |
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| Auteur principal: | |
| Autres auteurs: | , , , |
| Format: | Article |
| Langue: | English |
| Publié: |
2007
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| Accès à la collection: | Langmuir : the ACS journal of surfaces and colloids |
| Sujets: | Journal Article |
| Résumé: | The oxidation kinetics of a-CHx overcoats during exposure to oxygen and water vapor have been measured using X-ray photoemission spectroscopy (XPS) in an apparatus that allows oxidation and analysis of freshly deposited a-CHx overcoats without prior exposure of the overcoats to air. The uptake of oxygen on the surfaces of the a-CHx overcoats has been measured at O2 and H2O pressures in the range 10(-7)-10(-3) Torr at room temperature. The uptake of oxygen during O2 exposures on the order of 10(7) Langmuirs leads to saturation of the a-CHx overcoat surfaces at oxidation levels on the order of 20%. This indicates that the surfaces of a-CHx overcoats are relatively inert to oxidation in the sense that the dissociative sticking coefficient of O2 is approximately 10(-6). Oxygen uptake during exposure to H2O vapor is similar to the uptake during exposure to O2 gas. Although the surfaces of the a-CHx overcoats are quite inhomogeneous, it has been possible to model the uptake of oxygen on their surfaces using a fairly simple Langmuir-Hinshelwood mechanism. Interestingly, the saturation coverage of oxygen during exposure to air at atmospheric pressure is approximately 6%, significantly lower than that obtained during low-pressure exposure to O2 gas or H2O vapor |
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| Description: | Date Completed 27.06.2007 Date Revised 01.05.2007 published: Print-Electronic Citation Status PubMed-not-MEDLINE |
| ISSN: | 0743-7463 |