Plasma post-oxidation mechanisms of nitrided ferrous alloys
| Autor: | Israel Jacob Rabin Baumvol, A.C. Rovani, Rodrigo Leonardo de Oliveira Basso, F. Cemin, Carlos A. Figueroa, Cintia L.G. Amorim, V. Sonda, A.E. Crespi, Fernando G. Echeverrigaray |
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| Rok vydání: | 2011 |
| Předmět: |
Materials science
Chemistry(all) Metallurgy Iron oxide Oxide Surfaces and Interfaces General Chemistry Activation energy Plasma Post-oxidation Condensed Matter Physics Surfaces Coatings and Films Ferrous Magnetite chemistry.chemical_compound Plasma processes chemistry Chemical engineering Mechanisms Materials Chemistry Plasma processing Nitriding |
| Zdroj: | Surface and Coatings Technology. 205:3422-3428 |
| ISSN: | 0257-8972 |
| Popis: | The mechanisms of plasma post-oxidation of plasma nitrided AISI 1045 plain steel were investigated. The influence of plasma post-oxidation temperature and time on the oxide layer thickness, morphology, and composition were addressed. The oxide thickness grows exponentially with temperature, with activation energy of 68 ± 5 kJ mol − 1. The time dependence of the oxide layer thickness, on the other hand, is governed by a diffusion-reaction process. It was verified that temperature plays an important role on the morphology of the oxide. Indeed, at the highest temperature, 550 °C, the oxide layer is not homogeneous and has a lower hardness than oxide layers obtained at 480 to 500 °C. The latter seem to be more favorable temperatures to grow compact, homogeneous, and harder oxide layers. The oxide–nitride bi-layer produced here contains a mixture of γ′-Fe4N and e-Fe2-3N and only one iron oxide, Fe3O4 (magnetite). The proportions between these phases vary with the plasma processing temperature and time. |
| Databáze: | OpenAIRE |
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