STUDY OF SOME MECHANICAL PROPERTIES OF THIN HARD COATING CHROMIUM CARBIDES

C HARKATI, L. CHEKOUR L. CHEKOUR, R HALIMI

Résumé


In the present work, some mechanical properties of chromium carbides coating on steel substrates were
studied. The samples were prepared by d.c. magnetron sputtering of a pure Chromium (Cr) layer on steel
substrates containing 1%wt of Carbon. The system (substrate/coating) was then annealed in vacuum at a
temperature at which the carbon of the substrate may diffuse into the Cr metallic film. This fact leads to the
formation of chromium carbides, which are identified by X-ray diffraction as Cr7C3, Cr23C6 and (Cr,Fe)7C3.
The study by nanoindentation shows that the microhardness decreases with increasing of annealing
temperature until 800°C, then increases rapidly to reach a maximum (≈2800 Kg.mm-2) at 1000°C. The
internal stresses, measured by X-ray diffraction, are compressive at 900°C and tensile at 1000°C in the
chromium coating. Nevertheless, they are tensile in the substrates regardless the temperature. The sign
change of the stresses in the coating is probably due to the phase transformation (Cr7C3→(Cr,Fe)7C3)).


Mots-clés


Chromium; carbides; hard coating; nanoindentation

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Références


- Richardt A. et Durand A.-M., "Le vide, les couches minces -

les couches dures", Ed. In Fine, Paris, (1994).

- Collonges R., "La non stoechiométrie", Masson & Cie

éditeurs, Paris (1971).

- Sundgren E. and Hentzell H.T.G., J. Vac. Sci. Technol. A4

(5), (1986), p. 2259.

- Chekour L., Thèse de Magister, Université de Constantine

(1987).

- Harkati C., Thèse de Magister, Université de Constantine

(1998).

- Chaussin C. et Hilly G., "Métallurgie", Tome 1, Ed. Dunod,

Paris (1978).

- Castex L., Lebrun J.L., Maeder G. et Sprauel J.M.,

Publication n°22, ENSAM, Paris (1981)

- Harkati C., Chekour L., Halimi R., 6ème Journées

Maghrébines sur les Sciences des Matériaux, Annaba, 9-11

Novembre (1998).

- Chekour L., Krier J., Halimi R., Cornet A., Journal de

Physique III, C4, (1996), p. 251.

- J. A. Thornton and D. W. Hoffman, J. Vac. Sci. Technol. A3,

(1985), p. 576.


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