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JUNE 28 WEDNESDAY AFTERNOON
JS2-WeA-P.7 STUDY OF SOME PROPERTIES OF HARD TUNGSTEN CARBIDE
COATINGS. F. Khalfallah, Y. Hadjar, R. Halimi. Laboratoire des Couches Minces et Interfaces,
Département de Physique, Faculté des Sciences, Université Mentouri, 25000 Constantine, Algérie.
In this work, we have studied the properties of hard coatings of tungsten carbides. The samples are
thin layers of Tungsten deposited at 500°C on two types of steel (containing 1 and 0,7% wt. carbon)
substrates. The samples were then heat treated in vacuum, at various temperatures (500-1000°C) and
during different times.
The formation of tungsten carbides, the evolution of the microstructure and the morphology of the surface
of samples were followed by X-ray diffraction (XRD) and scanning electron microscopy (SEM).
The measurements of micro-hardness were carried out by Vickers tests.
Thermal annealing produces reactions and some other structural changes in the tungsten layers which
depend on the carbon content in substrate.
It is established that the formation of tungsten carbides occurs above annealing at 800°C. The reaction
is more rapid on substrate containing 1%C. The mono-carbide WC forms after annealing at 1000°C.
The hardness of coatings increases continuously from 400 to 1200 Kg/mm² as the temperature of annealing
increases from 500 to 900°C. The samples rich on carbon show higher hardness.
Key words: hard coatings, tungsten, carbides, thin films.
Presenting author: F. KHALFALLAH
Contacts and email: Tel/Fax: 213 31 61 47 11; fa_fares@yahoo.fr
Presentation type: Poster
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