Study Of Structural And Mechanical Properties Of Tungsten Carbides Coatings

Hard coatings of tungsten carbides have been obtained by the deposition of tungsten thin layers, on steel substrates (containing 0.7% wt. carbon), according to the cathodic magnetron sputtering held at temperature of 500°C. It is established by X-rays diffraction that, in the temperature range 500-800°C, no formation of tungsten carbides was observed. However, the annealing at a temperature greater than or equal to 900°C promotes the reaction between the constituents of the samples (W, Fe, C) and hence the formation of W C carbide. No other compounds were detected. The micro-hardness measured by Vickers tests, increases with the rise in temperature, particularly from 900°C. The morphology of the surface samples depends on the temperature and duration of thermal annealing.