ION-BEAM-INDUCED ATOMIC MIXING AT THE W-C INTERFACE

Thin films of carbon were deposited onto tungsten substrates using las er-induced physical vapour deposition (LPVD) from a high purity pyroli tic graphite target. An excimer laser was used for the deposition of t hese films. The films were irradiated with Ar+ ions up to an ion dose of 1 x 10(16) ions cm-2 to promote ion beam induced atomic mixing at t he W-C interface. Since the state of the mixed region is expected to b e metastable, the possibility of transformation of this state to a mor e ordered state via thermal annealing treatment was explored. These tr eatments clearly revealed the formation of tungsten carbide at the int erface. X-ray diffraction (XRD) studies were performed at every stage of processing using a low angle XRD technique. Scanning electron micro scopy was used for qualitative characterization of the surface morphol ogy of samples. The microhardness was measured using a conventional Vi cker's microhardness testing machine.