Plasma focus assisted carburizing of aluminium

Carburizing of aluminium using the energetic carbon ions emitted from a low energy (1.45 kJ) Mather type plasma focus device operated with methane is reported. The aluminium samples are placed in front of a hollow tapered aluminium anode at a fix distance and are exposed to different carbon ion dose. Raman spectroscopy and X-ray diffraction analyses confirm the presence of Al4C3 phase in the irradiated samples. Raman spectroscopic analysis verifies the existence of sp(2) and sp(3) hybridized carbon content also in the treated aluminium surface. Energy dispersive X-ray spectroscopy analyses show a gradual increase of carbon concentration in the treated samples as a function of ion dose. Scanning electron microscope results reveal that the surface smoothness improves initially with ion beam exposure, but deteriorates with increasing ion dose above an optimum value. Vickers micro-indentation technique reveals maximum hardness of about 1990 +/- 100 MPa, approximately 7 times as compared to that of aluminium bulk, for the sample treated with 30 plasma focus discharges. (C) 2009 Elsevier B.V. All rights reserved.