Production of sub-micron size carbon composites by high energy carbon ion beams irradiation of solid targets
We report on the production of different types of sub-micron characteristic size carbon composite coatings, using high energy carbon ion beam irradiation of solid targets. The carbon ion beams of characteristic charge state C+ 4 and C+ 5 and energy in the 50 to 600 keV range, are produced in a 1.8 kJ, 160 kA plasma focus (PF) device operating in CH4, with a hollow anode. The interaction of the high energy carbon ion beams with different substrates, including silicon (100) and titanium, result in the formation of surface coatings, with different characteristic morphologies and compositions. In the case of a silicon substrate, a step bunched surface layer of hexagonal SiC or an amorphous carbon layer is formed, depending on the PF anode material, whereas, in the case of titanium, gradient layers of TiC with embedded carbon nanostructures are observed. Detailed characterizations of the different surface coatings have been conducted, using SEM, EDX, XRD, AFM, AES and Raman spectroscopy. The natural angular anisotropy of PF ion beams allows the effect of ion beam characteristic energy and flux on the resulting coatings to be investigated. On the base of the different morphologies and compositions of the resulting coatings an empirical model of PF induced deposition is discussed, which attributes the process to a combination of ion beam implantation and transient physical vapour deposition due to a plasma bubble ejected from the anode, as a result of high energy electron beam bombardment.
H. Bhuyan, M. Favre, A. Henriquez, G. Vogel, E. Valderrama, E. Wyndham, and H. Chuaqui, “Production of sub-micron size carbon composites by high energy carbon ion beams irradiation of solid targets,” Surface and Coatings Technology, vol. 204, no. 18–19, pp. 2950–2953, Jun. 2010. https://doi.org/10.1016/j.surfcoat.2010.03.008