Laser chemical vapor deposition of TiC fibers and tubes

Abstract

Laser Chemical Vapor Deposition (LCVD) is a process in which fibers are deposited from a gaseous precursor to a solid phase under a traversing laser focal point. Here, we grow titanium carbide (TiC) fibers and tubes dependent upon a hyperbaric hydrogen-rich, hydrogen-balanced, and hydrogen-lean environment referenced to a titanium tetrachloride and ethylene gas mixture under three different laser intensities. X-ray diffraction confirms the deposition of TiC with energy dispersive spectroscopy noting a radial compositional gradient of titanium and carbon in the diameter of the deposit. Depending on the hydrogen concentration, the TiC encased a core carbon-rich fiber or formed a hollow tube, with these formations explained by thermophoresis. Furthermore, depending on the gas mixture and laser intensity, the carbon-rich interior and TiC outer shell exhibited different morphologies that are discussed in terms of growth rate regimes. The collective outcomes demonstrate the complex processing space in forming ceramic materials by LCVD.