Effects of Duty Cycle on Texture Orientation and Composition of TiC_x Nanostructured coatings

Nanostructured titanium carbide (TiC_x) coatings are deposited on steel substrates by plasma chemical vapor deposition using three different duty cycles of 33, 40, and 50% and characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The relationship between the texture orientation/elemental concentration and duty cycle can be divided into two regimes, carbide (TiC_x) state and oxycarbide (TiC_xO_y) state. The coatings crystallize into a TiC NaCl-type crystal structure (FCC) in the carbide and oxycarbide states and a smaller “x” in the TiC_x coatings causes the transformation of the preferred orientation of (200) in the carbide state to (111) in the oxycarbide state. A poorly crystallized anatase phase is also observed from the coatings deposited using duty cycles of 40 and 50% and this anatase phase is detected from the oxycarbide state.