Nanocomposite Ti–Si–N, Zr–Si–N, Ti–Al–Si–N, Ti–Al–V–Si–N thin film coatings deposited by vacuum arc deposition

Thin films of Ti–Si–N, Zr–Si–N, Ti–Al–V–Si–N and Ti–Al–Si–N have been synthesized by reactively evaporating a metal or metal alloy cathode by a vacuum arc in a background of nitrogen gas and tetramethylsilane. The amount of silicon in the films was varied from 0 to 19 at.%. With increasing silicon content, the Ti–Si–N, Ti–Al–V–Si–N and Zr–Si–N films were found to increase in hardness, the maximum recorded value being 42 GPa. The Ti–Al–Si–N films showed either a slight increase or decrease in hardness with silicon content. Structural studies showed that the increased hardness was accompanied by a reduction in the grain size, in the case of Ti–Al–V–Si–N, from 24 to 7.7 nm. Transmission electron microscopy (TEM) studies confirmed the X-ray diffraction (XRD) results and showed that the major diffraction lines were associated with the nitride phases. X-ray photoelectron spectroscopy (XPS) studies indicated the presence of Si3N4 and also small amounts of carbide which may be amorphous and possibly located at the grain boundaries.