Characterization of diamond-like carbon films deposited on Zr-2.5Nb pressure tube material by excimer laser

Diamond-like carbon films were deposited by excimer laser ablation of graphite on Zr-2.5Nb pressure tube material at substrate temperatures of 25 and 200 °C. Characterizations of the films by nanoindentation, Raman spectroscopy, and Fourier transform infrared reflection spectroscopy show that the films have a very high hardness, are transparent to infrared light, and exhibit Raman spectra typical of diamond-like carbon films. The films also exhibit a high refractive index in the infrared spectrum. Increasing the substrate temperature from 25 to 200 °C results in a 25% increase in the deposition rate, but produces lower mechanical properties for the DLC films. The high refractive index was attributed to a lack of incorporation of hydrogen into the films and the lower mechanical properties of the films deposited on the heated substrate were explained by an increase in the sp2sp3 bonds ratio.