Uniformity of Si-containing diamond-like carbon films deposited at different positions by mesh hollow cathode discharge

Diamond-like carbon (DLC) films exhibit exceptional tribological characteristics, but their practical application requires the development of scalable methods for uniform film deposition. For large-area DLC films, the properties of films deposited at different positions may be different, it is necessary to study the uniformity of DLC films. In this study, Si-containing DLC (Si-DLC) films were deposited by mesh hollow cathode discharge. The uniformity of the microstructure and mechanical properties of the DLC films deposited in the x, y, and z directions were studied. The Si-DLC films were characterized by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and nanoindentation tests. The wear resistance was evaluated using a ball-on-disk tester and the wear scars were studied using a metalloscope. The thickness distributions of the Si-DLC films deposited in the x, y, and z directions exhibited thick middles and thin edges. However, the thickness distributions of the films deposited in the x and y directions were more uniform than the films deposited in the z direction. Compared with the films deposited in the z direction, the intensity ratio of the D and G peaks in the Raman spectra, the ratio of sp(3) and sp(2) carbons, the shift of the G peak position, and the full width at half maximum of the G peak of the films deposited in the x and y directions varied in a smaller range. Furthermore, the hardness, friction coefficient, and tribological performance of the films deposited in the x and y directions showed better uniformity than those of the films deposited in the z direction. Overall, mesh hollow cathode discharge provides good uniformity for films deposited in the x and y directions, but improved film deposition in the z direction is required. The study of the uniformity of Si-DLC films deposited at different positions by mesh hollow cathode discharge is benefit for understanding the working rule of mesh hollow cathode discharge, so as to prepare larger area and more uniform DLC film.