Papers by Author: Di Chun Chen

Abstract: Cr films with different doping elements were deposited onto silicon wafer by magnetron sputtering. The microstructure and preferred orientation of Cr films were analyzed by TEM and XRD. The results show that the doping element W with bcc structure can strongly inhibit preferred orientation growth trend along (110) crystal plane of Cr film. A nano-multilayer structure is easily formed in the film, which is composed of Cr and W single layer. The doping element Al with fcc structure can strongly inhibit preferred orientation growth trend along all crystal planes of Cr film. The average grain size of Al (Ce) doped Cr film decreased significantly and the crystallization degree improved with the rare earth element Ce added. Both the doping element Zn with hcp structure and the doping element C with hexagonal structure can inhibit preferred orientation growth trend along (110) crystal plane of Cr film. The mechanism is to form the replacement solid solution and interstitial solid solution with Cr atoms, respectively. Nano-multilayer structure composed of Cr and Zn (or C) single layer formed in the films.

Abstract: CrAlTiCN multilayer films have been prepared by closed-field unbalanced magnetron sputtering technology using graphite target as the C supplier. TEM observation results show that the CrAlTiCN films have a clear multilayer structure with the modulate periods changed with the current of graphite target. The higher the current of graphite target, the thicker the periodical thickness of multilayer film. The microstructure of CrAlTiCN films is that the (Cr,Al,Ti)N/amorphous carbon multilayer where (Cr,Al,Ti)N layer and amorphous carbon layer appeared interval, the volume fraction of the amorphous carbon increased with the increasing current of graphite target. Measurement results showed that the CrAlTiCN multilayer films have high microhardness and low friction coefficient. Based on the relationship of the microstructure and properties of films, the multilayer structure and fine grain size of (Cr,Al,Ti)N phase are responsible for their excellent mechanical properties. The good tribological properties are attributed to the amorphous carbon phase (sp² C-C).

Abstract: The addition of metal atoms within the matrix of the graphite-like carbon films lead to the improvement of their mechanical properties. In this paper, metal (Cr, Al, Zr, W) doped graphite-like carbon(GLC) films were deposited on silicon substrates by closed field unbalanced magnetron sputtering from pure metal target and pure graphite target. Chemical composition and chemical states of films were measured by X-ray photoelectron spectroscopy (XPS) and show that mainly sp2 bond existing in all the metal doped films, and sp2/sp3 ratios are not depend on the doped metal. Cross-section micrographs were observed by high resolution transmission electron microscopy (HRTEM) and revealed a structure of composite that metal or metal carbides embedded in amorphous carbon matrix. The relationship between microstructure and chemical composition was discussed.