Structure And Nano-Tribological Behavior Of BCN Films Deposited By Magnetron Sputtering

BCN films were deposited by unbalanced magnetron sputtering in this dissertation. The composition, bonding structures, nano-mechanical properties and nano-tribological properties of the BCN films deposited at different process parameters were studied systematically. The effect of process parameters on the structure and properties of the BCN films were obtained. The growth mechanism, scratch and crack mechanism of the BCN films were illuminated. Otherwise,annealing tests of typical BCN film were carried out in vacuum and atmosphere, and thermal stability of the film were studied.The composition and bonding structure of BCN films were studied by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR), and the results indicated that the composition of BCN films is controllable by adjusting the magnetic field of the target surface and NB2B partial pressure. The content of like BCB3.4B B-C bonding decreased and that of like BB4BC B-C bonding increased with the decreasing of the concentration of C from 25at% to 14at%. N was prior to bonding with B to form B-N bonding, and then bonded with C to form C=N bonding with the increasing of N to stable value in the films. Besides of the composition, the deposition process also affects the bonding structure of the films. The disordered degree of the films increased with the increasing of target power. The content of B-N bonding increased with the increasing of bias and spP3P B-N bonding appeared when the bias reached -400V. The content of B-N bonding increased with the increasing of the deposition temperature.Nano-mechanical properties of BCN films deposited at different deposition process parameters were tested, and the results indicated nano-mechanical properties were related with the disorder degree, type and number of bonding structures. The mechanical properties of BCN films with low disorder degree and more spP2 PB-N,C=N bonding were worst. The mechanical properties of BCN films increased with the increasing of the disorder degree and the decreasing of the spP2P bonding content. The mechanical properties of BCN films would be improved further with the increasing of the contents of spP3P B-N and B-C bonding. The nano-hardness and modulus of BCN films in the dissertation were in the range of 0.3GPa～36GPa and 15GPa～356GPa, respectively.The nano-tribological properties of BCN films were studied systematically in the dissertation, and the relation among tribological properties, structure and mechanical properties of BCN films was obtained. The results indicated the increasing of the nano-mechanical properties was in favor of the enhancement of the tribological properties of BCN films which contained N. Films with no N exhibited high mechanical properties, but the tribological properties is worse. That is to say the mechanical properties were not consistent absolutely with the tribological properties. Based on the studies of tribological properties, the scratch mechanism and crack process of three different types were proposed. For the film which contained no N and owned high mechanical properties, critical load is small and friction coefficient is about 0.3. Brittle break and peel off took place under the load, and the scratch and crack process with the increasing of the load was: elastic deformation→microcrack appeared in the films→delamination and peel off→crack. For the BCN films which contained N and owned better mechanical properties, critical load increased and friction coefficient was below 0.1. The scratch and crack process of films with the increasing of the load was: entirety elastic deformation→elastic deformation is dominant and plastic deformation is lesser→crack. For the BCN films which contained N and owned the worst mechanical properties, critical load decreased and friction coefficient increased over 0.4, and deep furrow appeared with the increasing of the load.In order to study the thermal stability of typical BCN film, annealing tests of the film were carried out in vacuum and air. The results indicated that the order degree increased, and the mechanical properties of the film decreased with the increasing of annealing temperatures. The film exhibited better vacuum thermal stability, and did not decompound when the annealing temperature rose to 1000PoPC. Otherwise, the tribological properties of the film annealing in vacuum did not decrease obviously. The film was oxidized and decompounded when the annealing temperature rose to 600PoPC in air.