| According to the volt-ampere characteristics at "ohm-anti-ohm" transition interval in gas discharge bimodal curve, the flux of electron transfer in chamber is dozens of magnetron sputtering and the target voltage is several times of multi-arc ion plating. With the help of the pulse power mode, building a discharge environment that satisfy strong glow and weak arc discharge condition by broad pulse highfield, and through by controlling pulse parameters to maintain the gas discharge at various stages of the strong glow and weak arc interval. Based on this to prepare Ti films and TiN films, also the morphology, crystal structure and hardness of the films were characterized by SEM, AFM, XRD, TEM, nanoindentation. For the sake of exploring the influence of the energy content of the coating particles and the deposition behavior of the particles on the growth process and performance of the films in the pulsed environment.The results show that the surface morphology of the Ti film changes from the globular cluster to the loose angular growth and the cross-sectional morphology changes from a slender columnar shape to a loose dendritic structure by the increase of pulse duration. At the same time,the particle size increases obviously and the film flatness and hardness value decrease. The increase of the pulse peak current does not have a significant effect on the film morphology, but to a certain extent, it plays the role of grain refinement. The film roughness values were maintained at 4 nm or less. Meanwhile, the increase of the peak current makes the deposition rate increase effectively. It can be seen from the results of the phase analysis of the films that the increase of the pulse duration and peak current improves the crystallinity of the film and the preferential orientation also changes. From the microstructure of the film, it can be seen that when the pulse duration is 1.6 ms, the grain size is less than 10 nm. The smaller the pulse duration, the higher the hardness of the film (about 6.741 GPa). When the peak current is between 15 A and 30 A, there is a maximum hardness (about 7.203 GPa).For the TiN films, the increase of the pulse duration and peak current dose not change the morphology of the film, which is a typical triangular pyramid structure for (111) plane. The increase of the two parameters promotes the crystallinity of the film, and the tendency of the films to grow along the (111) crystal plane gradually enhanced. To a certain extent, with the increase of peak current, the film has a similar melting phenomenon, which makes the grain size and roughness value decrease, and the film tends to densify. Similarly, the smaller the pulse duration, the higher the hardness of TiN film (about 23.325 GPa).The above phenomena shows that, at the lower pulse duration, the nucleation rate is larger than the growth rate when the gas discharge is located at the strong glow and weak arc interval.At this point, the film particles are small and uniform, and the density and performance of films are better. Meanwhile, there is a suitable peak current range, which not only can improve the deposition rate, but also optimize the film s morphology and performance further. |
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