Research On Microstructure And Properties Of TiN-Based Composite Films And Multilayers Films

In this paper,TiN films with different N content,TiN/AlN multilayers with different modulation period,TiAlMoN and ZrAlMoN composite films with different Mo content were deposited using reactive magnetron sputtering system.The elemental composition,microstructure,mechanical properties and tribology properties of the films were characterized using energy dispersive spectroscopy?EDS?,X-ray diffraction?XRD?,scanningelectronmicroscope?SEM?,transmissionelectronmicroscopy?TEM?,nano-indentater,high-temperature ball-on-disc tribo-meter and surface profilometer.The thermal diffusivity of TiN films were investigated by laser thermal conductivity analyzer.The main results are as follows:The study of the TiN films with a N content of 40.6⁶4.0 at.%showed that the films exhibited a single face-centered cubic?fcc?structure.The excess N atoms were found to preferentially occupy interstitial positions of TiN lattice from the perspective of energy analysis.The thermal diffusivity of TiN thin films decreased gradually and reached a stable range with an increase of N content in the films.The minimum thermal diffusivity value was 2.291×10^-6m²/s at 60.2 at.%N.This reduction of thermal diffusivity could be attribute to the decreased grain size,the change of preferential orientation and the increased lattice distortion.With the increase of N content,the hardnenss of the films first increased and then decreased.The maximum hardness was 22.9 GPa at 60.2 at.%N.The average friction coefficient of the films at room temperature decreased gradually and then increases sharply with the increase of N content.The friction coefficient and wear rate were at a low level with below 60.2 at.%N at 50?,then in the sharp rise in later.The study of the TiN/AlN multilayer films with different modulation period???showed that AlN layers grew epitaxilly on the TiN layers as fcc structure when?was less than or equal to 12 nm.When?was 36 nm,there was no obvious component mixing region at the interface of the two modulation layers,and there were lattice fringes with different orientations in each modulation layer.Specifically,TiN was cubic structure and AlN was hexagonal structure.The residual stress first increased and then decreased with the increase of modulation period.The minimum residual stress value was-3.97 GPa when?was 12 nm.When?was 12 nm,the hardness of the multilayer films reached the maximum value of29.27GPa.When?was less than 12 nm,with the increase of?,the corrosion resistance of the film increased gradually,and decreased with the continuous increase of?.When?was less than or equal to 12 nm,the anti-corrosion performance of TiN/AlN multilayer film was better than that of the multilayer film with large modulation period.excellent because the AlN was co-grown with cubic structure on the TiN surface,of which the coherent interface was equivalent to no interface.When?was less than 12 nm,although the interface was coherent,the disorder of atomic arrangement at the interface increased with the decrease of the modulation layer thickness.As a result,the corrosion resistance decreased.When the modulation period was large,the corrosion resistance of the film decreased due to the existence of the modulation interface.In order to optimize the tribological properties of the previous films,self-adaptive lubricating effect of Magnéli phase was applied by adding molybdenum.The comparison study of the TiAlMoN and ZrAlMoN composite films with various Mo content was carried out.The results showed that both the films exhibited a fcc structure at the low Mo content.When the content of Mo reached a certain level,fcc-Mo₂N phase was formed in the film.By comparing the effects of Mo content on the mechanical properties of TiAlMoN and ZrAlMoN films,it was found that the common factors affecting the hardness of these two thin films include phase structure,solid solution strengthening and fine crystal strengthening.For TiAlMoN film,the hardness first increased and then decreased with the increase of Mo content.By comparing the effects of Mo content on tribological properties of TiAlMoN and ZrAlMoN film,it was found that the phase structure was the main factor that changed the friction coefficient and wear rate of the two kinds of thin films.Meanwhile,H/E,H³/E*²values and the generation of MoO₃ oxide in the marks also played a certain role.With the increase of Mo content,the average friction coefficient of the two kinds of films decreased gradually.The wear rate first decreased and then increased with the increase of Mo content,the minimum wear rate was 3.3×10^-8mm³·N^-1·mm^-1and 5.0×10^-8mm³·N^-1·mm^-1,respectively.Through comparison,it was found that Mo content had a great influence on the mechanical properties of TiAlMoN thin films,and had a similar influence on the tribological properties of the two kinds of thin films.