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A multilayer film, composed by ZrN-Ag (20 nm) and Mo-S-N (10 nm) layers, combining the intrinsic lubricant characteristics of each layer was deposited using DC magnetron sputtering system, to promote lubrication in a wide-range of temperatures. The results showed that the ZrN-Ag/Mo-S-N multilayer film exhibited a sharp interface between the different layers. A face-centered cubic (fcc) dual-phases of ZrN and Ag co-existed in the ZrN-Ag layers, whilst the Mo-S-N layers displayed a mixture of hexagonal close-packed MoS2(hcp-MoS2) nano-particles and an amorphous phase. The multilayer film exhibited excellent room temperature (RT) triblogical behavior, as compared to the individual monolayer film, due to the combination of a relative high hardness with the low friction properties of both layers. The reorientation of MoS2parallel to the sliding direction also contributed to the enhanced anti-frictional performance at RT. At 400 °C, the reorientation of MoS2as well as the formation of MoO3phase were responsible for the lubrication, whilst the hard t-ZrO2phase promoted abrasion and, consequently, led to increasing wear rate. At 600 °C, the Ag2MoO4double-metal oxide was the responsible for the low friction and wear-resistance; furthermore, the observed transformation from t-ZrO2to m-ZrO2, could also have contributed to the better tribological performance.

A series of composite TaMgN films with various Mg content were deposited using reactive magnetron sputtering. The microstructural, mechanical, oxidation resistance and tribological properties of the films were measured. The results showed that when the Mg content is between 0 and 11.9 at.-%, the films are composed of fcc-(Ta,Mg)N and hcp-(Ta,Mg)N phases. While the further increase of Mg content induced the appearance of hcp-Mg phase and the films consisted of fcc-(Ta, Mg)N, hcp-(Ta, Mg)N and hcp-Mg, the hardness of the thin films was first increased and then decreased with the increase of Mg content due to the combined action of solution strengthening, internal stress and phase composition. The highest hardness value is 33 GPa, (Mg content is 11.9 at.-%). With a further increase of Mg content, the average friction coefficient further increased gradually, while the wear rate first decreased and then increased.

ABSTRACTA series of composite TaMgN films with various Mg content were deposited using reactive magnetron sputtering. The microstructural, mechanical, oxidation resistance and tribological properties of the films were measured. The results showed that when the Mg content is between 0 and 11.9 at.-%, the films are composed of fcc-(Ta,Mg)N and hcp-(Ta,Mg)N phases. While the further increase of Mg content induced the appearance of hcp-Mg phase and the films consisted of fcc-(Ta, Mg)N, hcp-(Ta, Mg)N and hcp-Mg, the hardness of the thin films was first increased and then decreased with the increase of Mg content due to the combined action of solution strengthening, internal stress and phase composition. The highest hardness value is 33 GPa, (Mg content is 11.9 at.-%). With a further increase of Mg content, the average friction coefficient further increased gradually, while the wear rate first decreased and then increased.

ABSTRACTTi–Al–Mo–N composite films with different molybdenum content were deposited by reactive magnetron sputtering. The results showed that the films consisted of fcc-(Ti, Al, Mo) N substitutional solid solution within 8.2 at.-% Mo. The films consisted of two phases which were fcc-(Ti, Al, Mo) N substitutional solid solution and fcc-Mo2N at 27.7–49.4 at.-% Mo. The hardness increased slowly at 0–27.7 at.-% Mo and then increased rapidly at above 27.7 at.-% Mo. A ball-on-disc dry sliding test was conducted on films deposited on stainless-steel substrates. The friction coefficient quickly decreased within 8.2 at.-% Mo and then gently declined at 8.2–49.4 at.-% Mo. The value of wear rate remained quite constant for compositions in the range 0–34.3 at.-% Mo and then dropped quickly at 34.3–49.4 at.-% Mo. The addition of Mo content effectively improved the hardness and tribological properties of the films.

Ti–Al–Mo–N composite films with different molybdenum content were deposited by reactive magnetron sputtering. The results showed that the films consisted of fcc-(Ti, Al, Mo) N substitutional solid solution within 8.2 at.-% Mo. The films consisted of two phases which were fcc-(Ti, Al, Mo) N substitutional solid solution and fcc-Mo2N at 27.7–49.4 at.-% Mo. The hardness increased slowly at 0–27.7 at.-% Mo and then increased rapidly at above 27.7 at.-% Mo. A ball-on-disc dry sliding test was conducted on films deposited on stainless-steel substrates. The friction coefficient quickly decreased within 8.2 at.-% Mo and then gently declined at 8.2–49.4 at.-% Mo. The value of wear rate remained quite constant for compositions in the range 0–34.3 at.-% Mo and then dropped quickly at 34.3–49.4 at.-% Mo. The addition of Mo content effectively improved the hardness and tribological properties of the films.

TiN films with various nitrogen content were deposited using reactive magnetron sputtering system and the influence of TiN film's microstructure on thermal diffusivity was investigated. The results showed that the titanium nitride film with 40.6–64.0at.% N exhibited a single face-centered cubic (fcc) structure. The density of states calculations of TiNx showed that excess N atoms in TiN matrix weaken the Ti-N bonds. The thermal diffusivity of TiN thin films decreased gradually and reached a stable range with an increase of N content. The minimum thermal diffusivity value was 2.291×10-6m2/s at 60.2at.% N. This reduction of thermal diffusivity could be attribute to the films’ microstructure, including the increased grain boundaries due to the decrease of grain size, the change of preferential orientation and the increased lattice distortion.

ABSTRACTTiN films with various nitrogen content were deposited using reactive magnetron sputtering system and the influence of TiN film’s microstructure on thermal diffusivity was investigated. The results showed that the titanium nitride film with 40.6–64.0at.% N exhibited a single face-centered cubic (fcc) structure. The density of states calculations of TiNx showed that excess N atoms in TiN matrix weaken the Ti-N bonds. The thermal diffusivity of TiN thin films decreased gradually and reached a stable range with an increase of N content. The minimum thermal diffusivity value was 2.291×10−6m2/s at 60.2at.% N. This reduction of thermal diffusivity could be attribute to the films’ microstructure, including the increased grain boundaries due to the decrease of grain size, the change of preferential orientation and the increased lattice distortion.

ABSTRACTTitanium boron nitride (Ti-B-N) films with various boron contents were deposited using titanium and boron targets in a reactive magnetron sputtering system. The boron content in the film was varied from 0 at.-% to 8.7 at.-%, to evaluate its properties. Various analytical techniques such as X-ray diffraction, high-resolution electron microscopy, nanoindentation and ball-on-disk dry sliding etc. were used. Incorporation of B into the film influenced the microstructure, mechanical and room-temperature tribological properties. At a B content of 0.2 at.-%, the film exhibited the highest hardness of ∼27 GPa. It also presented the lowest wear rate of ∼2.9 × 10−7 mm3 N−1 mm−1. However, there was a gradual decrease in coefficient of friction (CoF) values of the film when the B content was increased, with a minimum of 0.2 attained at 8.7 at.-% boron. The increased volume fraction of amorphous boron nitride phase contributed to the decrease in coefficient of friction.

ABSTRACTTi–B–N (nc-TiN/ a-BN) composite coatings with various boron contents were deposited by magnetron sputtering. nano-indentation, ball-on-disc dry sliding X-ray diffraction, and, Raman spectroscopy was used in evaluating the compositional, mechanical and tribological properties of these coatings. The corrosion behaviour of the Ti–B–N coatings was assessed by the electrochemical potentiodynamic polarisation method in a 3 mol-% of NaCl solution. The coefficient of friction (CoF) of the coatings initially increased to 1.0 when the test temperature was 200°C, but a further increase in temperature to 700°C resulted in a decrease in the CoF value to ∼0.18 which was due to the presence of Magneli-type TinO2n−1oxides. In contrast to the CoF, there was a consistent increase in wear rate when the temperature was increased; the highest wear rate was obtained at 700°C. The B incorporated coatings exhibited improvement in both oxidation and corrosion resistance properties.

Titanium boron nitride (Ti-B-N) films with various boron contents were deposited using titanium and boron targets in a reactive magnetron sputtering system. The boron content in the film was varied from 0 at.-% to 8.7 at.-%, to evaluate its properties. Various analytical techniques such as X-ray diffraction, high-resolution electron microscopy, nanoindentation and ball-on-disk dry sliding etc. were used. Incorporation of B into the film influenced the microstructure, mechanical and room-temperature tribological properties. At a B content of 0.2 at.-%, the film exhibited the highest hardness of ~27 GPa. It also presented the lowest wear rate of ~2.9?×?10-7 mm3 N-1 mm-1. However, there was a gradual decrease in coefficient of friction (CoF) values of the film when the B content was increased, with a minimum of 0.2 attained at 8.7 at.-% boron. The increased volume fraction of amorphous boron nitride phase contributed to the decrease in coefficient of friction.

Ti–B–N (nc-TiN/ a-BN) composite coatings with various boron contents were deposited by magnetron sputtering. nano-indentation, ball-on-disc dry sliding X-ray diffraction, and, Raman spectroscopy was used in evaluating the compositional, mechanical and tribological properties of these coatings. The corrosion behaviour of the Ti–B–N coatings was assessed by the electrochemical potentiodynamic polarisation method in a 3 mol-% of NaCl solution. The coefficient of friction (CoF) of the coatings initially increased to 1.0 when the test temperature was 200°C, but a further increase in temperature to 700°C resulted in a decrease in the CoF value to ~0.18 which was due to the presence of Magneli-type TinO2n-1oxides. In contrast to the CoF, there was a consistent increase in wear rate when the temperature was increased; the highest wear rate was obtained at 700°C. The B incorporated coatings exhibited improvement in both oxidation and corrosion resistance properties.

ABSTRACTTi–W–V–N composite films with different vanadium contents were synthesised by multi-target reactive magnetron sputtering. The microstructure, mechanical and tribological properties of Ti–W–V–N films were investigated by X-ray diffraction, scanning electron microscope, high-resolution transmission electron microscopy, nanoindentation and high-temperature ball-on-disc tribometer. The results showed that all the Ti–W–V–N composite films were face-centred cubic (fcc) structure, consisting of fcc-(Ti,W,V)N substitutional solid solution. When the V content ≥21.5 at.-%, the films consisted of fcc-(Ti,W,V)N and fcc-VN. The hardness of the films first increased and then decreased with the maximum value of 32.4 GPa, at 21.5 at.-% V. The test temperature had a significant effect on the tribological properties of Ti–W–V–N film with 21.5 at.-% V, the coefficient of friction (CoF) first increased and then decreased, with a minimum value of 0.304 at 700°C.While the wear rate increased gradually with increasing temperature.

Ti–W–V–N composite films with different vanadium contents were synthesised by multi-target reactive magnetron sputtering. The microstructure, mechanical and tribological properties of Ti–W–V–N films were investigated by X-ray diffraction, scanning electron microscope, high-resolution transmission electron microscopy, nanoindentation and high-temperature ball-on-disc tribometer. The results showed that all the Ti–W–V–N composite films were face-centred cubic (fcc) structure, consisting of fcc-(Ti,W,V)N substitutional solid solution. When the V content =21.5 at.-%, the films consisted of fcc-(Ti,W,V)N and fcc-VN. The hardness of the films first increased and then decreased with the maximum value of 32.4 GPa, at 21.5 at.-% V. The test temperature had a significant effect on the tribological properties of Ti–W–V–N film with 21.5 at.-% V, the coefficient of friction (CoF) first increased and then decreased, with a minimum value of 0.304 at 700°C.While the wear rate increased gradually with increasing temperature.

ABSTRACTVCN films with various carbon contents were deposited by reactive magnetron sputtering. The elemental compositions, microstructure, mechanical and tribological properties were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), energy-dispersive spectrometer, scanning electron microscope (SEM), nano-indentation and friction and wear test. The results showed that the microstructure, mechanical properties and tribological properties of VCN films were influenced by the variation of the carbon content. The VCN films exhibited a face-centered cubic (fcc) structure. By increasing of carbon content of the film, the grain size of VCN films decreases gradually. The hardness of the films first increased and then decreased with increasing carbon content, after reaching the maximum values of 28.1 GPa, at 16.89 at.-% carbon. The average friction coefficient and wear rate decreased with the increasing carbon content at room temperature.

VCN films with various carbon contents were deposited by reactive magnetron sputtering. The elemental compositions, microstructure, mechanical and tribological properties were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), energy-dispersive spectrometer, scanning electron microscope (SEM), nano-indentation and friction and wear test. The results showed that the microstructure, mechanical properties and tribological properties of VCN films were influenced by the variation of the carbon content. The VCN films exhibited a face-centered cubic (fcc) structure. By increasing of carbon content of the film, the grain size of VCN films decreases gradually. The hardness of the films first increased and then decreased with increasing carbon content, after reaching the maximum values of 28.1 GPa, at 16.89 at.-% carbon. The average friction coefficient and wear rate decreased with the increasing carbon content at room temperature.