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 mm 3 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.

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Abstract:In this study, reactive magnetron sputtering was applied for preparing NbCN-Ag films with different Ag additions. Ag contents in the as-deposited NbCN-Ag films were achieved by adjusting Ag target power. The composition, microstructure, mechanical properties, and tribological properties were characterized using energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), high resolution transmission electron microscopy (HRTEM), Raman spectrometry, nano-indentation, and high-temperature sliding wear tests. Results indicated that face-centered cubic (fcc) NbN, hexagonal close-packed (hcp) NbN and fcc Ag, amorphous C and amorphous CN x phase co-existed in the as-deposited NbCN-Ag films. After doping with 2.0 at.% Ag, the hardness and elastic modulus reached a maximum value of 33 GPa and 340 GPa, respectively. Tribological properties were enhanced by adding Ag in NbCN-Ag films at room temperature. When the test temperature rose from 300 to 500 • C, the addition of Ag was found beneficial for the friction properties, showing a lowest friction coefficient of~0.35 for NbCN-12.9 at.% Ag films at 500 • C. This was mainly attributed to the existence of AgO x , NbO x , and AgNbO x lubrication phases that acted as solid lubricants to modify the wear mechanism.

VCN-Cu films with different Cu contents were deposited by reactive magnetron sputtering technique. The films were evaluated in terms of their microstructure, elemental composition, mechanical, and tribological properties by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), high resolution transmission electron microscopy (HR-TEM), Raman spectrometry, nano-indentation, field emission scanning electron microscope (FE-SEM), Bruker three-dimensional (3D) profiler, and high-temperature ball on disc tribo-meter. The results showed that face-centered cubic (fcc) VCN, hexagonal close-packed (hcp) V 2 CN, fcc-Cu, amorphous graphite and CN x phases co-existed in VCN-Cu films. After doping with 0.6 at.% Cu, the hardness reached a maximum value of~32 GPa. At room temperature (RT), the friction coefficient and wear rate increased with increasing Cu content. In the temperature range of 100-500 • C, the friction coefficient decreased, but the wear rate increased with the increase of Cu content.