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The (CrAlTiNbV)N x coatings are fabricated by controlling the substrate bias via magnetron sputtering method. Under low substrate bias, the coating tends to form a loose columnar crystal structure with (200) preferred orientation. However, when the substrate bias increases, the coating transforms into a dense nanocrystalline structure, and the (111) orientation is enhanced. As the substrate bias increases, the residual stress and hardness of the coating gradually increase, while the adhesion strength decreases slightly. Friction tests show that the coating possesses the lowest average friction coefficient (about 0.06) and wear rate (8.7 × 10-9 mm3/N·m) in 4050# aviation lubricant, which is achieved under the substrate bias of -96 V and -126 V, respectively. [ABSTRACT FROM AUTHOR]

High temperature coatings possess great potential for improving operation temperature of 4th generation nuclear reactor. In this paper, a high-entropy alloy nitride coatings (CrAlTiNbV)N x were investigated for the application in corrosive lead-bismuth alloy (LBE). The coatings were synthesized by unbalanced magnetron sputtering on ferritic/martensitic (F/M) steel. Properties of (CrAlTiNbV)N x are systematically investigated from perspective of the electron structure, crystalline, and mechanical properties under different bias voltage applied on samples. Significant improvement of hardness (30 GPa) is obtained at bias voltage of -156 V. Furthermore, the corrosion behavior in 550 °C lead bismuth eutectic (LBE) was conducted for 1200 h with saturated oxygen content, which demonstrates the dense structure of coatings with no obvious crack, spallation that characterized by the SEM, EDS, and TEM. Upon the application of high bias voltage, more prone formation of high-density grain boundary with fine grains extends the diffusion path of Pb and Bi are achieved for excellent LBE corrosion resistance. Our work not only provide an insight to the electron structure of high entropy alloy nitrides, but also shows a potential application for (CrAlTiNbV)N x protecting fuel cladding in the next generation lead based reactor. [ABSTRACT FROM AUTHOR]

(CrNbTiAlV)N x high-entropy nitride films were prepared using magnetron sputtering method. The effect of substrate bias on the microstructure, mechanical, electrochemical, and tribo-corrosion properties of the films was systematically studied. The results show that the microstructure of the film changes from a loose columnar structure to a compact nanocrystal structure with the increase of substrate bias, accompanied by the preferred orientation from (200) to (111). The hardness, modulus and residual stress are positively correlated with increased substrate bias, reaching the maximum values of 35.3 GPa, 353.7 GPa and −6.41 GPa at −156 V, respectively. Under static corrosion, the film deposited under −126 V has the most positive E corr of −0.05 V and the lowest i corr of 0.013 μA/cm2. Under tribo-corrosion, the films deposited at −96 V and −126 V show the lowest coefficient of friction (~0.2) and wear rate (~4.4 × 10−7 mm3·N−1·m−1), respectively. The evolution of microstructure and mechanical property are the main factors affecting the tribo-corrosion behavior of (CrNbTiAlV)N x films. [Display omitted] • (CrNbTiAlV)N x high-entropy films were deposited at various substrate bias by magnetron sputtering. • The structure of the films changed from loose columnar to compact with the increase of substrate bias. • The hardness, modulus and residual stress of the films were positively correlated with increasing bias. • The influencing factors of (CrNbTiAlV)N x films under static corrosion and dynamic tribocorrosion were discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • The (CrAlTiNbV)N x high-entropy coatings are prepared by magnetron sputtering method. • All coatings exhibit columnar growth morphology and own a single FCC structure. • The S-38 owns a friction coefficient of 0.096 and wear rate of 1.8 × 10−7 mm3/(N·m). • The excellent wear resistance of S-38 is mainly attributed to its dense structure. (CrAlTiNbV)N x high-entropy nitride coatings are deposited via tuning nitrogen flow rates, and evaluating their influence on the microstructure, mechanical and tribological properties of the coatings. All deposited coatings exhibit columnar growth morphology and own a single face-center-cubic structure. As the nitrogen flow rate increases, the preferred orientation of the coating gradually transfers from (1 1 1) to (2 0 0) and (2 2 0), and then changes back to (1 1 1) with the nitrogen flow rate continues to increase. The S-38 sample possesses the optimal plastic deformation resistance and adhesion strength. Friction and wear results show that the (CrAlTiNbV)N x coating deposited at nitrogen flow rate of 38 sccm owns the best tribological properties with a friction coefficient of 0.096 and wear rate of 1.8 × 10−7 mm3/(N·m) in 4050# aviation oil. [ABSTRACT FROM AUTHOR]