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The influence of nitriding treatment on wheel/rail rolling contact fatigue and surface wear behavior of CL60 wheel was studied on JD-DRCF/M rolling contact fatigue/wear tester,the wheel surface nitriding treatment on the mechanisms of wheel/rail surface damage are compared and analyzed. The results showed that the surface nitriding treatment could form a uniform and dense white layer about 3 μm ～ 5 μm thick and a diffusion layer about 20 μm thick on the wheel surface. Under the wheel surface after nitriding process,the adhesive coefficient between wheel/rail was reduced by 11. 7% in dry condition,and reduced by 18. 4% in aqueous media,but the nitriding treatment still can keep the higher adhesive coefficient between wheel/rail system,which can prevent the occurrence of the phenomenon such as wheel-slip; Nitriding treatment not only significantly improve the wear resistance on the surface of the wheel,but also effectively reduce the wear of the rail sample,the amount of damage reduced by 58. 05% and 10. 77%,respectively. In short,the nitriding on wheel for wheel/rail system can effectively reduce the wear,improve the rolling contact fatigue resistance of wheel materials. The method is applied to the actual,it can effectively improve the service life of wheel/rail system,reduce the damage of wheel/rail material under the heavy-load condition.

Carbide coatings are frequently used to improve the wear resistance of industrial components in various wear environments. In this research, aiming at the service characteristics of easy wear and short service life of ball mill liners, WC–10Cr3C2–12Ni coatings were prepared by supersonic flame spraying technology (HVOF). The reciprocating sliding tests were conducted under four different WC particle size conditions, and the differences in the tribological behavior of the coatings and three–body abrasive wear mechanism were obtained. The findings reveal that the average nanohardness of the WC–Cr3C2–Ni coating is nearly five times greater than that of the steel substance. The COF of tribo-pairs decreases and then increases as the particle size increases. In the case of no particles, the surface of the coating is slightly worn, with fatigue and oxidative wear being the primary wear mechanisms. Small particles (1.5 μm and 4 μm) are crushed and coated on the coating surface, in which the extremely fine particles are plasticized to form friction layers that have a protective effect on the coatings. The protective effect of the particles disappears as the particle size increases and is replaced by a powerful chiseling effect on the coatings, resulting in serious material loss. The particle size has a direct relationship with coating wear. [ABSTRACT FROM AUTHOR]

Polymers with relatively higher thermal conductivity are in great demand for many advanced functional applications that often require thermally conductive as well as flexible materials. However, enhancing the thermal conductivity of polymers, while maintaining their mechanical properties, is still a formidable challenge. Here it is reported on the successful fabrication of polyethylene (PE)/boron nitride nanoplate (BNNP) nanocomposite films, with excellent flexibility and ultrahigh through‐plane thermal conductivity, by a uniaxially hot‐stretching process. Results from this study show that the nanocomposite films with ϕv = 6.7 vol% BNNPs, under low stretching ratio (Λ = 5), exhibit a through‐plane thermal conductivity of ≈14.54 W m−1 K−1, about 44.4 times higher than the corresponding bulk value for PE (0.32 W m−1 K−1), while also having improved the Young's modulus of elasticity. The theoretical analysis also shows that such a dramatic enhancement can be attributed to the formation of a 3D continuous network structure within the nanocomposite films. Thus, these flexible films offer possibilities as passive heat exchange matrices in various advanced applications that often require the materials with higher flexibility, lighter weight, easy/scalable processing attributes, and with a higher thermal conductivity. [ABSTRACT FROM AUTHOR]