Multilayered antifriction nanostraction covering for lubrication in the tribocoupling

In article principles of creation of a new way of the lubrication a wheel-rail tribosystem by drawing on a lateral side of a rail head of a multilayered antifriction nanostructurial covering possessing property of blocking negative segregation phenomena in metals of a wheel and a rail are considered

Boriding of steel surface with beams of boron atoms

We consider a new method for hardening the steel surface, which differs from the known CHT boriding method in the possibility of creating a surface with a lower fragility. Within this approach, the boriding is carried out by treating the steel surface with atomic beams of boron at a temperature below 750 °C. In this case, a friable layer of pure boron appears on the outer surface of the steel. Then, boron atoms diffuse from this layer into the surface layers of the steel. To detect boron in a steel sample, we used the X-ray photoelectron spectroscopy method. With its help we have obtained spectra of both the outer surface of a steel sample and surface layers at depths up to 8 nm. The spectra of the surface layers showed that as a result of boriding in the sample there appeared the boron in the zero oxidation state. This fact is consistent with the notion that, in the case of a small concentration of boron, it is located on the boundaries between the grains in the surface layer of steel and strengthens the bonds between the boundaries

Tribological Properties of Ultrananocrystalline Diamond Films: Mechanochemical Transformation of Sliding Interfaces

Improving the tribological properties of materials in ambient and high vacuum tribo-conditions is useful for inter-atmospheric applications. Highly-hydrogenated and less-hydrogenated ultrananocrystalline diamond (UNCD) films with distinct microstructural characteristics were deposited on Ti-6Al-4 V alloy, by optimizing the plasma conditions in the chemical vapor deposition. Both the UNCD films showed less friction coefficient in ambient atmospheric tribo-contact conditions due to the passivation. This provides chemical stability to UNCD films under the tribo-mechanical stressed conditions which limits the transferlayer formation and conversion of UNCD phase into graphitization/amorphization. However, in the high vacuum tribo-conditions, highly-hydrogenated UNCD films showed low friction value which gradually increased to the higher magnitude at longer sliding cycles. The low friction coefficient was indicative of passivation provided by the hydrogen network intrinsically present in the UNCD films. It gradually desorbs and the dangling bonds are progressively activated in the contact regime, leading to a gradual increase in the friction value. In contrast, less-hydrogenated UNCD films do not exhibit low friction regime in high vacuum conditions due to the lack of internal passivation. In this case, the conversion of UNCD to amorphized carbon structure in the wear tracks and amorphous carbon (a-C) tribofilm formation on ball scars were observed. © 2017 The Author(s)1

Multilayered antifriction nanostraction covering for lubrication in the tribocoupling "wheel-rail"

In article principles of creation of a new way of the lubrication a wheel-rail tribosystem by drawing on a lateral side of a rail head of a multilayered antifriction nanostructurial covering possessing property of blocking negative segregation phenomena in metals of a wheel and a rail are considered