Воздействие дуплексной обработки на механические свойства нержавеющей стали марки 316L

The results of experimental research on modifying the surface layer of 316L steel by duplex treatment are presented. The latter includes ion-plasma treatment in a nitrogen atmosphere with subsequent plasma-enhanced chemical vapor deposition of hydrocarbon films doped with silicon and oxygen (a-C:H:SiOx). Mechanical properties of steel surface (hardness, modulus of elasticity, plasticity index, plastic deformation resistance) were determined by the nanoindentation method, and adhesion of the films was evaluated by a scratch test. It was found that the greatest improvement in the mechanical properties of the film-substrate system occurs after the deposition of a-C:H:SiOx film on a surface previously hardened in a nitrogen plasma.

Solidification and superlubricity with molecular alkane films

Hydrocarbon films confined between smooth mica surfaces have long provided an experimental playground for model studies of structure and dynamics of confined liquids. However, fundamental questions regarding the phase behavior and shear properties in this simple system remain unsolved. With ultrasensitive resolution in film thickness and shear stress, and control over the crystallographic alignment of the confining surfaces, we here investigate the shear forces transmitted across nanoscale films of dodecane down to a single molecular layer. We resolve the conditions under which liquid–solid phase transitions occur and explain friction coefficients spanning several orders of magnitude. We find that commensurate surface alignment and presence of water at the interfaces each lead to moderate or high friction, whereas friction coefficients down toμ≈0.001are observed for a single molecular layer of dodecane trapped between crystallographically misaligned dry surfaces. This ultralow friction is attributed to sliding at the incommensurate interface between one of the mica surfaces and the laterally ordered solid molecular film, reconciling previous interpretations.

Main Pattern of the Caspian Sea Surface Oil Pollution Revealed by Satellite Data

Over the years, oil pollution has been the primary environmental problem of the Caspian Sea. In this paper, we present the results of our satellite survey in 2019 of the whole aquatic area of the Caspian Sea. These results reveal the spatial and temporal distribution of hydrocarbon films of various origins on the sea surface. Our primary attention was focused on the main types of petroleum hydrocarbon films polluting the sea surface. They get into the aquatic area via several different ways: (i) from natural marine hydrocarbon emissions from the seabed; (ii) from the mouths of numerous mud volcanoes; (iii) from offshore oil production and transportation; (iv) from oily wastewaters discharged by ships. We mapped the petroleum hydrocarbon pollution of the Caspian Sea surface on the base of satellite data. For each type of pollution, specific manifestation features were revealed, regions of regular pollution occurrence were outlined, and polluted areas were estimated. The relative contribution of every kind of pollution to the total oil pollution of the Caspian Sea is assessed on the base of satellite data. Comparison with the previous results of our long-term survey of the Caspian Sea is made. The problem of reliability of quantitative estimates of surfaced oil volumes on the base of slick areas seen in the satellite images is discussed.