Yu. A. Fadin

Synthesis and tribotechnical properties of composite coatings with PM–DADPE polyimide matrix and fillers of tungsten dichalcogenide nanoparticles upon dry sliding friction

A synthesis is described and tribological characteristics are presented for composite coatings 40 μm thick with a PM–DADPE polyimide matrix and a filler of tungsten disulfide nanoparticles with size of 4 nm and tungsten diselenide nanoparticles 60 × 5 nm in size obtained via gas-phase synthesis.

Composite coatings based on A–OOO polyimide and WS2 nanoparticles with enhanced dry sliding characteristics

One- and two-step syntheses of composite coatings with an A–OOO polyimide matrix filled with 40-nm tungsten disulfide nanoparticles produced using gas-phase synthesis, which are intended for operation under dry friction conditions, are described. Results of studying the tribological behavior of these coatings are presented.

Application of acoustic emissions for mass wear analysis

An experimental method is considered for measuring the mass wear of friction pairs during operation. The method is based on the analysis of acoustic emission characteristics. The conditions for creation of the experimental data array are discussed. A formula for computing the mass wear as a function of the total energy of the acoustic emission signals was derived.

Synthesis and dry sliding behavior of composite coating with (R–OOO)FT polyimide matrix and tungsten disulfide nanoparticle filler

The synthesis of a composite coating with an (R–OOO)FT polyimide matrix is described and results of studying the tribological behavior of this coating are presented. Spherical 40-nm tungsten disulfide nanoparticles produced using gas-phase synthesis are used as a filler.

Excitation of the elastic half-space surface by normal rebounding impact of an indenter

A dynamic contact problem of the linear theory of elasticity regarding the response of the elastic half-space surface to the normal impact of an indenter is considered. If the indenter is spherical, the Hertzian theory serves to determine the impact parameters. The displacements of points on the surface remote from the contact spot are described by solving Lamb’s problem. In the case of impacts by a flexible plate indenter that transfers uniformly distributed load to the elastic half-space surface, a first order asymptotic model is applied, which takes into account the dissipative properties of the elastic base due to elastic energy transfer by waves to infinity. The main results of the work are obtained in closed form.

Mathematical modeling of the periodic wear process in elastic contact between two bodies

A mathematical model is constructed of periodic phenomena that evolve in the process of wearing of two contacting bodies in dry friction. The derivation of the solution assumes that the Kragelskii criterion is a variable value. In particular, the model describes combined fluctuations of wear rates of subsurface layers and values characterizing variations in the roughness of each contacting surface. The main results of the work are theoretical in nature and they can be treated as the basis of experimentation with two contacting bodies exposed to periodic wear.

Dynamics of surface damage in dry friction

A new approach is proposed to describe friction, based on the dynamic interaction of surface roughnesses. An analysis is made of two types of interaction, one causing only deformation of the roughnesses and the other ultimately leading to the appearance of damage particles.

Acoustic emission and surface roughness of brittle materials

An approach to evaluation of the surface roughness of brittle materials during friction (without stopping the process) is developed that is based on measurement of friction-induced acoustic emission signals.

Tribotechnical Properties of Composite Material “Aluminum–Carbon Nanofibers” under Friction on Steels 12Kh1 and ShKh15

Antifriction and wear-resistant properties of “aluminum–carbon nanofiber” composite materials fabricated using various hot pressing modes are studied under dry sliding friction on 12Kh1 and ShKh15 steels. The best tribotechnical characteristics are achieved in a composite material with 1.5% CNF. The antifriction effect of carbon nanofibers manifests itself upon crack initiation and during the motion of friction surfaces relative to each to other.

Antiwear Properties of Composite Greases “Litol-24–Magnesium Hydrosilicate Particles”

Addition of magnesium hydrosilicate particles (talcum and serpentinite) with sizes of 1–30 μm to Litol-24 ARGO grease reduces surface wear of balls made of steel grade ShKh15. Between friction surfaces, local metal–mineral composite films are generated with high microhardness which reduce wear of friction elements. Forsterite, wollastanite, and some other modifications serve as minerals; they are generated owing to solidification of talcum and serpentinite under high pressures and temperatures.