Studying the tribological properties of mated materials C61900 - A48-25BC1.25BNo. 25 in composite oils containing geomodifiers

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This paper reports a comparative study of the polymeric materials operating in conjugation with steel. In agricultural engineering, a significant role in structural materials belongs to polymer composites. This type of material is characterized by the low price, small technological cost, as well as acceptable processing characteristics. It has been found that it is necessary to form, for each type of mated parts, a set of materials that could maximally meet the operational conditions. To describe the operating conditions in more detail, they need to be generalized for the specific tribological and loading characteristics. Based on this, such load regimes were selected that correspond to the movable mated parts in sowing complexes. For these mated parts, it was necessary, in the course of the tribological study, to choose a material with minimal technological deviations but with enhanced tribotechnical characteristics. The result of this study has established that under the predefined conditions a polymer-composite material with the high-modulus filler PA-6.6+30 % F demonstrates the best tribophysical characteristics compared to the material PA-6.6. The proposed material, in conjugation with steel 1.1191, has a friction coefficient that is 38...41 % lower, while the temperature in the contact area is 8...12 % less, than that in conjugation with the material PA-6.6. Based on the metallographic analysis of friction surfaces, one can argue that a polymer composite with a high-modulus filler creates favorable conditions for their implementation in the moving units of machines. The results reported here make it possible to analyze and synthesize composite materials primarily for agricultural engineering, taking into consideration their tribological properties. The findings may be particularly interesting for service departments and enterprises producing parts for sowing complexes

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Design of mated parts using polymeric materials with enhanced tribotechnical characteristics

Kobets

Аулин

Derkach

et al. 2020

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“…The non-stable processes in the operation of friction nodes in automotive equipment in the presence of motor lubricants were considered in papers [6][7][8][9]. The experimental studies have established the effect of various additives to oils on the stabilization of friction forces and reducing the wear of rubbing surfaces.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

“…Expressions (14), (15) describe the right-hand (high-frequency) side of the threesomes of disturbances (8). The low-frequency part of these threesomes with the energy ΔE competes with two high-frequency components in view of the sharp increase in the role of forced thermal radiation relative to the spontaneous one with an increase in the wavelength.…”

Section: The Pseudo-equilibrium and Collapse Models Of Contact Disturmentioning

confidence: 99%

Exchange interaction and models of contact generation of disturbances in tribosystems

Zaspa

Dykha

Marchenko

et al. 2020

The physical mechanisms have been investigated that form and transform the corpuscular-vortex-wave thermal complexes of disturbances in contact tribosystems based on the quantum-mechanical exchange interaction. The presence of a contact gap determines the generation of pairs of quasi-particles-disturbances stabilized by wavelength and frequency. Internal instability and collapse processes in such a system of disturbances lead to the formation of defects in a tribopair's material and underlie the emergency friction regimes. This paper gives specific technical examples of the generation of thermal complexes at fretting, during the friction of sliding and rolling, and at cutting. It has been established that the destructive nature of the process of fretting at low values of reverse sliding speeds is caused by the generation and collapse of the corpuscular-vortex-wave thermal complexes. An example of acoustic friction emission in the ultrasonic region of the spectrum has been used to show the quantum nature of the disturbances generated by friction. The high-frequency spectrum of acoustic emission corresponds to the unbalanced composition of the disturbances and leads to the formation of wear particles. The exchange interaction in a tribosystem involving rolling on the plane has been considered. The results of statistical analysis of such rolling showed the existence of the effect of negative friction caused by the quantum generation of longwave disturbances. It has been demonstrated that the collapsed component of the generation of disturbances is significantly increased under the modes of materials destruction, including when cutting the materials. The corpuscular-vortex-wave mechanism of selective transfer and hydrogen wear in tribosystems has been described. It is shown that the properties of a servovite film under the mode of selective transfer are provided by the collapse processes in the system of disturbances. Similar processes at the vortex-wave transfer of hydrogen atoms in metals lead to the wear and destruction of the surface layer of friction

“…With the development of nanomaterials, in tribology, it was possible to effectively use functional additives in the form of geomodifiers [1,2]. It was revealed that oils modified with nanomaterials, which form dispersed systems in lubricants, increase the durability of working surfaces of different types of tribosystems.…”

Section: Introductionmentioning

confidence: 99%

Development of a rheological model of stress relaxation in the structure of an oil film on the friction surface with fullerene additives

Suska

Biekirov

Levkin

2021

A rheological model of stress relaxation in a thin lubricant film, which is formed on the friction surface under the influence of the force field of the friction surface in the presence of fullerene compositions in lubricants, was developed. Analysis of the model made it possible to establish that the existence of elastic or viscous properties in surface structures depends on the ratio of two parameters. This is the time of stress relaxation in the structure on spots of actual contact and the duration of stress action on these spots, which is termed the lifetime of an actual contact spot. It was shown that an increase in the sliding rate reduces the time of relaxation of stresses in the surface structure. This is due to the destruction of aggregates in the structure of gel and the appearance of rotational movements of separate units ‒ flocs. An increase in the load on the tribosystem significantly increases the value of relaxation time. This is due to squeezing the viscous component out of the structure of a surface film. It was established that if the relaxation time exceeds the duration of actions of stresses on actual contact spots, the structure of a surface film behaves like an elastic solid. Conversely, if relaxation time becomes shorter than the duration of stress action, the film behaves like a viscous medium. Theoretically, it was shown that in the range of sliding and loading rates, when a film behaves like an elastic solid, a decrease in stresses on actual contact spots does not exceed the values of 1.1‒22.8 %. This property provides the bearing capacity of a film. The development of the model will make it possible to simulate elastic and viscous properties of "stitched" structures and substantiate the rational concentrations of additives to lubricants, as well as the ranges of their use.