scholarly journals Wear resistance of nanostructured metal-polymer self-lubricating powder composites

2021 ◽  
Vol 66 (2) ◽  
pp. 154-160
Author(s):  
V. N. Pasovets ◽  
V. A. Kovtun ◽  
Yu. M. Pleskachevsky
Keyword(s):  
Carbon Nanoparticles ◽  
Friction Surface ◽  
Copper Matrix ◽  
Strength Properties ◽  
Transportation Industry ◽  
Friction Zone ◽  
Polymer Layers ◽  
Polymer Filler ◽  
The Coefficient Of Friction ◽  
Powder Composites

Tribotechnical tests and microstructural studies were carried out. Wear mechanism of nanostructured metalpolymer self-lubricating composite materials has been established. This mechanism involves in the formation of separating polymer layers on the friction surface, which reduces the coefficient of friction and running-in period of parts of friction units. Carbon nanoparticles move along the friction surface, hinder the development of seizure processes during the interaction of microroughnesses of the contacting surfaces of the material and the counterbody during the destruction of the separating polymer layers. It was found that the polymer filler is displaced from the friction zone, carbon nanoparticles are pressed into the open areas of the surface of the copper matrix of the composite when the pressure in the tribocontact is higher than 1.5 MPa. The temperature in the tribocontact increases, the polymer filler degrades, the carbon nanoparticles are removed from the friction zone, the strength properties of the composite decrease, the friction coefficient and the wear rate increase at a sliding speed above 1.5 m/s. The obtained research results can be used in mechanical engineering, transportation industry and power engineering.

scholarly journals Investigation of Structure and Physico-Mechanical Properties of Composite Materials Based on Copper - Carbon Nanoparticles Powder Systems

2015 ◽  
Vol 60 (1) ◽  
pp. 51-55
Author(s):  
V. Kovtun ◽  
V. Pasovets ◽  
T. Pieczonka
Keyword(s):  
Mechanical Properties ◽  
Mechanical Activation ◽  
Metal Matrix ◽  
Carbon Nanoparticles ◽  
Copper Matrix ◽  
Metal Particles ◽  
Powder Materials ◽  
Sintered Copper ◽  
Mechanical Bonding ◽  
Preliminary Mechanical Activation

Abstract Physico-mechanical and structural properties of electrocontact sintered copper matrix- carbon nanoparticles composite powder materials are presented. Scanning electron microscopy revealed the influence of preliminary mechanical activation of the powder system on distribution of carbon nanoparticles in the metal matrix. Mechanical activation ensures mechanical bonding of nanoparticles to the surface of metal particles, thus giving a possibility for manufacture of a composite with high physico-mechanical properties.

The Data Processing Technique of Metallic Sheet Friction Coefficient Determination

2012 ◽  
Vol 184-185 ◽  
pp. 688-691
Author(s):  
Huan Xue ◽  
Rong Feng Li ◽  
Hong Chuan Zhu
Keyword(s):  
Data Processing ◽  
Coefficient Of Friction ◽  
Normal Pressure ◽  
Processing Technique ◽  
Test Results ◽  
Friction Zone ◽  
Data Processing Method ◽  
The Coefficient Of Friction ◽  
Processing Techniques ◽  
Metallic Sheet

The definition and research background of friction is introduced. The reason of generation of friction is analyzed, the importance of the coefficient of friction test in sheet metal forming field is indicated. The testing principle of coefficient of friction on metallic sheet is presented. The basic data processing method of the test is described. Two important data processing techniques which will obviously effects the test results, including effective friction zone and normal pressure have been carefully studied. The comparison result shows these techniques can effectively enhance the testing stability and precision.

scholarly journals Influence of basalt fiber on tribological properties of secondary polyethylene terephthalate

2021 ◽  
Vol 100 (2) ◽  
pp. 58-64
Author(s):  
A.-M. Tomina ◽  
◽  
A. Yerоmenko ◽  
V. Makarov ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polyethylene Terephthalate ◽  
Polymer Matrix ◽  
Tribological Properties ◽  
Basalt Fiber ◽  
Fiber Content ◽  
Linear Wear ◽  
Friction Zone ◽  
Initial Polymer ◽  
The Coefficient Of Friction

The article considers the influence of discrete (3 mm) basalt fiber on the tribological properties of secondary agglomerated polyethylene terephthalate. It was found that the introduction of the filler reduces the coefficient of friction and the intensity of linear wear of the initial polymer 1,5 and 4,5 times, respectively, reaching the minimum values at a basalt fiber content of 5 mass.%. The obtained results are due to the fact that the appearance of basalt fiber strengthens the polymer matrix that confirms the increase in hardness by 15%, and inhibits the development of cracks on the surface of the composite. The study of the temperature in the contact zone showed its increase that is due to the low thermal conductivity of the filler (0,064 - 0,096); as a result, there is an accumulation of heat in the friction zone. Further increase in fiber content (up to 10 mass.%) leads to a sharp deterioration of the tribological and physico-mechanical properties of basaltoplastics because of the increase in the defect of the material. It is determined that the effective content of filler in the polymer matrix is 5 mass.%. As a result, this composite was recommended for the manufacture of parts for movable joints of agricultural, automotive and metallurgical equipment.

Application of Thermodynamic Modeling for Optimization of the Composition of Nanostructured Low-Alloyed Hafnium Bronzes by High-Pressure Torsion

2021 ◽  
Vol 410 ◽  
pp. 85-90
Author(s):  
Alexey V. Stolbovsky ◽  
Polina Y. Shirshova
Keyword(s):  
Experimental Data ◽  
Precipitation Hardening ◽  
Mechanical Characteristics ◽  
High Pressure Torsion ◽  
Copper Matrix ◽  
Strength Properties ◽  
Average Grain Size ◽  
Hardness Values ◽  
Determining Factor ◽  
Thermal Stability Of

According to the results of thermodynamic calculations, it has been determined that the usage of alloys with Hf content near to its maximum possible value solubility in the copper matrix is not appropriate. It is more appropriate to use alloy compositions with lower Hf content. With the help of calculations and analysis of experimental data, it has been established that in order to ensure the thermal stability of SPD-formed structures it is sufficient to obtain a concentration of dissolved in copper matrix Hf of about 0.01 at.%. It has also been shown that the average grain size formed by the SPD is a determining factor in the strength properties of these alloys; an increasing Hf concentration in the copper matrix is not always a condition for higher hardness values. However, higher concentrations of dissolved hafnium in the copper matrix will determine the higher mechanical characteristics of precipitation hardening of the alloys after heat treatment.

Study of Metal Friction Materials Using Hot Press

2013 ◽  
Vol 750-752 ◽  
pp. 2084-2087
Author(s):  
Shenq Yih Luo ◽  
Can Yu Bai
Keyword(s):  
Coefficient Of Friction ◽  
Wear Mechanisms ◽  
Bending Strength ◽  
Copper Matrix ◽  
Friction Material ◽  
The Other ◽  
Hot Press ◽  
Friction Materials ◽  
The Coefficient Of Friction ◽  
Metal Friction

The metal friction materials of copper matrix with and without resin using hot press were investigated to study their hardness, porosities, bending strengths, microstructures, coefficient of frictions, and wear mechanisms. The experiment results show that the hardness and bending strength of the friction materials with increase of amount of copper increase, but the porosity decreases. The resulting coefficient of frictions show more stable and their values are about 0.5~0.6. In addition, the wear mechanism of friction material shows mainly grit abrasive and adhesion, which cause the coefficient of friction to become stable. On the other hand, when the copper matrix containing resin is used, the resulting porosity of friction materials becomes higher and the bending strength decreases. This shows that the wear mechanisms of grit abrasive, roughness, and adhesion cause the coefficient of friction to produce a higher value.

scholarly journals Investigation of the structural viscosity of oil films on the friction surface with fullerene compositions

2021 ◽  
Vol 99 (1) ◽  
pp. 13-19
Author(s):  
A. Kravtsov ◽  
Keyword(s):  
Dynamic Viscosity ◽  
Friction Surface ◽  
Theoretical Studies ◽  
Structural Viscosity ◽  
Electrostatic Forces ◽  
Gel Structure ◽  
Structural Dynamic ◽  
Oil Film ◽  
The Coefficient Of Friction ◽  
Oil Films

The paper presents theoretical studies of changes in the structural viscosity of oil films on the friction surface with fullerene compositions in the field of action of electrostatic forces of the friction surface and the base lubricant. A feature of the use of fullerene additives in lubricants is that fullerenes are readily soluble in a wide class of organic and inorganic solvents. At the same time, poor solubility of fullerenes in technical oils (mineral, semi-synthetic and synthetic). The purpose of this work is to carry out theoretical studies of changes in the structural viscosity of oil films on the friction surface with fullerene compositions in the field of action of electrostatic forces of the friction surface and the base lubricant. On the basis of the working hypothesis, it was theoretically established that for a thin oil film, located in the field of action of electrostatic forces of the friction surface, it is necessary to consider the structural dynamic viscosity of the lubricant, which at the friction surface has a gel structure, and as the electrostatic forces from the friction surface decrease, the gel structure transforms into the sol structure. It is shown that the value of the structural viscosity of the considered aggregates is comparable with the viscosity of polymers or bitumen. Moreover, the viscosity of the gel structure is four orders of magnitude higher than the viscosity of the sol structure. An increase in the concentration of fullerenes leads to an increase in the dynamic viscosity of aggregates. It is theoretically shown that the structure of the oil film, which corresponds to the structure of the gel, belongs to the class of non-Newtonian fluids. With an increase in the sliding speed, the dynamic viscosity of such structures decreases by a factor of 4, which explains the destruction of micelle clusters and the appearance of rotational motions of elastic flocks. It is assumed that this will lead to a decrease in the value of the coefficient of friction. It is shown that for the gel structure, the concentration of fullerenes in the bulk of the base lubricant does not have a large effect on the structural viscosity. Conversely, for the structure of a sol, the concentration of fullerenes has a significant effect on the value of the structural dynamic viscosity.

scholarly journals Ways to improve the reliability of the nodes of the rolling mill

2020 ◽  
pp. 10-19
Author(s):  
Oleksii Hrechanyi ◽  
Tatiana Vasilchenko ◽  
Yukhym Linnyk ◽  
Oleksii Riazanov ◽  
Andriy Shein
Keyword(s):  
Coefficient Of Friction ◽  
Rolling Mill ◽  
Average Diameter ◽  
The Body ◽  
Correct Selection ◽  
Screw Thread ◽  
Working Capacity ◽  
Friction Zone ◽  
The Coefficient Of Friction ◽  
Selection Of

The performance of the crimping mill is determined by the speed of the pressure device. The main purpose of the pressure device is to regulate the relative position of the rolls, which is necessary to ensure the rolling of the profile of a given size and predetermined reductions, and in reversing mills, the distance between the rolls changes almost after each pass.An industrial survey of crimping rolling mills has shown that their reliability and durability significantly depend on the working capacity of the friction units, one of which is a screw pair of a pressure device. At this time, there is no information in the literature on the patterns of wear intensity of turns of screw pairs of rolling mills.Basically, increasing the resistance of nuts is done by balancing the load on the threads by changing the shape of the body of the nut. All these structural improvements of the nuts of the screw pair of the pressing mechanisms should be taken into account at the stage of designing the rolling stand, since changing the external shape of the nut can cause inevitable downtime of the production line associated with the coordination of seats in the bed of the rolling mill, which are unacceptable in the conditions of continuous production.In order to increase the working capacity of the screw pair of the pressing mechanism of the crimping mill, the task was set to analytically study the influence of the design of the threaded connection of the screw pair of the pressing mechanism on its efficiency.For crimping mills, in contrast to rolling a strip or sheet, more important is the speed of the pressure mechanism. An increase in the thread pitch leads to an increase in the efficiency of the helical gear, but the use of a thread with a large pitch has limitations associated with the displacement of the average diameter to the projections of the thread, reducing its reliability and the accuracy of the gap between the rolling rolls. Screw thread - single thrust resistant. If you thread according to current standards, only the friction angle in the thread remains - a factor that can be varied with an increase in the efficiency of the screw pair.The decrease in the angle of friction in the thread, with its proportional dependence on the coefficient of friction-slip, causes a significant increase in the efficiency of the screw pair. Reducing the coefficient of friction-slip is possible by the correct selection of rubbing pairs and the timely supply of lubricant to the friction zone. Since in the process of rolling technological operations, moments may occur when the lubricant is not supplied to the friction zone, one of the ways to increase the efficiency of the threaded joint should be the option of the correct selection of friction pairs that are less affected by the lack of lubricant supply to the friction zone.

Evaluation of the tribological properties of two PEEKs sliding against Al2O3, WC and DLC coatings under dry friction and water lubrication

2021 ◽  
Author(s):  
Bin Lin ◽  
Hongbo Zou ◽  
Yaqi Meng ◽  
Tianyi Sui ◽  
Shuai Yan
Keyword(s):  
Wear Resistance ◽  
Dry Friction ◽  
Friction Surface ◽  
Friction And Wear ◽  
Water Lubrication ◽  
Carbon Fibres ◽  
Dlc Coatings ◽  
Pin On Disc ◽  
The Coefficient Of Friction ◽  
Tribology Performance

Abstract The tribology performance of two carbon fibre-reinforced polyether-ether-ketones (450FC30 and WG101) sliding against stainless steel 3Cr13 and 3Cr13 coated with aluminium oxide (Al2O3), tungsten carbide (WC) and diamond-like carbon (DLC) under dry friction and water lubrication were studied to reduce the coefficient of friction and improve the wear resistance of water-lubricated bearings. The friction and wear mechanism of different tribopairs were determined via pin-on-disc sliding tests. Experimental results showed that the WG101/Al2O3 tribopair exhibited excellent wear resistance under dry friction and water lubrication. Carbon fibres were exposed on the friction surface of WG101 when WG101 slid against Al2O3. These carbon fibres bore most of the load to reduce wear. This work provides a practical basis for selecting the optimal tribopair for water-lubricated bearings.

Research on the Mixing way and Content of Molybdenum Disulfide with Copper Matrix Self-Lubricating Composites

2014 ◽  
Vol 1015 ◽  
pp. 42-45
Author(s):  
Xu Ran ◽  
Xiang Ren ◽  
Hao Hao Zou ◽  
Yi Fei Ye
Keyword(s):  
Molybdenum Disulfide ◽  
Mass Fraction ◽  
Three Dimensional ◽  
Copper Matrix ◽  
Lubricating Film ◽  
Dimensional Network ◽  
The Coefficient Of Friction ◽  
New Type ◽  
Powder Metallurgy Route ◽  
Self Lubricating Composites

The new type of copper matrix self-lubricating composites were prepared by powder metallurgy route. The influences of milling way and content of molybdenum disulfide on composites’ microstructure and tribological properties were researched. It is found that, MoS2 can’t participate in the process of mechanical alloying together with graphite and copper powder. When the mass fraction of MoS2 increases from 0% to 10%, the coefficient of friction of composites MoS2-G-Cu reduces correspondingly, however the three-dimensional network structure of copper matrix was damaged seriously in sample 10% MoS2-G-Cu .After the wear text there will come out solid self-lubricating film on the surface of sample 5% MoS2-G-Cu and 10% MoS2-G-Cu .

scholarly journals 3D simulation of dry friction of metal-based composites

2019 ◽  
Vol 221 ◽  
pp. 01046
Author(s):  
Alexey Smolin ◽  
Galina Eremina ◽  
Dmitriy Parpura
Keyword(s):  
Contact Region ◽  
Plastic Body ◽  
Friction Zone ◽  
Elastic Plastic ◽  
Quasi Liquid Layer ◽  
The Coefficient Of Friction ◽  
Basic Parameters ◽  
Cellular Automaton Method ◽  
Model Of Friction ◽  
Von Mises

A numerical 3D model of friction at mesoscale of the contact patch between steel samples and composite steel samples with carbon nanoinclusions has been developed based on the movable cellular automaton method. The response function of automata simulating steel corresponds to an elastic-plastic body with linear hardening, and the function for simulating carbon corresponds to an elastic-plastic body with bilinear hardening. Von Mises criterion is used for breaking bonds between the automata, and the criterion based on plastic heat is used for coupling the automata. The values of basic parameters of the model, as well as the loading conditions, that allow the formation of the characteristic quasi-liquid layer in the friction zone are determined. It was shown that the presence of carbon nanoinclusions in the contact region leads to decreasing of the coefficient of friction, lower values of stress, and higher shear strain in the friction zone.

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