scholarly journals Optimization of Mechanical Properties of Cr3C2-Ni20Cr/Graphite Cold Sprayed Coatings

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3458
Author(s):  
Wojciech Żórawski ◽  
Anna Góral ◽  
Medard Makrenek ◽  
Dominika Soboń ◽  
Anna Trelka ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Coefficient Of Friction ◽  
Solid Lubricant ◽  
Gas Composition ◽  
Graphite Content ◽  
Process Gas ◽  
The Coefficient Of Friction ◽  
Parameter Values ◽  
Sprayed Coatings ◽  
Friction Analysis

This study analyzed the mechanical properties of cold-sprayed Cr3C2-25(Ni20Cr) blended with Ni-graphite as a solid lubricant deposited on 7075 aluminum alloy substrate. To optimize the coating properties, different sets of parameters (graphite content in feedstock, process gas composition, spraying distance, and traverse gun speed) were tested in the frame of the Taguchi experiment. The cold-sprayed coatings were evaluated for their chromium carbide and graphite content, hardness, and coefficient of friction. Analysis of the microstructure of the deposited coatings revealed that graphite as a soft and brittle component fills all voids in the coating and its quantity depends on its content in the feedstock. The experimental results show that the composition of the process gas has the greatest impact on the Cr3C2 content in the coating and the proportion of graphite in the sprayed blend directly affects its hardness. In the case of the coefficient of friction, the most significant parameters were the graphite content in the sprayed blend, the spraying distance, and process gas composition. The conducted verification experiment with the optimum parameter values allowed a coating with the highest hardness and the lowest coefficient of friction to be obtained.

scholarly journals МОДЕЛЮВАННЯ ПРОЦЕСУ ТЕРТЯ В ТЕКСТИЛЬНИХ МАТЕРІАЛАХ

2020 ◽  
Vol 144 (2) ◽  
pp. 45-53
Author(s):  
Н. П. Супрун ◽  
М. Л. Рябчиков ◽  
І. О. Іванов
Keyword(s):  
Mechanical Properties ◽  
Coefficient Of Friction ◽  
Textile Material ◽  
Structural Elements ◽  
Friction Process ◽  
Textile Materials ◽  
Factors Influencing ◽  
The Coefficient Of Friction ◽  
Properties Of Materials ◽  
Main Factors

Create a model for determining the coefficient of friction of textile materials to identify the main factors influencing the process of friction, taking into account the structural and mechanical properties of materials. Modeling of friction process in textile materials as a combination of adhesive and elastic phenomena. Roughness of solid bodies and the main parameters of roughness, such as the height of micro-irregularities, their pitch, sharpening, etc. described in many standards and scientific papers. However, the modeling of the friction process in such systems is very complicated due to the irregularity of distribution of microroughness. The analysis of literature data showed that the surface roughness of textile materials is an important and effective factor in predicting the tactile properties of products for various purposes. Estimation of surface roughness is usually carried out using subjective and objective methods, and the latter can be contact and non-contact. The paper develops a model for determining the coefficient of friction of textile materials to identify the main factors influencing the friction process, taking into account the structural and mechanical properties of materials. Friction force is presented as a combination of two main factors. The first is the elastic resistance to deformation, the second is the adhesive resistance to compression of the structural elements of the material. The main parameters influencing the coefficient of friction of textile fabrics - modulus of elasticity of structural elements, their geometrical parameters - surface density of textile material, linear density of structural elements are established. The obtained results allow to qualitatively predict the friction forces of a textile material with known parameters of its structural elements, as well as to normalize these parameters to create materials with specified friction indices. The obtained results make it possible to select the threads that form the textile material, according to the values of the modulus of elasticity, thickness, location density to ensure the minimum friction force.

Morphological Characteristics and Physical & Mechanical Properties of seeds of small-seeded crops

2020 ◽  
pp. 27-35
Author(s):  
Elchyn Aliiev ◽  
◽  
Christina Lupko ◽  
Keyword(s):  
Mechanical Properties ◽  
Coefficient Of Friction ◽  
Morphological Characteristics ◽  
Physical And Mechanical Properties ◽  
Specific Weight ◽  
Test Material ◽  
Effective Diameter ◽  
Morphological Parameters ◽  
Separation Processes ◽  
The Coefficient Of Friction

To create a database and systematize the seeds of samples of small-seeded crops, it is necessary to determine the patterns of influence of morphological parameters on their physical and mechanical properties. The development of the latest technologies and technical devices for cleaning and separation is possible due to the understanding of the characteristic morphological parameters for each of the small-seeded crops. The aim of the research is to determine the physical and mechanical properties of the seed material of small-seeded crops (mustard, flax, ryegrass, rapeseed), necessary to increase the efficiency of their cleaning and separation processes. To achieve this goal, a plan of experimental research was developed, which provided for the determination of physical and mechanical parameters of seeds of small-seeded crops, namely: indicators that characterize the flowability of seeds (angle of natural bias); frictional properties of seeds (static coefficient of friction); porosity (density) and density; size and mass characteristics of seeds (length, width, thickness, effective diameter, weight of 1000 seeds). It is established that the physical and mechanical properties of seeds of small-seeded crops are greatly influenced by its humidity. With increasing humidity, the performance of the test material increases. This is due to the fact that with increasing humidity, the shape of the seed almost turns into a spherical, which, in turn, leads to an increase in the curvature of the surface and reduce the points of contact between the seeds. As a result, the angle of natural inclination increases. The coefficient of friction of seeds of small-seeded crops depends on the roughness of the friction surface and decreases with increasing humidity. This is due to the fact that with increasing humidity decreases the forces of molecular attraction of the seed coat to the surface of the material. Seed density increases with increasing humidity. From this we can conclude that the absorption of moisture by the investigated material increases the total weight of the seed, and as a result - increases its specific weight.

A Theory of Thermo-Elastohydrodynamic Lubrication of Liquid-Solid Lubricated Cylinders

1990 ◽  
Vol 112 (2) ◽  
pp. 259-265 ◽  
Author(s):  
M. M. Khonsari ◽  
S. H. Wang ◽  
Y. L. Qi
Keyword(s):  
Mechanical Properties ◽  
Solid Lubricant ◽  
Elastohydrodynamic Lubrication ◽  
Solid Lubricants ◽  
Theoretical Development ◽  
Rheological Characteristics ◽  
Combined Effects ◽  
Line Contact ◽  
The Coefficient Of Friction ◽  
Bounding Surfaces

The purpose of this research is to extend the theory of the concentrated thermo-elastohydrodynamic line contact to include the influence of the existence of solid lubricant dispersed in liquid-base lubricant. The combined effects of the rheological characteristics of the oil and the mechanical properties of the particles and those of the bounding surfaces are taken into consideration in theoretical development. Results are presented for the pressure distribution, the oil film thickness, the temperature rise, and the coefficient of friction for two commonly used solid lubricants namely MOS2 and graphite.

Simulating the Mechanical Properties of a Yarn Based on the Properties and Arrangement of its Fibers Part II: Results of Simulations

1997 ◽  
Vol 67 (5) ◽  
pp. 342-347 ◽  
Author(s):  
Lieva Van Langenhove
Keyword(s):  
Mechanical Properties ◽  
Theoretical Model ◽  
Coefficient Of Friction ◽  
Stress Strain ◽  
Fiber Property ◽  
The Coefficient Of Friction ◽  
Predicted Values

Part I established a theoretical model that was able to predict the stress-strain and torque-strain curves of a yarn. This second part evaluates the model. The influence of fiber and yarn parameters on the predicted values is also discussed. The most critical fiber property is the coefficient of friction.

Effect of Copper on the Friction Properties of Gray Cast Iron

2014 ◽  
Vol 698 ◽  
pp. 364-368 ◽  
Author(s):  
Natalia Stepanova ◽  
Elena Lozhkina ◽  
Alexey Razumakov
Keyword(s):  
Mechanical Properties ◽  
Cast Iron ◽  
Coefficient Of Friction ◽  
Copper Content ◽  
Gray Cast Iron ◽  
Gray Cast ◽  
The Coefficient Of Friction ◽  
Effect Of Copper ◽  
20 Nm

The structure and mechanical properties of gray cast iron with a copper content of from 0.08 to 14.7 wt. % is investigated. Inclusions of ε-copper ranging from 20 nm to 240 microns are formed in the structure with an content of Cu and 0,9 % Al 14,7 % Cu. Increasing a copper content in iron results in increasing the microhardness of pearlite and reducing the coefficient of friction

Influence of corrosion on prestress strands

1999 ◽  
Vol 26 (6) ◽  
pp. 782-788 ◽  
Author(s):  
SMR Lopes ◽  
L MLP Simões
Keyword(s):  
Mechanical Properties ◽  
Coefficient Of Friction ◽  
Prestressed Concrete ◽  
Surface Condition ◽  
Fatigue Properties ◽  
Structural Members ◽  
The Coefficient Of Friction ◽  
Bond Characteristics ◽  
Beams And Girders ◽  
Prestressed Beams

Corrosion on prestress strands affects their mechanical properties as well as the coefficient of friction in the surface strand/duct. In previous research on prestress beams, the authors have observed different coefficients of friction depending on the surface condition of the strands and wires used in investigation. Some of the strands used for the experiments were stored for some months in the laboratory and gained some rust on the surface. This was enough to influence the coefficient of friction in a noticeable manner. To study the influence of corrosion on the mechanical properties of prestress strands several samples were stored under different environmental conditions to produce various levels of corrosion. These samples were tested afterwards to determine the influence of corrosion on fatigue properties and the coefficient of friction. Apart from the coefficient of friction, light rust decreases none of the other studied mechanical properties of the strands and may even increase the bond characteristics. The presence of rust does not necessarily mean that the strands should be rejected. The work described in this paper was conducted to investigate the level of rust that could be considered acceptable and how corrosion influences some mechanical properties of prestressing strands.Key words: reinforced concrete, prestressed concrete, prestressed beams and girders, structural design, structural members, corrosion, fatigue, losses.

The Efficiency of Tribocoupling with МоS2-Based Solid Lubricant Coatings Using Magnetron and Suspension Sputtering

2019 ◽  
pp. 96-104
Author(s):  
P.N. Khopin
Keyword(s):  
Magnetron Sputtering ◽  
Coefficient Of Friction ◽  
Solid Lubricant ◽  
Preliminary Treatment ◽  
Nickel Plating ◽  
Working Capacity ◽  
Metal Base ◽  
Operational Life ◽  
The Coefficient Of Friction ◽  
Ceramic Base

An analysis of studies conducted under vacuum conditions revealed that MoS2-based solid lubricant coatings applied to a titanium base using magnetron sputtering was virtually unusable. It was established that satisfactory working capacity of the considered couplings could be achieved by preliminary treatment of the base, that is by galvanic chrome plating and nickel plating. It was shown that life of a coupling with solid lubricant coatings sputtered using the magnetron method on a ceramic base was higher than those sputtered on a metal base. However, starting from the middle of operational life, temporary “surges” in the coefficient of friction occurred and subsequently stabilized. The life of coatings sputtered using the magnetron method was 2.51 times lower than that of a coupling with coatings of the BNII NP 212 type obtained using the suspension method, and 3.65 times lower than that of similar types by foreign manufacturers. The coefficient of friction for the considered couplings under vacuum conditions varied from 0.02 to 0.07.

Tribological performances of graphite–MoS2 coating at various high temperatures

2019 ◽  
Vol 233 (12) ◽  
pp. 1888-1902 ◽  
Author(s):  
Huali Han ◽  
Zhiyuan Qian ◽  
Fanming Meng ◽  
Zhongtao Cui
Keyword(s):  
High Temperatures ◽  
Coefficient Of Friction ◽  
Rotational Speed ◽  
Friction And Wear ◽  
Applied Load ◽  
Wear Scar ◽  
Graphite Content ◽  
Critical Rotational Speed ◽  
The Coefficient Of Friction ◽  
Scar Width

The tribological performances of the graphite–MoS2 coating deposited on the disc specimen, whose material is GCr15 steel, are experimentally investigated under high temperatures. Effects of graphite content, applied load, rotational speed and test temperature on the coefficient of friction and wear scar width of the coating are evaluated. The graphite–MoS2 coating with 20 wt% graphite addition exhibits the relatively small coefficient of friction and wear scar width at 200 ℃. At or beyond 400 ℃, the coating's lubricating effect is severely deteriorated with the testing time. At 200 ℃, there exists a critical applied load of 10 N and a critical rotational speed of 1250 rpm beyond which the MoS2 coating with 20 wt% graphite content is worn through and brings out a large coefficient of friction. The test results indicate that adding 20 wt% to 33 wt% graphite to MoS2 coating leads to an obvious reduction of the coefficient of friction and wear scar width for the coating at 200 ℃.

Mechanical Properties of Aluminium Matrix Composites Reinforced with Glassy Carbon Particles

2011 ◽  
Vol 176 ◽  
pp. 39-48 ◽  
Author(s):  
Jerzy Myalski ◽  
Józef Śleziona
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Coefficient Of Friction ◽  
Glassy Carbon ◽  
Friction And Wear ◽  
Matrix Composites ◽  
Carbon Particles ◽  
Small Influence ◽  
The Coefficient Of Friction ◽  
Reinforcement Value

The mechanical properties of composite materials with glassy carbon (GC) have been presented. The effect of size and reinforcement value on tensile strength, impact and tribological characteristics (coefficient of friction and wear) were estimated. It has been found that the reinforcement value decide on mechanical properties. Enlargement of particles value leads to decreasing of tensile strength and impact strength. It has been shown that particle size has small influence on studied properties. Destruction energy for the composites with particles exceeding 100 µm is similar. The measurement of coefficient of friction proved, that increase of reinforcement value leads to decreasing of coefficient of friction from 0.4 for 5% value to about 0.12 for 20% of particle value. The coefficient of friction is comparable for the composites containing particles of 200 µm size and is less dependent on reinforcement value. However size of the particles decide on the character of coefficient of friction changes.

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