Survival and factorial analysis of durability and friction coefficient of a solid lubricant under different working conditions

Wear ◽  
2013 ◽  
Vol 302 (1-2) ◽  
pp. 998-1009 ◽  
Author(s):  
J. Yang ◽  
V. Fridrici ◽  
M. Messaadi ◽  
Ph. Kapsa
Author(s):  
Daniel Miler ◽  
Stanko Škec ◽  
Branko Katana ◽  
Dragan Žeželj

Plain bearings are often used due to their compact dimensions and low cost. Their frictional and wear properties are affected by several parameters: load, sliding velocity, temperature, and surface roughness, among others. In this article, the authors have experimentally investigated the influence of clearance size on the friction and wear in composite plain bearings. An experimental rig was designed to enable the testing of plain bearings in working conditions similar to those encountered throughout their exploitation. Two load levels, two lubrication types, and four clearance levels were varied, resulting in 48 experiments, as each was replicated twice. The friction coefficient and bearing temperature were measured during the experiment, while the material loss and change in surface roughness were determined post-experiment. The results have shown that clearance affects the friction in both the dry running specimens and specimens lubricated using a solid lubricant (polytetrafluoroethylene).


2022 ◽  
Vol 1049 ◽  
pp. 130-137
Author(s):  
Natalia Antonova

New porous films based on polyanionic cellulose with AlOOH nanoparticles have been developed. The morphology of the films has been studied by electron microscopy: the size of the formed pores is 1000-500 microns; the total surface porosity of the films is 30%. Using infrared microscopy, it was shown that during the formation of porous films, their chemical composition remains unchanged. Differential scanning calorimetry was used to determine the threshold for thermal destruction of porous films: 306 С. The possibility of using the obtained materials as antifriction coatings when filling the pores with solid lubricant MoS2 is considered. It is shown that for a steel sample protected by a porous coating with MoS2, the friction coefficient decreases by 50% compared to the friction coefficient for a steel surface under a load of up to 450 MPa.


2013 ◽  
Vol 815 ◽  
pp. 574-578
Author(s):  
Xiao Zhen Liu ◽  
Yu Zhen Li ◽  
Ling Ling Song ◽  
Xiao Dong Yu ◽  
Wei Ting Lu

TiB2and Gd2O3were used as codeposited particles for the first time in preparing Ni-TiB2-Gd2O3composite coatings to improve its performance. Ni-TiB2-Gd2O3composite coatings were prepared by electrodeposition method from a nickel cetyltrimethylammonium bromide and hexadecylpyridinium bromide solution containing TiB2and Gd2O3particles. The content of codeposited TiB2and Gd2O3in the composite coatings was controlled by the addition of different TiB2and Gd2O3particles concentrations in the solution, respectively. The effects of TiB2and Gd2O3content on microhardness, wear weight loss, and friction coefficient of composite coatings were investigated, respectively. Ni-TiB2-Gd2O3composite coatings shows higher microhardness and lower wear weight loss, friction coefficient than those of the pure Ni coating and Ni-TiB2composite coatings. The wear weight loss of Ni-TiB2-Gd2O3composite coatings is lower 9.13 and 1.59 times than that of the pure Ni coating and Ni-TiB2composite coatings, respectively. The friction coefficients of pure Ni coating, Ni-TiB2and Ni-TiB2-Gd2O3composite coatings are 0.723, 0.815 and 0.43, respectively. Ni-TiB2-Gd2O3composite coatings shows the least friction coefficient among the three coatings. Gd2O3particles in composite coatings serves as solid lubricant between contact surfaces, decreases the friction coefficient, abates the wear and increases the corrosion resistance of the composite coatings. The loading-bearing capacity and the wear-reducing effect of the Gd2O3particles in the composite coatings are closely related to the content of Gd2O3particles in the composite coatings.


Author(s):  
Masanori Iwaki ◽  
Thierry Le Mogne ◽  
Julien Fontaine ◽  
Jean-Michel Martin

Among diamond-like carbon (DLC) coatings, hydrogenated amorphous carbon (a-C:H) coatings are of great interest since some of them may exhibit coefficients of friction in the millirange, so-called “superlow friction” in ultrahigh vacuum. However, there are still many points to be clarified and improved to employ them as solid lubricant for actual vacuum applications. For example, in space environment solid lubricants are required to function at both low and high temperature ranging from −150 to 100°C. To apply them as solid lubricant in such an extreme environment, it is necessary to know the evolution of the tribological behavior in temperature, leading to their application limit. Furthermore, tribological behavior of a-C:H coatings is known to depend on tribochemistry and on mechanical properties like viscoplasticity. Since both could be affected by temperature, a better understanding of superlow friction mechanisms is expected from experiments at various temperatures. In this present work, pin-on-disk reciprocating friction tests were conducted at various temperature conditions ranging from −130 to 300°C under ultrahigh vacuum (10−7Pa) to study the effect of temperature on the coefficient of friction of an a C:H coated flat mated against steel (AISI 52100) pins. For all temperatures, superlow friction regime could be reached, as it was observed usually at room temperature for this sample. However, an effect of temperature is evidenced on the duration of “running-in” phase, i.e. the number of cycles required to reach a superlow friction regime. The duration becomes shorter at higher temperatures and longer at lower temperatures. Also, the application limit in temperature is found between 200 and 300°C, at which the friction coefficient slowly increases after running-in, to reach values above 0.01. In light of these results, the mechanisms of superlow friction are discussed in terms of tribochemistry and mechanical properties of the coating.


2021 ◽  
Vol 871 ◽  
pp. 176-188
Author(s):  
Ben Yuan Wang ◽  
Guang Chun Xiao ◽  
Zhao Qiang Chen ◽  
Ming Dong Yi ◽  
Jing Jie Zhang ◽  
...  

In this paper, the dry cutting performance of Al2O3/TiC-based ceramic composites with nanoCaF2 was studied. Compared with the Al2O3/TiC ceramic tool, the Al2O3/TiC/CaF2 ceramic tool has lower cutting force, cutting temperature and surface roughness when milling 40Cr hardened steel. Three cutting parameters of cutting speed, feed per tooth, and cutting depth were used to conduct orthogonal experiments to study its changing trend. Through testing of cutting force, cutting temperature and surface roughness, and by comparison with ceramic tools without nanosolid lubricant added, the order of influence of three cutting parameters on cutting force, cutting temperature and surface roughness was obtained. The experimental results showed that the cutting force, cutting temperature and surface roughness of Al2O3/TiC/CaF2 ceramic tools containing nanoCaF2 werebetter than those of Al2O3/TiC ceramic tools. The cutting force, the cutting temperature, and the surface roughness were respectively reduced by 16.5%, 25.8% and 43% compared to when no solid lubricant was added. In addition, after adding solid lubricant, the effect of cutting depth on cutting force was significantly reduced. The average friction coefficient of the tool rake surface was 31.1% lower than that of ceramic tools without solid lubricant. In order to explain this phenomenon, through scanning electron microscopy (SEM) scanning and energy spectroscopy (EDS) elemental analysis, the wear reduction mechanism of solid lubricants was analyzed, that is, during the cutting process, nanosolid lubricants precipitated and formed lubricating film on the rake surface of the tool to reduce the friction coefficient. This was also the main reason for reducing the cutting temperature.


SPE Journal ◽  
2021 ◽  
pp. 1-16
Author(s):  
Y. Zhou ◽  
J. H. Hu ◽  
B. Tan ◽  
Y. Jiang ◽  
Y. F. Tang

Summary Sealing is a technical bottleneck that affects drilling efficiency and cost in deep, difficult-to-drill formations. The spiral combination seal with active sand removal performance is a new type of seal, and the wear mechanism is not clear, resulting in no effective design. In this study, the wear properties of materials were measured by a friction-and-wear testing machine, and the measurement methods and criteria of wear loss and friction coefficient were established. The fitting function of working condition and friction coefficient was studied by fitting regression method. The law of influence of working conditions on friction coefficient and wear amount was determined. The actual wear model and evaluation criteria of wear condition were established by using wear test data and geometric relationship. The relationship among working conditions, contact stress, and wear depth is determined by numerical simulation method, and the wear mechanism of the new seal is revealed, which provides a theoretical basis for its application.


2021 ◽  
pp. 1-19
Author(s):  
Temel Savaşkan ◽  
Ali Paşa Hekimoğlu ◽  
Zeki Azakli ◽  
Merve Çaliş

Abstract In order to determine the effect of working conditions on the lubricated wear behavior of Zn-40Al-2Cu-2Si alloy in the as cast and T6 heat-treated states, its tribological properties were studied at different oil flow rates, contact pressures, and sliding speeds in comparison with SAE 660 bronze. It was observed that the friction coefficient, temperature, and wear volume of both materials decrease, but their average surface roughness increase with increasing oil flow rate. As the pressure increased, the friction coefficient and average surface roughness of the experimental materials decreased, but their temperature and wear volume increased. It was also found that the working temperature of these materials increased, but their wear volume showed a decrement and a subsequent increment with increasing sliding speed. In addition, their wear volume and average surface roughness showed opposite changes with the sliding speed. The results of the lubricated friction and wear tests were discussed in terms of the microstructure and mechanical properties of the experimental materials and test conditions. Zn-40Al-2Cu-2Si alloy in both as cast and heat-treated conditions showed lower wear volume and friction coefficient than SAE 660 bronze. This indicates that Zn-40Al-2Cu-2Si alloy can be used to manufacture diesel engine crankshaft journal bearings.


2011 ◽  
Vol 314-316 ◽  
pp. 1628-1632
Author(s):  
Cui Lian Fan ◽  
Shun Ming Li

In order to know about the damping characteristics of leaf spring in the actual working conditions, the finite element model was build with large deformation, interleaf friction and contact considered simultaneously. In the single sinusoidal excitation, the effects of different friction coefficient, amplitude and excitation frequency on the hysteresis and damping characteristics of leaf spring were studied. Many results were reached in the paper. It provided the references for researching the vibration characteristics of leaf spring further in the nonlinear states.


2011 ◽  
Vol 148-149 ◽  
pp. 778-784
Author(s):  
Rattapasakorn Sountaree ◽  
Panichakorn Jesda ◽  
Mongkolwongrojn Mongkol

This paper presents the performance characteristics of two surfaces in line contact under isothermal mixed lubrication with non-Newtonian liquid–solid lubricant base on Power law viscosity model. The time dependent Reynolds equation, elastic equation and viscosity equation were formulated for compressible fluid. Newton-Raphson method and multigrid technique were implemented to obtain film thickness profiles, friction coefficient and load carrying in the contact region at various roughness amplitudes, applied loads, speeds and the concentration of solid lubricant. The simulation results showed that roughness amplitude has a significant effect on the film pressure, film thickness and surface contact pressure in the contact region. The film thickness decrease but friction coefficient and asperities load rapidly increases when surface roughness amplitude increases or surface speed decreases. When the concentration of solid lubricant increased, friction coefficient and asperities load decrease but traction and film thickness increase.


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