Analysis of sliding friction of WC-Co composite on particleboard

2020 ◽  
Vol 111 ◽  
pp. 60-67
Author(s):  
Jacek Wilkowski ◽  
Marek Barlak ◽  
Radosław Jałocha ◽  
Zbigniew Werner ◽  
Alicja Auriga

Analysis of sliding friction of WC-Co composite on particleboard. The paper presents the analysis of the coefficient of friction at the contact area between WC-Co composite and particleboard. The four types of WC-Co composite in the form of milling indexable knives for wood materials machining were tested. The tests were carried out on a linear reciprocating tribotester (pin-on-flat), where the sample was the clearance surface of WC-Co indexable knives and the counter-sample was made of three-layer particleboard. Before and after tribological tests, the surface roughness of tested knives was measured. The highest values of friction coefficient were obtained for the type UMG04 of cemented carbide - with nano size of WC grains and the lowest content of cobalt. The average coefficient of friction for selected types of WC-Co correlated with the average increase in surface roughness (the roughness parameter Ry).

Micromachines ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 448 ◽  
Author(s):  
Jichun Xing ◽  
Huajun Li ◽  
Dechun Liu

Tactile feedback technology has important development prospects in interactive technology. In order to enrich the tactile sense of haptic devices under simple control, a piezoelectric haptic feedback device is proposed. The piezoelectric tactile feedback device can realize tactile changes in different excitation voltage amplitudes, different excitation frequencies, and different directions through the ciliary body structure. The principle of the anisotropic vibration of the ciliary body structure was analyzed here, and a tactile model was established. The equivalent friction coefficient under full-coverage and local-coverage of the skin of the touch beam was deduced and solved. The effect of system parameters on the friction coefficient was analyzed. The results showed that in the full-coverage, the tactile effect is mainly affected by the proportion of the same directional ciliary bodies and the excitation frequency. The larger the proportion of the same direction ciliary body is, the smaller the coefficient of friction is. The larger the excitation frequency is, the greater the coefficient of friction is. In the local-coverage, the tactile effect is mainly affected by the touch position and voltage amplitude. When changing the touch pressure, it has a certain effect on the change of touch, but it is relatively weak. The experiment on the sliding friction of a cantilever touch beam and the experiment of human factor were conducted. The experimental results of the sliding friction experiment are basically consistent with the theoretical calculations. In the human factor experiment, the effects of haptic regulation are mainly affected by voltage or structure of the ciliary bodies.


1999 ◽  
Vol 121 (2) ◽  
pp. 282-285 ◽  
Author(s):  
D. P. Hess

The influence of harmonic normal loads on sliding friction is investigated through analysis of contacts consisting of conical and spherical sliders of hard materials on softer metal surfaces. Friction for such contacts is assumed to result from a plowing component and a shearing component. Calculations and experiments show that the coefficient of friction is essentially independent of normal load for contacts with conical sliders. However, for spherical sliders the relation between the coefficient of friction and normal load is highly nonlinear. In the presence of harmonic variations in normal load, this non-linearity causes a shift in the average coefficient of friction. For ideal lubricated contacts, the shearing component of friction is very small and for this case, it is shown that the maximum average reduction in the coefficient of friction is ten percent. When the shearing component is more significant, as with dry contacts, the shift is less. For example, when the shear strength is one-sixth the hardness of the softer material, the maximum average reduction in the coefficient of friction is five percent.


Author(s):  
Vahid Mortazavi ◽  
Pradeep L. Menezes ◽  
Michael Nosonovsky

When frictional sliding is initiated, the coefficient of friction is often high during the initial transient running-in process. After that, the coefficient of friction reaches its stationary value. Running-in is interpreted as friction-induced self-organization stage in that two sliding surfaces adjust to each other due to surface roughness evolution. Shannon entropy was proposed as a surface roughness parameter, and its decrease can be used as a simple test for self-organization. Sliding experiments were conducted on the hard steel plate using a soft Al-Mg alloy pin under both dry and lubricated conditions. Based on the results of the surface profile evolution, obtained by an optical profilometer, during running-in, we discuss change of Shannon entropy for various surface textures. Various textures which are characterized in terms of roughness parameters were produced on the steel plates. We compare how self-organization occurs for different textures during running-in stage.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ting Wang ◽  
Hanfei Guo ◽  
Jianjun Qiao ◽  
Xiaoxue Liu ◽  
Zhixin Fan

PurposeTo address the lack of data in this field and determine the relationship between the coefficient of friction and the interference between locomotive wheels and axles, this study evaluates the theoretical relationship between the coefficient of friction and the interference under elastic deformation.Design/methodology/approachWhen using numerical analyses to study the mechanical state of the contacting components of the wheels and axle, the interference between the axle parts and the coefficient of friction between the axle parts are two important influencing factors. Currently, as the range of the coefficient of friction between the wheel and axle in interference remains unknown, it is generally considered that the coefficient of friction is only related to the materials of the friction pair; the relationship between the interference and the coefficient of friction is often neglected.FindingsA total of 520 press-fitting experiments were conducted for 130 sets of wheels and axles of the HXD2 locomotive with 4 types of interferences, in order to obtain the relationship between the coefficient of friction between the locomotive wheel and axle and the amount of interference. These results are expected to serve as a reference for selecting the coefficient of friction when designing axle structures with the rolling stock, research on the press-fitting process and evaluations of the fatigue life.Originality/valueThe study provides a basis for the selection of friction coefficient and interference amount in the design of locomotive wheels and axles.


2007 ◽  
Vol 14 (05) ◽  
pp. 1007-1013 ◽  
Author(s):  
ESAH HAMZAH ◽  
ALI OURDJINI ◽  
MUBARAK ALI ◽  
PARVEZ AKHTER ◽  
MOHD RADZI HJ. MOHD TOFF ◽  
...  

In the present study, the effect of various N 2 gas flow rates on friction coefficient and surface roughness of TiN -coated D2 tool steel was examined by a commercially available cathodic arc physical vapor deposition (CAPVD) technique. A Pin-on-Disc test was carried out to study the Coefficient of friction (COF) versus sliding distance. A surface roughness tester measured the surface roughness parameters. The minimum values for the COF and surface roughness were recorded at a N 2 gas flow rate of 200 sccm. The increase in the COF and surface roughness at a N 2 gas flow rate of 100 sccm was mainly attributed to an increase in both size and number of titanium particles, whereas the increase at 300 sccm was attributed to a larger number of growth defects generated during the coating process. These ideas make it possible to optimize the coating properties as a function of N 2 gas flow rate for specific applications, e.g. cutting tools for automobiles, aircraft, and various mechanical parts.


Author(s):  
K. Miyoshi ◽  
K. W. Street ◽  
R. L. Vander Wal ◽  
R. Andrews ◽  
David Jacques ◽  
...  

To evaluate recently developed aligned multiwalled carbon nanotubes (MWNTs) and dispersed MWNTs for solid lubrication applications, unidirectional sliding friction experiments were conducted with 440C stainless steel balls and hemispherical alumina-yttria stabilized zirconia pins in sliding contact with the MWNTs deposited on quartz disks in air and in vacuum. The results indicate that MWNTs have superior solid lubrication friction properties and endurance lives in air and vacuum under dry conditions. The coefficient of friction of the dispersed MWNTs is close to 0.05 and 0.009 in air and in vacuum, respectively, showing good dry lubricating ability. The wear life of MWNTs exceeds 1 million passes in both air and vacuum showing good durability. In general, the low coefficient of friction can be attributed to the combination of the transferred, agglomerated patches of MWNTs on the counterpart ball or pin surfaces and the presence of tubular MWNTs at interfaces.


2019 ◽  
Vol 803 ◽  
pp. 167-171
Author(s):  
Aphinan Phukaoluan ◽  
Anak Khantachawana ◽  
Pongpan Kaewtatip ◽  
Surachai Dechkunakorn

The tribological behavior of Ti49.4Ni50.6, Ti49Ni46Cu5 and Ti50Ni47Co3 (at%) alloy in dry and wet conditions was studied. The alloy was prepared in a Vacuum Arc Re-melting (VAR), homogenized at 800°C for 3600 s and quenched in water. The phase transformation temperatures were measured by differential scanning calorimetry. Before a tribology test, it is necessary to determine surface roughness, because high surface roughness affects friction. The hardness behavior, based on the load over residual indent area, was determined by a Vickers hardness tester. The sliding friction tests were performed using a ball-on-disk tribometer in dry condition at room temperature and wet condition in artificial saliva (pH 5.35) at 37°C (Oral temperature). The results showed that transformation temperature (Af) lowered oral temperature (37°C), this was mainly attributed to the superelastic properties that can be taken into orthodontic applications. The studies showed significant influences in dry condition of coefficient of friction. Caused by the force between the ball and the disk, contact pressure of surface area effect in wear occurred. The debris could not be removed from the surface area tested. TiNiCu and TiNiCo generated significantly lower average coefficient of friction when tested under dry condition, which may have been due to the addition of Cu and Co. Wet condition decreased coefficient of friction more than dry condition, owing to the lubricating effects of artificial saliva.


MRS Advances ◽  
2020 ◽  
Vol 5 (54-55) ◽  
pp. 2753-2762
Author(s):  
Mathew Brownell ◽  
Arun K. Nair

AbstractPolytetrafluoroethylene (PTFE) film is observed to increase surface roughness during annealing. Longer annealing times leads to greater surface roughness. The coefficient of friction of PTFE film is affected by the shape of microscale sized particles on the film surface. In this study, we investigate the coefficient of friction of PTFE films using a coarse-grained molecular dynamics model based on experimental observations. We observe how the variation in PTFE chain length and film density affect the topography of PTFE films. We also investigate how these properties of PTFE, and the indenter radius affect the coefficient of friction observed during surface scratch. We find that short PTFE chain lengths create a dense film with greater particle spacing, but longer chains form a mesh structure which reduces the density and creates overlapping portions of particles in the film. We develop a convolutional neural network to classify PTFE film surface and predict the coefficient of friction of a modeled film based solely on the equilibrated film topography. The accuracy of the network was seen to increase when the density and images of internal fiber orientation were added as input features. These results indicate that the coefficient of friction of PTFE films in part is governed by the internal structure of the film.


Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1862 ◽  
Author(s):  
Luanxia Chen ◽  
Zhanqiang Liu ◽  
Bing Wang ◽  
Qinghua Song ◽  
Yi Wan ◽  
...  

Eutectic aluminum-silicon alloys present high frictional coefficient and a high wear rate due to the low hardness under sliding friction conditions. In this paper, the eutectic aluminum-silicon alloy was textured firstly by micro-milling operations. Then, the micro-textured specimen was subjected to anodizing to fabricate alumina films. The surface topography, surface roughness, and bearing area ratio of micro-textured and anodizing micro-textured specimens were measured and characterized. For the anodizing micro-textured specimens, the surface roughness and superficial hardness increase compared with those for micro-textured ones. Tribological tests indicate that anodizing micro-textured samples present lower friction coefficient of 0.37 than that of flat samples of 0.43 under dry sliding conditions. However, they exhibit higher friction coefficient at 0.16 than that of flat samples of 0.13 under oil-lubricated conditions. The difference between the friction coefficient of anodizing micro-textured and flat samples under dry and oil-lubricated conditions is ascribed to the influence mechanism of surface roughness, bearing area ratio curves, and its relative parameters on the tribological performance of testing samples. The dry sliding friction coefficient has a positive correlation with bearing area ratio curves, while they present negative correlation with bearing area ratio curves under oil-lubricated conditions. The synergy method treated with micro-milling and anodizing provides an effective approach to enhance the dry sliding friction property of eutectic aluminum-silicon alloys.


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