Effect of Surface Energy on the Wear Process

1964 ◽  
Vol 86 (2) ◽  
pp. 306-310 ◽  
Author(s):  
E. Rabinowicz ◽  
R. G. Foster
Keyword(s):  
Particle Size ◽  
Surface Energy ◽  
Wear Particle ◽  
Particle Sizes ◽  
Wear Particles ◽  
Wear Process ◽  
External Variables ◽  
Particle Measurement ◽  
Effect Of Surface ◽  
Correct Size

It was previously shown that the size of loose wear particles formed during the sliding of two materials is equal to 60,000 Wab/P, where Wab is the surface energy of adhesion and p the penetration hardness. Experimental results are presented which show that the experimental particle sizes obtained with a few materials do indeed obey the theoretical relationship, and that the particle size is, as predicted, almost independent of such external variables as speed, time, geometry, and load, provided the load is not too great. Indeed, if particles of the wrong size are fed into the system, then they tend to be broken down or built up until the correct size is reached. However, changes of atmosphere and the use of lubricants, which alter the energy of adhesion, do have a marked influence on wear-particle size, and this fact suggests a possible use of wear-particle measurement to rate boundary lubricants. Other surface interaction phenomena which are governed by the W/p ratio are discussed, and it is suggested that the surface roughness generated during sliding is a function of this ratio.

Surface energy of cellulosic materials: The effect of particle morphology, particle size, and hydroxyl number

TAPPI Journal ◽  
2015 ◽  
Vol 14 (9) ◽  
pp. 565-576 ◽  
Author(s):  
YUCHENG PENG ◽  
DOUGLAS J. GARDNER
Keyword(s):  
Particle Size ◽  
Surface Energy ◽  
Particle Morphology ◽  
Nanofibrillated Cellulose ◽  
Particle Sizes ◽  
Hydroxyl Number ◽  
Small Individual ◽  
Dispersion Component ◽  
Commercial Applications ◽  
Lower Temperature

Understanding the surface properties of cellulose materials is important for proper commercial applications. The effect of particle size, particle morphology, and hydroxyl number on the surface energy of three microcrystalline cellulose (MCC) preparations and one nanofibrillated cellulose (NFC) preparation were investigated using inverse gas chromatography at column temperatures ranging from 30ºC to 60ºC. The mean particle sizes for the three MCC samples and the NFC sample were 120.1, 62.3, 13.9, and 9.3 μm. The corresponding dispersion components of surface energy at 30°C were 55.7 ± 0.1, 59.7 ± 1.3, 71.7 ± 1.0, and 57.4 ± 0.3 mJ/m2. MCC samples are agglomerates of small individual cellulose particles. The different particle sizes and morphologies of the three MCC samples resulted in various hydroxyl numbers, which in turn affected their dispersion component of surface energy. Cellulose samples exhibiting a higher hydroxyl number have a higher dispersion component of surface energy. The dispersion component of surface energy of all the cellulose samples decreased linearly with increasing temperature. MCC samples with larger agglomerates had a lower temperature coefficient of dispersion component of surface energy.

Brake Wear Particle Size and Shape Analysis of Non-Asbestos Organic (NAO) and Semi Metallic Brake Pad

2014 ◽  
Vol 71 (2) ◽  
Author(s):  
Hussain, S. ◽  
M.K Abdul Hamid ◽  
A.R Mat Lazim ◽  
A.R. Abu Bakar
Keyword(s):  
Particle Size ◽  
Wear Particle ◽  
Brake Disc ◽  
Wear Particles ◽  
Brake Pad ◽  
Brake Pads ◽  
Size And Shape ◽  
Brake Wear Particles ◽  
Brake Wear ◽  
Particle Size And Shape

Brake wear particles resulting from friction between the brake pad and disc are common in brake system. In this work brake wear particles were analyzed based on the size and shape to investigate the effects of speed and load applied to the generation of brake wear particles. Scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) was used to identify the size, shape and element compositions of these particles. Two types of brake pads were studied which are non-asbestos organic and semi metallic brake pads. Results showed that the size and shape of the particles generatedvary significantly depending on the applied brake load, and less significantly on brake disc speed. The wear particle becomes bigger with increasing applied brake pressure. The wear particle size varies from 300 nm to 600 µm, and contained elements such as carbon, oxygen, magnesium, aluminum, sulfur and iron.

A Quantitative Model of Wear Loss Based on On-Line Visual Ferrograph

2013 ◽  
Vol 330 ◽  
pp. 338-345
Author(s):  
Chun Hui Wang ◽  
Wei Yuan ◽  
Guang Neng Dong ◽  
Jun Hong Mao
Keyword(s):  
Condition Monitoring ◽  
Testing Machine ◽  
Three Dimensional ◽  
Wear Particle ◽  
Quantitative Model ◽  
Wear Loss ◽  
Wear Particles ◽  
Coverage Area ◽  
Wear Process ◽  
On Line

On-line visual ferrograph (OLVF) is an efficient and real-time condition monitoring device. From the point of flow conservation, on the basis of the particle coverage area data collected by OLVF, this paper deduced two models about wear loss of the tribo-pairs in the wear process, one is general mathematical (GM) model including distribution impact factor of wear particle, and other simplified GM (SGM) model which does not contain the factor. The key factor affecting the accuracy of the two models is the three dimensional information of wear particles referring to particle area and thickness. This model using the disc and the ball whose materials were GCr15 were experimentally demonstrated on a pin-on-disc testing machine. And the OLVF was used to acquire the coverage area of the wear particles, which can reflect the wear loss. It shows that, in some cases, the approximate wear loss in the process was obtained on-line conveniently. Compared with experiment values derived from other wear measurement methods like weighing mass method and surface profilometry method, the SGM model can reflect tendency of wear loss about the tribo-pairs continuously. The deviations about wear loss by the model were discussed. Meanwhile, compared with the traditional means to compute the wear loss, this SGM model could be employed both for off-line analysis and on-line condition monitoring programs.

Study on the correlation between the running-in attractor and the wear particle group

2019 ◽  
Vol 72 (5) ◽  
pp. 681-686
Author(s):  
Cong Ding ◽  
Zhen-Yu Zhou ◽  
Zhi-Peng Yuan ◽  
Hua Zhu ◽  
Zhong-Yu Piao
Keyword(s):  
Correlation Dimension ◽  
Design Methodology ◽  
Wear Particle ◽  
Chord Length ◽  
Wear Particles ◽  
Dynamic Features ◽  
Dynamic Nature ◽  
Content Type ◽  
Wear Process ◽  
Particle Group

Purpose The purpose of this paper is to study the correlation between the dynamic features of the running-in attractor and the wear particle group, so as to characterize the running-in attractor by means of the wear particle group. Design/methodology/approach Wear particles are collected in phased wear experiments, and their dynamic features are investigated by the equivalent mean chord length L. Then, the correlation between the equivalent mean chord length L and the correlation dimension D of the running-in attractor is studied. Findings In the wear process, the equivalent means chord length L first decreases, then remains steady, and finally increases, this process agrees with the increase, stabilization and decrease of the correlation dimension D. Therefore, the wear particle group has a dynamic nature, which characterizes the formation, stabilization, and disappearance of a running-in attractor. Consequently, the dynamic characteristics and evolution of a running-in attractor can be revealed by the wear particle group. Originality/value The intrinsic relationship between the wear particle group and the running-in attractor is proved, and this is advantageous for further revealing the dynamic features of the running-in attractor and identifying the wear states.

Wear Debris Formation and Agglomeration

1992 ◽  
Vol 114 (2) ◽  
pp. 379-393 ◽  
Author(s):  
S. Tu¨rker Oktay ◽  
Nam P. Suh
Keyword(s):  
Particle Size ◽  
Friction Coefficient ◽  
Wear Particle ◽  
Field Analysis ◽  
Analytical Models ◽  
Wear Particles ◽  
Particle Agglomeration ◽  
Sliding Surfaces ◽  
Sliding Test ◽  
Lubricated Sliding

The hypothesis that one of the primary roles of an effective lubricant is to prevent wear particle agglomeration, thus reduce the plowing of the interfaces by the particles, and lower the frictional force, has been tested through a series of experiments and modeling. The friction coefficient, and the interfacial separation of the sliding surfaces due to entrapped wear particles, were measured on a number of sliding pairs in both dry and lubricated sliding. The results showed that the particle size, even during a single sliding test, did not remain constant but increased as sliding progressed. This increase in the wear particle size was found to be due not to the formation of larger wear particles but to the agglomeration of the small wear particles produced during sliding. The formation of large wear particle agglomerates caused an increase in the amount of plowing and often a concurrent increase in the friction coefficient. When one of the sliding surfaces was textured with undulations, no wear particle agglomeration was observed. The newly formed wear particles simply got entrapped in surface microgrooves and were immediately removed from the sliding interface before their subsequent growth by agglomeration. It was further shown that “good” lubricants prevented agglomeration, thus the friction coefficient remained more or less at the initial low value. Both the dry and lubricated sliding test results are presented and discussed in light of the analytical models based on the plastic deformation of the individual wear particles and the slip-line field analysis of the wear particle agglomerate.

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