Geometrical Effects on the Wear of Polymers and Carbons

1975 ◽  
Vol 97 (2) ◽  
pp. 187-194 ◽  
Author(s):  
J. K. Lancaster
Keyword(s):  
Wear Rate ◽  
Contact Area ◽  
Wear Process ◽  
Wear Rates ◽  
Small Areas ◽  
Bearing Materials ◽  
Geometrical Effects ◽  
Basic Studies ◽  
Wear Tests

Accelerated wear tests involving small areas of contact are frequently used both as an aid to materials selection for dry bearings and for basic studies of wear. It is shown that whilst a general correlation may exist between the wear rates of polymer composites in accelerated tests and during operation as dry journal bearings, discrepancies can occur. The latter are primarily attributable to the differences in the apparent areas of contact. The various ways in which the apparent contact area may influence the wear of dry bearing materials—polymers and carbons—are examined and discussed. Particular attention is given to the role of transfer to, and polishing of the counterface metal during the early stages of sliding. The wear process of polymers and carbons during sliding, against relatively smooth metals is often assumed to be one of fatigue on a localised asperity scale. The implications of this process on the variations of wear rate with load and counterface surface roughness are examined. The use of very small contact areas, to increase the sensitivity of wear measurement, can give rise to misleading variations of wear rate with load, resulting from the trapping of debris within the contact area.

Microstructure and Wear Behavior of Squeezed Magnesium Alloy (AM100) Based Composites Reinforced with ZrB2, Graphite and Hybrid of ZrB2 and Graphite Particles

2020 ◽  
Vol 835 ◽  
pp. 155-162
Author(s):  
Malak Abou El-Khair ◽  
Fatma Firouz ◽  
Ahmed Lotfy ◽  
Essam Mohamed ◽  
Atef Daoud
Keyword(s):  
Magnesium Alloy ◽  
Wear Rate ◽  
Wear Behavior ◽  
Matrix Alloy ◽  
Inert Gases ◽  
Dry Sliding Wear ◽  
Unreinforced Alloy ◽  
Wear Rates ◽  
Graphite Particles ◽  
Wear Tests

An attempt has been made to investigate the microstructures and wear behavior of magnesium alloy AM100 (Mg-Al-Mn) based composites reinforced with 7 vol. % of ZrB2, graphite or hybrid of (1:1) ZrB2 and graphite particles as well as the unreinforced magnesium alloy. Magnesium alloy was melt under shield of inert gases and composites were prepared using stir casting method. Optical microscopy was used to study the microstructures of the unreinforced alloy and composites. The composites characterized primarily by the uniform distribution of particles in the matrix and a good adherence between the particles and matrix. XRD analysis was used to identify the phases of the unreinforced alloy and composites. The XRD diffraction pattern of AM100 matrix reveals different phases, namely, Mg, AlMn and Al12Mg17. Formation of these phases is due to the reaction between alloy constituents. Dry sliding wear tests were conducted by using a pin-on-ring apparatus. The wear rates of the composites and matrix alloy were measured at loads of 10, 20 and 30 N, and sliding speed of 0.7 m/s. The worn surfaces of the composite pins were examined by scanning electron microscopy (SEM). The experimental results of the wear tests showed that the magnesium based composites exhibited higher wear rate at all the applied loads when compared to those of the unreinforced magnesium alloy. The ZrB2 reinforced magnesium composite exhibited the lowest wear rate amongst the composites material investigated in the present work.

Dry sliding friction and wear behavior of self-lubricating wollastonite filled polycarbonate composites

2015 ◽  
Vol 67 (1) ◽  
pp. 22-29 ◽  
Author(s):  
Akin Akinci
Keyword(s):  
Wear Rate ◽  
Friction And Wear ◽  
Sliding Friction ◽  
Wear Behavior ◽  
Xrd Analysis ◽  
Dry Sliding ◽  
Wear Performance ◽  
Content Type ◽  
Wear Rates ◽  
Wear Tests

Purpose – The purpose of this paper is to investigate the friction and wear performance of pure polycarbonate (PC) and 5-30 per cent wollastonite-filled (by weight) PC were comparatively evaluated under dry sliding conditions. Wear tests were carried out at room temperature under the loads of 5-20 N and at the sliding speeds of 0.5-1.5 m/s. Design/methodology/approach – The microstructures of the wollastonite, pure PC and composites were examined by optical microscopy, scanning electron microscopy, energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis. The friction and wear tests were realized using a pin-on-disk arrangement against the hardened AISI 4140 steel. Findings – The result of this study indicated that the coefficients of friction wear rate of the materials were significantly influenced by an increase in wollastonite content. The friction coefficient of the PC was getting decreased from 0.457 to 0.198 with an increase in wollastonite content, depending on applied loads and sliding speeds. On the other hand, the results showed that the wear rates of pure PC and wollastonite-filled PCs decreased with an increase in loads. The wear rate of the PC decreased from 1.2 × 10−6 to 8.7 × 10−6 mm3/m with an increase in wollastonite content, depending on applied loads. Originality/value – There are many reports which deal with the friction and wear performance of the polymers and polymer composites. However, the effect of wollastonite effect on tribological performance of PC has up to now not been extensively researched.

The dry wear of steels I. The general pattern of behaviour

1965 ◽  
Vol 257 (1077) ◽  
pp. 31-50 ◽  
Keyword(s):  
Wear Rate ◽  
General Framework ◽  
General Pattern ◽  
Sliding Speed ◽  
Wear Process ◽  
Wear Rates ◽  
Mild Wear ◽  
Wide Range ◽  
A Minor ◽  
Severe Type

The broad trends of the wear rate when steels rub together without lubrication have been studied by means of pin and ring apparatus. Over a wide range of load (10 g to 40 Kg) and sliding speed (1.7 to 266 cm/s) the wear process at equilibrium is either of a severe type, producing coarse metallic debris, or of a mild type, producing fine oxidized debris. The corresponding wear rates differ by more than two orders of magnitude. Transitions from one wear process to the other occur at well-defined loads and for soft steels a basic pattern, comprising three transitions, has been identified: T1 a change from mild wear to severe at light loads; T2, a change from severe wear back to mild at higher loads; T3, a minor change in the mild wear rate at loads above T2, characterized by divergent wear rates of the pin and ring. The way in which this pattern varies with the sliding speed and with the composition and hardness of the steel is traced and the findings of previous investigations co-ordinated in the general framework.

Wear Mechanism of Ceramic Materials in Dry Rolling Friction

1986 ◽  
Vol 108 (4) ◽  
pp. 522-526 ◽  
Author(s):  
S. S. Kim ◽  
K. Kato ◽  
K. Hokkirigawa ◽  
H. Abe´
Keyword(s):  
Silicon Nitride ◽  
Wear Rate ◽  
Contact Area ◽  
Ceramic Materials ◽  
Rolling Friction ◽  
Bearing Steel ◽  
Rolling Contact ◽  
Hertzian Contact ◽  
Real Contact Area ◽  
Wear Process

Wear tests in dry rolling contact were carried out at room temperature on five ceramic materials, such as silicon nitride, silicon carbide, cermet, titania, and alumina. The results showed that wear rate of silicon nitride was smaller than any of the other ceramic materials and bearing steel. Observations of worn surface and wear debris revealed that ceramic materials have two types of wear, one related to real contact area and another related to Hertzian contact area. It was also found that brittle fracture dominates the wear process of ceramic materials in dry rolling contact. Based on the experimental results, wear rate of ceramic materials was expressed with a new nondimensional parameter.

scholarly journals Wear Behaviour of N Ion Implanted Ti-6Al-4V Alloy Processed by Selective Laser Melting

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1639
Author(s):  
Hua Li ◽  
Zhan W. Chen ◽  
Holger Fiedler ◽  
Maziar Ramezani
Keyword(s):  
Wear Rate ◽  
Ion Implantation ◽  
Selective Laser Melting ◽  
Wear Behaviour ◽  
Laser Melting ◽  
Powder Bed ◽  
Wear Process ◽  
Hardness Values ◽  
Wear Tests ◽  
Ion Implanted

Selective laser melting (SLM) is a laser-based powder bed fusion additive manufacturing technique extensively used in industry. One of the most commonly used alloys in SLM process is Ti-6Al-4V. However, its tribological properties when coated with N ion implantation is not well understood. In the ion implantation process used in this study, N2+ and N+ are accelerated to the energy of 60 keV and implanted to a fluence of 6 × 1017 at.cm−2. The effect of N ion implanted layer in terms of hardness values and how this implanted layer may affect wear process and wear rate is investigated in this paper. Sliding wear tests were conducted on SLM and conventionally processed samples implanted with N ions, followed by examining the wear tracks and coefficient of friction in order to explain the wear rate data obtained. The results showed that N+ implantation increased hardness within the depth of ~200 nm and reduced wear rate in SLM samples, while N2+ was not beneficial.

Wear of Artificial Joint Materials III

1981 ◽  
Vol 10 (3) ◽  
pp. 137-142 ◽  
Author(s):  
R W Treharne ◽  
R W Young ◽  
S R Young
Keyword(s):  
Wear Rate ◽  
Contact Area ◽  
Inverse Relationship ◽  
Wear Testing ◽  
Artificial Joint ◽  
Knee Prostheses ◽  
Wear Rates ◽  
Knee Simulator ◽  
Total Knee

This paper describes a new method for testing total knee prostheses under simulated in vivo conditions. Previous knee simulator work has been summarized and described. The major variables of testing are also described in detail. The results of wear testing five types of knee prostheses were that the wear rate was nearly an inverse relationship with contact area— knees with a higher contact area had lower wear rates.

The Importance of Multidirectional Motion on the Wear of Polyethylene

1996 ◽  
Vol 210 (3) ◽  
pp. 157-165 ◽  
Author(s):  
C R Bragdon ◽  
D O O'Connor ◽  
J D Lowenstein ◽  
M Jasty ◽  
W D Syniuta
Keyword(s):  
Complex Loading ◽  
Wear Process ◽  
Wear Rates ◽  
Total Joint Replacements ◽  
Total Hip ◽  
Hip Simulator ◽  
Hip Replacements ◽  
Bearing Materials ◽  
Physiological Motion ◽  
Materials Used

The development of a new hip simulator for the study of bearing materials used in total hip replacements has led to several findings which add important new information to the understanding of wear process of ultra-high molecular weight polyethylene, the most commonly used bearing material today for total joint replacements. Using this hip simulator which is capable of applying the physiological motion pathways occurring during gait to total hip components which are held in the correct anatomical position under the complex loading conditions of the hip in gait, the authors have shown that physiological motion pathways produce very different wear rates and morphology of the wear surface than unidirectional reciprocating pathways. Scanning electron microscopy studies show striking differences in the morphology of the wear surfaces of the polyethylene depending upon the relative motions of the components. Wear rates, surface morphology and particle debris generation consistent with clinical and retrieved studies are achieved when physiological conditions are simulated.

Strategies of maintenance and repair of agricultural machinery

2020 ◽  
pp. 38-48
Author(s):  
Aleksey S. Dorokhov ◽  
Aleksandr V. Denisov ◽  
Aleksey A. Solomashkin ◽  
Valeriy S. Gerasimov
Keyword(s):  
Wear Rate ◽  
Technical Condition ◽  
Research Purpose ◽  
Agricultural Machinery ◽  
Maintenance And Repair ◽  
Wear Rates ◽  
Urgent Task ◽  
Machine Parts ◽  
Current Value ◽  
Agricultural Machines

Modern machines are subject to progressive wear that occurs at different rates, which leads to unpredictable failures that reduce the reliability and durability of machines. The strategy of maintenance and repair is aimed at eliminating these problems. (Research purpose) The research purpose is in analyzing the basic principles of the strategy of maintenance and repair of agricultural machinery in order to ensure control of the technical condition of machine parts. (Materials and methods) When resource diagnostics is used, , the allowable value of the parameter is set in advance for a part . This value is the tolerance that corresponds to a certain wear rate of the part. The tolerance is set based on the condition that if the current value of the controlled resource parameter during the next diagnosis is less than the set value, then such a part at the current value of the wear rate can be finalized until the next inter-control check. Taking into account the wear rate of the same type of parts from the group when determining the allowable wear during their resource diagnostics becomes an urgent task. (Results and discussions) As a result of research, the article presents "Methodology for determining the main indicators of reliability of parts of agricultural machines with different wear rates" and "Methodology for determining the tolerance system of parts of agricultural machines with different wear rates". (Conclusions) The article presents the tolerance system that reduces the probability of failure of machine parts in operation. During resource diagnostics, those parts whose resource parameters exceed the tolerance are rejected.

scholarly journals Properties of Journal Bearing Materials That Determine Their Wear Resistance on the Example of Aluminum-Based Alloys

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 535
Author(s):  
Alexander Mironov ◽  
Iosif Gershman ◽  
Eugeniy Gershman ◽  
Pavel Podrabinnik ◽  
Ekaterina Kuznetsova ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Journal Bearing ◽  
Tribological Behavior ◽  
Secondary Structures ◽  
Magnesium Content ◽  
Wear Rates ◽  
Relative Extension ◽  
Bearing Materials ◽  
Antifriction Alloys

Potential relations of tribological characteristics of aluminum antifriction alloys with their compositions and mechanical properties were investigated. In this regard, the properties of eight aluminum alloys containing tin from 5.4% to 11% doped with lead, copper, silicon, zinc, magnesium, and titanium were studied. Mechanical properties such as hardness, strength, relative extension, and impact strength were analyzed. Within the tribological tests seizure load and wear of material were evaluated and secondary structures were studied afterwards. The absence of a definitive correlation between tribological behavior and mechanical properties was shown. It was determined that doping tin over 6% is excessive. The seizure load of the alloys increases with the magnesium content. Secondary structures of the alloys with higher wear rates contain one order less magnesium and tin.

scholarly journals Sliding Wear of Conventional and Suspension Sprayed Nanocomposite WC-Co Coatings: An Invited Review

2021 ◽  
Author(s):  
R. Ahmed ◽  
O. Ali ◽  
C. C. Berndt ◽  
A. Fardan
Keyword(s):  
Wear Rate ◽  
Thermal Spray ◽  
Sliding Wear ◽  
Failure Modes ◽  
Thermal Spray Coatings ◽  
Annual Growth Rate ◽  
Total Energy Consumption ◽  
Wear Performance ◽  
Wear Rates ◽  
Spray Coatings

AbstractThe global thermal spray coatings market was valued at USD 10.1 billion in 2019 and is expected to grow at a compound annual growth rate of 3.9% from 2020 to 2027. Carbide coatings form an essential segment of this market and provide cost-effective and environmental friendly tribological solutions for applications in aerospace, industrial gas turbine, automotive, printing, oil and gas, steel, and pulp and paper industries. Almost 23% of the world’s total energy consumption originates from tribological contacts. Thermal spray WC-Co coatings provide excellent wear resistance for industrial applications in sliding and rolling contacts. Some of these applications in abrasive, sliding and erosive conditions include sink rolls in zinc pots, conveyor screws, pump housings, impeller shafts, aircraft flap tracks, cam followers and expansion joints. These coatings are considered as a replacement of the hazardous chrome plating for tribological applications. The microstructure of thermal spray coatings is however complex, and the wear mechanisms and wear rates vary significantly when compared to cemented WC-Co carbides or vapour deposition WC coatings. This paper provides an expert review of the tribological considerations that dictate the sliding wear performance of thermal spray WC-Co coatings. Structure–property relationships and failure modes are discussed to grasp the design aspects of WC-Co coatings for tribological applications. Recent developments of suspension sprayed nanocomposite coatings are compared with conventional coatings in terms of performance and failure mechanisms. The dependency of coating microstructure, binder material, carbide size, fracture toughness, post-treatment and hardness on sliding wear performance and test methodology is discussed. Semiempirical mathematical models of wear rate related to the influence of tribological test conditions and coating characteristics are analysed for sliding contacts. Finally, advances for numerical modelling of sliding wear rate are discussed.

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