Dry sliding of composites with PBT matrix and micro glass beads on steel

2014 ◽  
Vol 66 (3) ◽  
pp. 424-433 ◽  
Author(s):  
Constantin Georgescu ◽  
Lorena Deleanu ◽  
Mihail Botan
Keyword(s):  
Friction Coefficient ◽  
Tribological Behavior ◽  
Early Stage ◽  
Normal Load ◽  
Glass Beads ◽  
Polybutylene Terephthalate ◽  
Sem Images ◽  
Neat Polymer ◽  
Content Type ◽  
Sliding Distance

Purpose – This research aims to characterize the tribological behavior of polybutylene terephthalate (PBT) and PBT composites with micro glass beads (MGB) on steel, in dry conditions and on a block-on-ring tester, pointing out the influence of sliding distance and speed. The tribology of PBT and its composites is still in an early stage because this thermoplastic polyester requires accurate technological and thermal treatment. Design/methodology/approach – The composites were produced by ICEFS Savinesti Romania and contain PBT grade Crastin6130NC010 (as supplied by Du Pont), 0.5 […] 1.0 per cent (weight) Relamyd B-2Nf (polyamide grade produced by ICEFS, for a better dispersion of MGB), 1 per cent (weight) black carbon for technological and tribological reasons and different micro glass beads (MGB) concentrations (10.0 and 20.0 per cent weight). Tests were done for different sliding distances (2,500, 5,000 and 7,500 m) and speeds (0.5, 1.0 and 1.5 m/s) and a normal load of 5 N. Findings – The friction coefficient and the wear parameter (as mass loss of polymeric blocks) pointed out a good tribological behavior for these composites. Scanning electron microscope (SEM) images revealed particular aspects of PBT local transfer on steel. Also, 10 per cent MGB in PBT reduces wear, especially for longer distances (75,000 m) and higher speeds (0.5 and 0.75 m/s); the friction coefficient is only slightly increased up to 0.23, being less influenced by the speed and the sliding distance as compared to neat polymer. Originality/value – PBT and PBT composites could become challengers for replacing materials in applications similar to tested ones. Even the neat polymer exhibits a good tribological behavior. The composites have a lower sensibility to higher speeds and sliding distances for the applied load.

Micro-Tribological Behavior of Boron Carbide Self-Mated Pairs

2007 ◽  
Vol 336-338 ◽  
pp. 1740-1742
Author(s):  
Fang Wu ◽  
Sheng Ming Xu ◽  
Song Zhe Chen ◽  
Lin Yan Li ◽  
Gang Xu ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Boron Carbide ◽  
Tribological Properties ◽  
Tribological Behavior ◽  
Normal Load ◽  
The Self ◽  
Sliding Velocity ◽  
Oxidation Treatment ◽  
Sliding Distance

Tribological behavior of B4C-SiC self-mated pairs was studied, and pre-oxidation treatment was adopted to improve the tribological properties of B4C-SiC. At the same SiC content, self-friction coefficient of B4C-SiC decreases with the increase of sliding distance, normal load, and sliding velocity; while the increasing of SiC content leads to increase of both self-friction coefficient and ware rate, which was determined to be within the range of 0.8×10-6~5.8×10-6 mm3·N-1·m-1. Pre-oxidation treatment of the B4C-SiC resulted in the formation of B2O3/H3BO3 lubricant layers, which effectively reduced the self-friction coefficient.

scholarly journals Tribological Behavior of Polymers and Polymer Composites

2020 ◽  
Author(s):  
Lorena Deleanu ◽  
Mihail Botan ◽  
Constantin Georgescu
Keyword(s):  
Friction Coefficient ◽  
Tribological Behavior ◽  
Glass Beads ◽  
Linear Wear ◽  
Neat Polymer ◽  
Linear Wear Rate ◽  
Test Parameters ◽  
Order Of Magnitude ◽  
Contact Durability

This chapter means to explain the tribological behavior of polymer-based materials, to support a beneficial introducing of those materials in actual applications based on test campaigns and their results. Generally, the designers have to take into consideration a set of tribological parameters, not only one, including friction coefficient, wear, temperature in contact, contact durability related to application. Adding materials in polymers could improve especially wear with more than one order of magnitude, but when harder fillers are added (as glass beads, short fibers, minerals) the friction coefficient is slightly increased as compared to neat polymer. In this chapter, there are presented several research studies done by the authors, from which there is point out the importance of composite formulation based on experimental results. For instance, for PBT sliding on steel there was obtained a friction coefficient between 0.15 and 0.3, but for the composite with PBT + micro glass beads, the value of friction coefficient was greater. Adding a polymer playing the role of a solid lubricant (PTFE) in these composites and also only in PBT, decreased the friction coefficient till a maximum value of 0.25. The wear parameter, linear wear rate of the block (from block-on-ring tester) was reduced from 4.5 μm/(N⋅km) till bellow 1 μm/(N⋅km) for a dry sliding regime of 2.5…5 N, for all tested sliding velocities, for the composite PBT + 10% glass beads +10% PTFE, the most promising composite from this family of materials. This study emphasis the importance of polymer composite recipe and the test parameters. Also there are presented failure mechanisms within the tribolayer of polymer-based materials and their counterparts.

scholarly journals Tribology of Polymer Blends PBT + PTFE

2021 ◽  
Author(s):  
Constantin Georgescu ◽  
Lorena Deleanu ◽  
Larisa Chiper (Titire) ◽  
Alina Cantaragiu Ceoromila
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Polymer Blends ◽  
Tribological Characteristics ◽  
Processing Temperature ◽  
Polybutylene Terephthalate ◽  
Neat Polymer ◽  
Uniform Dispersion ◽  
Sliding Distance ◽  
Sem Investigation

This paper presents results on tribological characteristics for polymer blends made of polybutylene terephthalate (PBT) and polytetrafluoroethylene (PTFE). This blend is relatively new in research as PBT has restricted processability because of its processing temperature near the degradation one. Tests were done block-on-ring tribotester, in dry regime, the variables being the PTFE concentration (0%, 5%, 10% and 15%wt) and the sliding regime parameters (load: 1 N, 2.5 N and 5 N, the sliding speed: 0.25 m/s, 0.5 m/s and 0.75 m/s, and the sliding distance: 2500 m, 5000 m and 7500 m). Results are encouraging as PBT as neat polymer has very good tribological characteristics in terms of friction coefficient and wear rate. SEM investigation reveals a quite uniform dispersion of PTFE drops in the PBT matrix.

The investigation of tribological behavior of carbon fiber-reinforced composite materials

2018 ◽  
Vol 72 (2) ◽  
pp. 211-216
Author(s):  
İsmail Kaya ◽  
Zeynep Parlar
Keyword(s):  
Friction Coefficient ◽  
Carbon Fiber ◽  
Fiber Orientation ◽  
Tribological Behavior ◽  
Epoxy Composite ◽  
Sliding Velocity ◽  
Fiber Reinforced ◽  
Content Type ◽  
Carbon Fiber Reinforced ◽  
Sliding Distance

Purpose The tribological behavior of composites varies on matrices materials, the reinforcement material and the direction of reinforcement materials. The purpose of this study is to examine the effects of fiber orientation on the tribological properties of carbon fiber–reinforced epoxy composite. Design/methodology/approach The experiments were carried out with a pin-on-ring tribometer. The tests were executed according to three different parameters: load, sliding velocity and direction of reinforcement. Loads measuring 92 N and 150 N were applied at sliding velocities of 1 and 2 m/s, in parallel, antiparallel and normal directions of fiber reinforcements. The frictional force was read every 500 m of sliding distance. To calculate specific wear rate, the mass of the samples was measured before and after each experiment. Moreover, temperature was measured every 1000 m of sliding distance via three-point infrared thermometer, to examine the effect of temperature variations. The sample surfaces were also examined in optic microscope after the experiments. Higher friction coefficient values were obtained in the normal direction-oriented carbon fiber specimen. Findings Comparing the friction coefficient values, antiparallel and parallel direction-oriented carbon fiber specimens gave lower friction coefficient values. The increase of sliding velocity and normal load resulted in the increase of surface temperature and this lead to the increase of friction coefficient. Originality/value This study shows the effects of fiber orientation on the tribological behavior of carbon fiber–reinforced epoxy composite. According to fiber orientations, relatively moving counter surfaces of this material shows different tribological behaviors.

Tribological behavior and film-forming mechanism of a polytetrafluoroethylene/polyester fabric composite

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Juan Wang ◽  
Xiongrong Huang ◽  
Wei Wang ◽  
Haosheng Han ◽  
Hongyu Duan ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
High Speed ◽  
Tribological Behavior ◽  
Elemental Content ◽  
Wear Depth ◽  
Content Type ◽  
Pet Fabric ◽  
Forming Mechanism ◽  
Fabric Composite ◽  
Film Forming

Purpose The purpose of this study is to determine the tribological behavior and wear mechanism of a polytetrafluoroethylene (PTFE)/polyester (PET) fabric composite for application as a self-lubricating liner suitable for high-speed and low-load friction conditions. Design/methodology/approach The effects of different loads and sliding speeds on the friction coefficients and wear characteristics of the composite were studied using reciprocating friction tests. Scanning electron microscopy, extended depth-of-field microscopy, and energy-dispersive X-ray spectrometry was used to analyze the worn surface morphology, wear depth and elemental content of the lubrication films, respectively. Findings The friction coefficient curves of the composites presented a long-term steady wear stage under different sliding conditions. With increasing sliding speed, the friction coefficient and wear depth of the composite slowly increased. The film-forming mechanism of the composite revealed that the PTFE/PET ply yarn on the composite surface formed complete PTFE lubrication films at the initial sliding stage. Originality/value The PTFE/PET fabric composite maintained good friction stability and high-speed adaptability, which demonstrates that the composite has broad application prospects as a highly reliable self-lubricating bearing liner with a long lifespan.

The effect of serpentine additive on energy-saving and auto-reconditioning surface layer formation

2017 ◽  
Vol 69 (2) ◽  
pp. 158-165 ◽  
Author(s):  
Xiao Wang ◽  
Junwei Wu ◽  
Xicheng Wei ◽  
Rende Liu ◽  
Qi Cao
Keyword(s):  
Surface Layer ◽  
Friction Coefficient ◽  
Mass Loss ◽  
Energy Saving ◽  
Normal Load ◽  
Lubricant Additive ◽  
Test Machine ◽  
Content Type ◽  
Saving Effect ◽  
Worn Surface

Purpose This paper aims to investigate the energy-saving effect and mechanism of serpentine as lubricant additive in the simulated condition. Design/methodology/approach An ABLT-1 bearing test machine was used for 1,350 hours and an MM-W1 three-pin-on-disk apparatus was used to investigate its anti-friction effect. The worn surface was characterized by scanning electron microscopy equipped with energy dispersive spectroscopy. Findings The results show that the energy-saving effect was improved after adding serpentine powder in oil and that both the friction coefficient and mass loss were dramatically decreased. The analysis on worn surface layer demonstrates that an auto-reconditioning surface layer was formed on the worn surface, which was responsible for the decrease in friction and wear. Originality/value The simulation test for the metal bearing was conducted over 1,350 hours using lubricant with and without serpentine powder. The addition of serpentine powder enhanced the energy-saving rate over time, stabilizing at about 13 per cent after 1,000 hours. An auto-reconditioning surface layer was formed on the surfaces of disassembled bearing lubricated with serpentine doped oil, resulting in dramatic decrease of both the friction coefficient and the mass loss. In addition to normal load and the accumulation of serpentine powder in the furrows and scratches of the deformed layer, the formation of the surface layer was possibly related to the substrate deformation induced by friction force.

A Comparing Tribological Study of PBT and PBT with Aramid Fibers, for Block-on-Ring Dry Regime

2014 ◽  
Vol 658 ◽  
pp. 283-288 ◽  
Author(s):  
Mihail Botan ◽  
Constantin Georgescu ◽  
Lorena Deleanu
Keyword(s):  
Wear Resistance ◽  
Comparative Study ◽  
Tribological Behavior ◽  
Average Length ◽  
Aramid Fibers ◽  
Polybutylene Terephthalate ◽  
Normal Forces ◽  
Sliding Distance ◽  
Sem Investigation ◽  
Polymeric Blend

This paper presents a comparative study upon tribological behavior of polybutylene terephthalate (PBT) and a blend of PBT + This paper presents a comparative study upon tribological behavior of polybutylene terephthalate (PBT) and a blend of PBT + 10% aramid fibers, in dry regime. Some of the properties of PBT grade CRASTIN 6130 NC010®. The tested materials they were obtained by molding at ICEFS Savinesti Romania. The aramid fibers added into PBT were supplied by Teijin, and have an average length of 125 mm. Tests were done with the help of a block-on-ring tribotester. The tests parameters were: three normal forces (F = 5 N, F = 15 N and F = 30 N), three values of sliding speed (v = 0.25 m/s, v = 0.50 m/s and v = 0.75 m/s) and a sliding distance of L = 5000 m, in dry regime, each test characterized by (F, v, L) being done twice. The conclusion of this research was that adding short aramid fibers in PBT improves the wear resistance, but slightly increases the friction coefficient. Also, the recorded temperatures near the contact are higher for the blend with aramid fibers. SEM investigation revealed particular processes within superficial layers of polymeric blend.

Experiment and simulation of friction coefficient of polyoxymethylene

2018 ◽  
Vol 70 (2) ◽  
pp. 273-281 ◽  
Author(s):  
Xiaoshuang Xiong ◽  
Lin Hua ◽  
Xiaojin Wan ◽  
Can Yang ◽  
Chongyang Xie ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Friction Coefficient ◽  
Contact Pressure ◽  
Friction Force ◽  
Normal Load ◽  
Fe Model ◽  
Sliding Velocity ◽  
Experiment Data ◽  
Simulation Data ◽  
Content Type

Purpose The purposes of this paper include studying the friction coefficient of polyoxymethylene (POM) under a broad range of normal load and sliding velocity; developing a mathematical model of friction coefficient of POM under a broad range of normal loads and sliding velocities; and applying the model to dynamic finite element (FE) analysis of mechanical devices containing POM components. Design/methodology/approach Through pin-on-disc experiment, the friction coefficient of POM in different normal loads and sliding velocities is investigated; the average contact pressure is between 5 and 15 Mpa and the sliding velocity is from 0.05 to 0.9 m/s. A friction algorithm is developed and embedded in the FE model to simulate the friction of POM in different normal loads and sliding velocities. Findings The friction coefficient of POM against steel declines with the increase of normal loads when the contact pressure is between 5 and 15 Mpa. The friction coefficient of POM against steel increases markedly when the sliding velocity is between 0.05 and 0.15 m/s, it decreases sharply between 0.15-0.45 m/s and then it stabilizes at high sliding velocity between 0.45 and 0.9 m/s. The friction coefficient of POM in different working operations has a significant effect on contact stress and shear stress. The simulation data and experiment data of POM friction force fit very well; therefore, it can be concluded that the friction algorithm and FE model are accurate. Originality/value The friction coefficient of POM under a broad range of normal loads and sliding velocities is investigated. The friction coefficient model of POM is established as a function of normal loads and sliding velocities in the dry sliding condition. A friction algorithm is developed and embedded in the FE model of the friction of POM. The mathematical model of the friction coefficient accurately agrees with the experiment data, and simulation data and experiment data of the POM friction force fit very well.

Friction and wear behavior of hydrogenated diamond-like carbon coating against titanium alloys under large normal load and variable velocity

2017 ◽  
Vol 69 (2) ◽  
pp. 199-207 ◽  
Author(s):  
Jun Liu ◽  
Zhinan Zhang ◽  
Zhe Ji ◽  
Youbai Xie
Keyword(s):  
Friction Coefficient ◽  
Service Life ◽  
Carbon Coating ◽  
Friction And Wear ◽  
Wear Behavior ◽  
Normal Load ◽  
Diamond Like Carbon ◽  
Content Type ◽  
Friction And Wear Behavior ◽  
Dlc Coating

Purpose This paper aims to investigate the effects of reciprocating frequency, large normal load on friction and wear behavior of hydrogenated diamond-like carbon (H-DLC) coating against Ti-6Al-4V ball under dry and lubricated conditions. Design/methodology/approach The friction and wear mechanisms are analyzed by scanning electron microscope, energy dispersive spectroscopy and Raman spectroscopy. Findings The results show that as reciprocating frequency increases under lubricated conditions, the friction coefficient decreases first and then increases. When the reciprocating frequency is 2.54 Hz, the value of friction coefficient reaches the minimum. The friction reduction is because of the transformation from sp3 to sp2, the formation of transfer layer on Ti-6Al-4V ball and the reduction in viscous friction, whereas the increase of friction coefficient is related to wear. In dry conditions, the friction coefficient is between 0.06 and 0.1. And, the service life of H-DLC coating decreases with the increase in reciprocating frequency and normal load. Research limitations/implications It is confirmed that adding the lubricant could prolong the service life of H-DLC coating and reduce friction and wear efficiently. And, the wear mechanisms under dry and lubricated conditions encompass abrasive wear and adhesive wear. Originality/value The results are helpful for application of diamond-like carbon coating.

Optimization of friction properties of kenaf polymer composite as an alternative friction material

2017 ◽  
Vol 69 (2) ◽  
pp. 259-266 ◽  
Author(s):  
Ashafie Mustafa ◽  
Mohd Fadzli Bin Abdollah ◽  
Hilmi Amiruddin ◽  
Fairuz Fazillah Shuhimi ◽  
Noryani Muhammad
Keyword(s):  
Friction Coefficient ◽  
Friction Material ◽  
Optimal Parameters ◽  
Compression Technique ◽  
Content Type ◽  
Kenaf Fibre ◽  
Confirmation Test ◽  
Different Types ◽  
Pin On Disc ◽  
Sliding Distance

Purpose The aim of this study is to determine the optimal parameters for friction coefficient of kenaf/epoxy (KE) composite as an alternative friction material. Design/methodology/approach The design of experiment was constructed using the Taguchi method. KE specimens were formed into 10 mm diameter pins using hot compression technique with different types, weight concentrations and treatments of kenaf. The samples were tested using a pin-on-disc tribometer at different applied loads, speeds and operating temperatures with a constant sliding distance of 3 km under dry sliding conditions. Findings The sample with 45 wt.% of non-treated kenaf fibre, tested at 19.62 N, 500 rpm and 100°C was found to be the optimized combination to obtain higher friction. From the confirmation test, the experimental friction coefficient is acceptable because of fall within 95 per cent confidence interval. Predominant wear mechanisms are identified as micro-crack and debonding of fibre. Originality/value KE composite can be considered as an alternative friction material, as the tested friction coefficient is within the suggested range for the friction material applications.

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