Tribological properties of pyrolytic carbon in high-speed tests

2020 ◽  
pp. 71-75
Author(s):  
V. A. Khorev ◽  
V. I. Rumyantsev ◽  
G. A. Ponomarenko ◽  
A. S. Osmakov ◽  
V. N. Fischev
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
High Speed ◽  
Tribological Behavior ◽  
Pyrolytic Carbon ◽  
Extreme Conditions ◽  
Friction Units ◽  
The Difference

The friction units of modern power turbines require the use of special materials with a stable and low coefficient of friction in extreme conditions. The most successfully used for these purposes are antifriction carbon-graphite materials, in particular isotropic pyrolytic carbon. It is established that isotropic pyrolytic carbon has a lower friction coefficient and wear rate than ATG-S antifriction graphite. Based on the analysis of the microstructure and fractograms of wear traces, it was suggested that the difference in the tribological behavior of materials is caused by various mechanisms of material destruction. It is also shown that isotropic pyrolytic carbon tends to decrease the wear rate and friction coefficient with increasing density. Ill. 7. Ref. 10. Tab. 1.

The influence of laser surface texture on the tribological properties of friction layer materials in ultrasound motors

2021 ◽  
pp. 135065012110527
Author(s):  
Xijun Hua ◽  
Julius Caesar Puoza ◽  
Peiyun Zhang
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Dry Friction ◽  
Friction And Wear ◽  
Ultrasonic Motor ◽  
Area Ratio ◽  
Ultrasonic Motors ◽  
Increase Rate

Ultrasonic motors are typically driven by the dry friction force between the rotor and the stator; the friction pairs’ high friction coefficient and low wear rate are two essential elements for improving the operational stability with longer service life. In this research article, high-precision microgroove arrays were manufactured on the surfaces of the stator and rotor of the TRUSM60 ultrasonic motor using laser machining. Dry friction and wear tests between the stator and the rotor were carried out with pin-on-disc using HSR-2M high-speed reciprocating friction and wear tester to determine the tribological properties of the ultrasonic motor. According to a different distribution of microgrooves on the two contact surfaces, the influence of smooth surface, single-sided texture, and double-sided texture on the friction pair's friction performance were discussed. The results show that the textured surface can substantially increase the coefficient of friction of the contact surface and reduce the rate of wear. The one-sided textured phosphor bronze surface with a microgroove width of 200μm and an area ratio of 20% had the highest coefficient of friction of 0.334 and a friction increase rate of 36.3%. Similarly, the single-sided textured Polyimide surface attained the highest friction coefficient of 0.355 and friction increase rate of 44.9% when the groove width is 150μm and the area ratio is 30%. A higher friction coefficient of the double-sided texture can be obtained through reasonable parameter configuration than the single-sided texture. The included angle of 0° between the two textured surfaces produced the highest friction coefficient of 0.368 and the wear rate of the phosphor bronze and polyimide surfaces were 2.01 × 10−4 mm3/N-m and 1.949 × 10−3 mm3/N-m, respectively. The result provides an essential benchmark for enhancing the tribological performance of ultrasonic motors and increasing the output torque.

Research on Tribological Properties of Cast Iron at High-Speed Dry Sliding Condition

2014 ◽  
Vol 936 ◽  
pp. 2063-2067
Author(s):  
Chen Yue ◽  
Shang Guan Bao ◽  
Ying Yu Huang
Keyword(s):  
Cast Iron ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Abrasive Wear ◽  
Tribological Properties ◽  
High Speed ◽  
Friction Material ◽  
Dry Sliding ◽  
Oxidative Wear ◽  
Wear Properties

The friction and wear properties of cast iron with different graphite morphologies and matrix microstructure were investigated at high speed dry sliding against GCr15 steel on the MMS-1G high-speed tribometer apparatus. The various wear micro-mechanisms and tribo-metallographic phases were studied by using scanning electron microscopy. The results show that as friction material, vermicular iron exhibits excellent comprehensive tribological properties. The friction coefficient of cast iron sliding against GCr15 decreases while the wear rate increases with the increase of sliding speed, friction coefficient and wear rate decline with the increase of pearlite content. Under the experimental condition, the main wear mechanisms of flake iron are abrasive wear, of vermicular iron are abrasive wear and oxidative wear and of nodular iron are oxidative wear, abrasive wear and fatigue spalling.

Tribological Properties of Ti3SnC2/Cu Composite

2014 ◽  
Vol 602-603 ◽  
pp. 519-522 ◽  
Author(s):  
Zai Ji Zhan ◽  
Dan Dan Zhang ◽  
Chang Hong Guo ◽  
Wei Chai
Keyword(s):  
Wear Resistance ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Abrasive Wear ◽  
Tribological Properties ◽  
Applied Load ◽  
Tribological Behavior ◽  
Oxidative Wear ◽  
The Matrix ◽  
Steel Balls

In this study, 5 wt. % Ti3SnC2/Cu composite was synthesized by hot pressed sintering, and its tribological properties against AISI52100 steel balls were investigated using a ball-on-disk wear tester. The effects of sliding speeds and applied loads on the tribological behavior of Ti3SnC2/Cu were studied. The results showed the wear rate of Ti3SnC2/Cu composite increased with the increase of applied load and decreased with increase of sliding speed. The main tribological mechanisms of Ti3SnC2/Cu were abrasive wear and slightly oxidative wear. The friction coefficient of Ti3SnC2/Cu composite was stable and much lower than that of Cu at the same conditions. The loads were effectively born by the Ti3SnC2particles and the wear resistance of the matrix was obviously improved.

Experimental study on the effect of surface texture on tribological properties of nanodiamond films under water lubrication

2021 ◽  
pp. 135065012110334
Author(s):  
Ying Yan ◽  
Xuelin Lei ◽  
Yun He
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Tribological Properties ◽  
Surface Texture ◽  
Diamond Film ◽  
Diamond Films ◽  
Nanocrystalline Diamond ◽  
Water Contact ◽  
Texture Density ◽  
Short Run

The effect of nanoscale surface texture on the frictional and wear performances of nanocrystalline diamond films under water-lubricating conditions were comparatively investigated using a reciprocating ball-on-flat tribometer. Although the untreated nanocrystalline diamond film shows a stable frictional state with an average friction coefficient of 0.26, the subsequent textured films show a beneficial effect on rapidly reducing the friction coefficient, which decreased to a stable value of 0.1. Furthermore, compared with the nanocrystalline diamond coating, the textured films showed a large decreasing rate of the corresponding ball wear rate from 4.16 × 10−3 to 1.15 × 10−3 mm3/N/m. This is due to the fact that the hydrodynamic fluid film composed of water and debris can provide a good lubrication environment, so the entire friction process has reached the state of fluid lubrication. Meanwhile, the surface texture can greatly improve the hydrophilicity of the diamond films, and as the texture density increases, the water contact angle decreases from 94.75° of the nanocrystalline diamond film to 78.5° of the textured films. The proper textured diamond film (NCD90) exhibits superior tribological properties among all tested diamond films, such as short run-in period, low coefficient of friction, and wear rate.

Friction and Wear Behaviors of Solid Lubricants/Polyimide Composites in Liquid Mediums

2010 ◽  
Vol 654-656 ◽  
pp. 2763-2766 ◽  
Author(s):  
Li Wen Mu ◽  
Xin Feng ◽  
Yi Jun Shi ◽  
Huai Yuan Wang ◽  
Xiao Hua Lu
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Tribological Properties ◽  
Alkaline Solution ◽  
Dry Friction ◽  
Friction And Wear ◽  
Solid Lubricants ◽  
Polyimide Composites ◽  
Inorganic Fillers ◽  
Ptfe Composites

The tribological properties of polyimide (PI) composites reinforced with graphite or MoS2 sliding in liquid alkali and water as well as dry friction were investigated using a ring-on-ring tester. The results show that the friction coefficient (μ) and wear rate (W) for both graphite/PI and MoS2/PI composites in different liquid mediums are μdry>μwater >μalkali and Wwater>Wdry >Walkali. Results also indicate that the friction coefficient and wear rate of the PI composites filled with different solid lubricants are μMoS2 >μgraphite and W MoS2 >Wgraphite in different liquid mediums. In addition, the hydrophobic inorganic fillers are fit for the reinforcement of polymer-based composites sliding in liquid mediums. It is also concluded from the authors’ work that the wear rate and friction coefficient of polymer-based (such as PI, PTFE) composites in the alkali lubricated conditions is lowest among all the friction conditions. This may be attributed to the ionic hydration in the alkaline solution.

Mechanical and tribological properties of ice-bonded abrasive polishing tools

2017 ◽  
Vol 233 (1) ◽  
pp. 132-144 ◽  
Author(s):  
S Rambabu ◽  
N Ramesh Babu
Keyword(s):  
Wear Rate ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
Melting Rate ◽  
Wear Behaviour ◽  
Mechanical And Tribological Properties ◽  
Different Temperatures ◽  
Long Time ◽  
Polishing Tool ◽  
Hardness Coefficient

This article covers the efforts on characterising ice-bonded abrasive polishing tool in terms of the mechanical and tribological properties such as hardness, coefficient of friction, and wear rate. These studies were attempted on the tools prepared at different temperatures ranging from −10 °C to 0 °C with a view to identify the condition suitable to prepare ice-bonded abrasive polishing tool for effective polishing of Ti–6Al–4V alloy specimen. It also presents the methods adopted to determine various properties of ice-bonded abrasive polishing tool. Hardness was estimated from the measured penetration depth of cone shape indenter into the tool, coefficient of friction was determined from the change in power drawn by the motor rotating the tool mould, and wear behaviour of tool was assessed from the melting rate of the tool determined from the change in height of ice-bonded abrasive polishing tool at different stages of polishing. From the results of this study, it is clear that ice-bonded abrasive polishing tool prepared at −4 °C has possessed sufficient hardness, coefficient of friction, and reasonable wear rate suitable for polishing of Ti–6Al–4V specimens. This article also covers the details of low-temperature coolant supply unit developed to prepare the ice-bonded abrasive polishing tool at any desired temperature between 0 °C and −40 °C and thus to maintain it for a long time. Polishing studies with such ice-bonded abrasive polishing tool showed 72% improvement in finish after 90 min of polishing of Ti–6Al–4V specimen with tool, prepared at −4 °C.

scholarly journals Influence of load and reinforcement content on selected tribological properties of Al/SiC/Gr hybrid composites

2018 ◽  
Vol 18 (18) ◽  
pp. 18-23 ◽  
Author(s):  
Sandra Veličković ◽  
Slavica Miladinović ◽  
Blaža Stojanović ◽  
Ružica R. Nikolić ◽  
Branislav Hadzima ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Tribological Properties ◽  
Metal Matrix ◽  
Hybrid Composites ◽  
Tribological Characteristics ◽  
Volume Fractions ◽  
Sic Particles ◽  
The Matrix

Abstract Hybrid materials with the metal matrix are important engineering materials due to their outstanding mechanical and tribological properties. Here are presented selected tribological properties of the hybrid composites with the matrix made of aluminum alloy and reinforced by the silicon carbide and graphite particles. The tribological characteristics of such materials are superior to characteristics of the matrix – the aluminum alloy, as well as to characteristics of the classical metal-matrix composites with a single reinforcing material. Those characteristics depend on the volume fractions of the reinforcing components, sizes of the reinforcing particles, as well as on the fabrication process of the hybrid composites. The considered tribological characteristics are the friction coefficient and the wear rate as functions of the load levels and the volume fractions of the graphite and the SiC particles. The wear rate increases with increase of the load and the Gr particles content and with reduction of the SiC particles content. The friction coefficient increases with the load, as well as with the SiC particles content increase.

Tribological Properties of Polyoxymethylene Composites Against Aluminum

2003 ◽  
Vol 125 (3) ◽  
pp. 661-669 ◽  
Author(s):  
Masaya Kurokawa ◽  
Yoshitaka Uchiyama ◽  
Tomoaki Iwai ◽  
Susumu Nagai
Keyword(s):  
Wear Rate ◽  
Coefficient Of Friction ◽  
Tribological Properties ◽  
High Surface ◽  
Surface Hardness ◽  
Disk Surface ◽  
Optical Microscope ◽  
Transfer Film ◽  
The Other ◽  
The Coefficient Of Friction

Tribological properties of several kinds of polyoxymethylene (POM) composites were evaluated for the purpose of developing a polymeric tribomaterial especially suited for mating with aluminum parts having low surface hardness. POM composites containing small amounts of silicon carbide (SiC), POM/SiC; those containing a small amount of calcium octacosanonoate besides SiC, POM/SiC/Ca-OCA; and the one blended with 24 wt % of polytetrafluoroethylene, POM/PTFE(24); were injection-molded into pin specimens and their tribological properties were tested by means of a pin-on-disk type wear apparatus using an aluminum (A5056) mating disk in comparison with a 303 stainless steel (SUS303) disk. Evaluation was focused on observation of the sliding surfaces of the pin specimens and the mating disks by a scanning electron microscope and an optical microscope together with the measurement of surface roughness. In the case of mating against a SUS303 disk having high surface hardness, all pin specimens did not roughen the disk surfaces even after long time of rubbing. Only POM/PTFE(24) composite obviously made a transfer film on the disk surface, while the other composites made an extremely thin one on it. POM/SiC(0.1)/Ca-OCA(1) composite, containing SiC 0.1 wt. % and Ca-OCA 1 wt. %, was found to show the lowest coefficient of friction and the lowest wear rate forming extremely thin transfer film on the mating disk. On the other hand, against an A5056 disk which has lower surface hardness than that of SUS303 disk, unfilled POM and POM composites except POM/SiC(0.1)/Ca-OCA(1) composite roughened the disk surfaces. However, the sliding surface of the A5056 disk rubbed with POM/SiC(0.1)/Ca-OCA(1) composite was significantly smoother and that of the pin specimen was also quite smooth in comparison with other pin specimens. Further, when each POM composite was rubbed against the A5056 disk, formation of transfer film was not obvious on the disk surfaces. For POM/SiC(0.1)/Ca-OCA(1) composite, the wear rate was the lowest of all POM composites, and the coefficient of friction was as low level as 60 percent of that of unfilled POM, but slightly higher than that of POM/PTFE(24) composite. For POM/SiC(0.1)/Ca-OCA(1) composite, the nucleating effect of SiC and Ca-OCA, which accelerated the crystallization of POM during its injection molding to form a matrix containing fine spherulites, must have resulted in increasing the toughness of the matrix and lowering the wear rate. Also, the lubricant effect of Ca-OCA should have lowered the coefficient of friction of the same matrix for rubbing against aluminum mating disk. POM/SiC(0.1)/Ca-OCA(1) composite was concluded as an excellent tribomaterial for mating with aluminum parts.

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.

scholarly journals Fabrication and Tribological Properties of Copper Matrix Solid Self-Lubricant Composites Reinforced with Ni/NbSe2 Composites

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1854
Author(s):  
Fei-xia Zhang ◽  
Yan-qiu Chu ◽  
Chang-sheng Li
Keyword(s):  
Powder Metallurgy ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Tribological Properties ◽  
Friction And Wear ◽  
Copper Matrix ◽  
Wear Properties ◽  
Disk Friction ◽  
Friction Reducing ◽  
Properties Of Composites

This paper presents a facile and effective method for preparing Ni/NbSe2 composites in order to improve the wettability of NbSe2 and copper matrix, which is helpful in enhancing the friction-reducing and anti-wear properties of copper-based composites. The powder metallurgy (P/M) technique was used to fabricate copper-based composites with different weight fractions of Ni/NbSe2, and tribological properties of composites were evaluated by using a ball-on-disk friction-and-wear tester. Results indicated that tribological properties of copper-based composites were improved by the addition of Ni/NbSe2. In particular, copper-based composites containing 15 wt.% Ni/NbSe2 showed the lowest friction coefficient (0.16) and wear rate (4.1 × 10−5 mm3·N−1·m−1) among all composites.

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