scholarly journals The tribological properties of single-layer hybrid PTFE/Nomex fabric/phenolic resin composites underwater

Open Physics ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 609-617
Author(s):  
Liu Ying ◽  
Gao Gengyuan ◽  
Jiang Dan ◽  
Yin Zhongwei

Abstract In this study, the tribological properties of hybrid polytetrafluoroethylene (PTFE)/Nomex fabric/phenolic resin composites were investigated under three operating conditions: dry sliding, dry sliding after soaking in water for 12 h, and water dripping lubrication. The friction coefficient (COF) was measured with a pin-on-disk tribometer. The wear surface was analyzed with a scanning electron microscope. The results show that water weakens the tribological properties of single-layer hybrid PTFE/Nomex fabric/phenolic resin composites. The fabric composites show slight abrasive wear with stable COF under dry sliding conditions, significant abrasive wear with oscillating COF after soaking, and destruction with severely oscillating COF under water dripping lubrication. Generally, water weakens the effect in two ways. The first is weakening the binding force between phenolic resin and Nomex fiber. The second is that Nomex fiber absorbs water and expands, which reduces its strength. Finally, the ideas to improve the tribological properties under water dripping lubrication are presented.

Author(s):  
Sarbjeet Kaushal ◽  
Dheeraj Gupta ◽  
Hiralal Bhowmick

In this study, functional performance of Ni/Cr3C2 functionally graded claddings (FGCs) was investigated under dry sliding wear environment. The Ni/Cr3C2-based FGCs were produced by varying Cr3C2 fraction (Ni-XCr3C2) (X=10%–30% by weight) using microwave irradiation. The FGC layers were composed of cellular-structure with reinforced particles dispersed randomly inside Ni-based matrix. Variation of Cr3C2 particles inside Ni matrix exhibited significant impact on micro-structural and mechanical properties. The microhardness profile of the FGC layers showed an increase in hardness value with an increase in the amount of reinforced Cr3C2 particles. FGC top layers showed the maximum value of micro-hardness of 555 ± 34 HV. Functional performance of microwave processed FGCs was studied through the pin-on-disk tribometer under varying sliding velocity and sliding distances. For comprehension study, wear study was also carried out on microwave processed single layer clads with compositions corresponding to FGC layers. The FGC sample showed better wear resistance than all single clad layers and substrate material. The FGC sample exhibited 1.6 times less wear rate than the Ni-based + 30% Cr3C2 single layer clad. The worn-out surfaces of FGC and single-layer-clads showed presence of multiples cracks and grooves, which resulted in their weight loss during dry sliding contact. Material debonding and the formation of craters and cracks are the main phenomena responsible for the wear loss in the FGC surface.


2011 ◽  
Vol 704-705 ◽  
pp. 877-885
Author(s):  
San Ming Du ◽  
Yong Zhen Zhang ◽  
Bao Shangguan

Abstract: In this article, the high-speed dry sliding tribological behaviors of CrNiMo steel against brass in nitrogen and oxygen atmospheres are investigated using a pin-on-disc tribometer. The worn surface is characterized by scanning electron microscopy and electron dispersion spectrums analysis. The wear mechanisms of CrNiMo steel are also analyzed. The results indicate that the tribological properties of CrNiMo steel are coincidental with the law of dry sliding of metal, where the friction coefficients decreases with an increase in sliding speed and with normal load. However, the atmosphere has obvious effects on the tribological properties of CrNiMo steel. In the sliding process, friction heat plays an important role on the tribological properties of materials in high-speed dry friction. The high-speed wear mechanism of CrNiMo steel varies at different atmospheres. In a nitrogen atmosphere, the wear mechanism of CrNiMo steel is mainly characterized by adhesion at a lower speed and load. When the speed and load are increased, melting trace is found in the worn surface accompanied by an abrasive wear. In an oxygen atmosphere, the mechanism is characterized by adhesion at a lower speed and load; with an increase in speed and load, it gradually transformed into oxidation wear and abrasive wear. The difference of the wear mechanisms in the different atmospheres and test parameters is primarily due to the transfer films formed on the contact surfaces of the sliding pairs. In our experimental conditions, the surface film is mainly the metal film in nitrogen, whereas, it is the oxide film in oxygen.


2014 ◽  
Vol 53 (7) ◽  
pp. 678-683 ◽  
Author(s):  
Bingli Pan ◽  
Mingke Xu ◽  
Hongguang Wang ◽  
Erlei Ye ◽  
Jichun Liu ◽  
...  

2021 ◽  
Vol 143 (6) ◽  
Author(s):  
Lenko Stanev ◽  
Mihail Kolev ◽  
Ludmil Drenchev

Abstract In this article, a new hybrid material is elaborated, which combines the advantages of the mechanically more resistive alloy-based composites and the effective lubricating properties of tin-based alloys with the purpose of enhancing the tribological properties and especially to enhance resistance under extreme and transient operating conditions for the application of sliding bearings. The hybrid material consists of an aluminum composite skeleton obtained via a replication method with NaCl particles as spacers and a tin-based alloy that is infiltrated into the composite skeleton. The hybrid material is characterized in respect to its microstructure and tribological parameters, such as the wear-rate and coefficient of friction. Data from the conducted tribological tests using the pin-on-disk method under dry friction conditions are obtained and compared with the results of the same tribological tests for the Al alloy, Al alloy-based porous skeleton, Al alloy-based porous composite skeleton, and tin-based alloy. It is concluded that the new hybrid material possesses superior tribological properties in comparison with the tin-based alloy, Al alloy, Al alloy-based porous skeleton, and Al alloy-based porous composite skeleton.


2014 ◽  
Vol 936 ◽  
pp. 2063-2067
Author(s):  
Chen Yue ◽  
Shang Guan Bao ◽  
Ying Yu Huang

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.


2011 ◽  
Vol 338 ◽  
pp. 607-610 ◽  
Author(s):  
Ming Qiu ◽  
Zhi Lun Gao ◽  
Guo Feng Wang ◽  
Long Chen

The friction and wear behaviors of three kinds of spherical plain bearings with PTFE fabric composite liners were investigated by a high oscillating frequency and heavy load tribo-tester. Dry sliding tests were carried out at different oscillating frequencies. With the help of SEM and EDS, the differences of worn surfaces of the three spherical bearings were investigated. The results indicate that the fiber woven with PTFE effects the friction and wear characteristics of bearing, the tribological properties of bearing with Kevlar/PTFE fiber woven liner is the best in the three kinds of bearing. The abrasive wear are appeared on the surface of wore liners of bearingⅠ,while bearingⅡappeared normal wear, bearing III showed serious adhesive wear and abrasive wear.


2012 ◽  
Vol 565 ◽  
pp. 615-620
Author(s):  
Bin Shen ◽  
Liang Wang ◽  
Su Lin Chen ◽  
Fang Hong Sun

The CVD diamond/diamond-like carbon composite film is fabricated on the WC-Co substrate by depositing a layer of Diamond-like Carbon film on the surface of conventional Micro- or Nano-crystalline diamond film. The hot filament chemical vapor deposition (HFCVD) method and vacuum arc discharge with a graphite cathode are adopted respectively to deposit the MCD/NCD and DLC films. A variety of characterization techniques, including filed emission scanning electron microscope (FE-SEM) and Raman spectroscopy are employed to investigate the surface morphology and atomic bonding state of as-deposited MCD/DLC and NCD/DLC composite film. The results show that both MCD/DLC and NCD/DLC composite films present similar surface morphology with the MCD and NCD films, except for scattering a considerable amount of small-sized diamond crystallites among the grain boundary area. The atomic-bonding state of as-deposited MCD/DLC and NCD/DLC composite films is determined by the top-layered DLC film, which is mainly consisted of amorphous carbon phase and no discernible sp3 characteristic peak can be observed from their Raman spectrum. Furthermore, the tribological properties of as-deposited MCD/DLC and NCD/DLC composite films is examined using a ball-on-plate reciprocating friction tester under both dry sliding and water-lubricating conditions, comparing with conventional DLC, MCD and NCD films. Silicon nitride balls are used as counterpart materials. For the CVD diamond/DLC composite films, the self-lubricating effect of top-layered DLC film is beneficial for suppressing the initial friction peak, as well as shortening the run-in period. The average friction coefficients of MCD/DLC and NCD/DLC composite films during stable sliding period are 0.07 and 0.10 respectively in dry sliding; while under water-lubricating condition, they further decreases to 0.03 and 0.07.


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