Tribological and Mechanical Properties of Carbon Nanofiber-Filled PTFE Composites

2007 ◽  
Vol 121-123 ◽  
pp. 975-978
Author(s):  
Yi Jun Shi ◽  
Xin Feng ◽  
X.S. Diao ◽  
Huai Yuan Wang ◽  
Xiao Hua Lu

The tribological and mechanical properties of carbon nanofiber (CNF)-filled polytetrafluoroethylene (PTFE) composites with different filler proportions were studied. The worn surfaces of PTFE and carbon nanofiber/PTFE (CNF/PTFE) composites were then examined with scanning electron microscope (SEM). The results show the friction properties of CNF/PTFE composites decreased then increased with the increasing content of CNFs, while the anti-wear properties of CNF/PTFE composites were much higher than that of pure PTFE. The best anti-wear property was obtained with the composite containing 2 wt.% CNFs. The wear volume loss of the composite contained 2 wt.% CNFs was only about 1/700 that of PTFE without CNFs under the condition of 150N and 1.4m/s. Meanwhile, the results also indicate that the mechanical properties of CNF/PTFE composites increased then decreased with the increasing filler concentration, and the composite contained 1 wt.% CNFs has the best mechanical properties. Compare to pure PTFE, the tensile strength and the elongation of CNF/PTFE composites increased about 20% and 70% respectively when the filler content is 1 wt.%. It was seen from the worn surfaces micrographs of PTFE and CNF/PTFE composites that CNFs greatly reduce the adhesive wear of PTFE.

2007 ◽  
Vol 334-335 ◽  
pp. 689-692 ◽  
Author(s):  
Yi Jun Shi ◽  
Xin Feng ◽  
Huai Yuan Wang ◽  
Xiao Hua Lu

The tribological and mechanical properties of polytetrafluoroethylene (PTFE) composites filled with carbon nano-fiber (CNF), short carbon fiber (SCF) and the combination of them were studied. The results indicate that the wear volume loss of the PTFE composite filled with CNF or SCF, in comparison with that of pure PTFE, decreases by 1~2 orders of magnitude. And the best wear resistant composition is achieved by the combination of SCF with CNF; as an example, PTFE+2 wt% CNF+18 wt% SCF exhibits a specific wear volume loss of 0.88 mm3, which is about 11 times lower when compared to the PTFE composite filled with 18 wt% SCF. Meanwhile, the results also show that the tensile strength of SCF or CNF filled PTFE composites is better than that of pure PTFE. However, the combination of the two fillers decreases the tensile strength of PTFE composites. Worn surfaces were investigated using a scanning electron microscope, from which it is assumed that a mechanism of rolling effect, due to the filling of nanoparticles, which has a positive protective effect for PTFE matrix.


2020 ◽  
Vol 861 ◽  
pp. 35-40
Author(s):  
Yu Liu ◽  
Tian Hao Xu ◽  
Ying Liu ◽  
Hai Cheng Zhang ◽  
Xing Xing Li ◽  
...  

The surface of 45 steel is quenched by CO2 laser with scanning speed 1000 mm/min and different laser power 1000W, 1200W, 1400W, 1600W and 1800W. Experiments are carried out to analyze microstructure, friction and wear properties of quenched 45 steel. The results show that the quenching layer thickness increases gradually with the increase of laser power,and the maximum value of quenching layer hardness increases first and then decreases. When the laser power is 1600W, the maximum hardness value is 883HV0.5. But when the laser power is 1800W, the hardness of quenching layer becomes to decrease. The reason is the surface of 45 steel becomes to melt. The wear volume increases first and then decreases too. When laser power is 1600W, the minimum wear volume is 0.08mm3, which is 6.4% to the wear volume of 45 steel matrix without laser quenching. Therefore, better microstructure and properties of 45 steel can be obtained when laser scanning speed is 1000mm/min and laser power is 1600W.


2013 ◽  
Vol 834-836 ◽  
pp. 23-28 ◽  
Author(s):  
Jun Ma ◽  
Chong Hai Xu ◽  
Ming Dong Yi ◽  
Guang Chun Xiao ◽  
Xing Hai Wang

Ti (C,N)/ZrO2/WC nanocomposite cermet die materials were fabricated by vacuum hot pressing process, the materials have better comprehensive mechanical properties. The friction and wear properties of Ti (C,N)-based nanocomposite cermet die materials were studied, and the worn surfaces microstructure were observed and analysed by SEM and XRD. The experimental results showed that when the rotate speed was higher, the coefficient of friction of the developed cermet die material, which is 0.3-0.4, was lower than that without the addition of nanoZrO2 and micrometer WC. The main wear mechanisms were abrasive wear, oxidation wear and adhesive wear.


2021 ◽  
Author(s):  
Zhenya Zhang ◽  
Kunpeng Cai ◽  
Yaxin Guo ◽  
Xiaohua Liu ◽  
Suqin He ◽  
...  

Abstract Halogen-free flame retardants are ideal plastic additives that meet carbon neutral requirements. In this work, halogen free flame retardant with glass fiber reinforced PA66/PPO composites were prepared by using coated red phosphorus (FRM-150B) and phosphorus-silicon flame retardant (WR6002). The mechanical properties, heat resistance, friction and wear properties and flame retardancy were carried out to evaluate the performances of composites using as structural parts that require heat resistance, dimensional stability and accuracy. It was found that the friction coefficient and wear volume of the composites were improved with the contents of glass fiber increased, as a result, PA66/PPO composites was obtained with excellent comprehensive performance when the content of compatilizer is 7%, the glass fiber was 30%, the content of FRM is 8% and the phosphorous-silicon flame retardant is 16%. The flame retardant effect of FRM-150B and WR6002 in PA66/PPO was presented in the condensed phase, the results showed that the composite material with 16% WR6002 forms a carbon layer with excellent thermal stability. On the other hand, the mechanical properties of composites were hardly affected, has important prospects in automotive components and household appliances


2020 ◽  
Vol 10 (20) ◽  
pp. 7363
Author(s):  
Lei Xu ◽  
Erkuo Yang ◽  
Yasong Wang ◽  
Changyun Li ◽  
Zhiru Chen ◽  
...  

Ultra high-pressure sintering (UHPS) was used to prepare AA6061/SiCp composites with different contents and the effect of sintering temperatures on microstructure and mechanical properties was investigated in this study. The results showed that a uniform distribution of nano-SiC particles (N-SiCp) is obtained by the UHPS method. With the increase in N-SiCp contents, the higher hardness and better wear resistance could be inspected. The interfacial reactions and Al4C3 phase appeared above 550 °C. The relative density of composites first increased and then decreased; with the temperature raising it reached 99.58% at 600 °C. The hardness and wear property showed the same trend with the hardness reaching 52 HRA and wear rate being 1.0 × 10−6 g/m at 600 °C. Besides, the wear mechanism of the composites is mainly composed of abrasive wear and adhesive wear.


Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5785
Author(s):  
Zhengyao Yi ◽  
Chenchen Song ◽  
Guohui Zhang ◽  
Tianqi Tong ◽  
Guangyi Ma ◽  
...  

For improving the wear properties of NiCrAlY, the 10 wt %, 20 wt % and 30 wt % ZrO2-added NiCrAlY samples were prepared by ultrasonic-assisted direct laser deposition, respectively. The results showed that the ultrasonic-assisted direct laser deposition can realize the ZrO2-added NiCrAlY preparation. Furthermore, due to the cavitation effect and agitation of the ultrasound in the molten pool, ultrasonic-assisted could make the upper surface of the samples smoother and flatter, and it also improved the microstructural homogeneity. The microstructure was mainly composed of columnar dendrites, and most of ZrO2 particles were located in the intergranular regions. The principal phase constituents were found to contain γ-Ni and t-NiZr2, and the amorphous (Ni, Zr) intermetallic phase generated, because of more rapid solidification after ultrasound assisted. The microhardness was improved slightly with the increase of ZrO2 contents, rising from 407.9 HV (10% ZrO2) to 420.4 HV (30% ZrO2). Correspondingly, wear mass loss was decreased with the maximum drop 22.7% of 30% ZrO2 compared to that of 10% ZrO2, and wear mechanisms were mainly abrasive wear with slightly adhesive wear. After applying ultrasound, the oxide islands in samples disappeared, and more ceramic particles were retained. Thus, the hardness and wear performance of the samples were improved.


Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 570
Author(s):  
Wenting Chen ◽  
Kunyapat Thummavichai ◽  
Xiaorong Chen ◽  
Guangsheng Liu ◽  
Xuefeng Lv ◽  
...  

Inorganic fullerene-like tungsten disulfide particles have been proved to have good anti-friction and anti-wear properties as lubricating materials. As far as we know, however, when it is used as a lubricant additive, its behavior and action mechanism in the friction process are rarely studied. Herein, IF–WS2 particles were synthesized by a Chemical Vapor Deposition (CVD) method. The effect of IF–WS2 particle concentrations in the PAO6 oil on the tribological behaviors was investigated with a four-ball wear machine at both 75 and 100 °C. Additionally, the analyzed morphology and composition of nanomaterials and worn surfaces were analyzed by Scanning electron microscopy (SEM), Transmission Electron Microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The friction behavior in actual working conditions was studied by a wear testing machine. The experimental results show that compared with the original PAO6 oil, at a dispersion of 0.25 wt% in PAO6 oil, the IF–WS2 particles showed the best performance in terms of coefficient of friction, wear scar diameter and wear mass, which significantly reduced by 27%, 43% and 87%, respectively. At the same time, in the process of friction, it was found that IF–WS2 particles accumulated in the depressions to fill the scratches, and adsorption films and chemical films, including FeS2, WS2 and WO3, were formed on the worn surfaces to avoid the direct contact among the friction pairs more effectively, resulting in the improved anti-wear performances. Additionally, the addition of IF–WS2 particles effectively delayed the rise of lubricating oil temperature. In addition, dispersant span 80 can effectively improve the dispersion and stability of IF–WS2 in PAO6. This work provides us for understanding the effective lubrication mechanism of IF–WS2 particles in more detail and having a new acknowledge of the comprehensive performance of IF–WS2/PAO6 oil.


Author(s):  
Yi Jun Shi ◽  
Xin Feng ◽  
X.S. Diao ◽  
Huai Yuan Wang ◽  
Xiao Hua Lu

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1464 ◽  
Author(s):  
Feng Qiu ◽  
Xiangzheng Duan ◽  
Baixin Dong ◽  
Hongyu Yang ◽  
Jianbang Lu ◽  
...  

: In situ micro-TiB2/Cu cermets with a different TiB2 content (40, 50, and 60 vol %) were successfully fabricated by combustion synthesis (CS) and hot press consolidation in Cu-Ti-B systems. In addition, different contents of Cr and Zr were added to the Cu-Ti-B systems. The microstructure, mechanical properties, and abrasive wear properties of the TiB2/Cu cermets were investigated. As the ceramic content increased, the yield strength and compressive strength of the cermets were found to increase, while the strain decreased. An increase in load and abrasive particle size caused the wear volume loss of the TiB2/Cu cermets to increase. When the ceramic content was 60 vol %, the wear resistance of the TiB2/Cu cermets was 3.3 times higher than that of pure copper. The addition of the alloying elements Zr and Cr had a significant effect on the mechanical properties of the cermets. When the Cr content was 5 wt %, the yield strength, ultimate compressive strength, and microhardness of the cermets reached a maximum of 997 MPa, 1183 MPa, and 491 Hv, respectively. Correspondingly, when the Zr content was 5 wt %, those three values reached 1764 MPa, 1967 MPa, and 655 Hv, respectively, which are 871 MPa, 919 MPa, and 223 Hv higher than those of the unalloyed cermets. The wear mechanism of the in-situ TiB2/Cu cermets, and the mechanisms by which the strength and wear resistance were enhanced by the addition of Zr, were preliminarily revealed.


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