Tribological Behaviors of Dense Gelcasting Nanocomposites

2016 ◽  
Vol 868 ◽  
pp. 56-60
Author(s):  
Sung Hun Cho ◽  
Sang Hoon Jeong ◽  
Bum Sung Kim ◽  
Tohru Sekino ◽  
Soo Wohn Lee ◽  
...  

Gelcasting/pressure less sintered Al2O3/SiC nanocomposites has a low sinterability. Also, mechanical and wear properties of these nanocomposites was degraded. Wear mechanism of low sinterability gelcasting nanocomposites was dominated by fracture mode of surface during wear tests. In this study, gelcasting processing and followed plressureless (PL) and hot isostatic pressing (HIP) sintering was attempted to fabricate dense Al2O3/SiC nanocomposites. Wear behaviors of high densities gelcasting nanocomposites were investigated under the identical wear test condition. The comparative specimen was used to hot pressed nanocomposites. Wear rates of dense gelcasting nanocomposites were related to closely initial friction coefficient.

SPE Journal ◽  
2021 ◽  
pp. 1-16
Author(s):  
Y. Zhou ◽  
J. H. Hu ◽  
B. Tan ◽  
Y. Jiang ◽  
Y. F. Tang

Summary Sealing is a technical bottleneck that affects drilling efficiency and cost in deep, difficult-to-drill formations. The spiral combination seal with active sand removal performance is a new type of seal, and the wear mechanism is not clear, resulting in no effective design. In this study, the wear properties of materials were measured by a friction-and-wear testing machine, and the measurement methods and criteria of wear loss and friction coefficient were established. The fitting function of working condition and friction coefficient was studied by fitting regression method. The law of influence of working conditions on friction coefficient and wear amount was determined. The actual wear model and evaluation criteria of wear condition were established by using wear test data and geometric relationship. The relationship among working conditions, contact stress, and wear depth is determined by numerical simulation method, and the wear mechanism of the new seal is revealed, which provides a theoretical basis for its application.


Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 743 ◽  
Author(s):  
Yoon-Seok Lee ◽  
Yuta Kondo ◽  
Mitsuhiro Okayasu

The wear characteristics of SUS304 and SUS316 stainless steels were evaluated at the rotation speeds of 100 m/s, 200 m/s, and 300 m/s under dry and wet conditions. The transition of friction-induced martensite occurred in wear-affected regions of two materials, regardless of the wear test conditions. The specific wear rates (Ws) of both stainless steels increase with increasing rotation speeds, regardless of the circumstances. Moreover, Ws of SUS304 and SUS316, obtained under dry conditions, is significantly higher than that of SUS304 and SUS316 obtained under wet conditions, respectively. This is because that the water film on the wet ring can act as a liquid lubricant between the ring and the block during the tests. After the wear tests, the hardness changes of both SUS304 and SUS316 are much higher under dry conditions, compared to those under wet conditions.


Author(s):  
Shao Lifan ◽  
Ge Yuan ◽  
Kong Dejun

In order to improve the friction and wear properties of Cu10Al–MoS2 coating, the addition of CeO2 is one of the present research hot spots. In this work, Cu10Al–MoS2 coatings with different CeO2 mass fractions were successfully fabricated on Q235 steel using a laser cladding. The microstructure and phase compositions of obtained coatings were analyzed using an ultra-depth of field microscope and X-ray diffraction, respectively. The friction-wear test was carried out under oil lubrication using a ball-on-disk wear tester, and the effects of CeO2 mass fraction on the microstructure, hardness, and friction-wear properties were studied, and the wear mechanism was also discussed. The results show that the laser cladded Cu10Al–MoS2 coatings with the different CeO2 mass fractions were mainly composed of Cu9Al4, Cu, AlFe3, Ni, MoS2, and CeO2 phases. The Vickers-hardness (HV) of Cu10Al–8MoS2–3CeO2, Cu10Al–8MoS2–6CeO2, and Cu10Al–8MoS2–9CeO2 coatings was 418, 445, and 457 HV0.3, respectively, which indicates an increase in hardness with the increase of CeO2 mass fraction. The average coefficients of friction (COF) and wear rates decrease with the increase of CeO2 mass fraction, presenting the outstanding friction reduction and wear resistance performances. The wear mechanism of Cu10Al–MoS2 coatings is changed from abrasive wear with slight fatigue wear to abrasive wear with the increase of CeO2 mass fraction.


Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 179 ◽  
Author(s):  
Jinchi Tang ◽  
Xiongfeng Hu ◽  
Fuqiang Lai ◽  
Xiaolong Guo ◽  
Shengguan Qu ◽  
...  

In this paper, the fretting wear properties of 20CrMnTi steel, a common material for a rocker bracket, was discussed for the first time after it was suffered carburizing treatment. Subsequently, the fretting wear behaviors of virgin, quenched, and carburized states were studied. The effect of loads (corresponding to different engine power output) and reciprocating frequencies (corresponding to different engine speed) on wear behaviors and mechanisms of carburized specimen were further discussed. The results showed that the coefficient of friction (CoF) and wear volume loss (WVL) of the carburized specimens were significantly lower than that of virgin and quenched states. During the wear test, the surface CoF decreased gradually with the increase of applied load, while the linear correlation trend was not observed with the increase of fretting frequency as it showed an increase first and then a decrease. It was observed that the WVL increased gradually with the increase of load and frequency. With an increase of the load, the wear mechanism gradually deteriorated from the initial adhesive wear to the mixed wear mechanism. When the load was high, the oxidative wear became more severe. However, no significant effect of frequency was observed on the wear mechanism.


2012 ◽  
Vol 476-478 ◽  
pp. 566-569
Author(s):  
Bao Guo Yuan ◽  
Hai Ping Yu ◽  
Ping Li ◽  
Gui Hua Xu ◽  
Chun Feng Li ◽  
...  

The effects of hydrogen on friction and wear properties of Ti–6Al–4V alloy sliding against GCr15 steel were investigated through dry sliding friction and wear tests in atmosphere at room temperature. Wear mechanism was determined by studying the morphology and chemical element of worn surface using SEM and EDS. Results show that friction coefficient decreases slightly and wear rate increases after hydrogenation. Wear mechanism is discussed.


2011 ◽  
Vol 314-316 ◽  
pp. 58-61 ◽  
Author(s):  
Wan Li Song ◽  
Chul Hee Lee ◽  
Seung Bok Choi ◽  
Myeong Woo Cho

In this paper, the effect of particle concentration and magnetic field on the tribological behavior of magneto-rheological (MR) fluid is investigated using a pin-on-disc tribometer. The wear loss and friction coefficient are measured to study the friction and wear properties of MR fluid. The morphology of the worn pin is also observed by scanning electron microscope (SEM) in order to analyze the wear mechanism. The results obtained in this work show that the wear loss and friction coefficient decrease with increasing particle concentration under the magnetic field. Furthermore, it is demonstrated that the magnetic field has a significant effect on improving tribological properties of MR fluid, especially the one with high particle concentration. The predominant wear mechanism of the MR fluid has been identified as abrasive wear.


2013 ◽  
Vol 470 ◽  
pp. 7-10
Author(s):  
Ki Woo Nam ◽  
Soo Chul Lee

Compacted vermicular (CV) graphitization cast iron is the name given to graphitization cast iron where the shape of the graphite looks like a vermicular. Castability and the thermal conductivity of CV graphitization cast iron is similar to those of Grey iron, while the strength of CV graphitization cast iron is similar to that of ductile iron. The thin film of diamond-like carbon (DLC) is one of the amorphous carbon thin films. It has various characteristics which are similar to those of diamond, such as high hardness, lubricity, abrasion resistance, chemical stability, electrical insulating properties and optical transparency. In this study, wear characteristics of Graphite Compacted Vermicular (GCV) material were investigated in accordance with changes in DLC coating time. The obtained results are as follows: the microstructure of GCV340 showed complex tissue with eccentric graphite and spherical graphite. The friction coefficient shows under 0.2 in all specimens. After enduring the wear test until 2000 m, the coating layer of the DLC coating specimen of 90 minute hardly showed any damage. It had only partial damage after taking the wear test until 2000 m. The friction coefficient was also the lowest.


2019 ◽  
Vol 71 (7) ◽  
pp. 931-941 ◽  
Author(s):  
Yazhou Mao ◽  
Yang Jianxi ◽  
Xu Wenjing ◽  
Liu Yonggang

Purpose The purpose of this paper is to investigate the effect of round pits arrangement patterns on tribological properties of journal bearing. In this paper, the tribological behaviors of journal bearing with different arrangement patterns under lubrication condition were studied based on M-2000 friction and wear tester. Design/methodology/approach The friction and wear of journal bearing contact surface were simulated by ANSYS. The wear mechanism of bearing contact surfaces was investigated by the means of energy dispersive spectrum analysis on the surface morphology and friction and wear status of the journal bearing specimens by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometer (EDS). Besides, the wearing capacity of the textured bearing was predicted by using the GM (1,1) and Grey–Markov model. Findings As the loads increase, the friction coefficient of journal bearing specimens decrease first and then increase slowly. The higher rotation speed, the lower friction coefficient and the faster temperature build-up. The main friction method of the bearing sample is three-body friction. The existence of texture can effectively reduce friction and wear. In many arrangement patterns, the best is 4# bearing with round pits cross-arrangement pattern. Its texturing diameters are 60 µm and 125 µm, and the spacing and depth are 200 µm and 25 µm, respectively. In addition, the Grey–Markov model prediction result is more accurate and fit the experimental value better. Originality/value The friction and wear mechanism is helpful for scientific research and engineers to understand the tribological behaviors and engineering applications of textured bearing. The wear capacity of textured bearing is predicted by using the Grey–Markov model, which provides technical help and theoretical guidance for the service life and reliability of textured bearing.


Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4547
Author(s):  
Bin Yang ◽  
Aiqin Wang ◽  
Kunding Liu ◽  
Chenlu Liu ◽  
Jingpei Xie ◽  
...  

SiCp/Al-Si composites with different CeO2 contents were prepared by a powder metallurgy method. The effect of CeO2 content on mechanical properties, friction and wear properties of the composites was studied. The results show that with the increase in CeO2 content from 0 to 1.8 wt%, the density, hardness, friction coefficient of the composites first increases and then decreases, the coefficient of thermal expansion (CTE) and wear rate of the composites first decreases and then increases. When the content of CeO2 was 0.6 wt%, the density and hardness of the composite reached the maximum value of 98.54% and 113.7 HBW, respectively, the CTE of the composite reached the minimum value of 11.1 × 10−6 K−1, the friction coefficient and wear rate of the composite reached the maximum value of 0.32 and the minimum value of 1.02 mg/m, respectively. CeO2 has little effect on the wear mechanism of composites, and the wear mechanism of composites with different CeO2 content is mainly abrasive wear under the load of 550 N. Compared with the content of CeO2, load has a great influence on the wear properties of the composites. The wear mechanism of the composites is mainly oxidation wear and abrasive wear under low load. With the increase in load, the wear degree of abrasive particles is aggravated, and adhesive wear occurs under higher load.


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