Does Thermal Conductivity Play a Role in Sliding Wear of Metals in Cryogenic Environment?

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Bikramjit Basu ◽  
Amartya Mukhopadhyay ◽  
Ankit Mishra ◽  
J. Sarkar

The thermal conductivity of a metallic test piece is one of the principal parameters that influence the temperature buildup at tribocontacts and this normally plays an important role in the unlubricated dry sliding wear of metallic materials. It is, however, not clear whether thermal conductivity is an equally important parameter in the case of wear of metals at cryogenic temperatures, in particular, at liquid nitrogen temperature (LN2) of −196°C. In order to assess the influence of such a physical property of selected nonferrous metals on their tribological behavior in the LN2 environment, we have studied the friction and wear properties of high purity copper (Cu) and titanium (Ti) against the bearing grade steel. These two materials have been processed to produce samples of comparable hardness that have widely different thermal conductivities at room temperature and at test temperature. Wear tests were conducted at three different sliding speeds (0.89 m/s, 1.11 m/s, and 1.34 m/s) under 10 N load, and the friction and wear data were compared. Ti exhibited an order of magnitude higher wear rate (∼10−3 mm3/N m) as compared with Cu in identical test conditions. While evidences of abrasive wear and adhesive wear, without any oxidative wear, were found in worn Cu surfaces, worn Ti surfaces showed evidences of significant oxidative wear and mechanical damage of tribolayers. Higher wear rate in Ti appeared to be a result of oxidative wear of Ti, which seemed to be driven by the depletion of LN2 blanket at the tribocontacts under the influence of high flash temperature (14–76°C) as compared with the boiling temperature of LN2(−196°C). These results demonstrate that the materials with similar hardness subjected to identical LN2 wear test conditions can have significantly different wear rates because of the difference in the flash temperatures, which depend on the thermal conductivity of the test pieces.

2010 ◽  
Vol 154-155 ◽  
pp. 617-620
Author(s):  
Wei Niu ◽  
Rong Lu Sun ◽  
Yi Wen Lei

Self-lubricating h-BN/Ni coating was prepared on a medium carbon steel substrate by CO2 laser cladding using a powder mixture of NiCrBSi+5%h-BN(wt.%). Microstructures and phase structure of the coating were analyzed using SEM, EDS and XRD. Wear tests were carried out using a M100 pin-on-ring wear tester. The results show that h-BN/Ni coating has much superior war resistance and noticeably lower fiction coefficient under dry sliding wear test conditions.


2011 ◽  
Vol 415-417 ◽  
pp. 170-173
Author(s):  
Jing Wang ◽  
Si Jing Fu ◽  
Yi Chao Ding ◽  
Yi San Wang

A wear resistant TiC-Cr7C3/Fe surface composite was produced by cast technique and in-situ synthesis technique. The microstructure and dry-sliding wear behavior of the surface composite was investigated using scanning electron microscope(SEM), X-ray diffraction(XRD) and MM-200 wear test machine. The results show that the surface composite consists of TiC and Cr7C3as the reinforcing phase, α-Fe and γ-Fe as the matrix. The surface composite has excellent wear-resistance under dry-sliding wear test condition with heavy loads.


2019 ◽  
Vol 9 (5) ◽  
pp. 567-572
Author(s):  
Li Hui ◽  
Jiao Lei ◽  
Miao Chang ◽  
Zhong Wu ◽  
Zhang Xiong ◽  
...  

The AZ91D composites reinforced by 10 wt.% AlN particles were welded via plasma welding and the dry sliding wear properties of the composites were investigated. The influence of welding current, welding speed and plasma flow rate were studied in detail. By using of OM, XRD, EDS and SEM, the crystalline phase, the microstructure and the wear properties were investigated. The experiment result shows that the AlN reinforcing particles is in the shape of strip and have a fine size under the condition of the welding speed 400 mm/min, the welding current 180 A and the plasma flow 2.0 L/min, which reaches 20–30 μm. The matrix grain in the composite were obviously refined, which reaches 60–70 μm. Wear test results showed that the wear rate of welding seam compared base metal decreased by 25%.


2014 ◽  
Vol 490-491 ◽  
pp. 83-87
Author(s):  
Qing Lin Li ◽  
Tian Dong Xia ◽  
Ye Feng Lan ◽  
Yi Sheng Jian

The effects of the primary Si phase and applied load on the dry sliding wear behaviors of hypereutectic Al-20Si alloy were investigated. The results show that coarse polygonal and star-like primary Si was refined into fine blocky shape by increasing superheat treatment temperature. The friction coefficient and wear rate significantly decrease after decreasing the size and changing the morphology of primary Si. Moreover, the friction coefficient and wear rate increase with the increase of applied load. Therefore, the wear properties are greatly influenced by the parameters like morphology and size of primary Si as well as applied load.


2017 ◽  
Vol 30 (2) ◽  
pp. 247-253 ◽  
Author(s):  
Ye Zhu ◽  
Yingshuang Shang ◽  
Haibo Zhang ◽  
Lianjun Ding ◽  
Yunping Zhao ◽  
...  

Poly(ether sulfone) (PES) with high coefficient of friction (COF) and wear rate needs treatment to enhance its tribological property in engineering plastic area. Here, the low surface energy of perfluorocarbon chains terminated poly (ether sulfone) (PES-F) had been used to improve the tribological property of such self-lubricating materials. In this research, the performance enhancement due to the existence of perfluorocarbon group on the material surface was discussed on improvement of anti-friction and wear resistance. On the premise of mechanical strength guarantee, the variation regularity of COF and volume wear rate of PES-F were quantitatively analyzed through the pin-on-disc wear test apparatus, combined with X-ray photoelectron spectroscopy analysis. It was found that PES-F exhibited the best tribological property during the initial phases of friction test, attributing to the highest content of F on the material surface. Observation of PES-F worn surface and wear debris revealed that the COF and wear rate of modified PES were decreased not only due to the effect of perfluorocarbon group but also by the change of worn surface morphology, both of which were the main reasons for anti-friction and anti-wear property enhancement.


Author(s):  
Akshay Shinde

Abstract: To improve the wear resistance of the hybrid powder coating, TiO2 nanoparticles was hot mixed to form a homogenous mixture with the powder in the range varying wt. dry sliding wear test conducted to determine the wear resistance. The experiments were design according to Taguchi L9 array to find the optimum nanoparticles content required to minimize the wear rate of the coating. ANOVA was used to determine the effect of the parameters on wear rate. It showed that reinforcement has the maximum contribution on the wear rate of the coating as compared to load and frequency. From the graph of means optimum parametric values was obtained at 2 % wt of reinforcement, 2 N load and 2 Hz frequency. The wear rate decrease with the increase in reinforcement. Keywords: Taguchi Method, Tribometer, Hybrid powder, TiO2, Wear Rate.


2013 ◽  
Vol 721 ◽  
pp. 303-307
Author(s):  
Hong Xu ◽  
Yi Chao Ding ◽  
Jing Wang

(Ti,V)C particles reinforced Fe-based surface composite coatings were fabricated by in-situ synthesis and powder metallurgy route. The microstructure and wear properties were investigated by scanning electron microscopy and dry sliding wear test. The results show that fine (Ti,V)C particulates distribute uniformly in pearlite matrix; when V/Ti atomic ratio is 0.4, the wear weight loss of the composites achieve minimum.


2019 ◽  
Vol 895 ◽  
pp. 200-205
Author(s):  
B.S. Kanthraju ◽  
Bheemappa Suresha ◽  
H.M. Somashekar

This paper presents the effect of zirconia filler on mechanical properties and dry sliding wear of bidirectional hybrid (glass and basalt fiber) fabric reinforced epoxy (G-B/E) composites. Fabrication was done by hand layup method followed by compression molding. The effect of zirconia filler loading on mechanical characteristics like hardness, tensile and flexure of fabricated G-B/E composites were determined according to ASTM standards. Also, wear behavior under dry sliding condition was performed using pin-on-disc machine for different applied normal loads/sliding distance. Experimental results reveal that incorporation of zirconia filler improves the mechanical properties. Further, the wear test results indicated addition of zirconia into G-B/E hybrid fiber composites plays important role on specific wear rate under the tribo-conditions selected for the study. Further, inclusion of zirconia into G-B/E composites shows improved wear resistance and addition of 6 wt. % of zirconia exhibits least specific wear rate compared to other hybrid G-B/E composites. In addition, Scanning electron microscope images of selected mechanical test fractured coupons also have been discussed.


2013 ◽  
Vol 747-748 ◽  
pp. 152-157 ◽  
Author(s):  
Shu Fa Chen ◽  
Cheng Long Feng ◽  
Jin Yang ◽  
Jin Song Chen

In this study, the dry sliding wear behavior of Ni-based self-lubricating wear-resistant coating was characterized under various loads at 300 . Morphologies and compositions of the worn surface were analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The experimental results showed that with the increase of load, both the frictional coefficient and wear rate decreased firstly, then slightly increased. A small amount of debris dispersed on the worn surface of the coating under low load (2 N). Since the effects of oxide layer and lubricant particles spreading onto the worn surface, the coating exhibited superior friction, and improved the wear properties under moderate load (5 N). As the load further increased, till up to 10N, the worn surface started to appear some shallow grooves and craters. This was contributed to the dispersion of carbides and lubricant particles.


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.


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