Thermal Stress Analysis of Lubricating Wear-Resisting Coating Prepared by Supersonic Plasma Spraying in the High-Heat Tribological Process

2011 ◽  
Vol 80-81 ◽  
pp. 667-672
Author(s):  
Yun Cai Zhao ◽  
Gao Jie Hao ◽  
Chun Ming Deng ◽  
Wem You Ma

This paper is about the study of the KF301/WS2 composite lubricating wear-resisting coatings prepared by supersonic plasma spraying. Basing on the research of the tribological characteristics, it has been discussed that the thermal stress of lubricating wear-resisting coating prepared by supersonic plasma spraying in the high-heat tribological process. Research shows that the wear rate of the coating increases with the increase of the temperature. At 300°C, the wear rate is 1.02×10-4mg/m; At 750°C, the wear rate is 2.61×10-4 mg/m. With the increase of temperature, friction coefficient of the coatings shows gradually increasing. When the temperature falls below 600°C, friction coefficient keeps around 0.08; At 750°C, the friction coefficient is 0.12. The thermal stress σ1max mainly is controlled by temperature, with the increase of temperature, the warping phenomena of solid lubricant film and the combined effects of heat stress and friction contact stress, which causes the insecure combination of the lubricant film and substrate, lubricant film’s warp, break, local direct contact between the metals, which is one of reasons to lead to decrease of the tribological properties of self-lubricating composite coating.

2011 ◽  
Vol 80-81 ◽  
pp. 661-666
Author(s):  
Yun Cai Zhao ◽  
Jia Jia Mao ◽  
Chun Ming Deng ◽  
Wem You Ma

This paper is about the study of the KF301/WS2composite lubrication wear-resisting coatings prepared by supersonic plasma spraying. Basing on the research of the tribological characteristics, it has been discussed the self-lubricity and the failure mechanism showed by composite lubrication coatings under high-temperature conditions. Research shows that the wear rate of the coatings increased with the increase of the temperature. At 300°C, the wear rate is 1.02×10-4mg/m; At 750°C, the wear rate is 2.61×10-4mg/m. With the increase of temperature, friction coefficient of the coatings shows gradually increasing. When the temperature falls below 600°C, friction coefficient keeps around 0.08; At 750°C, the friction coefficient is 0.12. Temperature has great effect on the friction and wear properties ofthe self-lubricating wear-resisting coatings, mainly manifests in two aspects: first, with the increase of the temperature, under the common influence of thermal stress and frictional contact stress, it promotes the WS2solid lubricant film cracking, breakage, shedding process, and lubrication and abrasive resistance reduces; on the other hand, the WS2occurs chemical reaction under high temperature, generating lubricity phase of NiWO4, CrS, and lubricity phases are well supplied, lubricating film has an effect of continuous lubrication on the rubbing surface, So the coating shows low-friction, and it also represents that the KF-301/ WS2self-lubricating composite coating has good lubrication and abrasive resistance under high temperature.


2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Cheng-Di Li ◽  
Wei-Wei Wang ◽  
Mei Jin ◽  
Yan Shen ◽  
Jiu-Jun Xu

To enhance the friction property of Al–Si alloy cylinder liner in running-in period, MoS2 coatings were electrodeposited on the chemical-etched surface of cylinder liner. The friction coefficient decreased by 15% comparing with the original honed surface, indicating the better friction property. This is because the synergistic action between solid lubricant and etched surface. MoS2 coatings prevent the direct contact between silicon particles and piston ring during friction. At top dead center, the oil film was thinnest and even was broken during the reciprocate friction. When oil film was invalidated, MoS2 coatings undertook lubrication. Then, MoS2 coatings were depleted, and advantage of etched surface became apparent.


2007 ◽  
Vol 539-543 ◽  
pp. 2275-2280
Author(s):  
Hiroyuki Saiki ◽  
Yasuo Marumo ◽  
Li Qun Ruan ◽  
Junpei Kozasa

The effect of the flow stress of solid lubricant for cold forging on the tribological conditions was investigated using a rigid-plastic finite element method. The thickness of lubricant film decreases with decreasing flow stress of the solid lubricant and then decreases rapidly. The apparent friction coefficient also decreases with the decrease in the flow stress of the solid lubricant. The thickness of lubricant film tends to decrease with decreasing friction shear factor. When flow stress of solid lubricant is low, the thickness of lubricant film decreases remarkably with increasing tool stroke. We can observe a good correlation between the flow stress of solid lubricant, friction shear factor, minimum film thickness and apparent friction coefficient.


2018 ◽  
Vol 72 (2) ◽  
pp. 203-210
Author(s):  
Binnur Sagbas

Purpose The purpose of this paper is to investigate applicability of hexagonal boron nitride (h-BN) powder as a solid lubricant additive in coconut oil and to determine the tribological behavior of PEEK rubbed with DIN2080 tool steel, under prepared green lubricating condition. Design/methodology/approach In this study, tiribological performance of PEEK against the DIN2080 tool steel is investigated with green lubricant. Coconut oil was used as green lubricant and 4 per cent wt. h-BN powder was added as lubricant additive into the coconut oil. Reciprocal pin-plate tribological test were applied under dry, coconut oil and coconut oil+h-BN lubrication condition. Friction coefficients were recorded and wear behavior of the samples investigated by mass loss measurement and topographical inspection of wear track by optical profilometer. Findings Using coconut oil as lubricant provided 80 per cent reduction of friction coefficient and 33.4 per cent reduction of wear rate. Addition of h-BN into the coconut oil provide 84 per cent reduction of friction coefficient and 56 per cent reduction of wear rate. The results showed that vegetable oil is promising lubricant for sustainable manufacturing. h-BN serves to increase lubricant performance and decrease wear of the surfaces. Practical implications Petrochemical lubricants are one of the major sources of environmental pollution and health hazards. Development and use of environmental and health friendly lubricants support sustainability and reduce wear, friction and energy consumption. With this consciousness, recent studies have focused on green tribology and green lubricants such as vegetable oils, ionic liquid bio-lubricants and bio-based polymers. Originality/value In literature study coconut oil was proposed as green lubricant while h-BN powder was proposed as solid lubricant. However, applicability of h-BN powder in coconut oil has not been explored yet. Moreover, wear and friction property of PEEK material with DIN 2080 tool steel pair surface has not been studied yet with green lubricants.


2020 ◽  
Vol 72 (10) ◽  
pp. 1153-1158 ◽  
Author(s):  
Yafei Deng ◽  
Xiaotao Pan ◽  
Guoxun Zeng ◽  
Jie Liu ◽  
Sinong Xiao ◽  
...  

Purpose This paper aims to improve the tribological properties of aluminum alloys and reduce their wear rate. Design/methodology/approach Carbon is placed in the model at room temperature, pour 680°C of molten aluminum into the pressure chamber, and then pressed it into the mold containing carbon felt through a die casting machine, and waited for it to cool, which used an injection pressure of 52.8 MPa and held the same pressure for 15 s. Findings The result indicated that the mechanical properties of matrix and composite are similar, and the compressive strength of the composite is only 95% of the matrix alloy. However, the composite showed a low friction coefficient, the friction coefficient of Gr/Al composite is only 0.15, which just is two-third than that of the matrix alloy. Similarly, the wear rate of the composite is less than 4% of the matrix. In addition, the composite can avoid severe wear before 200°C, but the matrix alloy only 100°C. Originality/value This material has excellent friction properties and is able to maintain this excellent performance at high temperatures. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2019-0454/


2008 ◽  
Vol 203 (5-7) ◽  
pp. 766-770 ◽  
Author(s):  
Ihsan Efeoglu ◽  
Özlem Baran ◽  
Fatih Yetim ◽  
Sabri Altıntaş

Author(s):  
Ying Yan ◽  
Xuelin Lei ◽  
Yun He

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.


2010 ◽  
Vol 654-656 ◽  
pp. 2763-2766 ◽  
Author(s):  
Li Wen Mu ◽  
Xin Feng ◽  
Yi Jun Shi ◽  
Huai Yuan Wang ◽  
Xiao Hua Lu

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.


RSC Advances ◽  
2015 ◽  
Vol 5 (79) ◽  
pp. 64254-64260 ◽  
Author(s):  
Jin Yang ◽  
Hongtao Zhang ◽  
Beibei Chen ◽  
Hua Tang ◽  
Changsheng Li ◽  
...  

The g-C3N4/Cu nanocomposite was prepared by in situ reduction of Cu2+ adsorbed on the surface defects of g-C3N4, and it exhibited the best lubricating behavior with the lowest friction coefficient and wear rate compared to g-C3N4 or Cu nanoparticles.


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