High-Temperature Friction and Wear Properties of NiCr/hBN Self-Lubricating Composites

Zhu, Xuewei; Wei, Xin; Huang, Yuxiang; Wang, Fu; Yan, Pengpeng

doi:10.3390/met9030356

Cited by 21 publications

(16 citation statements)

References 13 publications

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“…Moreover, the hBN inclusion led to a considerable rise in the wear rate and CoF for the HEBM-processed samples. Similar behavior of composites containing hBN was reported in [ 26 , 27 , 28 ]. Nevertheless, the friction coefficient values of SHS-processed composites were seen to be up to 40% lower than that of the HEBM-processed samples, signifying a positive effect of the SHS technique on Ni-W composite preparation.…”

Section: Resultssupporting

confidence: 87%

High-Temperature Wear Performance of hBN-Added Ni-W Composites Produced from Combustion-Synthesized Powders

et al. 2022

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This work reports on the spark plasma sintering (SPS) of self-propagating high-temperature-synthesis (SHS)-derived Ni-W and Ni-W-2wt%hBN (4:1 molar ratio of metals) powders. The synthesis was carried out from a mixture of NiO and WO3 using Mg + C combined reducers through a thermo-kinetic coupling approach. Experiments performed in the thermodynamically optimal area demonstrated the high sensitivity of combustion parameters and product phase composition to the amount of reducers and hBN powder. The powder precursors with and without the addition of hBN were consolidated using SPS at a temperature and pressure of 1300 °C and 50 MPa, respectively, followed by a thorough phase and microstructural characterization of the obtained specimens. SHS-derived powders comprised the nano-sized agglomerates and were characterized by a high sinterability. The specimens of >95% density were subjected to ball-on-plate dry sliding wear tests at a sliding speed of 0.1 ms−1 and a distance of 1000 m utilizing an alumina ball of 10 mm in diameter under a 15 N normal load. The tests were performed at a temperature of 800 °C. A significant improvement in wear behavior was demonstrated for SHS-processed composites in comparison with their counterparts produced via conventional high-energy ball milling technique owing to the phenomena of ‘micro-polishing’, cyclic ‘self-healing’ and fatigue. However, the decisive effect of hBN addition in imparting lubrication during an HT wear test was not confirmed.

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Section: Resultssupporting

confidence: 87%

High-Temperature Wear Performance of hBN-Added Ni-W Composites Produced from Combustion-Synthesized Powders

et al. 2022

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“…The most likely reactions are shown below. 4Ag+O2→2Ag2O (7) Mo+O2→MoO2 (8) 2MoO2+O2→2MoO3 (9) MoO3+Ag2O→Ag2MoO4 (10) At 400 • C, for the N alloy, the worn surface of the former becomes rough and many spalling pits and delamination appear, and the wear mechanism is adhesive wear (Figure 5a 2 ). For NA, the wear scar is wide and deep on the worn surface and produces a lot of wear debris alongside the peeling pits, and the wear mechanism is dominated by abrasive wear (Figure 5c 2 ).…”

Section: Mo+o2→moo2 (4)mentioning

confidence: 99%

“…Thus, Ni is an excellent matrix metal and has been widely applied in advanced engines. Introducing eligible solid lubricants into strengthened nickel-based alloys is an effective way to achieve the unification of high mechanical properties and good tribological behaviors, which has attracted the attention of researchers at home and abroad [6][7][8][9][10][11][12][13].Graphite and molybdenum disulfide (MoS 2 ) are a common solid lubricant and have low shear strength due to the lamellar structure. However, they will oxidize or decompose and lose lubrication at temperatures about 400 • C [14].…”

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confidence: 99%

Study on the Mechanical and Tribological Properties and the Mechanisms of Cr-Free Ni-Based Self-Lubricating Composites at a Wide Temperature Range

Zhang

Zhao

Wang

et al. 2020

Metals

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A Cr-free Ni-based self-lubricating composites with MoS 2 and Ag as lubricants were fabricated by the powder metallurgy method. The microstructures were examined. The mechanical properties and tribological behaviors of the composites were evaluated from room temperature to 800 • C. The fractography was observed and the fracture mechanisms were analyzed. The morphologies and the phase compositions of worn surfaces were determined and the wear mechanisms were elaborated. The results indicate that MoS 2 did not completely decompose after sintering, and the NiMoAl-MoS 2 -Ag composite has the best tribological properties (0.22, 1.68 × 10 −5 ) at 800 • C. The main wear mechanisms are micro-ploughing and plastic deformation. The improvement of tribological properties was attributed to the formation of the lubricating film consisting of NiO, Mo oxides, various molybdates, and Ag particles. The reactions resulting in these compositions are proposed. The mechanical properties degrade with the rise of temperature and the addition of lubricants. Both NiMoAl and NiMoAlAg alloys exhibit micro-void accumulation fracture while the composites with MoS 2 reveal intergranular fracture. such as high strength, satisfactory oxidation, hot corrosion resistance, and good microstructure stability. In addition, Ni can become a solid solution made of other metal elements and does not precipitate in a deleterious phase. Thus, Ni is an excellent matrix metal and has been widely applied in advanced engines. Introducing eligible solid lubricants into strengthened nickel-based alloys is an effective way to achieve the unification of high mechanical properties and good tribological behaviors, which has attracted the attention of researchers at home and abroad [6][7][8][9][10][11][12][13].Graphite and molybdenum disulfide (MoS 2 ) are a common solid lubricant and have low shear strength due to the lamellar structure. However, they will oxidize or decompose and lose lubrication at temperatures about 400 • C [14]. Silver (Ag), which is a soft metal, has often been added into composites as a lubricant serving at medium and low temperatures due to its low shear strength and large diffusion coefficient during sliding [15]. Metal oxides, fluoride, and oxysalt are high temperature lubricants [16][17][18]. Molybdates have gained increasing attention due to the lower friction coefficients at high temperatures [16,[19][20][21]. Adding low and high temperature lubricants to the metal matrix can achieve continuous lubrication in a wide temperature range, but may lead to a significant decline in the comprehensive mechanical properties of the composite. Thus, an alternative approach of taking advantage of the synergistic effect of the extrinsic low temperature lubricants and the in-situ formed high temperature lubricants generated by a tribo-chemical reaction was proposed [22,23]. For instance, Aouadi et al. [22] studied the tribological properties and mechanisms of Mo 2 N/MoS 2 /Ag coatings and found that the coatings exhibited lower friction coefficients (0....

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“…So far, the results on tribological studies of hBN as a solid lubricant give no clear idea of its usage. On the one hand, few studies report a positive influence of hBN in solid lubrication [ 3 , 10 , 74 , 75 , 76 ], while others state its negative or no effect on lubrication [ 77 , 78 , 79 , 80 ]. A decrease in CoF and wear rate with an increase in temperature up to 800 °C in Ni/hBN coating on stainless steel was perceived [ 75 ].…”

Section: Potential High-temperature Solid-lubricantsmentioning

confidence: 99%

Solid Lubrication at High-Temperatures—A Review

et al. 2022

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Understanding the complex nature of wear behavior of materials at high-temperature is of fundamental importance for several engineering applications, including metal processing (cutting, forming, forging), internal combustion engines, etc. At high temperatures (up to 1000 °C), the material removal is majorly governed by the changes in surface reactivity and wear mechanisms. The use of lubricants to minimize friction, wear and flash temperature to prevent seizing is a common approach in engine tribology. However, the degradation of conventional liquid-based lubricants at temperatures beyond 300 °C, in addition to its harmful effects on human and environmental health, is deeply concerning. Solid lubricants are a group of compounds exploiting the benefit of wear diminishing mechanisms over a wide range of operating temperatures. The materials incorporated with solid lubricants are herein called ‘self-lubricating’ materials. Moreover, the possibility to omit the use of conventional liquid-based lubricants is perceived. The objective of the present paper is to review the current state-of-the-art in solid-lubricating materials operating under dry wear conditions. By opening with a brief summary of the understanding of solid lubrication at a high temperature, the article initially describes the recent developments in the field. The mechanisms of formation and the nature of tribo-films (or layers) during high-temperature wear are discussed in detail. The trends and ways of further development of the solid-lubricating materials and their future evolutions are identified.

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High-Temperature Friction and Wear Properties of NiCr/hBN Self-Lubricating Composites

Cited by 21 publications

References 13 publications

High-Temperature Wear Performance of hBN-Added Ni-W Composites Produced from Combustion-Synthesized Powders

High-Temperature Wear Performance of hBN-Added Ni-W Composites Produced from Combustion-Synthesized Powders

Study on the Mechanical and Tribological Properties and the Mechanisms of Cr-Free Ni-Based Self-Lubricating Composites at a Wide Temperature Range

Solid Lubrication at High-Temperatures—A Review

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