Influence of the Chemical Composition and Local Atomic Packing of Nanostructured MoSx and MoSex Solid Lubricant Coatings on Their Tribological Properties under Complicated Conditions

2020 ◽  
Vol 46 (1) ◽  
pp. 83-86
Author(s):  
V. Yu. Fominski ◽  
V. N. Nevolin ◽  
D. V. Fominski ◽  
R. I. Romanov ◽  
M. D. Gritskevich
Keyword(s):  
Chemical Composition ◽  
Tribological Properties ◽  
Solid Lubricant ◽  
Atomic Packing ◽  
Complicated Conditions

Tribological properties of the epoxy resin-based solid lubricant coating modified by Kevlar fibers

2018 ◽  
Vol 70 (9) ◽  
pp. 1706-1713 ◽  
Author(s):  
Guotao Zhang ◽  
Yanguo Yin ◽  
Ting Xie ◽  
Dan Li ◽  
Ming Xu ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Epoxy Resin ◽  
Tribological Properties ◽  
Dry Friction ◽  
Friction And Wear ◽  
Solid Lubricant ◽  
Transfer Film ◽  
Wear Properties ◽  
Content Type ◽  
Friction And Wear Properties

Purpose This paper aims to obtain high mechanical and good tribological properties of epoxy resin-based coatings under dry friction conditions. Design/methodology/approach Bonded solid lubricant coatings containing Kevlar fibres were prepared by a spraying method. The friction and wear properties of the coatings were experimentally investigated with a face-to-face tribometre under dry friction conditions. Scanning electron microscopy, energy dispersive X-ray spectroscopy and 3D laser scanning technologies were used to characterise the tribological properties. The action mechanism of the Kevlar fibres on a solid lubricant transfer film was also analysed. Findings Adding Kevlar fibres can significantly improve the wear resistance of the coatings. When the Kevlar fibre content increases, the tribological properties of the coatings improve and then worsen. Superior properties are obtained with 0.03 g of Kevlar fibres. Appropriately increasing the load or speed is beneficial to the removal of the outer epoxy resin and the formation of a lubricant film. During friction, the solid lubricants wrapped in the epoxy resin accumulate on the surface to form a transfer film that shows a good self-lubricating performance. In the later friction stage, fatigue cracks occur on the solid lubricant film but cannot connect to one another because of the high wear resistance and the entanglement of the rod-like Kevlar fibres. Thus, no large-area film falls from the matrix, thereby ensuring the long-term functioning of solid lubricant coatings. Originality/value Epoxy resin-based solid lubricant coatings modified by Kevlar fibres were prepared, and their friction and wear properties were investigated. Their tribological mechanisms were also proposed. This work provided a basis for the analysis of the tribological properties and design of bonded solid lubricant coatings containing Kevlar fibres.

scholarly journals INVESTIGATION OF CHARACTERISTICS OF SPRAYED NI-CR AND NI-CR-WC COATINGS / PURKŠTINIŲ NI-CR IR NI-CR-WC DANGŲ SAVYBIŲ TYRIMAS

2017 ◽  
Vol 8 (6) ◽  
pp. 615-620
Author(s):  
Ovidijus Jarašūnas ◽  
Olegas Černašėjus
Keyword(s):  
Wear Resistance ◽  
Elastic Modulus ◽  
Chemical Composition ◽  
Tribological Properties ◽  
Substrate Heating ◽  
Steel Substrates ◽  
Sprayed Coatings

The article deals with the flame sprayed Ni-Cr and Ni-Cr-WC coatings on construction S235 steel substrates. Before spraying, the surfaces of substrates were treated mechanically. Using the different chemical composition of Ni-Cr and Ni-Cr-WC spraying powder and additional substrate heating till 250–290 °C, were sprayed coatings. The microstructure, porosity, hardness, elastic modulus, wear resistance of the Ni-Cr and Ni-Cr-WC coatings were investigated in the work. The influence of the chemical composition and WC content of the coatings on the various physical and tribological properties of the coatings were evaluated. Also the dependence of these coatings characteristics was investigated. Straipsnyje nagrinėjamos liepsninio purškimo būdu ant konstrukcinio S235 plieno substrato užpurkštos Ni-Cr dangos. Substrato paviršiai prieš purškiant buvo apdoroti mechaniniu būdu. Naudojant skirtingos cheminės sudėties Ni-Cr ir Ni-Cr-WC purškimo miltelius ir papildomai pakaitinus substratą iki 250–290 °C temperatūros, buvo užpurkštos dangos. Darbe ištirta gautų Ni-Cr ir Ni-Cr-WC dangų mikrostruktūra, akytumas, kietumas, tamprumo modulis ir atsparumas dilimui. Įvertinta dangų cheminės sudėties ir WC karbidų įtaka įvairioms dangų fizikinėms, tribologinėms savybėms, nustatytos šių dangų charakteristikų priklausomybės.

Effect of Atomic Oxygen Irradiation on the Structural and Tribological Properties of the MoS2/Al2O3/PI Composites

2016 ◽  
Vol 674 ◽  
pp. 239-243
Author(s):  
Gai Zhao ◽  
Qi Hua Wang ◽  
Irina Hussainova ◽  
Qing Jun Ding
Keyword(s):  
Wear Resistance ◽  
Chemical Composition ◽  
Tribological Properties ◽  
Photoelectron Spectroscopy ◽  
Atomic Oxygen ◽  
Wear Behavior ◽  
Low Earth Orbit ◽  
High Wear Resistance ◽  
Composite Surface ◽  
Good Thermal Stability

Polyimide (PI) composites have been widely used in a space science due to extraordinary properties, such as excellent mechanical and electrical properties, good thermal stability and chemical inertness, as well as high wear resistance. However, atomic oxygen (AO), as one of the main radiated constituents in low earth orbit, had an important influence on the structrural and tribological properties of the polyimide matrix. To investigate the mechanism of AO erosion on polyimide, MoS2/Al2O3/PI composites were fabricated by means of a hot-press molding technique and irradiated by AO in a ground-based simulation system. The chemical composition change of the irradiated surface was examined by X-ray photoelectron spectroscopy (XPS). Then, the friction and sliding wear behavior against GCr15 steel balls were evaluated in a ground-based simulation facility using ball-on-disk tribology test rig. The worn morphologies and radiated surfaces of the materials were observed by Scanning electron microscope (SEM) to reveal the wear mechanism. Experimental analysis indicated that oxidation induced by AO irradiation and degradation of PI molecular chains on the composite’ surface results in change in chemical composition and formation of “carpet-like” structures. Affected layer, gradually formed during the process of irradiation, plays an important role for wear performance of the materials increasing friction coefficient and wear rate. Incorporation of Al2O3 nanofibers and MoS2 nanoparticles is shown to be favourable for AO resistance, which is helpful for improvement in wear resistance of the PI.

scholarly journals Tribological Properties of Laser Microtextured Surface Bonded With Composite Solid Lubricant at High Temperature

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
Xijun Hua ◽  
Jianguo Sun ◽  
Peiyun Zhang ◽  
Kai Liu ◽  
Rong Wang ◽  
...  
Keyword(s):  
Tribological Properties ◽  
Smooth Surface ◽  
Solid Lubricant ◽  
Sliding Friction ◽  
Synergetic Effect ◽  
Laser Surface Texturing ◽  
Solid Lubrication ◽  
Textured Surface ◽  
Friction Coefficients ◽  
Composite Solid

A combination technology of the solid lubricant and the laser surface texturing (LST) can significantly improve the tribological properties of friction pairs. The plate sample was textured by fiber laser and composite lubricant of polyimide (PI) and molybdenum disulfide (MoS2) powders were filled in the microdimples. Sliding friction performances of micron-sized composite lubricant and nano-sized composite lubricant were investigated by ring-plate tribometer at temperatures ranging from room temperature (RT) to 400 °C. On the one hand, the results of the micron-sized composite lubricant show that the friction coefficient of the textured surface filled with composite lubricant (TS) exhibits the lowest level and the highest stability compared to a textured surface without solid lubrication, smooth surface without lubrication, smooth surface burnished with a layer of composite solid lubricant. The better dimple density range is 35–46%. The friction coefficients of the sample surface filled with micron-composite solid lubricant with the texture density of 35% are maintained at a low level (about 0.1) at temperatures ranging from RT to 300 °C. On the other hand, the results of the nano-sized composite lubricant show that these friction properties are better than those of MoS2-PI micron-sized composite. The friction coefficients of MoS2-PI-CNTs nano-sized composite solid lubricant are lower than those of the MoS2-PI composite lubricant at temperatures ranging from RT to 400 °C. In addition, the possible mechanisms involving the synergetic effect of the surface texture and the solid lubricant are discussed in the present work.

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