Preparation and Tribological Properties of Nb1-xTixSe2 Micro/Nanoparticles

2012 ◽  
Vol 619 ◽  
pp. 536-540
Author(s):  
Jia Qing Liang ◽  
Chang Sheng Li ◽  
Hua Tang ◽  
Yi Zhang ◽  
Wen Jing Li ◽  
...  

Nb1-xTixSe2(x=0~1) micro/nano-particles have been successfully prepared via solid-state thermal (750°C) reaction between microsized Nb, Ti with Se powders under seal environment in a seal quartz tube and characterization by X-ray diffractometer and scanning electron microscopy. It was found that the morphologies of the as-prepared products changed from microplates to micro-nanoparticles or aggregations composed of layer structure with the doping of Ti. And the amount of regular hexagonal microplates evidently reduced and nanoscaled particles increased with the increase of the contents of Ti dopant within a certain limit (1-20 atwt. %). The tribological properties of the as-prepared products as additives in paraffin were investigated by UMT-2 multispecimen tribotester. By the addition of Nb1-xTixSe2micro/nanoparticles in paraffin, the antiwear ability was improved and the friction coefficient was decreased. The paraffin with Nb1-xTixSe2micro/nanoparticles showed better tribological properties than that with pure NbSe2. A combination of the molecule-bearing mechanism of sliding friction, and fill in-repair work between the rubbing surfaces can explain the good friction and wear properties of Nb1-xTixSe2micro/nanoparticles.

2013 ◽  
Vol 645 ◽  
pp. 133-136
Author(s):  
Peng Qiao ◽  
Yan Qiu Xia ◽  
Xiang Yu Ge

Overbased calcium sulfonate complex greases have excellent friction and wear properties and have been widely used in metallurgy and mining equipment. The effects and tribological performance of molybdenum dialkydithiocarbamate (MoDTC) and ionic liquid 1-(2-hydroxyethyl)-3-methylimidazolium bis (trifluoromethylsulfonyl) imide ([C2OHMim][NTf2]), 1-(2-hydroxyethyl)-3-hexylimidazolium bis (trifluoromethylsulfonyl) imide ([C2OHHim][NTf2s]), added in overbased calcium sulfonate complex grease as additives were investigated by using reciprocating ball-on-disk sliding friction tester. The results showed that the two kinds of additives with a certain range of concentration could improve the tribological properties of greases.


2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Xinlei Gao ◽  
Jian Li ◽  
Wanzhen Gao ◽  
Li Wu

Poly-α-olefin (PAO) is an important synthetic fluid in the field of industry lubricants. To improve the tribological properties of PAO, a Schiff base copper complex was added to the lubricants. The tribological properties of steel and steel lubricated with PAO and PAOs containing a Schiff base copper complex were studied. The friction and wear properties of steel and steel lubricated with PAO and PAOs containing a Schiff base copper complex were evaluated using a SST-ST pin-disc tester. The sliding friction was measured using lubricants with or without a Schiff base copper complex and analyzed using surface analysis techniques including scanning electron microscopy, Fourier transform infrared spectroscopy, and confocal white light microscopy. A UMT-2 universal tribometer was also used to study the tribological properties of modifying PAO containing the Schiff base copper complex. The Schiff base copper complex structure was found to assist in the formation of a stronger tribofilm; more than the tribofilm prepared by lubricating only with PAO and this is crucial in obtaining a low and stable coefficient of friction. A lower stable friction coefficient and wear was found for the steel/steel surface contact when using the PAOs containing the Schiff base copper complex compared to the samples lubricated with the PAO without additives. The excellent tribological performance of the PAOs containing the Schiff base copper complex is attributed to the formation of a useful tribofilm with organic and inorganic groups on the sliding surface.


2011 ◽  
Vol 399-401 ◽  
pp. 1946-1950 ◽  
Author(s):  
Wen Jing Li ◽  
Chang Sheng Li ◽  
Kong Qiang Wu

The inorganic materials(MoSe2/C) and MoSe2 were synthesized via solid-state reaction methods and characterized by a series of techniques. The growth process of the products was discussed on the basis of the experimental facts. The tribological properties of MoSe2/C and MoSe2as additives in 150bn basic oil were investigated by UMT-2 multispecimen tribotester. Under the determinate conditions, the friction coefficient of the basic oil containing MoSe2/C (or MoSe2) was lower than that of the basic oil. Moreover, the tribological property of the basic oil with the MoSe2/C was better than that with MoSe2nanoflakes. A combination of sliding friction, stable tribofilm and fill in-repair mechanisms on the rubbing surface could explain the good friction and wear properties of MoSe2/C and MoSe2as additives.


2012 ◽  
Vol 504-506 ◽  
pp. 969-974 ◽  
Author(s):  
Harald Hetzner ◽  
Stephan Tremmel ◽  
Sandro Wartzack

In sheet bulk metal forming, locally adapted friction properties of the contact tool/workpiece are an appropriate means for the targeted enhancement of the material flow, enabling an improved form filling and lowered forming forces. However, the implementation of desirable friction conditions is not trivial. And further, friction is inseparably linked to wear and damage of the contacting surfaces. This calls for a methodological approach in order to consider tribology as a whole already in the early phases of process layout, so that tribological measures which allow fulfilling the requirements concerning local friction and wear properties of the tool surfaces, can already be selected during the conceptual design of the forming tools. Thin tribological coatings are an effective way of improving the friction and wear properties of functional surfaces. Metal-modified amorphous carbon coatings, which are still rather new to the field of metal forming, allow tackling friction and wear simultaneously. Unlike many other types of amorphous carbon, they have the mechanical toughness to be used in sheet bulk metal forming, and at the same time their friction properties can be varied over wide ranges by proper choice of the deposition parameters. Based on concrete research results, the mechanical, structural and special tribological properties of tungsten-modified hydrogenated amorphous carbon coatings (a-C:H:W) are presented and discussed against the background of the tribological requirements of a typical sheet bulk metal forming process.


2018 ◽  
Vol 70 (9) ◽  
pp. 1706-1713 ◽  
Author(s):  
Guotao Zhang ◽  
Yanguo Yin ◽  
Ting Xie ◽  
Dan Li ◽  
Ming Xu ◽  
...  

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.


Lubricants ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 11 ◽  
Author(s):  
Jankhan Patel ◽  
Amirkianoosh Kiani

In this study, reduced graphene oxide (rGO) nano platelets were used as an additive to enhance friction and wear properties of oil-based lubricants by preparing three samples at 0.01% w/w, 0.05% w/w, and 0.1% w/w concentrations. To analyze the direct effect of rGO nano platelets on tribological properties, 99.9% pure oil was used as a liquid lubricant. A comparative tribological study was done by performing a ball-on-disk wear test in situ under harsh conditions, which was further analyzed using a non-contact 3D optical profilometer. Morphological evaluation of the scar was done using transmission and scanning electron microscopy (TEM, SEM) at micro and nano levels. The lubricants’ physical properties, such as viscosity and oxidation number, were evaluated and compared for all samples including pure oil (control sample) as per ASTM standards. Findings of all these tests show that adding rGO nano platelets at 0.05% w/w showed significant reduction in friction at high speed and in wear up to 51.85%, which is very promising for increasing the life span of moving surfaces in machinery. Oxidation and viscosity tests also proved that adding rGO nano platelets to all samples does not sacrifice the physical properties of the lubricant, while it improves friction and wear properties.


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.


Friction ◽  
2020 ◽  
Author(s):  
Kang Liu ◽  
Jia-jie Kang ◽  
Guang-an Zhang ◽  
Zhi-bin Lu ◽  
Wen Yue

AbstractDiamond-like carbon (DLC) and graphite-like carbon (GLC) coatings have good prospects for improving the surface properties of engine parts. However, further understanding is needed on the effect of working conditions on tribological behaviors. In this study, GLC and two types of DLC coatings were deposited on GCr15 substrate for investigation. The friction and wear properties of self-mated and steel-mated pairs were evaluated. Two temperatures (25 and 90 °C), three lubrication conditions (base oil, molybdenum dithiocarbamate (MoDTC)-containing oil, MoDTC+zinc dialkyldithiophosphate (ZDDP)-containing oil), and high Hertz contact stress (2.41 GPa) were applied in the experiments. The results showed that high temperature promoted the effect of ZDDP on steel-mated pairs, but increased wear under base oil lubrication. The increased wear for steel-mated pairs lubricated by MoDTC-containing oil was due to abrasive wear probably caused by MoO3 and β-FeMoO4. It was also found that in most cases, the tribological properties of self-mated pairs were better than those of steel-mated pairs.


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