Preparation and Tribological Properties of Nb1-xTixSe2 Micro/Nanoparticles

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.

Characterization of Size and Antiwear Ability of Molybdenum Disulfide Nanoparticles

In this paper, the results of a study about using Molybdenum disulfide nanoparticle in base oil, which is used for engine oil production, are presented. The size characterization and morphology of nanoparticles were determined by atomic force microscopy (AFM), scanning electron microscopy (SEM) and X- ray diffractometry (XRD). Dispersion of nanoparticles in base oil was achieved by ultrasonic homogenizer and the antiwear ability was evaluated by four ball test.

Tribological Property of a Triazine Derivative in Rapeseed Oil

2-propylamino-4,6-(O,O’-dibuthyldithiophosphate)-s-1,3,5-triazine(DPOB)was synthesized and it’s tribological behavior as lubricant in rapeseed oil (RSO) were evaluated using a four-ball tester. The lubrication mechanism was investigated by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The results indicate that the compound possess excellent load-carrying capacity and antiwear ability, and has some friction-reducing property only under the low load condition. Based on the results of XPS and SEM analysis, it can be seen that tribochemical reaction occurred between the synthesized compounds and metal surfaces during the sliding process, to form a complex film which has excellent load-carrying capacity and antiwear ability.

Synthesis and Tribological Properties of S- and P-Free Borate Esters With Different Chain Lengths

Three kinds of S- and P-free borate esters containing N with different alkyl chain lengths were prepared by using boric acid, ethanolamine, and alkyl-alcohol as the starting materials. The chemical structure of the products was analyzed by means of Fourier transformation infrared spectrometry, elemental analysis, and so on. The thermal stability of the products was evaluated by thermogravimetric analysis. The tribological properties of the synthesized borate esters as lubricating oil additives in liquid paraffin were evaluated using a four-ball friction and wear tester while the morphologies of the worn scars of the steel balls were observed using a scanning electron microscope. The chemical components on the worn surfaces of the steel balls were analyzed using an X-ray photoelectron spectroscopy. Results show that all the three kinds of synthetic borate esters as additives in liquid paraffin possess good antiwear performance and may be used as promising S- and P-free environmentally acceptable lubricating oil additives. Particularly, borate ester with short alkyl chain length at a low concentration in liquid paraffin was more effective in reducing wear, and the antiwear ability of the additives decreased with increasing alkyl chain length. The antiwear ability of the N-containing borate esters as additives in liquid paraffin might be closely related to the formation of hydrogen bonds via N with a high electronegativity and small atomic radius and the easy permeation of electron-deficient B on the rubbing steel surfaces.

Surface Modification of CuS Nanoparticles and their Effect on the Tribological Properties of Hybrid PTFE/Kevlar Fabric/Phenolic Composite

Oleic acid-modified CuS nanoparticles were chemically synthesized. The tribological properties of surface modified and unmodified CuS nanoparticles as additives in the hybrid polytetrafluoroethylene (PTFE)/Kevlar fabric/phenolic composite were investigated in detail. The experimental results indicated that the incorporation of modified CuS nanoparticles improved the antiwear ability of the fabric/phenolic composite at varied loads and environmental temperatures. The reasons for the enhanced wear properties of the fabric/phenolic composite filled with surface-modified CuS nanoparticles were discussed based on the results of scanning electron microscopy and Fourier transform infrared spectroscopy.

Study on Lubrication Properties of Carboxymethyl Cellulose as a Novel Additive in Water-Based Stock

This paper reports cellulose derivative—carboxymethyl cellulose (CMC) as a novel additive in a water-based stock (water content above 95 wt.%). Cellulose is one of the richest renewable resources on earth and has many peculiar qualities. Several cellulose derivatives such as CMC can easily dissolve in water and form stable thin film on the surface of metal. Several apparatus involving four-ball machine were used to investigate lubrication properties of the based stock containing CMC. The worn surfaces were observed with a scanning electron microscope. As the results, the anti-wear ability of the base stock is effectively increased by addition of a small amount (0.7 wt.%) of CMC. The additive with peculiar molecular structure contributes to abate the adhesion and scuffing of frictional pair effectively, hence improves the antiwear ability of the base stock. Thus CMC provides a potential application in the field of water-based stock lubrication.