Lubrication Engineering 

About: Lubrication Engineering is an academic journal. The journal publishes majorly in the area(s): Lubrication & Lubricant. It has an ISSN identifier of 0024-7154. Over the lifetime, 978 publications have been published receiving 8655 citations.

Friction at the atomic scale

Abstract: Considering the current race to manufacture machine components with astoundingly small dimensions, what is today considered fundamental research on the atomic scale may give way tomorrow to direct applications. For instance, the authors now know why substances made of branched-chain molecules make better lubricant than straight-chain molecules, even though the branched-chain one are, in bulk form, more viscous. (They remain as a liquid under greater forces than do the straight-chained molecules and thus are better able to keep two solid surfaces from touching.) Nanotribologists working with known contact geometries may one day help chemists understand friction-induced reaction taking place on surfaces or aid materials scientists in designing substances that resist wear. As the need to conserve both energy and raw materials becomes more urgent, physicists` rush to understand basic frictional processes can be expected only to accelerate.

Oxidative stability and antiwear properties of high oleic vegetable oils

Abstract: Environmental concerns resulted in the utilization of vegetable oils as a possible replacement of mineral oil basestocks. Their low oxidative stability is often a major concern. Data from the Klaus Penn State microreactor test on steel surfaces at 225°C demonstrate that uninhibited high oleic vegetable oils are much poorer in oxidative stability than neat mineral oils. Nevertheless, they show an advantage of low volatility. The possibility to dramatically inhibit deposit formation in high oleic sunflower oil using 1 % wt. of proprietary antioxidant is demonstrated, resulting in oxidative stability comparable to 10W30 SG-grade commercial crankcase lubricant. Addition of ZDDP reduces the effect of the antioxidant but greatly improves antiwear properties of the fluid, as demonstrated by the four-ball wear test. Neat high oleic sunflower oil shows better lubricity than neat mineral oil and its formulation with the antioxidant and ZDDP is superior to commercial crankcase lubricant in antiwear properties.

Lubrication properties of castor oil -potential basestock for biodegradable Lubricants©

Abstract: Viscosity, oxidative stability, deposit formation, volatility, lubricity and additive compatibility of castor oil (88+% ricinoleic) were compared to super-refined mineral oil (SRMO) and high oleic sunflower oil (HOSO). A satisfactory viscosity index (VI) of 90 and the extraordinarily high viscosity of castor oil can be related to hydrogen bonding of hydroxy monounsaturated triglycerides. When oxidized in thin film microoxidation test on a steel surface at 225°C under controlled air flow, castor oil showed deposit forming tendencies lower than HOSO but much higher than SRMO. Both vegetable oils had low volatility and demonstrated similar high molecular weight oxidation product formation tendencies at 175°C. Castor oil solubilized higher concentrations of antioxidants, but the oxidative stability of the formulation was lower when compared to HOSO. Without additives castor oil was comparable to other vegetable oils and superior to SRMO in performance on the four-ball wear tester.

Tribological Properties of PM212: A High-Temperature, Self-Lubricating, Powder Metallurgy Composite

Abstract: This paper describes a research program to develop and evaluate a new high temperature, self-lubricating powder metallurgy composite, PM212. PM212 has the same composition as the plasma-sprayed coating, PS212, which contains 70 wt percent metal-bonded chromium carbide, 15 wt percent silver and 15 wt percent barium fluoride/calcium fluoride eutectic. The carbide acts as a wear resistant matrix and the silver and fluorides act as low and high temperature lubricants, respectively. The material is prepared by sequential cold press, cold isostatic pressing and sintering techniques. In this study, hemispherically tipped wear pins of PM212 were prepared and slid against superalloy disks at temperatures from 25 to 850 C in air in a pin-on-disk tribometer. Friction coefficients range from 0.29 to 0.38 and the wear of both the composite pins and superalloy disks was moderate to low in the 10(exp -5) to 10(exp -6) cubic mm/N-m range. Preliminary tests indicate that the material has a compressive strength of at least 130 MPa over the entire temperature range of 25 to 900 C. This material has promise for use as seal inserts, bushings, small inside diameter parts and other applications where plasma-sprayed coatings are impractical or too costly.

Base oil properties of ionic liquids

Abstract: Ionic liquids are organic salts that remain liquid at room temperature. They virtually have no vapor pressure; therefore, they may make ideal base oils for rolling aluminum due to a reduction in air emissions. The forces that hold ionic liquids together are strong coulombic forces rather than weak van der Waals forces. Hence, ionic liquids may have properties other than vapor pressure that are different from normal hydrocarbon base oils. To determine what these differences and similarities might be, a series of tests and measurements were done to determine the following properties: density, thermal stability, blended viscosity, viscosity index, pressure-viscosity coefficients, limiting shear stress (traction curves), friction (Stribeck curves), EP performance and additive solubility. The two ionic liquids studied were 1-ethyl-3-methylimidazolium his (trifluoromethylsulfonyl) imide (EMI Im) and 1-butyl-3-methylmidazolium hexafluorophosphate (BMI PF 6 ). Two blended polyalphaolefins (PAO) were used as controls.