From heavy duty lubricants to biobased fluids – legacy of Joseph Perez

Advancement in lubricant technology is driven by technical demands, oil market, innovations from related chemical areas and other conventional factors. Nevertheless, a personal impact of an individual scientist can also be very important. Few individuals can claim to have accelerated lubricant progress more than Dr. Joseph M. Perez, who initiated many new developments in lubricant technology and drove them to large scale implementation. Early in his career at PennState he worked on aerospace lubricants, developing highly efficient additives for supersonic planes. When working at Caterpillar he dealt with hydraulic fluids, gear oils and many heavy duty lubricants. During employment at NIST and upon return to PennState Dr. Perez realized the importance of vegetable oils. He pioneered many research directions for their applications, becoming directly involved in vegetable-based engine oils, hydraulic fluids, greases, biodiesel, elevator fluids and many other areas. His innovative thinking, enthusiasm and initiatives will be sorely missed by lubricant researchers

Miniaturization of lubricant degradation testing for natural gas engines

Lubricant evaluation in natural gas engines is expensive due to large sump volumes and high equipment costs. A new laboratory protocol was developed to miniaturize oil degradation conditions in order to provide a rapid screening method for lubricants. Steel coupons were coated with 200 μm films of three commercial lubricants for natural gas engines. The films were oxidized for up to 90 hrs at 150 °C, 180 °C or 200 °C, then their tribological properties were compared using ball-on-plate tests. No deterioration in tribological performance could be noticed after film oxidation. Sump drains of the three lubricants were also obtained from actual engines with service life in excess 5000 hrs. Only slight reduction in tribological properties was observed, despite dropping alkalinity. This testing protocol can be further refined and possibly applied in lubricant industry, where it would reduce development time of natural gas engine lubricants and further improve their effectiveness

Participation of suspended nanoparticles in tribofilm formalion

Vytauto Didžiojo universitetasŽemės ūkio akademij

Short-term and long-term volatilities of films from polyol ester and ether-based oils of various molecular weights

Viscosity and volatility parameters are very important for many technical applications, such as adhesives, lubricants or coatings. Often low viscosity and low volatility is desirable and various esters of oils from industrial crops are more appropriate than hydrocarbons. Short term evaporation can be quantified by thermogravimetric analysis (TGA), standard protocol of NOACK volatility or even flash point. But standardized tests of prolonged degradation do not address vaporization. In this study short and long-term volatilities of esters from industrial crops were compared to hydrocarbons and ethers using thin film methodologies. It turned out that mostly components of low molecular weight are responsible for NOACK results. Long term volatility is more dependent on decomposition reactions, which take place due to hydrolysis, oxidation and other degradation processes. Double bonds and ether linkages lead to higher long-term volatile emissions. Decomposition trends must be considered when selecting oils for applications, where low volatility and migration is important

Effects of electrolyte and Ti layers on static and dynamic friction of anodized alumina

Static friction is important for many non-lubricated surfaces, especially when friction is intermittent. Coefficients of Friction (COF) were evaluated on industrial aluminum alloys 1050 and 6082, which were freshly anodized in sulfuric/oxalic or phosphoric acid electrolytes to 60 μm coating thickness. Hard anodizing significantly reduced COF. Under 10 N load friction trends were nearly identical despite sliding velocity variation from 0.02 to 0.5 cm/s, while 1 N load led to higher static COF. Magnetron sputtering was used to deposit Ti layers. Static COF went down from over 0.4 to ~0.2 in 16 nm and 75 nm thick layers, while that of 2.3 μm had no positive effect. Dynamic COF was also similarly reduced, suggesting possible industrial applications

Wear resistance of electrodeposited Fe-W alloy coatings under dry conditions and in the presence of rapeseed oil

Amorphous Fe-W alloys with 25 at.% of W were electrodeposited under direct and pulse modes from glycolate-citrate bath with and without addition of polyethylene glycol. The tribological behavior of the coatings was studied at 1, 2 and 5 N loads under dry friction and in the presence of rapeseed oil films of 0.2-5.0 m thickness. The tribological behavior of obtained coatings at dry friction reveals their severe tribo-oxidation resulting in a high wear depth and coefficient of friction. Observed groove like surface with well-adhered particles inside the wear track point out on abrasive-adhesive wear mechanism of Fe-W alloys. In the presence of rapeseed oil films the wear mechanism changes, and values of coefficient of friction decrease up to 10 times compared to dry friction conditions. The optimum thickness of rapeseed oil film was 1 µm. This film has the satisfactory adhesion and uniform distribution on the surface, and could withstand up to 2 000 cycles

Tribologic behaviour of nanoparticles from selected metals, suspended in rapeseed and mineral oils

Vytauto Didžiojo universitetasŽemės ūkio akademij

Influence of Thermal Oxidation on Tribological Properties of Rapeseed Oil

Ageing and degradation of lubricant due to oxidation usually is undesirable. However, few studies relate oil oxidation to its tribological properties. In this investigation, additive-free Low Erucic Acid Rapeseed oil (LEAR) was oxidised and its anti wear properties tested. Four samples with different degrees of oxidation were produced by bubbling dry air through LEAR in glass vessel at 120 °C. Kinematic viscosity and acidity were measured as well. Friction tests were conducted using MAST-1 apparatus (equivalent to Four-Ball AW tester). Torque and temperature were monitored throughout the tribotest, and wear scars were analyzed using SEM. The results showed that oxidation has a significant effect on the lubricity of LEAR. Wear scar diameters showed major increase even after low extent of oxidation, while viscosity went up only slightly. Severe oxidation resulted in much higher viscosity. The wear scar diameters, however, became smaller than those of unoxidised LEAR. Microscopy and torque data also confirmed that late stages of oxidation might lead to improved lubricityChemijos institutasVytauto Didžiojo universitetasŽemės ūkio akademij

Influence of Thermal Oxidation on Tribological Properties of Rapeseed oil

Ageing and degradation of lubricant due to oxidation usually is undesirable. However, few studies relate oil oxidation to its tribological properties. In this investigation, additive-free Low Erucic Acid Rapeseed oil (LEAR) was oxidised and its anti wear properties tested. Four samples with different degrees of oxidation were produced by bubbling dry air through LEAR in glass vessel at 120 °C. Kinematic viscosity and acidity were measured as well. Friction tests were conducted using MAST-1 apparatus (equivalent to Four-Ball AW tester). Torque and temperature were monitored throughout the tribotest, and wear scars were analyzed using SEM. The results showed that oxidation has a significant effect on the lubricity of LEAR. Wear scar diameters showed major increase even after low extent of oxidation, while viscosity went up only slightly. Severe oxidation resulted in much higher viscosity. The wear scar diameters, however, became smaller than those of unoxidised LEAR. Microscopy and torque data also confirmed that late stages of oxidation might lead to improved lubricityVytauto Didžiojo universitetasŽemės ūkio akademij