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

Participation of suspended nanoparticles in tribofilm formalion

Vytauto Didžiojo universitetasŽemės ūkio akademij

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

Vytauto Didžiojo universitetasŽemės ūkio akademij

Tribologic behaviour and suspension stability of iron and copper nanoparticles in rapeseed and mineral oils

Metal particles, suspended as wear debris or as additives, have a major influence on lubrication technology. They are known mostly for negative roles, but even iron nanoparticles, which are likely to pass through most filters, have not yet been quantitatively evaluated for their effects on friction and wear. In this study iron and copper nanoparticle suspensions were formulated in high sulphur paraffinic mineral oils and food grade rapeseed oil. The suspension stabilisation mechanism based on steric repulsion appeared more effective than ionic repulsion principle. Iron nanoparticle suspensions were investigated using four ball antiwear tribotester. Iron nanoparticles did not show statistically significant effects on wear or friction in mineral oil suspension. However, addition of surfactants improved the tribological performance. Wear, friction and sample temperature data along with microscopy evaluation suggested that formation of protective films in the friction zone was the most likely reason for reduction of wear, average friction and the duration of break-in regimeVytauto Didžiojo universitetasŽemės ūkio akademij

Tribologic properties of vegetable and mineral oils with suspended nanoparticles

Wear of the surfaces results in substantial levels of metal nanoparticles in lubricants during their service life. Prefabricated Fe, Cu and Zn nanoparticles were characterized and then added to several vegetable and mineral oils, inhibited with antioxidant. Friction, wear and heat emission of 0.1 to 1% suspensions were tested on Four-ball AW tribotester at 150N load. Fe nanoparticles did not affect the performance of mineral oils, but reduced wear tendencies of rapeseed oil. Zn nanoparticles have somewhat beneficial effect on mineral oil, without affecting rapeseed oil significantly. Blends with 1.8% ZDDP showed excellent AW performance, which was not affected by 1% Fe nanoparticle addition. In oils with other lubricity additives, the nanoparticles were generally detrimental to wear prevention, they also resulted in higher static friction coefficient and higher test sample temperatures. Inclusion of pre-fabricated nanoparticles into bench tests can accelerate evaluation of lubricant tribologic propertiesVytauto Didžiojo universitetasŽemės ūkio akademij