Affiliation:
1. �Dunarea de Jos� University of Galati
Abstract
The rapeseed oil is a promising eco-friendly lubricant for applications involving environment protection. But any vegetal oil has shortcuts especially related to low viscosity and thermal stability. Research in additivation with nanoparticles is of interest for improving load capability of the contact and for reducing wear. Other tribological characteristics, as friction coefficient, could oscillate around values offered by the neat vegetal oil, with more or less influence of the system behavior. The four-ball tester offer a reliable ranking of the tribological characteristics when comparing two or more lubricants. Usually, researchers used test parameters recommended in ISO 20623:2017 Petroleum and related products. Determination of the extreme-pressure and anti-wear properties of lubricants. Four-ball method (European conditions) and ASTM D2596:2020 Standard Test Method for Measurement of Extreme-Pressure Properties of Lubricating Grease (Four-Ball Method), implying 1500 rpm for 1 hour for normal regime. This study proposes to evaluate the tribological characteristics (friction coefficient, wear scar diameter � WSD and temperature during the tests) for five sliding velocities and three loads, taking into account the same sliding distance for each test. The additives were at nano scale and they were supplied by the company PlasmaChem: hexagonal Boron nitride (h-BN) with a particle size of 100-1000 nm, mean value 500 � 100 nm, and nano graphene as foils, with a thickness of 1.4 nm and particle size up to 2 ?m. The additivated lubricants were obtained by sonication.