Tribological behavior of rapeseed oil additivated with boron nitride

Abstract

This paper presents results of testing the coarse rapeseed oil additivated with 1%wt hexagonal boron nitride (hBN). Tests are done on a four-ball machine from the laboratory LubriTest, at “Dunarea de Jos” University of Galati. Tests were done in mild regime (recommended for applications) and in severe regime. The mild test parameters were: load on the main shaft of the machine (100 N, 200 N and 300 N) and the sliding speed of 0.38 m/s, 0.53 m/s and 0.69 m/s, test duration 1 h. Severe test were run in step of 50 N till 900 N, each test being run for 1 minute at 0.53 m/s. The concentration of 1%wt hBN does not improve the friction coefficient, but it makes it stable for a larger domain of test parameters. The wear rate of wear scar diameter was lower than that obtained with the base oil, especially for high loads. Also, the paper presents the influence of the additive on the temperature of oil bath and the wear load curve of the neat oil and the additivated one. The additivation of rapeseed oil with hNB is still efficient for the tested ranges of load as compared to the rapeseed oil. The load-wear curve for the severe regime points out a sudden increase of wear scar diameter (WSD) for the rapeseed oil +1% hNB at 700 N, but the neat vegetal oil starts the increase of WSD at 550 N, followed by a greater slope, meaning the additive protect the rubbing surfaces under these high loads.