Effects of Sulfur and a Lubricity Improver on the Tribological Characteristics of Si3N4 Ceramics against Steel in Fuel

The effects of sulfur (dibenzothiophene) and a lubricity improver (glyceride) on the tribological behavior of combinations of Si3N4 ceramics and steel were investigated in kerosene at 373 K. The tests were performed by sliding the circumferential surface of a rotating disk with two plates. Lubricity was not improved by the addition of glyceride for the combination of the different materials. The oxidation wear of the Si3N4 was considered to have occurred by a trace amount of water as an impurity in the kerosene. The steel plate was mainly removed by mechanical wear, which was accelerated by increasing the sulfur concentration.