Tribological properties of biodiesel: a review of recent advances

The aim of this paper is to review recent advances in the tribological characterization of biodiesel and various attempts to improve its lubricity by applying additives and optimizing its components. Lubricity of biodiesel or biodiesel contained blend in both metallic and nonmetallic contacts are presented. In biodiesel lubrication, properly selected nonmetallic surface is able to reduce friction and wear compared to metal-on-metal contact. The impact of the primary parameters, such as load, velocity, and temperature, on the tribological performance of biodiesel are described. Positive dependence of friction and wear on load and temperature and negative dependence on velocity are determined. Current challenges in application of biodiesel and future directions to potential solutions are summarized as well.