Tribological Properties of the Nanoscale Spherical Y2O3 Particles as Lubricant Additives in Automotive Application

The continuous tribological development of engine lubricants is becoming more and more vital due to its fuel efficiency improvement and lifetime increasing potential. The antiwear additives play a high role in the lubricants to protect the contacting surfaces even in the presence of thinner oil film. Nanoscale spherical particles in the lubricant may increase the necessary protecting effect. This paper presents the results of the experimental tribological investigation of nanoscale spherical Y2O3 (yttria) ceramic particles as an engine lubricant additive. The ball-on-disc tribological measurements have revealed an optimum concentration at 0.5 wt% with about 45% wear scar diameter and 90% wear volume decrease, compared to the reference, neat Group III base oil. The high-magnitude SEM analysis revealed the working mechanisms of yttria: the particles collected in the roughness valleys resulted in a smoother contacting surface, they were tribo-sintered and they have also caused slight plastic deformation of the outer layer of the metallic surface.

Automated summary

The continuous development of engine lubricants in terms of tribology is of great importance for improving fuel efficiency and extending the lifetime. This study investigates the effects of nanoscale spherical Y2O3 ceramic particles as an engine lubricant additive, revealing an optimal concentration at 0.5 wt% that significantly reduces wear scar diameter and wear volume. The high-magnitude SEM analysis highlights the working mechanisms of yttria in terms of surface smoothing and tribo-sintering.