Aluminum Di-Borides for Engineered Surfaces for Low Friction Applications

Abstract

Careful consideration of friction and wear could save the U.S. economy as much as $120 billion per year. Friction, wear, and lubrication have direct influence on the performance, reliability, and service life of a device that contains moving components. These components are found in applications of energy conversion, power generation, energy harvesting in the broader fields such as agriculture, transportation, and bioengineering etc. The useful life of these systems and their energy efficiency can further be improved by improving the surface performances of sliding systems. Ceramics matrix multifunctional composite due to their unique properties are one of the alternatives for these applications. We report development of alumina based ceramic matrix composites (CMCs) with in-situ functional phases. The overview of properties will be provided. The mechanism for low friction will be discussed. In this investigation, the reinforcement (boron) addition showed strong influence on the in-situ phase formation and surface performance. The phase characterization confirmed formation of AlB2, B2O3, and Al18B4O33. The sintering temperature showed influence on the stability of these phases. The mixed mode failure was evident from the wear tests. It was found that the coefficient of friction was reduced up to 30% when compared to parent alumina. These newly designed multifunctional composites potential candidate materials that improve the energy efficiency and sustainability.