Tribological behavior under 1200°C elevated temperature of spark plasma sintered h-BN bulk

Abstract

h-BN with a layered crystal structure is one type of effective solid lubricants, especially at elevated temperatures. In present work, h-BN with relative density of about 91% was prepared by SPS technology, and its tribological behavior under 1200 °C was investigated. The results exhibited that the friction coefficient of h-BN was relatively stable when paired with Si3N4, which stayed at the range of 0.215–0.305. Low friction coefficient under 1200 °C was mainly thought to be the effect of weaker interlaminar binding of h-BN and easier slip of h-BN plates under higher temperature. Because of low hardness and fracture toughness, wear mechanism of h-BN was mainly brittle fracture, while coexistence of B2O3 and Al5BO9 was beneficial for reducing wear rate.