Enhanced wear resistance and strength synergy in Ti3AlC2 MAX through in-situ synthesis of nano TiB2 heterostructure

Abstract

The rapid development of science and technology poses the core parts and techniques of industrial tribo-systems facing more stringent situations like high temperature exceeding 600 °C. For this case, solid lubrication materials are required to possess high strength, low friction coefficient and high wear resistance over a wide temperature range. However, achieving such “strong wearable yet lubricated” materials have proven challenging. Here we report a unique reinforced strategy for lubricated Ti₃AlC₂ MAX ceramic by in-situ synthesis of nano TiB₂ heterostructure, which results in a superior high temperature strength and lubrication simultaneously excess other traditional solid-lubrication materials. Such TiB₂/Ti₃AlC₂ composite employs a high level of compressive strength (1120 MPa ∼ 1368 MPa), wear resistance (<10^‐5 mm³/(N∙m)) and low friction coefficient (<0.4) at even 800 °C. We show that its unusual properties stem from the introduction of TiB₂ nanocrystalline densified and strengthened the Ti₃AlC₂ matrix thus to ensure the high strength. Meanwhile, the TiB₂ also undergoes rapid oxidation along high temperatures friction, resulting in the formation of a continuous and smooth lubricative tribofilm containing solid lubricant B₂O₃, leading to exceptional solid lubrication effect at high temperature. Our finding provides a potential material portfolio and a new design strategy for high temperature solid-lubricative applications.