Thousand‐Degree High‐Temperature Self‐Lubricating “Oil” Achieved by Operando Formation of Liquid B 2 O 3 Through Tungsten Tetraboride Superhard Material Tribo‐Chemistry

ABSTRACT Thousand‐degree high‐temperature lubrication has been a formidable challenge in the fields of tribology and materials science. This work proposes a novel strategy for high‐temperature lubrication material achieved by integrating fluid lubrication and solid lubrication. Based on in‐situ formation of a lubricating “oil” film on the friction surface under tribo‐chemistry, we constructed WB 4 ‐βB self‐lubricating material with a friction coefficient as low as 0.07–0.1 at 800 – 1100°C, which surpasses the lubrication properties of high temperature alloys, ceramics, and solid‐lubricating materials. In particular, at 1100°C, the molten boron oxide “oil” formed through tribo‐oxidation of WB 4 ‐βB superhard ceramic provides effective fluid lubrication. This thousand‐degree high‐temperature self‐lubricating “oil” combines the low‐friction characteristics of fluid lubrication with the self‐lubrication advantages of solid lubrication, providing a brand‐new solution for lubrication technology in high‐temperature mechanical engineering.