A new study published in Tribology Advances reports that an Al10Cr28Co28Ni34/Ag high-entropy alloy composite coating, designed with FCC/FCC structural compatibility, delivers synergistic lubrication, anti-wear, and cavitation erosion protection in low-viscosity aviation kerosene. The coating, fabricated via high-velocity oxygen fuel spraying, achieved a friction coefficient below 0.1, a wear rate approaching zero, and a cavitation erosion mass loss rate of less than 0.1 mg/h, according to the paper (DOI: https://doi.org/10.3724/trad-20260019).
The research addresses a critical problem in aero-engine fuel pumps, often described as the heart of an aero-engine. Thrust bearings inside these pumps must maintain positioning accuracy and sealing under high-speed rotation, but aviation kerosene's extremely low viscosity makes it difficult to form a stable oil film. This leads to lubrication failure, wear, and cavitation erosion, ultimately affecting fuel delivery efficiency and flight safety. Existing bonded solid lubricating coatings can mitigate wear under oil-starved conditions, but they struggle to provide cavitation erosion protection due to insufficient matrix strength, poor heat resistance, and property mismatches between phases that cause cracking and selective removal of lubricant fillers.
The study's key innovation lies in exploiting the structural compatibility between the Al10Cr28Co28Ni34 high-entropy alloy and silver, both of which have face-centered cubic (FCC) structures. FCC structures possess abundant slip systems that promote slip under shear forces and accommodate greater deformation under impact loading, reducing friction and dissipating impact energy. The high-entropy alloy's four core effects give it high work-hardening capacity and strength, confining deformation from load impact and providing excellent cavitation erosion resistance. Silver, a solid lubricant, forms a low-shear film. Together, they exhibit similar response behaviors under friction and impact, and spherical particles formed in situ at the friction interface contribute a rolling effect that further enhances lubrication.
This development matters because it offers a new perspective on addressing the combined wear and cavitation erosion damage in friction pairs of aero-engine fuel pumps—a common challenge that has lacked a single-coating solution. By achieving near-zero wear and long-term cavitation erosion resistance simultaneously, the coating could extend the service life and reliability of fuel pumps, reduce maintenance costs, and improve flight safety. The research was financially supported by the National Science and Technology Major Project (Grant No. J2022-VI-0006-0037), the National Natural Science Foundation of China (Grant No. 52175200), the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDB0470102), the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant No. 2020416), and the Longyuan Youth Talent Project.
For more information, the original source URL is 10.3724/trad-20260019.
