A novel Al10Cr28Co28Ni34/Ag high-entropy alloy composite coating, fabricated via high-velocity oxygen fuel (HVOF) spraying, demonstrates exceptional synergistic lubrication, anti-wear, and cavitation erosion resistance in low-viscosity aviation kerosene. The research, published in Tribology Advances, addresses a critical challenge in aero-engine fuel pumps, where thrust bearings endure combined wear and cavitation erosion due to kerosene's poor lubricity.
The study exploits the face-centered cubic (FCC) structure shared by both the Al10Cr28Co28Ni34 high-entropy alloy (HEA) and silver. This structural compatibility ensures similar deformation behaviors under friction and impact, reducing phase boundary cracking and enabling uniform stress response. The HEA provides high strength and work-hardening capacity, while silver offers low shear-induced friction reduction. In situ formed spherical particles at the friction interface introduce a rolling effect, further enhancing lubrication. The result is 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 in aviation kerosene.
The implications for aviation safety are significant. Fuel pumps, often called the heart of an aero-engine, rely on thrust bearings to maintain positioning and sealing under axial loads. Kerosene's low viscosity prevents stable oil film formation, leading to lubrication failure and cavitation damage. Existing bonded solid lubricating coatings (BSLCs) address wear but fail under cavitation erosion because their organic resin matrices have insufficient strength and poor heat resistance. The property mismatch between matrix and lubricating phases also causes incompatible deformation and selective filler removal. The new coating overcomes these limitations by using an all-metallic FCC/FCC design that balances friction reduction, wear resistance, and cavitation erosion protection.
Funded by the National Science and Technology Major Project and the National Natural Science Foundation of China, this work offers a new perspective on mitigating combined damage in fuel pump friction pairs. The full study, titled “FCC/FCC structural compatibility enabling synergistic lubrication, anti-wear and cavitation erosion of Al10Cr28Co28Ni34/Ag composite coating in aviation kerosene,” is available at https://doi.org/10.3724/trad-20260019. This advancement could extend the service life and reliability of critical aero-engine components, reducing maintenance costs and enhancing flight safety.
