FCC-compatible alloy coating cuts wear and cavitation in aviation kerosene

Researchers say a new high-entropy alloy and silver composite coating delivered near-zero wear, low friction and strong cavitation erosion resistance in aviation kerosene. The work could help fuel pumps in aero-engines withstand combined damage that has been hard to solve with existing lubricating coatings.

Why it matters: - Aero-engine fuel pumps face a combined damage problem: wear from poor lubrication and cavitation erosion from bubble collapse. - Aviation kerosene is so low-viscosity that it is hard to maintain a stable oil film at bearing and gear contact points. - A coating that can handle both problems could improve fuel pump durability, sealing and delivery efficiency.

What happened: - Researchers designed and fabricated an Al10Cr28Co28Ni34/Ag high-entropy alloy composite coating using high-velocity oxygen fuel spraying. - The study focused on thrust bearings inside aero-engine fuel pumps, where end-face contact carries axial load and helps maintain positioning accuracy. - The findings were published in Tribology Advances under the title “FCC/FCC structural compatibility enabling synergistic lubrication, anti-wear and cavitation erosion of Al10Cr28Co28Ni34/Ag composite coating in aviation kerosene.” - The study DOI is 10.3724/trad-20260019.

The details: - The coating combines a high-entropy alloy matrix with silver, and both phases share an FCC crystal structure. - That FCC/FCC compatibility is designed to produce similar deformation responses under friction and impact. - The coating also forms spherical particles in situ at the friction interface, which support a rolling-sliding mechanism. - Reported performance in low-viscosity aviation kerosene included a friction coefficient below 0.1, a wear rate approaching zero and a cavitation erosion mass loss rate below 0.1 mg/h. - The researchers link the result to the FCC structure’s many slip systems, which can help reduce friction and absorb impact energy. - The Al10Cr28Co28Ni34 high-entropy alloy is described as a strong FCC material with high work-hardening capacity and strong cavitation erosion resistance. - The authors say the design aims to balance friction reduction, wear resistance and cavitation erosion resistance in one coating.

Between the lines: - Existing bonded solid lubricating coatings can reduce wear in oil-starved conditions, but they struggle to protect against cavitation erosion at the same time. - Traditional coating matrices such as organic resins can fail under impact loads and cavitation heat because of limited strength and heat resistance. - Property mismatch between a coating matrix and lubricant phase can trigger cracking at phase boundaries and accelerate filler loss. - The FCC/FCC approach tries to remove that mismatch by using materials with more compatible deformation behavior. - If the results hold in broader testing, the design could point to a more durable materials route for harsh lubrication environments.

What's next: - The work provides a materials strategy for fuel pump friction pairs exposed to combined wear and cavitation. - Further validation would likely focus on longer-duration service conditions, scale-up of the HVOF coating process and testing in engine-relevant hardware. - Funding came from multiple Chinese national and Chinese Academy of Sciences programs, which suggests continued research support for this line of work.

The bottom line: - An FCC-compatible alloy-silver coating appears to give fuel pump surfaces a rare combination of lubrication, wear resistance and cavitation protection in aviation kerosene.