Research on the Lubrication Properties of Perfluoropolyether-Based Magnetic Fluid as a Space Bearing Candidate Lubricant

As a promising solution to lubrication failure in space environments where conventional oils suffer from splashing and leakage, magnetic fluids (MFs) offer significant potential. This study synthesized a perfluoropolyether (PFPE)-based MF tailored for space applications, demonstrating low-temperature fluidity at −40 °C, low saturated vapor pressure (3.37 Pa at 75 °C), and high stability (>6 months). To evaluate its lubrication effect, four magnetic thrust ball bearing structures were designed, with magnetic fields optimized via simulation. A magnetic field-controllable lubrication test bench was constructed accordingly. Comparative tests under varying friction conditions revealed that MF lubrication extended bearing service life. Specifically, the bearings lubricated with 7.5 wt.% MF exhibited the longest service life, which was doubled compared to the service life of the bearings lubricated with the carrier liquids. When compared to bearings without the application of a magnetic field, the service life of bearings lubricated with MFs of the same mass fraction increased by a factor of 3 to 4. This initial finding suggests the viability of using MFs in space lubrication applications.