Vacuum Thermal Cycling and Creep Resistance Properties of Low Surface Energy Fluorocarbon Polymer Coating

Low surface energy fluorocarbon polymer coating is a key material to inhibit the creep and loss of space grease lubricants. The application of this material would provide technical supports for the long-life and highly reliable operation of space grease lubricating moving mechanisms. In this paper, water contact angle tester, X-ray fluorescence energy spectrometer, optical microscope, etc. were used to study and analyze the properties of the developed low surface energy fluorocarbon polymer materials before and after vacuum thermal cycling. And the creep resistance properties of low surface energy fluorocarbon polymer coatings to MACs lubricating oils were studied. The results showed that the surface energies of 9Cr18 stainless steel, 2A12 aluminum alloy and TC4 titanium alloy coated with polymer coatings were 8.797 mN/m, 9.083 mN/m and 9.203 mN/m, respectively. In the temperature range of −45 ~ +90 ℃, after 60 vacuum thermal cycles in 30 days, the coatings still has low surface energies , which were 8.915 mN/m, 9.209 mN/m and 9.266 mN/m, respectively. In addition, there presented an obvious interface between the low surface energy fluorocarbon polymer coating and MACs lubricanting oil. And no characteristic peaks of MACs lubricating oil were detected at the coating 200 μm away from the lubricating oil by XPS analysis, which exhibited that no lubricating oil creeped and diffused to the coating. The low surface energy fluorocarbon polymer coating can play an " creep resistance" role to the MACs lubricating oil effectively.