Vacuum grease

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As vacuum greases masses are called who take similar normal greases sealing and lubrication tasks, but also have properties that are favorable at very low pressures.

properties

  • The viscosity is high enough not to be forced out of the sealing gaps by the pressure difference between atmosphere and vacuum
  • The lowest possible vapor pressure
  • Chemical stability at both low and high temperatures
  • Stability against oxygen , ionizing radiation, ionized gases and radicals is often required
  • Low in particles due to high viscosity and high stability

Materials based on perfluoropolyether under various trade names have such properties, Teflon can also be a component of these agents. It is an inert and chemically stable synthetic polymer and the product description often contains the statement "silicone-free". Other means have been developed on the basis of silicone oils . Silicone-based agents are preferred when using glass equipment.

The term vacuum grease is misleading because such lubricants do not contain any grease or fat-like substances, but it has become common practice. Two-component epoxy resins are also used for permanent connections and connections are also used for flanges, etc. in which soft metals such. B. an indium seal can be deformed and in this way create a tight joint.

literature

  • Karl Jousten (Hrsg.): Wutz manual vacuum technology . 10th edition. Vieweg + Teubner, Wiesbaden 2010, ISBN 978-3-8348-0695-6 , pp. 686 f . ( limited preview in Google Book search).

Web links