Invoil Silicone Diffusion Pump Oil

Inland Vacuum’s silicone diffusion pump oils – Invoil 702, 704, and 705 – are durable fluids designed for a variety of high vacuum applications and for fast pumping large volumes of gas. They are drop-in replacements to – and completely miscible with – the DOW CORNING® DC-702, 704, and 705 silicone fluids, respectively. Invoil 702, 704, and 705 silicone diffusion pump oils offer equal or better performance compared to the equivalent DOW CORNING products.

Invoil® 702

Invoil 702 is designed for rapid pumping of large volumes of gas and has the important advantages of thermal stability and oxidation resistance. This silicone-based fluid is resistant to air at operating temperatures, the pumps require no cooling between cycles.

Invoil® 704

Invoil 704 is a silicone diffusion pump oil with low vapor pressure and great thermal stability, making it desirable in processes such as vacuum coating, metallurgical work, and various other applications. It offers superior vapor pressure capabilities and quick pump down cycles.

Invoil® 705

Invoil 705, with a higher viscosity than the other Invoil fluids, is designed to produce an ultra-high and ultra clean vacuum. With the use of traps, Invoil 705 is capable of attaining a pressure of 10-11 torr, and without a trap 10-9 torr.

Invoil® 940

Invoil 940 is a silicone diffusion pump fluid with both low vapor pressure and thermal stability, enabling it to be used in vacuum coating, metallurgical work, and various other applications. It is oxidation and explosion resistant, and offers quick pump down cycles.

    High thermal stability

  • Highly pure silicone fluids absent of volatile or unstable contaminants
  • Flash points well above normal diffusion pump operating temperatures
  • No fire point
  • Suitable for continuous pumping of oxygen and for regular venting of hot systems to atmospheric pressure

    Radiation resistance

  • High phenyl content allows for excellent resistance to gamma radiation
  • Small viscosity changes when exposed to radiation

    Chemical resistance

  • Chemically inert silicone fluids for longer service life without contamination of degradation
  • Will not breakdown or deteriorate as a result of chemical exposure

    Low to ultra-low vapor pressure

  • Invoil 704 and 705 capable of attaining vapor pressure of 10-11 torr with trap
  • Invoil 705 has vapor pressure of 2.4×10-9 torr at 25°C
  • Invoil 704 has vapor pressure of 2×10-8 torr at 25°C

    Minimal backstreaming

  • Invoil 705’s extremely low vapor pressure allows for ultra-clean vacuum system
  • Contamination rates close to 0 because of ultra-high vacuum achieved

    Oxidation resistance

  • Does not react with metal parts and seals in vacuum system
  • Will not be oxidized by air at operating temperatures
  • Will not undergo hydrolysis by water vapor

Invoil silicone diffusion pump oil is designed to meet the increasingly demanding and diversifying needs of multiple industries.

    Electronics and Circuitry

  • Chemical and physical vapor deposition
  • Thin film sputtering and evaporation
  • Evacuating power and microwave tubes
  • Electron, vacuum, and cathode-ray tubes

    Vacuum Coating

  • Optical coating
  • Architectural glass and materials coating
  • Decorative coating


  • Thick film deposition
  • Plasma and electronic beam welding
  • Melting, refining, and atomizing

    Research and Development

  • Surface and materials analysis
  • Mass spectrometry
  • Spectroscopy, microscopy, and tomography
  • Particle acceleration and gravitational wave detection

SpecificationsInvoil 702Invoil 704Invoil 705Invoil 940
Vapor Pressure at 25ºC (torr)3.3x10-62x10-82.4x10-92x10-8
Boiling Point at .5 torr  (ºC)190210243221
Viscosity at 40ºC (cSt)26.824.26624.2
Viscosity at 100ºC (cSt)
Pour Point (ºC)<0<-9<0<-9
Flash Point (ºC)193221243221
Fire Point (ºC)NoneNoneNoneNone
Density at 25ºC (g/ml)

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