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Diffusion Pump Oil RUI705-oil for diffusion pump

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Diffusion Pump Oil RUI705-oil for diffusion pump Synonyms:

   1. Pentaphenyl trimethyl trisiloxane

   2. 705 Super high vacuum diffusion pump oil

   3. 705 Diffusion Pump Fluid

   4. PhenylmethylsiloxaneOligomers

   5. Oil for diffusion pump

CAS No: 3390-61-2

Chemical structure:

Diffusion Pump Oil RUI705 is a colorless transparent oily, single-component fluid designed for ultrahigh vacuum applications in the range of 5x(10-9~10-10) torr (untrapped). The vapor pressure and backstreaming rate of RUI705 is so low that the use of traps or refrigeration is unnecessary for some ultra-high and ultra-clean vacuum applications. It has the highest phenyl content of all silicone diffusion pump oils and the best resistance to radiation. 

Technical Index



Chemical composition

Pentaphenyl trimethyl trisiloxane

Ultimate Vacuum, torr



Saturated Vapor Pressure, torr


Specific Gravity

1.090 ~ 1.100

Viscosity (25°C), cSt

               (40°C), cSt



Flash Point °C


Refractive Index 25°C


Congealing Point °C

-14 ~ -18

Molecular Description


GC-MS and IR test reports for every batch of Diffusion Pump Oil RUI705 is available from RUIchem silicones, if you need it, please send email to


Diffusion Pump Oil RUI705 can be used in variety of applications, including:

Electrical and electronics industry

TV tubes, fluorescent tubes, cathode ray tubes

ordinary bulbs


rectifier metallised film vacuum system

Optical industry

surface improvements

anti reflective coatings

optical filters and mirrors

Metallurgy industry

high-vacuum furnaces

melting, degassing and sintering refractory metals; thick-film deposition

Plastics industry

surface improvements

mirror coatings

protective coatings

film coatings

Other industries

processing metals and fuels


molecular plants

R & D plants

mass spectrometry



Be used as transmission fluid in high-temperature carriers and various instruments.

Package, Transportation & Storage

Diffusion Pump Oil RUI705 is available in 1kg plastic bottles, 1gallon plastic drums,5kg plastic drums, 25kg plastic drums, 25kg Iron drums or 200kg Iron drums.

Transport as non-hazardous chemicals, keeping away from rain and sunlight.

Shelf life: 3 years.