Apiezon N Cryogenic Heat-Transfer Greases

Specifications Table

Vapor Pressure	@20°C: 6 x 10-10
Specific Gravity	0.911 (g/cc)
Melting Point	42-52 (°C)
Temperature Range	-269 to 30 (°C)
Thermal Conductivity	@20°C: 0.194 (W/m °C)
Lubricity 4 Ball Test	150 (kg)
Outgassing Characteristics	TML: <1% CVCM: <0.1%
Radiation Resistance	Not recommended
Coeff. of Expansion	20°C-30°C: 0.00072 cm/°C
Volume Resistivity	2.0 x 1016 (ohm cm)
Permitivity	2.3
Loss Tangent	<0.0001
Surface Breakdown at Flash Over	27 (kV)
Electric Strength	820 (V/mil)

Charts

 

High vacuum

Apiezon N grease is suitable for use in high vacuum applications. The vapour pressure for this grease over its working temperature range is shown in the graph on the right.

Cryogenic temperatures

Apiezon N grease is widely recognised and recommended as the cryogenic vacuum grease of choice as a sealant or sample mount medium. Although a good lubricant at ambient temperatures, N grease should not be used as a lubricant at cryogenic temperatures.

Added cushioning

Apiezon N grease has a special additive which gives it a tenacious, rubbery consistency. This provides an extra cushioning effect, which absorbs vibrations in equipment. N grease is thus invaluable for use in fragile glass to glass joints, such as burette taps, which continually run the risk of fracture.

Silicone free

As a hydrocarbon-based grease, Apiezon N grease is highly resistant to 'creep' or 'carry over', a phenomenon associated with silicone-based products (silicone tends to travel away from the area of application and contaminate adjacent surfaces). The creep resistance of Apiezon hydrocarbon greases benefits scientific users as it reduces sample contamination and the risk of interference in analytical techniques such as infra-red and mass spectrometry.

Silicone contamination is of particular concern in surface coating applications such as industrial paint or metal deposition processes, as trace amounts of silicone on surfaces prevent the adherence of paint and poor or incomplete coverage results.

In semiconductor manufacture, yields can be severely affected by silicone contamination. When using Apiezon hydrocarbon greases, the problems associated with silicone creep and contamination are avoided.

Easily Removed

Apiezon hydrocarbon greases are easily removed by wiping with a soft, clean lint free cloth. Any residues of grease can be washed away with warm soapy water or by using any aromatic hydrocarbon solvent (toluene, xylene). For a more environmentally friendly solvent, we recommend limonene. Apiezon hydrocarbon greases are not soluble in alcohols (ethanol, IPA) or ketones (acetone, MEK) so these cannot be used for cleaning.

'Gettering' action

Apiezon hydrocarbon greases are manufactured from a unique feedstock containing a high proportion of branched and unsaturated structures. These give the greases a very high molecular weight and consequently strong powers of absorption, particularly for other hydrocarbon molecules.

Strong absorption properties ensure that Apiezon hydrocarbon greases have a powerful 'gettering' action, i.e., the power to absorb greasy or chemical impurities on metal and glass surfaces – important in the electronics industry where scrupulous cleanliness is required.

Apiezon hydrocarbon greases have no contaminating effect on electrical equipment and are easily removed by hydrocarbon solvents. This process removes many trace impurities which are not removed by solvents alone.

Compatibility

Apiezon N grease is compatible with a wide range of O-ring materials including:

• Viton
• Nitrile (>30% nitrile content)
• Nylon
• Polyurethane
• Polyethylene
• Polypropylene

Due to its hydrocarbon base, Apiezon M grease is not compatible with:

• EPDM (ethylene propylene diene M-class rubber)
• EPR (ethylene propylene rubber)
• Butyl rubber
• PVC seals

Shelf life

The shelf life of Apiezon N grease is ten years from date of manufacture, providing the product is in the original unopened packaging and has been stored at ambient (10 to 30°C) temperature.