Apiezon N Cryogenic Heat-Transfer Greases
Apiezon® N is a high molecular weight polymeric additive with a rubbery consistency that is approved by NASA and the US Navy. A special additive component of Apiezon® N gives it the rubbery consistency that allows for a cushioning effect to absorb vibrations in equipment, and makes this grease useful in fragile glass applications. Apiezon® N grease is most recognized for its use in cyrogenic applications as a cryogenic vacuum seal where it has the ability to improve heat transfer at very low temperatures. The ability for Apiezon® N grease to reach cryogenic temperatures quickly, allows it to resist cracking at low temperatures by filling micropores of adjoining surfaces. From this capability, Apiezon® N grease increases area of contact to improve thermal coupling across the entire contact area.
- Similar to Apiezon® L, but contact grease contains a high molecular weight polymeric additive
- Popular in high vacuum applications and as a general laboratory lubricant (burette taps)
- Uses include Coupling of cooling systems to superconducting magnets, cryostats, temperature sensors, systems reaching cryogenic temperatures quickly, superconductor manufacturing applications (due to Apiezon® N’s low level of magnetic susceptibility), cryogenic equipment, MRI magnets, cryostats, and scientific instruments (electron microscopes)
- Thermal coupling, sensor mounting, and sample mounting medium
- Silicone and halogen free
Apiezon® N grease has no contamination effect on electrical equipment and is easily removed through use of water, soapy water, hydrocarbon solvents (Limonene, Toluene, Xylene) or chlorinated solvents (Trichloroethylene). When Apiezon® N is removed, it also takes away trace impurities that are not removed by solvents alone.
Research by NASA has shown Apiezon® N to have superior heat-transfer properties across metallic joints (held together by mechanical pressure) at liquid helium temperatures. Though indium foil has a long history and tradition in cryogenic sealing and heat-transfer applications, Apiezon® N, which costs less than one twentieth of indium's cost, offers a sound alternative on technical and conservation grounds. Indium is not soft enough to fill micropores in surfaces, but Apiezon® N covers evenly and fully at room temperature to give excellent thermal conductivity at cryogenic temperatures.
The specifications charts, taken from NASA's report, show the value of thermal conductance measured at various cryogenic temperatures. Both sides of the mating pair for each sample were made from the same material: OFHC copper, 6061-T6 aluminum, free-machining brass, or 304 stainless steel.
All contacting surfaces on the sample pairs were lapped to an 0.8-mm finish. Between the contacting surfaces, researchers placed either a thin layer of indium foil (99.9% purity and 0.005" thick), Apiezon® N grease, a gold-plated washer, gold-plated contact, or nothing. Then a mechanical arm pressed the surfaces together at 8 different forces ranging from 22 to 670N. Measurements of temperature, made with the lower contacts linked to a liquid helium bath held at 1.6K and 4.2K, yielded the results summarized in the various charts.
|Vapor Pressure (Torr)|
|Lubricity 4 Ball Test|
|Coeff. of Expansion|
|Surface Breakdown at|
As shown below, Apiezon® N grease has low vapor pressures at ambient temperatures so it may be used at high vacuum ranges. Apiezon® N has vapor pressures below 10-9 torr at ambient temperatures (20 °C).
It is strongly recommend using all fluids and greases at the time of receipt, however when storage is necessary, rotate older stock into use first and observe the recommended parameters listed below.
All Apiezon products have a shelf life of 10 years if unopened in their original container and stored at ambient temperatures. If the product has been opened, resealed and then stored in clean, dry, dark environment under ambient conditions in the original container, it should last up to 10 years, but this is not guaranteed.
Safety Data Sheets
|Download SDS: PDF for APNB|
All dimensions listed below, unless otherwise stated, are in grams.