Plastic to use in a cyrogenic equipment?

[bilim100]

What kind of non-metallic materials are good choices for equipments that are immersed in 77 K ? (for example level or temperature sensor in a LNG tank)

Thanks

 

[iainuts]

If it's for something that has little or no significant stress on it, I'd suggest glass filled Teflon. It maintains its shape well over time, has no ill effects from being cycled to low temperature and is relatively inexpensive. For materials that need properties such as significant strength, wear resistance, high modulas of elasticity, etc... there are plenty of other plastics available but you'll need to be more specific.