Good thermal conductor but insulator

[csopi]

Hi,

Does anybody know a material which is a good thermal conductor and an insulator at the same time (at temperatures around 4 K) and is "easy" to fabricate? For e.g. sapphire fulfils the first two requirements, but is extrmely hard.

 

[RocketSci5KN]

First throught was diamond, but 'easy' to fabricate rules that out. Second thought is BeO ceramic, but must be processed very carefully to prevent Be poisoning. You may want to research thermally conductive ceramics - there may be some that are not dangerous to process. There are some thermally conductive plastics, best to contact www.coolpolymers.com

 

[csopi]

Thank you very much for your help, I'll look into the hints!

 

[RocketSci5KN]

You might also consider simple hard anodized aluminum. The anodized layers should give you a thick enough oxide to prevent any electrical conduction. Of course, anything contacting it should not be able to break through this oxide layer.

 

[csopi]

Good idea, but unfortunatelly this won't solve my problem. I'll use it as a sample holder at 4 K, and it'll be subjected to AC magnetic fields. The aim is to get rid of the eddy currents and for this I need the bulk to be an insulator as well.

 

[Diomarte]

Have you considered Boron Nitride?