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A lot of insulating materials are also non-metallic, which typically don't have a high specific heat. However, I am interested in experimenting with insulators that conduct heat as well as metal, but impede currents just as effectively as typical insulators. Does such a material exist?

Glass for instance can act as an insulating material, but it has a pretty high specific heat. On the other hand, rubber often has a lower specific heat, but it will melt rather easily. Copper has a low specific heat and a high melting point, but, it conducts electricity very well. You can see there is some challenge in figuring this out without explicit experience with such a material.

The temperature range is high, which when you talk about electrical components that can tolerate high heat means it's at least high enough enough to burn your skin. Since I am concerned with melting points in materials like rubber, glass and different metals, the range is least a few hundred degrees (either ºC or ºF) to 2000 degrees, depending on the actual impedance of the material. However, it should be publicly viable for experimentation, the highest possible grade material like diamond is not necessary.

John Joe
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  • Comments have been moved to chat. – Nick Alexeev Jul 01 '18 at 22:55
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    2000 degrees F or C? When you get to 2000 degrees C, you are in a realm of really specialized refractive materials. But 2000F is not THAT bad. – user57037 Jul 01 '18 at 22:57
  • It is on the higher side, but I'm willing to make compromises since this kind of material seems hard to find. – John Joe Jul 01 '18 at 23:05
  • The usual solution is to have a thin insulator that doesn't conduct electrically to the degree necessary, and then have a highly conductive material take the heat away - but if you must have a single material, have you looked at potting compounds? – user2813274 Jul 02 '18 at 00:30
  • @user2813274, he is talking about 2000 degrees (still not sure if that is F or C). I guess you could use alumina or silica or something. But I don't think those are normally considered to be potting materials. – user57037 Jul 02 '18 at 01:06
  • The problem here is that the same mechanisms that make a lot of materials good electrical isolators also contribute to making them good thermal isolators – PlasmaHH Jul 02 '18 at 06:36

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Diamond, BeO and AlN are useful heat transfer materials with negligible electrical conductivity. There's nothing perfect, however, and diamond is expensive, BeO is associated with toxic dusts at manufacturing time, and AlN is a modern material few people are familiar with.

Aluminum's thermal conductivity is a little over 200 watts per meter x Kelvin (W/K-m), while diamond is 900-2320 W/K-m. BeO is 330 W/K-m, and AlN is 285 W/K-m.

Whit3rd
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    Al2O3 (alumina) is more commonly available, and used as electrically isolated thermal conductor for many transistor packages. – Jeroen3 Jul 02 '18 at 06:47