Apple's interest in cooling technology is not limited to liquid means, a new document from the US Patent and Trademark Office shows. The company is attempting to patent two heatsink technologies, both connected by the use of a diamond-based thermal material. In the first, a heatsink would be linked to circuits that need cooling, but only through an intermediate layer, where the thermal material in question would be located.

Contained in the material is an allotrope (different bonding) of carbon with a face-centered cubic crystal structure, namely single- or polycrystalline diamond. This is said to be useful in handling heat capacity and conductivity, particularly as it may match the expansion coefficients for circuits and the heatsink. The rest of the material can be composed of one or more separate chemicals, such as copper or aluminum grain.

Also described in the patent is use of the material in a fin stack, normally the last part of a cooling system in which heat finally dissipates. Here the fins would be coated with the thermal material, as a means of reducing resistance.