Editor’s note: This question was asked in response to Electronics Cooling’s recent webinar by Carl Zwebin. To view the webinar, click here.
1. Question: The thermal conductivity of diamond-Ag composites was quoted at 983W/mK. This was sure news to me. I was under the impression that an electrical insulator (diamond) was not compatible with an electrical conductor (Ag) in the conduction of heat because of the phonon scattering phenomena. What am I missing?
Answer: I am not a physicist, but I can make some general comments on the issue.
Phonon scattering is a complex phenomenon that depends on interface characteristics. Slide 37 in my presentation (which is attached), makes the point that thermal conductivity of diamond/copper depends on the matrix alloy and manufacturing process, both of which affect the interface. Particle coatings are also used to reduce phonon scattering.
Experimentally, the fact is that well-designed and fabricated diamond particle-reinforced copper, aluminum and silver all have high thermal conductivities.
Oliver Heaviside famously said, when he could not explain his mathematical operations, that he did not stop eating just because he did not understand the digestive process.
-Carl Zwebin
