Amanda Hartnett was interviewed on this subject for a recent issue of Thermal News. Amanda is an Applications Engineer at Indium and has done a lot of work in the thermal interface material arena. You can read the full article here.
So why does indium warrant a starring role in today's electronics as a thermal interface material? It has high thermal conductivity, is very compressible, and its solid state make it easy to introduce into your process.
Indium is unique in that you can use it by compressing preforms, or sheets of it, between two surfaces, reflow it like traditional solder (at generally lower temperatures), or coat two mating surfaces with indium and cold weld them together. For more information on the thermal properties of indium, go to our web site.