transistors - Electrically conductive thermal paste

I need a thermally AND electrically conductive heat sink compound for attaching power transistors to an aluminium heat sink. I've given Coollaboratory's LiquidPro a try and that oxidized the aluminium. Artic Silver 5 was completely the wrong solution, not conductive at all (I had some exploding FETs on my hands).

Any suggestions?

Answer

I hardly can see why you need a conductive paste? The aluminum is covered with thin insulation layer of Al-oxide and will break the electrical contact anyway with the time, regardless of the paste properties.

1. 
   

   If you need the heat sink to be electrically connected to the element - use a wire instead and screw it on the heat sink.

   
   


2. 
   

   Use copper heat sink and solder the element on it - this way you will get the best electrical and thermal contact possible and very effective heat sink at the same time. (Use very thin solder layer).