Silicone foam based thermal pads are the most common and effective material on the market for filling large irregular gaps between heat sinks and electronic components. Their low thermal resistance and soft compliant nature make them the materials of choice for thermal gap fillers.

The Drawback: Silicone foams contain anywhere from 5% - 20% extractable silicone oil.

Under compression, and with time, these extractable oils will leach from the gap fillers and coat the surrounding surfaces.

Silicone oils can contaminate factory handling and cleaning equipment effecting most coating and soldering processes. Many electronics assembly manufacturers have banned silicone based materials from their premises.

 

Oil Contamination

An unencapsulated silicone thermal pad leaves oil residue.