Particle-filled silicone are elastomeric compounds that combine the advantages of silicone with electrical properties of metals. Conductive silicone materials can include the following filler materials: nickel, graphite, silver, copper, and aluminum.
Particle-filled silicone materials provide shielding against electromagnetic interference (EMI) and radio frequency interference (RFI). Silicone in itself boasts a number of tremendous properties, including high performance at extreme temperatures (-50°C - 350°C), durability and abrasion resistance, chemical stability, and electrical insulation. This combination of features makes particle-filled silicone materials ideal for EMI seals and gaskets in a range of applications and industries, including the demanding applications of the military and aerospace industries.
Some designers have concerns about using particle-filled silicone. Silicone has desirable material properties, but loading a high percentage of particle filler into the rubber in an effort to increase conductivity can result in negative tradeoffs. Typically industry professionals worry that particle filled electrically-conductive silicone will exhibit the following negative material features:
- too hard
- too brittle
- too expensive
- have long lead times
- limited by mold size dimensions
- not thin enough for newer, thinner designs