Thermally conductive silicones are used in electronic devices to dissipate heat away from the component and the surrounding equipment. Modern devices are required to be smaller and more powerful and consequently generate more heat. It is imperative keep these devices cool in order to prolong the life of the equipment, reduce energy consumption and prevent damage to surrounding components.

There are many types of silicone materials available including pastes, cured pads, RTVs, gels, adhesives, gap fillers, phase change materials and greases. The choice will be governed by the application and dispensing method preferred. Below we explore the different types of thermally conduction silicones available to help you narrow down which product type you are looking for.

Silicone Adhesives, RTVs, Pastes and Greases

Silicone thermal interface materials, including adhesives, pastes, and RTVs, are applied in a thin layer of material between the electronic component and its heatsink in order to minimise its thermal resistance. Pastes and greases are non-curing, allowing rework. RTVs and adhesives are used to bond the heat sink to the component while also offering an effective heat transfer medium.

Silicone Thermal Gap Filler Pastes

Used as a liquid dispensed alternative to prefabricated thermal pads. They offer improved thermal dissipation thanks to excellent wet-out compared to rigid pads. As these fillers can be dispensed by automated systems there are used by sectors demanding higher production throughput, thinner bond lines, and reduced mechanical pressure on components and solder joints. As a further advantage any design changes that alter the position or types of components used can be accommodated quickly by changing the shape and volume of thermal material deposited. If automatic dispensing equipment is used, it can be reprogrammed, avoiding any need to reorder gap-filler pads in different sizes or shapes.

Silicone Potting Compounds

Some heat generating circuits benefit from potting or encapsulation in a heatsink enclosure using a thermally conductive silicone potting compound. This has the benefit of providing both heat dissipation and environmental protection all in one.

Prefabricated Silicone Thermal Gap Filler Pads

Silicone thermal gap filler pads can be cut to size and applied by hand. They have a higher thermal resistance when compared with thermal pastes due to the thickness of the gap pad versus the very low thickness achievable with a thermal paste.

Silicone Phase Change Materials

Phase change silicone materials are an effective alternative to thermal greases. The materials change from a solid at specific phase change temperatures and flow to provide a total wet-out of the interface without overflow. The result is a thermal interface comparable to grease.

For more information or to speak to one of our technical team contact us on technical@techsil.co.uk.