Gap fillers are used when a requirement exists to thermally couple a hot Semiconductor to a nearby cold wall or heat sink

This is done by filling the air gap above the device and providing a thermally conductive path for the heat to travel. Our gap filler materials are unique in that they provide electrical isolation and are very soft to assist with interfacial thermal resistance as well as create low pressure forces on the device during operation. Typical applications include coupling hot FR4 pcb’s to chassis for instance; LED arrays. Other applications include cooling DSP (Digital Signal Processing) in computer applications & power devices in PSU's or power converters.

Typically an air gap of greater than 0.5mm (0.020”) between the device and heat sink often means a Gap Filler should be used. Uneven surfaces or components at different heights would also be an ideal area where under compression contact can be made to assist heat flow to or from a package.

Two types of Gap Filling materials are available, our pad types can be pre-punched into a required shape for placement in the interface. Or our putty type which can be squeezed into position by syringe between a hot device and heat sink.

All gap-filling products are ROHS compliant.

Gap pad products are available in thicknesses starting from 0.5mm to 6mm in 0.5mm increments

Gap FIller Data Sheets

Thermal Conductivity
Part Number

1.5 W/m K

2.0 W/m K

2.5 W/m K

2.8W/m K

3.0 W/m K

3.5 W/m K

4.0 W/m K

8.0 W/m K











GCS thermal interface materials are designed specifically for high performance heat transfer. Our materials scientists can rapidly develop and mix the material formulas for volume custom applications.

The parts need to be mounted together under mechanical pressure to assure the soft nature of the material “cold flows” into the micro-air voids and thermally couples the two surfaces. Generally medium to high mounting pressure is preferred i.e. by screwing the surfaces together. This to an optimum pressure after which further pressure does not effect the performance at the interface. At that given pressure the air voids are filled.

GCS thermal interface materials are low cost and ultra high performance for metal to metal applications requiring no electrical isolation to mount Insulated Metal circuits to a further heat sink.

Thermal Grease








Phase Change Material




Thermal Putty




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