Graphite Pads & Films are composed of graphite, the isotope of pure carbon that arranges itself in stacked sheets. Graphite’s sheet-like crystals, graphene, offers superior in-plane thermal conductivity compared to its through-plane thermal conductivity. With low mass and high heat transfer capabilities, Graphite Pads & Films are high performance, high heat spreading thermal interface materials available in ultra-thin and light weight configurations.
Graphite films come in two main forms: Pyrolytic Graphite (PG) or Pyrolytic Graphite Sheets (PGS) and Annealed Pyrolytic Graphite (APG) also known as Thermally Annealed Pyrolytic Graphite (TPG). Both are created through chemical vapor deposition (CVD) with high purity hydrocarbons. The annealing process eliminates the variation of planar conductivity (heat spreading properties) between graphene sheets, which is how APG attains higher bulk planar thermal conductivities compared to PGS.
Graphite’s crystalline structure also enables electricity to easily pass through the material, making it an electrically conductive, heat spreading thermal interface material. Graphite Sheets and Films are continually getting thinner and have been increasing in through-plane conductivity, making it ideal for ultra-thin heat spreading thermal interface material applications.
Graphite’s sheet-like structure enables a limited amount of bending but can be used in conjunction with a protective layer to prevent flaking as it has high in-plate stiffness. Unprotected graphite can produce particulates, which can cause electrical shorting and contamination for sensitive environments. Boyd has developed proprietary graphite enveloping processes combining the heat spreading performance of graphite with the protective layer of an ultra-thin, electrically isolating film to reduce or eliminate particulates. For applications that require electrical conduction, we custom design accessible contact points within the graphite envelope solution for selective electrical conduction.
Graphite materials have high temperature resistance and can be used in applications at temperatures beyond 200°C. At temperatures beyond 200°C, graphite films should be used in a vacuum environment to prevent oxidation and performance reduction. Graphite can withstand up to 3300°C (6000°F) prior to material degradation.
Graphite films can be used for EMI shielding up to the GHz range, with superior attenuation.
Boyd’s precision converting capabilities enable us to cleanly and reliably produce customized graphite thermal interface material solutions. Our process and material expertise enable us to not only handle graphite with precision, but combine it with other materials for a single, multi-functional integrated heat spreading solution. For sensitive applications, graphite processing can be done within a Cleanroom environment classified from Class 100, Class 1000, Class 10,000 or Class 100,000 depending particulate requirements.