What Is Graphite Sheet?
As electronic devices such as mobile devices become lighter, thinner, and smaller, and at the same time, more advanced and sophisticated, the problem of heat generation is becoming more serious.
The thermal conductivity of graphite sheets is two to five times that of copper, which has the highest thermal conductivity among metals, and although slightly lower than that of diamond, it is higher than that of other metals. It is expected to be a heat countermeasure material that has excellent heat conductivity (heat dissipation and heat diffusion) and is both thin and flexible.
PGS (PGS = Pyrolytic Graphite Sheet) is known as a domestically produced crystalline graphite sheet with high thermal conductivity and flexibility (registered trademark of Panasonic Corporation).
Uses of Graphite Sheet
It is highly effective for heat diffusion and dissipation in various applications including mobile electronic devices.
Graphite sheets are used in semiconductor manufacturing equipment (sputtering, dry etching, etc.), optical communications, and base stations, in addition to home appliances such as smartphones, cell phones, digital cameras, tablet PCs, PC peripherals, and LED devices.
Graphite sheets are also used as a heat-resistant material in various fields other than those mentioned above, and the market is rapidly growing.
Principle of Graphite Sheet
Simply put, the manufacturing process for graphite sheets involves a very simple principle: a polymer film with a special molecular structure is thermally decomposed at high temperatures and then fired at ultra-high temperatures to create a highly oriented crystal structure in the planar direction that resembles a single crystal.
However, this special raw material is a trade secret, and we cannot explain why graphite is formed when this special raw material is used.
Then, why is high-temperature processing necessary? There is a clear answer here.
When polymeric materials containing carbon are heated under oxygen-free conditions:
Hydrogen at 500°C
Oxygen at 1000°C
Nitrogen at 2000°C
and finally, when heated to 3000°C, only carbon atoms remain. The carbon atoms are calcined and crystallized into high-quality graphite crystals.
Due to this layered structure, the thermal conductivity of graphite sheet is characterized by the fact that heat is hardly transferred in the direction of thickness, but is quickly transferred in the direction of creepage.
In addition, the graphite sheet does not require complex manufacturing processes and can be produced at a low cost.