High purity graphite soft felt

Thermal field insulation carbon materials application background

Thermal field insulation carbon materials are coated on the periphery of thermal field functional components and inside various furnace bodies, and are mainly used to construct thermal field space and thermal insulation. Although carbon fiber has a high thermal conductivity, carbon fiber material is a loose and porous carbon fiber polymer. The fibers rely on friction to maintain the shape of the felt body. The fibers are overlapped together, which is a point contact, which greatly reduces the heat transferred through the solid heat conduction path. Especially in high-temperature thermal fields (such as above 800℃), the radiation intensity increases, and thermal radiation becomes the main form of heat transfer. The radiation waves are continuously reflected between the fibers and dissipated inside the felt body, thereby achieving the effect of thermal insulation.

The most commonly used thermal insulation material is high purity graphite soft felt in different forms. high purity graphite soft felt is made of thin fibers. The soft high purity graphite soft felt is woven into relatively thin sheets, then cut into the desired shape and tightly bent into a reasonable radius.

High purity graphite soft felt classification

According to the different raw materials used, high purity graphite soft felt can be divided into three categories: PAN-based, viscose-based and asphalt-based:

Compared with PAN-based and asphalt-based materials, viscose-based carbon materials have better performance in thermal insulation. Therefore, viscose-based high purity graphite soft felt is also the mainstream choice for semiconductor and photovoltaic thermal field insulation carbon materials.

Application of high purity graphite soft felt in PVT method

PVT method is usually used to grow silicon carbide single crystal in the industry. The SiC powder is filled with the bottom of the graphite crucible, and the SiC seed crystal is bonded inside the graphite crucible cover with a certain distance from the raw material surface, and then the graphite crucible is placed in the graphite heating body as a whole. By adjusting the temperature of the external high purity graphite soft felt, the SiC raw material is placed in the high temperature zone, and the SiC seed crystal is in the low temperature zone accordingly.

In this process, the thermal field area composed of the crucible and the surrounding thermal insulation material is the most important area for SiC single crystal growth. Crystal growth chamber can reach a very high temperature (up to 3000℃), at this high temperature, VeTek semiconductor high purity graphite soft felt can withstand such high temperature, and at such high temperature does not react with SiC sublimation, with excellent thermal insulation performance, thermal insulation performance to ensure the growth of high-quality SiC crystal.

VeTek semiconductor high purity graphite soft felt is an indispensable insulation material in induction furnaces. Induction furnaces generate a lot of heat when working, and high purity graphite soft felt has low thermal conductivity and low specific heat, which can ensure the stability and uniformity of the temperature in the furnace and improve the thermal efficiency of the furnace. At the same time, high purity graphite soft felt also plays a role in sealing and insulating the induction furnace body, preventing the leakage of heat and gas in the furnace.

Data sheet for VeTek semiconductor high purity high purity graphite soft felt

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