What are the differences between graphite felt and carbon felt?

Graphite felt: It is made by carbon felt being subjected to a graphiteification process at a temperature of over 2000°C (usually 2200 - 2500°C) under vacuum or an inert atmosphere. This process makes the carbon atoms in the material arrange in a more ordered manner, and the structure becomes closer to that of graphite crystals.

Carbon felt： It is made by carbonizing polyacrylonitrile (PAN) and asphalt-based organic fibers at a relatively low temperature (about 1000℃) without undergoing graphitization treatment.

Key Performance Comparison

‌1.Carbon Content and Structure‌: Graphite felt typically has a carbon content of ≥ 99.9%, with a denser structure; Carbon felt usually has a carbon content ranging from 90% to 95%, with a lower degree of graphitization.

2.Temperature resistance performance: Graphite felt can withstand temperatures above 2000℃ for long-term use in non-oxidizing atmosphere, and can tolerate up to 3000℃ for short-term use; Carbon felt's long-term operating temperature range is usually between 300 and 1200℃, and can reach around 1400℃ for short-term use.

3.Thermal conductivity: The thermal conductivities of both are relatively low, making them heat insulation materials. The specific values vary depending on the product type and measurement direction, but after being graphitized, the thermal conductivity of graphite felt is usually slightly higher than that of carbon felt (for example, graphite felt is approximately 0.1 - 0.3 W/m·K, while carbon felt is approximately 0.05 - 0.2 W/m·K).

4.Physical Properties: Graphite felt possesses the corrosion-resistant and non-melting characteristics of block graphite, and it is elastic and foldable for cutting; Carbon felt has a porous fiber structure and excellent adsorption performance.

Main application fields:

‌Graphite felt‌: Due to its extremely high temperature resistance and purity, it is mainly used as the insulation layer in the high-temperature zone of single-crystal silicon and polycrystalline silicon smelting furnaces, as well as a filtering material for high-purity corrosive chemical reagents. It is also applied in fields such as all-vanadium flow battery electrodes and aerospace insulation.

Carbon felt: Primarily used for insulation in the low-temperature zone of single-crystal furnaces (such as the lower part of the crucible and the furnace walls), and also for chemical corrosion prevention, adsorption purification, and structural reinforcement in buildings, etc., in situations where the requirement for absolute temperature resistance is relatively low.