Rigid Graphite Felt – Thermal Insulation Materials for Industrial Furnaces

  • High temperature stability.
  • Low thermal conductivity coefficient, good thermal insulation effect.
  • Ablative resistance and thermal shock resistance.
Rigid graphite felt after different surface treatments
Description

Rigid graphite felt has excellent ablative resistance, thermal shock resistance, airflow erosion resistance, good high temperature insulation effect and high temperature stability, etc. It is widely used in most high-end markets, including solar energy industry, semiconductor monocrystalline silicon industry, artificial crystal industry, optical fiber industry, high temperature vacuum sintering furnaces, heat treatment furnace, etc.

Rigid graphite felt is a thermal insulation material that is based on soft graphite felt and then formed by using a small amount of binder to composite any shape (for example, barrel, disk, cuboid) after high-temperature graphitization treatment. It can effectively improvs the original working environment and operability. Besides, it can also have different surface coating treatments upon request to meet the needs of various applications. Compared with soft felt, its fume forming rate is significantly reduced, thereby extending its service life.

Rigid graphite felt is generally divided into pitch-based rigid graphite felt, PAN-based rigid graphite felt and rayon-based rigid graphite felt.

In addition to rigid felt based on soft graphite felt, we also have a new type of rigid graphite felt made from a laminated material composed of fiber filaments and binder, which is then graphitized at high temperatures to form a complete felt.

Features
  • Rigid graphite felt can withstand high temperature treatment (about 2250 °C and above), and has low shrinkage and low volatile emission.
  • Low ash content and high purity, high purity rigid felt after purification has an ash content of less than 20 ppm, which ensures the purity of thermal field.
  • Low thermal conductivity, good thermal insulation effect, energy saving, and good consistency of product quality.
  • Fiber matrix to ensure uniform thermal insulation effect and good high temperature stability.
Category
  • PAN-Based Rigid Graphite Felt
  • Rayon-Based Rigid Graphite Felt
  • Pitch-Based Rigid Graphite Felt
PAN-Based Rigid Graphite Felt

It is made from high-quality PAN-based carbon felt that has been graphitized. It is used in the protective atmosphere and insulation of vacuum furnaces, and features high temperature resistance, corrosion resistance, low thermal conductivity, etc. Surfaces and edges are sealed to reduce the porosity and increase the oxidation resistance. Besides, it can be layered internally to improve radiation heat retention and reduce the furnace contaminant. It often serves as the insulation layer of industrial furnaces including single crystal furnaces, carbonized furnaces, quartz furnaces, vacuum furnaces, induction furnaces, high-frequency furnaces and reaction heat balance, heat treatment furnaces, sintering furnaces, welding furnaces. Moreover, it can also be used as a corrosion-resistant filter material.

Table 1: Specifications of PAN-Based Rigid Graphite Felt
Model Heat Treatment Temperature Carbon Content Density (g/cc) Ash (ppm) Surface Treatment Shape
CRF-1 Carbonized Rigid Felts 1200 °C ≥ 97% 0.2–0.35 ≤ 500 Graphite foil coated; CFC (Carbon Cloth) coated; Anti-oxidation painting Graphite rigid board: Thickness 20–600 mm; Graphite Cylinder: Diameter: up to 1500–1800 mm
GRF-1 Graphite Rigid Felts 2200 °C ≥ 99% 0.16–0.32 ≤ 200
Notes:
  • 1 MPa = 10.2 kgf/cm2; 1 W/m.k = 0.86 kcal/cm.h.°C
  • These properties are typical values and not guaranteed.
Rayon-Based Rigid Graphite Felt

It is used in the protective atmosphere and insulation of vacuum furnaces. It can be easily cut or machine-customized to desired sizes and is suitable for square and circular hot zones. Surfaces and edges are sealed to reduce the porosity and increase the oxidation resistance. A foil can be added to the surface of graphite felt that can be layered internally to improve radiation heat retention and reduce the furnace contamination. It is widely used in vacuum furnaces, powder metal sintering, sputtering targets, CVD, CVI and CVR furnaces, carbon fiber heat treatment furnaces, silicon/GaAs crystal growing furnaces, annealing and hot pressing, and fiber optics production.

Table 2: Specifications of Rayon-Based Rigid Graphite Felt
Model Heat Treatment Temperature Carbon Content Density (g/cc) Ash (ppm) Surface Treatment Shape
CRF-1 Carbonized Rigid Felts 1200 °C ≥ 98% 0.15–0.30 ≤ 500 Graphite foil coated; CFC (Carbon Cloth) coated; Anti-oxidation painting Graphite rigid board: Thickness 20–600 mm; Graphite cylinder: Diameter: up to 1500–1800 mm
GRF-1 Graphite Rigid Felts 2200 °C ≥ 99% 0.12–0.25 ≤ 200
Notes:
  • 1 MPa = 10.2 kgf/cm2; 1 W/m.k = 0.86 kcal/cm.h.°C
  • These properties are typical values and not guaranteed.
Pitch-Based Rigid Graphite Felt

It is made of It is made of asphalt carbon fiber mat hardened and compounded asphalt carbon fiber with certain rigidity, self-supporting property, low density, no short fiber shedding, and excellent insulation efficiency. It is widely used as insulation material for various high-temperature vacuum furnaces including vacuum heat treatment furnaces, sintering furnaces, melting furnaces, and recrystallization furnaces. It has a long service life and is easy to install and remove.

Table 3: Specifications of Pitch-Based Rigid Graphite Felt
Model Carbon Content Thermal Conductivity (W/m·K) Nitrogen Environment1000 °C Compressive Strength (MPa) Flexural Strength (MPa) Bulk Density (g/cm3) Ash Content Treatment Temperature
GAF-1 > 99.80% 0.20 - 0.27 0.17–0.6 1.0–1.8 0.15–0.30 < 0.1% 2000 °C
Notes:
  • 1 MPa = 10.2 kgf/cm2; 1 W/m.k = 0.86 kcal/cm.h.°C
  • These properties are typical values and not guaranteed.