Soft Graphite Felt – Flexible Refractory Insulating Material

  • High purity, high thermal stability.
  • Low thermal conductivity coefficient, no static electricity.
  • Easy cutting and machining.
Orderly placed soft graphite felt samples
Description

Soft graphite felt is a flexible insulating material for high temperature applications in inert or vacuum environments and is entirely made of carbon fibers. When used as an insulation material for high-temperature industrial furnaces, it can be bound and stitched with carbon ropes woven through special process. Due to its controlled internal structure and electrical conductivity, soft felts can also be used for energy storage like redox flow cells. Soft graphite felts are divided into PAN-based soft graphite felts, rayon based soft graphite felts, and soft felts for battery.

Features
  • Low thermal conductivity and static-free
  • Low specific heat
    Allow for rapid heating and cooling of furnaces.
  • High temperature stability
    In oxidizing environments up to 350 °C, in protective or vacuum environments up to about 3000 °C for graphite and 1000 °C for carbon.
  • Easy machining
    Can be cut with scissors or blades and suitable for small bending radius.
  • Good surface properties
    Not subject to all molten metals.
  • High purity
    Low sulfur and ash contents.
  • High resistivity
    Coupling in an inductive field only occurs above 12 kHz.
Category
  • PAN-Based Soft Graphite Felt
  • Rayon-Based Soft Graphite Felt
  • Soft Felt for Battery
PAN-Based Soft Graphite Felt

It is a refractory insulating material specially used in high temperature vacuum furnaces and inert gas furnaces with a working temperature of 3992 °F (2200 °C). It features high carbon content, good thermal resistance, low ash content, low sulfur content, good oxidization resistance, easy cutting and installation. If required, it can be purified to less than 10 ppm.

Table 1: Specification of PAN-Based Soft Graphite Felt
Model Heat Treatment Temperature Carbon Content Density (g/cc) Ash (ppm) Available Thickness (mm)
CSF-1 Carbonized Soft Felts 1200 °C ≥ 97.5% 0.14–0.16 ≤ 800 3/5/6/8/10/12.7
GSF-1 Graphite Soft Felts 2200 °C ≥ 99.5% 0.12–0.14 ≤ 300
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.
Application
  • Redox flow cell
  • Microbial fuel cells or biofuel cells
  • Furnace body insulation and parts
  • Heat shields and heat sinks
  • Backing strips for welding
  • Cathodes for flow cell applications
  • Used on the reaction surface in the electrochemical process
  • Work as catalyst substrates in the electrochemical process
  • Glass blowing pads and plumber pads.
  • Ultralight furnace lamp wick
  • Automotive exhaust lining
  • Thermal insulation materials
Rayon-Based Soft Graphite Felt

Also known as viscose graphite felt, it is made of viscose based fibers (rayon) that are cured, shaped, and purified through secondary high-temperature processing, and pre-calcined at 4532 °F (2500 °C) to complete the graphitization of the material, making it suitable for working in environments above 2200 °C. It is a soft felt material with good flexibility and compressibility, and can be easily cut into different sizes.

Table 2: Specifications of Rayon-Based Soft Graphite Felt
Model Heat Treatment Temperature Carbon Content Density (g/cc) Ash (ppm) Available Thickness (mm)
CSF-2 Carbonized Soft Felts 1200 °C ≥ 98.5% 0.10–0.14 ≤ 500 3/5/6/8/10/12.7
GSF-2 Graphite Soft Felts 2200 °C ≥ 99.9% 0.08–0.14 ≤ 300
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.
Application
  • Redox flow cell
  • Microbial fuel cells
  • Furnace body insulation and parts
  • Heat shields and heat sinks
  • Backing strips for welding
  • Cathodes for flow cell applications
  • Used on the reaction surface in the electrochemical process
  • Glass blowing pads and plumber pads.
  • Ultralight furnace lamp wick
  • Automotive exhaust lining
  • Thermal insulation materials
Soft Felt for Battery

It is specially used as quality electrode material for most energy storage systems like vanadium redox flow battery. It adopts special fibers and weave design, aiming to achieve high liquid absorption and electrical efficiency applications. As continuous production equipment is adopted, it has many unique properties including flat, smooth surface, uniform thickness and overall electrochemical uniformity. Therefore , as electrode, it has excellent performance in Vanadium Redox Flow Battery (VRFB) battery packs with low internal resistance, uelectrochemical quality with uniform activity, good corrosion resistance, slow decay after multiple cycles and high energy efficiency.

Table 3: Technical Data of Soft Felt for Battery
Model Carbon Content Ash Content Bulk Density (g/cm3) Specific Surface Area (m2/g) Fiber Peeling Rate (μg/g) Oxidation Rate (600 °C) Porosity Surface Resistivity (mΩ/cm3) Internal Resistivity (mΩ) Energy Efficiency
GBF-1 > 99% < 0.2% 0.08–0.11 2.3–4.0 2.0–3.0 < 2.6% 85%–95% 0.165–0.193 15.3–26.7 Current Density 80 mA/cm2 Current Density 100 mA/cm2 Current Density 110 mA/cm2
85.33% 84.22% 82.68%
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.
Table 4: Specifications of Soft Felt for Battery
Length (m) 10, 20, 50, 100
Width (m) 1.22, 1.35, 1.42, 1.45
Thickness (m) 2.2, 3.0, 3.6, 4.2, 4.8, 5.0, 5.6, 6.0, 7.0
Application
  • Electrode material for most energy storage systems like vanadium redox flow battery.