MaxGraphite Isostatic Graphite
Uniform, high-purity graphite engineered for superior strength, thermal stability, and isotropic properties.
Specification of
Isostatic Graphite
We provide isostatic graphite in a wide variety of standard sizes and can supply custom-machined dimensions to fit your application requirements.
Typical Grade Specifications: All values are typical; custom grades available on request.
Certifications:
Size of
Isostatic Graphite
Max Graphite offers a wide range of isostatic graphite blocks, cylinders, and pre-machined blanks to suit various industrial applications. Below are the typical dimension ranges available. Custom sizes and machining services are also offered upon request.
Contact us for a detailed stock list or to discuss your custom size requirements.
What is Isostatic Graphite?
Isostatic graphite, also known as isostatically pressed graphite or isotropic graphite, is a synthetic graphite material known for its uniform microstructure and consistent mechanical and thermal properties in all directions. It is manufactured using Cold Isostatic Pressing (CIP), where fine graphite powder is compacted in a flexible mold under equal fluid pressure from all sides, producing a high-density graphite block with a fine, homogeneous grain structure. Unlike extruded or molded graphite, isostatic graphite has no directional weaknesses, offering high strength, excellent thermal shock resistance, and reliable performance regardless of orientation. When purified, high-purity isostatic graphite can achieve ash content below 5 ppm, making it ideal for semiconductor manufacturing, high-vacuum applications, and other precision industries operating under extreme conditions.
Properties of Isostatic Graphite
- Isotropic Structure: Uniform physical and mechanical properties in all directions.
- High Strength & Density: Superior compressive and flexural strength.
- Exceptional Thermal Conductivity: Efficient heat dissipation for uniform temperature profiles.
- Outstanding Thermal Shock Resistance: Withstands rapid heating/cooling cycles without cracking.
- High-Temperature Stability: Performs in inert or vacuum environments at temperatures >3000 °C.
- Excellent Machinability: Can be precision-machined into complex shapes with tight tolerances and smooth finishes.
- High Purity & Chemical Inertness: Very low ash (impurity) content and resistant to most acids and corrosive media.
- Good Electrical Conductivity: Suitable for electrical and electrochemical applications (e.g. electrodes).
- Self-Lubricating: Graphite’s low friction reduces wear in mechanical applications like seals and bearings.
- Optional SiC/PyC Coatings: SiliconCarbide, pyrolytic carbon, or pyrolytic graphite coatings can be applied tofurther improve oxidation resistance of graphite parts.
Production Process of Isostatic Graphite
The superior quality of isostatic graphite is achieved through a controlled, multi-step manufacturing process:
- Raw Material Preparation: High-puritypetroleum coke and coal tar pitch binders are pulverized and homogeneouslymixed.
- Kneading & Granulation: Themixture is kneaded, then granulated into a free-flowing powder.
- ColdIsostatic Pressing (CIP): The powder is packed into a flexible mold andsubjected to ultra-high liquid pressure from all directions simultaneously.This creates a “green” block with uniform density and eliminates directionalgrain.
- Carbonization: The pressed block is slowly baked at ~900 °C in an inert atmosphere tocarbonize the binder, forming a solid carbon matrix.
- PitchImpregnation (optional): For higher density grades, the carbonized blockis impregnated with pitch under vacuum and re-baked (this cycle may repeat toreduce porosity).
- Graphitization: The block is heat-treated to ~2800 °C in an Acheson furnace, transforming theamorphous carbon into crystalline graphite.
- Purification& Coating: For ultra-high purity, graphite blocks are further purified in halogen gas athigh temperature to reduce ash content to <5 ppm. Optionally, a protectiveSilicon Carbide (SiC), pyrolytic carbon (PyC), or pyrolytic graphite (PyG)coating can be applied to finished parts for enhanced oxidation resistance.
- QualityControl & Machining: Each graphite block undergoes rigorous testingfor consistency and properties. Finally, it is precision-machined into therequired shape per customer specifications.
Application of
Isostatic Graphite
Semiconductor Manufacturing
Susceptors, heaters, and wafer boats requiring high purity, thermal stability, and excellent cleanability.
Electrical Discharge Machining (EDM)
Electrodes with fine grain structure, uniform wear characteristics, and excellent machinability for intricate details.
Heat Treatment & Vacuum Furnaces
Fixtures, heating elements, and insulation components offering high-temperature resistance and low outgassing.
Solar & PV Industry
Crucibles, heaters, and support structures in crystal growth processes for silicon and other semiconductors.
Continuous Casting
Dies and nozzles for metal casting, offering superior thermal shock resistance and non-wetting properties.
Aerospace, Automotive & Nuclear
Applications requiring high strength, thermal conductivity, and chemical inertness at elevated temperatures.
Mechanical Sealing
Pump seals utilizing self-lubricating properties and corrosion resistance.