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Graphite is a good electrical conductor, which is useful in certain molding applications, such as those involving electrodischarge machining (EDM).
Graphite's layered structure allows it to act as a solid lubricant, reducing friction and wear in sliding or rotating applications.
Graphite is generally inert to many chemicals, making it suitable for use in aggressive environments.
The starting graphite powder can be very pure, and the isostatic pressing process doesn't introduce significant contamination.
Despite its high density, isostatic graphite is readily machinable using conventional techniques, allowing for the creation of complex shapes and intricate details.
The uniform structure and high density contribute to a low coefficient of thermal expansion (CTE), making the material dimensionally stable at elevated temperatures.
Graphite inherently has good thermal conductivity, and isostatic pressing enhances it by reducing porosity and creating better particle-to-particle contact. This is vital for:
Faster Heating and Cooling: Improves the efficiency of thermal processes.
Uniform Temperature Distribution: Minimizes hot spots and ensures consistent heating.
Due to the high density and fine grain size, isostatically pressed graphite exhibits high compressive and flexural strength compared to other types of graphite.
Closely related to homogeneity, isotropy means that the material properties are the same in all directions. While perfect isotropy is difficult to achieve, isostatic pressing gets you much closer to it than other graphite manufacturing methods (like extrusion). This is important because:
Predictable Response to Stress: The material will deform or fail in a predictable manner, regardless of the direction of the applied force.
Reduced Warping or Distortion: Minimizes dimensional changes under varying temperatures or pressures.
This is a critical advantage. The consistent pressure from all directions results in a very uniform material structure throughout the entire volume. This means:
Consistent Properties: Mechanical, thermal, and electrical properties are consistent regardless of location within the graphite block.
Predictable Performance: You can rely on consistent behavior under stress or temperature variations.
Reduced Risk of Weak Points: No localized areas of weakness or defects.
The uniform compression during pressing helps to reduce grain size and produces a very fine-grained structure. Smaller grain size contributes to:
Higher Strength: Finer grain structures generally exhibit greater strength.
Better Machinability: Easier to achieve smooth surfaces and intricate details during machining.
Improved Surface Finish: A finer surface finish on molded parts.
T
his is a primary benefit of the isostatic pressing process. Uniform pressure leads to exceptional particle packing and minimal porosity. Higher density translates to:
Increased Strength: More resistance to mechanical stress.
Improved Thermal Conductivity: Heat flows more efficiently through the material.
Reduced Permeability: Less prone to gas or liquid penetration.
High strength: due to the high pressure conditions during the isostatic pressing process, the graphite material reaches an extremely high degree of compactness during the pressing process, which makes the strength of isostatically pressed graphite significantly higher, usually 2-3 times higher than that of ordinary graphite.
High density: the density of isostatically pressed graphite can reach 1.8-2.0g/cm³, this value is more than twice the density of ordinary graphite, reflecting its high density characteristics.
High thermal conductivity: The thermal conductivity of isostatic graphite is also more than twice that of ordinary graphite, and the coefficient of thermal expansion is low, which makes it perform well in application scenarios that require efficient heat conduction.
High Temperature Resistance: Isostatic graphite is capable of being used at high temperatures for extended periods of time and has excellent heat resistance. In an inert atmosphere, its mechanical strength will also increase as the temperature rises, reaching its maximum value at around 2500℃.
Uniformity of organizational structure: isostatic pressure molding process, the powder in all directions by the pressure is equal, so the resulting isostatic graphite material has a uniform organizational structure, there is no uneven distribution of density phenomenon.
Isostatically pressed graphite has a wide range of uses, mainly in the following important areas.
Isostatic graphite is a key material in the manufacture of single crystal furnace, metal continuous casting graphite crystallizer, and graphite electrodes for EDM. In non-ferrous metallurgy, isostatic graphite is widely used in large-scale copper production line, used to improve production quality, reduce costs, and reduce environmental pollution.
In the atomic energy industry, isostatic graphite also plays an irreplaceable role. It is an important material to maintain the stability of plasma in nuclear fusion reaction, and at the same time, it occupies an important position in the field of nuclear industry as a neutron moderator and excellent reflector.
In addition, isostatic graphite is widely used in machinery, chemical industry, electronics, aerospace and other high-tech fields. Its high strength, high density, good electrical and thermal conductivity, as well as self-lubrication and low coefficient of thermal expansion make it extremely valuable in these fields.
Specifically, in the direct-drawing monocrystalline silicon hot field, isostatic graphite parts include crucibles, heaters, electrodes, and many other key components, of which 80% of isostatic graphite is used to manufacture crucibles and heaters, etc. In the solar energy industry, isostatic graphite is also widely used because of its excellent performance.
Physical and chemical performance index of isostatic graphite
| Physical and Chemical Performance Indicators |
KBD-4 |
KBD-5 | KBD-6 |
KBD-7 |
KBD-8 |
| Bulk Density g/cm³ | ≥1.75 |
≥1.85 |
≥1.9 |
≥1.85 |
≥1.9 |
| Maximum Particle Size µm | ≤15 |
≤15 |
≤10 |
≤7 |
≤5 |
| Ash Content PPM |
≤500 |
≤500 |
≤500 |
≤500 |
≤500 |
| Resistivity μΩ-m | 8~11 | 8~10 | 8~9 | 11~13 |
11~13 |
| Flexural Strength Mpa |
≥38 |
≥45 |
≥55 | ≥62 |
≥72 |
| Compressive Strength Mpa |
≥65 |
≥70 |
≥95 |
≥115 |
≥135 |
|
Shore Hardness |
≥42 |
≥55 |
≤53 |
≤65 |
≤70 |
| Expansion Coefficient 10-6 |
≤5.4 |
≤4.8 |
≤5.1 |
≤5.5 |
≤5.8 |
| Elastic Strength Gpa |
≥9 |
≥10.5 |
≥12 |
≥11 |
≥12 |
The ash content of all isostatically pressed materials can be purified to 50ppm.
Special requirements for indicators can also be specially produced.
Specifications and dimensions
|
Rod |
Diameter (mm) | Length (mm) |
| Size range | 0-980 | 0-800 |
| Standard size | 400/500/600/700/760/850/920/980 | 500/700/720/740/800 |
| Block | Length |
Width |
Height |
|
Size range |
0-1800（mm） |
0-1100（mm） |
0-300(mm) |
|
Standard size |
200-1800（mm） |
125-1100（mm） |
50-300(mm) |
Attention
1. The above data is for reference, if there is any error, the actual measured data shall prevail.
2. Larger sizes can be specially pressed, smaller ones can be further processed, and processed parts can be made with anti-oxidation and anti-corrosion coatings according to the drawing requirements. (Antioxidant coating or silicon carbide coating).
Store in a dry, dust-free environment. Handle with care to avoid chipping or cracking. Use protective coatings if exposed to harsh environments.
What industries use isostatic graphite? It is widely used in industries such as: Semiconductor & Electronics: Used in wafer processing and LED manufacturing. Aerospace: Rocket nozzles, heat shields, and aircraft brake components. Metallurgy: Continuous casting molds and furnace parts. EDM (Electrical Discharge Machining): Electrodes for precision machining. Nuclear Industry: Reactor components due to high purity and heat resistance.
Isostatic molding graphite is a type of high-performance graphite manufactured using isostatic pressing. This process ensures uniform density, fine grain structure, and excellent mechanical properties, making it suitable for high-tech applications.
Compared to extruded or molded graphite, isostatic graphite has: Higher density and uniformity Finer grain structure Better mechanical strength Improved thermal and chemical resistance Lower porosity
High thermal and electrical conductivity Low thermal expansion coefficient High mechanical strength and wear resistance Excellent resistance to chemical corrosion Low porosity and high purity
Raw Material Selection: High-purity coke mixed with binders. Isostatic Pressing: A uniform hydraulic press applies pressure in all directions. Carbonization: The material is heat-treated at around 1000°C. Graphitization: The material is further heated above 2500°C to improve properties. Machining & Finishing: Cutting, shaping, and surface treatments for specific applications.
Yes, it is more costly than regular graphite due to the advanced manufacturing process and high purity. However, its superior performance justifies the investment in critical applications.
Yes, it can be machined into various shapes and sizes, depending on industrial needs. It can also undergo surface treatments for enhanced durability.
Graphite EDM electrodes are lighter, easier to machine, and have higher wear resistance. Copper electrodes offer better conductivity but wear faster. Graphite is preferred for complex and fine-detail machining.
Major global suppliers include: Toyo Tanso (Japan) SGL Carbon (Germany) Tokai Carbon (Japan) Mersen (France) Graphite India Limited (India)
Russian