Graphitization, through high-temperature treatment at 3000℃, transforms the carbon atoms in petroleum coke from a disordered structure into a highly ordered layered graphite structure, significantly enhancing its electrical conductivity, thermal conductivity, reducing electrical resistance and ash content, while also improving mechanical properties and chemical stability. This results in a substantial performance difference between graphitized petroleum coke and ordinary petroleum coke. A detailed analysis is as follows:
1. Microstructural Reorganization: From Disorder to Order
Ordinary Petroleum Coke: Produced through delayed coking of petroleum residue, its carbon atoms are arranged in a disordered manner, with numerous defects and impurities, forming a structure akin to “disordered layer stacking.” This structure impedes electron migration and reduces heat transfer efficiency, while impurities (such as sulfur and ash) further interfere with performance.
Graphitized Petroleum Coke: After high-temperature treatment at 3000℃, carbon atoms undergo diffusion and reorganization through thermal activation, forming a layered structure similar to graphite. In this structure, carbon atoms are arranged in a hexagonal grid, with layers bound together by van der Waals forces, creating a highly ordered crystal. This transformation is analogous to “organizing scattered sheets of paper into neat books,” enabling more efficient electron and heat transfer.
2. Core Mechanisms of Performance Enhancement
Electrical Conductivity: The electrical resistance of graphitized petroleum coke significantly decreases, and its conductivity surpasses that of ordinary petroleum coke. This is because the ordered layered structure reduces electron scattering, allowing electrons to move more freely. For instance, in battery electrode materials, graphitized petroleum coke can provide a more stable current output.
Thermal Conductivity: The closely arranged carbon atoms in the layered structure facilitate rapid heat transfer through lattice vibrations. This property makes graphitized petroleum coke excellent for use in heat dissipation materials, such as heat sinks for electronic components.
Mechanical Properties: The crystalline structure of graphitized petroleum coke endows it with higher hardness and wear resistance, while maintaining a certain degree of flexibility, making it less prone to brittle fracture.
Chemical Stability: High-temperature treatment removes most impurities (such as sulfur and ash), reducing the number of active sites for chemical reactions and rendering graphitized petroleum coke more stable in corrosive environments.
3. Differentiated Selection of Application Scenarios
Ordinary Petroleum Coke: Due to its lower cost, it is commonly used in fields with less stringent performance requirements, such as fuel, road construction materials, or as a raw material for graphitization treatment.
Graphitized Petroleum Coke: Owing to its superior electrical conductivity, thermal conductivity, and chemical stability, it is widely applied in high-end fields:
- Battery Electrodes: As a negative electrode material, it enhances the charging and discharging efficiency and cycle life of batteries.
- Metallurgical Industry: As a carburizer, it adjusts the carbon content of molten steel and improves steel properties.
- Semiconductor Manufacturing: It is used to produce high-purity graphite products, meeting the demands of precision machining.
- Aerospace: It serves as a thermal protection material, withstanding extreme high-temperature environments.
4. Key Roles of Graphitization Process
Temperature Control: 3000℃ is the critical temperature threshold for graphitization. Below this temperature, carbon atoms cannot fully rearrange, resulting in insufficient graphitization degree; above this temperature, excessive sintering of the material may occur, affecting performance.
Atmosphere Protection: The process is typically carried out in an inert atmosphere, such as argon or nitrogen, to prevent carbon atoms from reacting with oxygen to form carbon dioxide, which would lead to material loss.
Time and Catalysts: Prolonging the holding time or adding catalysts (such as boron or titanium) can accelerate the graphitization process, but it increases costs.
Post time: Dec-25-2025