Many of CD Graphite Company’s products require graphitization, such as all graphite block raw materials, graphite machining parts, various soft felts (battery felts, graphite felts), hard felts, and carbon-carbon composite materials. Today, we will mainly discuss the graphitization process of graphite raw materials.
The Purpose and Function of Graphitization
The production process of carbon graphite materials and products is characterized by multiple stages, with graphitization being the most complex and critical stage. Graphitization refers to the high-temperature heat treatment process of placing calcined products in a high-temperature furnace and heating them to temperatures above 2300-2500°C in a protective medium, thereby transforming the two-dimensional disordered arrangement of hexagonal carbon atom planar grids (amorphous carbon structure) into a three-dimensional ordered graphite structure.
The purpose and functions of graphitization are:
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To enhance the material’s thermal conductivity and electrical conductivity
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To improve the material’s thermal stability, resistance to thermal shock, and chemical stability
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To enhance the material’s lubricity and wear resistance
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To reduce the material’s hardness, facilitating mechanical processing.
Graphitization Methods
Since E.G. Acheson (A Cheson) invented the graphitization furnace (known as the Acheson furnace) in 1895, the production of artificial graphite has had a history of over a century. During this period, although artificial graphite production has always been based on the principle of the Acheson furnace, with the development of industry, graphitization equipment and structures have undergone numerous improvements and developments. For example, the Acheson furnace includes both alternating current (AC) furnaces and direct current (DC) furnaces. In addition to the Acheson furnace, there are also internal heat series furnaces, Type II furnaces, PC furnaces, and continuous graphitization furnaces.
Graphitization Methods:
- By heating method, they can be divided into direct and indirect methods. The direct method typically refers to the power source directly contacting the product, where the product itself serves as a conductor, and resistance heating is used to raise the product to the graphitization temperature. The indirect method involves the power source not directly contacting the product, with heat energy transferred through induction or radiation. Generally, the product moves within the furnace. For example, continuous graphitization furnaces.
- Based on operating methods, they can be divided into intermittent and continuous types. Acheson furnaces and series furnaces are both intermittent graphitization processes.
- Based on whether the current is rectified, they can be divided into AC graphitization and DC graphitization.