Graphite paper is a high-performance material made from specially processed natural or synthetic graphite. It boasts excellent thermal and electrical conductivity, is lightweight, and is flexible. It is widely used in electronic device cooling, new energy batteries, aerospace, and other fields. The production process involves multiple precision steps, including raw material pretreatment, graphitization, calendering, and post-processing.
Raw Material Pretreatment
Graphite paper is typically produced from natural flake graphite or synthetic graphite. First, the raw material undergoes pulverization and classification, grinding bulk graphite into a micron-sized fine powder to improve uniformity in subsequent processing steps. Subsequently, impurities such as silicates and iron oxides are removed through flotation or chemical purification to ensure a graphite purity exceeding 99%. For graphite paper requiring high purity, further purification is performed using high-temperature acid washing or alkali fusion.
Graphitization
The pretreated graphite powder undergoes graphitization at high temperatures to enhance its layered structure. This process typically takes place in a graphitization furnace (such as an Acheson or induction furnace) at temperatures exceeding 2800°C, converting amorphous carbon into a highly crystalline graphite structure. Graphitization not only improves the material's thermal and electrical conductivity but also enhances its mechanical strength. In some processes, a binder (such as phenolic resin or pitch) is added to improve subsequent rolling performance, but complete carbonization at high temperatures is required to prevent residual impurities.
Calendaring
The graphitized material is crushed and screened, then mixed with a small amount of lubricant (such as molybdenum disulfide) and continuously rolled through a multi-stage calender. Initially, roughing rolls are used to reduce the thickness, followed by gradual refinement to the target thickness (typically 0.05-2mm). During the calendering process, temperature (approximately 100-300°C) and pressure must be strictly controlled to ensure tight bonding between the graphite layers and a smooth surface. Some high-end graphite papers also undergo cold rolling to further improve density and dimensional stability.
Post-Processing and Quality Inspection
After forming, the graphite paper undergoes cutting, trimming, and surface treatment (such as anti-oxidation coating) as required. Finally, it undergoes rigorous quality testing, including thickness tolerance, thermal conductivity (reaching 1500-2000 W/m·K), tensile strength, and purity analysis, to ensure that the product meets industry standards.
The production process for graphite paper integrates materials science and precision manufacturing technology. Optimizing the process directly impacts final performance, making it a key foundational material for modern high-end manufacturing.
