Amorphous graphite—also known as earthy graphite, microcrystalline graphite, or black lead powder—does not actually lack graphite crystals as its name might suggest; rather, its crystals are extremely small, forming a microcrystalline structure. X-ray analysis reveals that amorphous earthy graphite
Crystalline graphite (or flake graphite) is essentially natural graphite, referring to graphite minerals found in nature that possess a well-developed crystal structure and visible crystal forms; man-made materials are typically referred to as "artificial graphite" or "synthetic graphite" and are ge
Impregnated graphite refers to placing graphite products in an autoclave and allowing the impregnated material in a liquid state to penetrate into the pores of the graphite products under a certain temperature and pressure, thereby improving or changing specific aspects of the physical and chemical properties of the graphite products. Currently, common impregnating materials include: resins (phenolic, furan, polytetrafluoroethylene), metals (antimony, babbitt, copper).
Impregnated resin makes graphite materials more wear-resistant and is often used in sealing rings, bearings, and pistons; impregnated metals further optimize the conductive properties of graphite on the basis of improved wear resistance. For example, impregnated copper is used to make pantograph carbon slides. It is an important power transmission equipment for urban rail transit.