由于碳纤维复合材料在结构和功能方面的重要性，碳纤维的结构重要性源于其高

Due to the importance of carbon fiber composites in structure and function, the structural importance of carbon fiber stems from its high strength, high modulus and low density. The functional importance of carbon fibers stems from their high electrical conductivity. There are three forms of carbon fiber, namely graphite, diamond and fullerene. Carbon fibers belong to the graphite family, although they may not be crystalline. Graphite has a layered crystal structure, and carbon layers are stacked in the graphite sequence (Figure 2.1). In one layer, chemical bonding is a mixture of co-bonding and metal bonding. The covalent bond generated by the p2 hybridization of each carbon atom is responsible for the high modulus and strength of the carbon layer plane. The metal bond formed due to the delocalization of pz electrons is responsible for the high electrical conductivity and high thermal conductivity in the plane of the carbon layer. Perpendicular to the carbon layer, the bonding involves van der Waals forces (secondary bonding). Due to the weak interlayer bonding, the carbon layers easily slide on each other, making graphite a good solid lubricant. Due to the difference in in-plane and out-of-plane bonding, graphite is mechanically harder and conducts more electricity and heat in the plane of the carbon layer than in the direction perpendicular to the carbon layer.

Due to the structural and functional importance of carbon fiber composites, the structural importance of carbon fiber is due to its high strength, high modulus and low density. The functional importance of carbon fiber sits due to their high conductivity. Carbon fiber is available in three forms: graphite, diamond and Fullerene. Carbon fiber belongs to the graphite family, although they may not be crystals. Graphite has a layered crystal structure, with carbon layers piled up in the graphite sequence (Figure 2.1). In a layer, a chemical bond is a mixture of co-bonding and metal bonding. The covalent bonds produced by p2 hybridization of each carbon atom are the reasonfor for the high modulus and high intensity of the carbon layer plane. The metal bonds formed by the off-domainization of the pz electrons are the reasons for the high conductivity and high thermal conductivity on the carbon layer plane. Perpendicular to the carbon layer, the bonding involves Van der Waal (secondary bonding). Due to the combination of weak middle layers, carbon layers easily slide each other, making graphite a good solid lubricant. Due to the difference between the in-face and extra-face binding, graphite is mechanically harder, conducting more electricity on the plane of the carbon layer than in the direction perpendicular to the carbon layer.

Due to the importance of carbon fiber composite in structure and function, the structural importance of carbon fiber comes from its high strength, high modulus and low density. The functional importance of carbon fibers stems from their high conductivity. There are three forms of carbon fiber: graphite, diamond and fullerene. Carbon fibers belong to the graphite family, although they may not be crystals. Graphite has a layered crystal structure, and the carbon layer is accumulated in the graphite sequence (Fig. 2.1). In one layer, chemical bonding is a mixture of CO bonding and metal bonding. The covalent bond produced by p 2 hybridization of each carbon atom is the reason for the high modulus and strength of the carbon layer. The metal bond formed by the delocalization of PZ electrons is the reason of high conductivity and thermal conductivity in the carbon layer plane. Perpendicular to the carbon layer, bonding involves van der Waals force (secondary bonding). Due to the weak interlayer bonding, the carbon layers are easy to slide each other, making graphite a good solid lubricant. Due to the difference between in-plane and out of plane bonding, graphite is mechanically harder, conducting and conducting more heat in the plane of the carbon layer than in the direction perpendicular to the carbon layer.