碳纤维是含碳量高于90％的无机高分子纤维 。其中含碳量高于99％的称石墨纤维。碳纤维的轴向强度和模量高，无蠕变，耐疲劳性好，比热及导电性介于非金属和金属之间，热膨胀系数小，耐腐蚀性好，纤维的密度低，X射线透过性好。但其耐冲击性较差，容易损伤，在强酸作用下发生氧化，与金属复合时会发生金属碳化、渗碳及电化学腐蚀现象。因此，碳纤维在使用前须进行表面处理。
制备 碳(tan)(tan)(tan)(tan)(tan)纤(xian)(xian)(xian)(xian)维(wei)可分别用(yong)聚丙(bing)烯(xi)(xi)腈纤(xian)(xian)(xian)(xian)维(wei)、沥青(qing)纤(xian)(xian)(xian)(xian)维(wei)、粘(zhan)胶丝(si)(si)或酚醛纤(xian)(xian)(xian)(xian)维(wei)经(jing)碳(tan)(tan)(tan)(tan)(tan)化(hua)制得；按(an)状态(tai)分为(wei)(wei)(wei)(wei)长丝(si)(si)、短纤(xian)(xian)(xian)(xian)维(wei)和短切纤(xian)(xian)(xian)(xian)维(wei)；按(an)力学性(xing)能(neng)分为(wei)(wei)(wei)(wei)通(tong)用(yong)型(xing)和高(gao)性(xing)能(neng)型(xing) 。通(tong)用(yong)型(xing)碳(tan)(tan)(tan)(tan)(tan)纤(xian)(xian)(xian)(xian)维(wei)强度为(wei)(wei)(wei)(wei)1000兆(zhao)帕（MPa）、模(mo)(mo)(mo)量(liang)为(wei)(wei)(wei)(wei)100GPa左右。高(gao)性(xing)能(neng)型(xing)碳(tan)(tan)(tan)(tan)(tan)纤(xian)(xian)(xian)(xian)维(wei)又(you)分为(wei)(wei)(wei)(wei)高(gao)强型(xing)（强度2000MPa、模(mo)(mo)(mo)量(liang)250GPa）和高(gao)模(mo)(mo)(mo)型(xing)（模(mo)(mo)(mo)量(liang)300GPa以(yi)上(shang)）。强度大(da)于4000MPa的(de)又(you)称为(wei)(wei)(wei)(wei)超高(gao)强型(xing)；模(mo)(mo)(mo)量(liang)大(da)于450GPa的(de)称为(wei)(wei)(wei)(wei)超高(gao)模(mo)(mo)(mo)型(xing)。随(sui)着航(hang)天和航(hang)空工业的(de)发(fa)展，还出现了高(gao)强高(gao)伸(shen)型(xing)碳(tan)(tan)(tan)(tan)(tan)纤(xian)(xian)(xian)(xian)维(wei)，其延伸(shen)率(lv)大(da)于2％。用(yong)量(liang)最大(da)的(de)是聚丙(bing)烯(xi)(xi)腈PAN基碳(tan)(tan)(tan)(tan)(tan)纤(xian)(xian)(xian)(xian)维(wei)。 目前(qian)应用(yong)较普遍的(de)碳(tan)(tan)(tan)(tan)(tan)纤(xian)(xian)(xian)(xian)维(wei)主(zhu)要(yao)是聚丙(bing)烯(xi)(xi)腈碳(tan)(tan)(tan)(tan)(tan)纤(xian)(xian)(xian)(xian)维(wei)和沥青(qing)碳(tan)(tan)(tan)(tan)(tan)纤(xian)(xian)(xian)(xian)维(wei)。碳(tan)(tan)(tan)(tan)(tan)纤(xian)(xian)(xian)(xian)维(wei)的(de)制造包括纤(xian)(xian)(xian)(xian)维(wei)纺丝(si)(si)、热稳(wen)定化(hua)（预氧化(hua)）、碳(tan)(tan)(tan)(tan)(tan)化(hua)、石墨(mo)化(hua)等4个过程(cheng)。其间(jian)伴(ban)随(sui)的(de)化(hua)学变化(hua)包括，脱氢、环化(hua)、氧化(hua)及脱氧等。
