PRODUCTION OF CARBON FIBER

PURPOSE:To obtain carbon fiber having a fine diameter and excellent strength characteristics by melt spinning a polyacrylonitrile-based or pitch-based substance, subjecting the resultant fiber to infusibilizing or stabilizing treatment, carbonizing the resultant carbon fiber raw yarn, then carrying out anodization in an aqueous solution of an electrolyte using the carbonized fiber as an anode and etching the surface thereof. CONSTITUTION:For example, a polyacrylonitrile-, pitch-based substance, etc., is melt spun to provide fiber, which is then subjected to infusibilizing or stabilizing treatment in air to afford carbon fiber raw yarn. The resultant yarn is subsequently carbonized or graphitized in an air stream and the resultant carbonized or graphitized yarn is used as an anode and anodized in an aqueous solution of an electrolyte (e.g. a solution of LiOH or NaOH) to etch the surface thereof. The obtained fiber is then calcined in an inert atmosphere to remove low oriented parts and afford carbon fiber having high orientation properties and excellent tensile strength.