Continuous mfr. of profiles of fibre reinforced carbon - for structural or surgical applications, by co-extrusion of organic fibres and tar followed by heat treatment

摘要

Profiles of carbon incorporating longitudinally aligned carbon fibres are made by feeding a vertical extrusion die simultaneously with an annular array of carbon-based filaments (polyacrylonitrile) and molten tar and then heat-treating the extrudate to cause carbonisation. The tar may be premixed with a densification agent, such as powdered graphite, a plasticiser, such as wax and/or a blowing agent. Pref. the blowing agent has a decomposition temp. between 700 degrees C and 3000 degrees C, e.g. comprises crystals of salt (NaCl) or copper threads (opt. interlaced with the organic filaments). Used for mfr. of profiles having high specific strength (strength/wt. ratio) and/or high temperature resistance, e.g. for spacers for insulation jackets for atomic reactor cores or for bone prostheses. The profiles are light, strong, pure, sterile and biologically stable.