Patent ID: 9546438
Date: 2017-01-17
CPC Classifications: C04B,D01F,D04H,D06C,F16D

Claim:
1. A method for forming a fibrous preform comprising: superposing a first fibrous layer aligned in a machine direction with an additional fibrous layer aligned in an acute angle to the machine direction; needling the first fibrous layer and the additional fibrous layer together at a needle density of between approximately 60 and 65 needle punches per square centimeter to form a first combined fibrous mat; superposing an additional combined fibrous mat with the first combined fibrous mat; needling the first combined fibrous mat and the additional combined fibrous mat at a needle density of between approximately 45 and 55 needle punches per square centimeter to form the fibrous preform comprising oxidized polyacrylonitrile (OPF) fibers extending in multiple directions and having pores extending therethrough, wherein a fiber volume ratio of the fibrous preform is between about 30% fiber volume and about 35% fiber volume; compressing the fibrous preform; and carbonizing the fibrous preform by heating the fibrous preform to convert fibers of the fibrous preform into carbon fibers, wherein the fiber volume ratio of the fibrous preform after the carbonizing is between about 20% to 24% fiber volume.