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AssigneeHexcel Corporation
InventorCarlos A. Léon y Léon
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The invention is directed to carbon fibers having high tensile strength and modulus of elasticity. The invention also provides a method and apparatus for making the carbon fibers. The method comprises advancing a precursor fiber through an oxidation oven wherein the fiber is subjected to controlled stretching in an oxidizing atmosphere in which tension loads are distributed amongst a plurality of passes through the oxidation oven, which permits higher cumulative stretches to be achieved. The method also includes subjecting the fiber to controlled stretching in two or more of the passes that is sufficient to cause the fiber to undergo one or more transitions in each of the two or more passes. The invention is also directed to an oxidation oven having a plurality of cooperating drive rolls in series that can be driven independently of each other so that the amount of stretch applied to the oven in each of the plurality of passes can be independently controlled.
A carbon fiber having a tensile strength of at least 950 ksi and modulus of elasticity of at least 45 Msi, the carbon fiber having an atomic force microscopy surface image that is characterized by the presence of a plurality of striations of low phase angle domains and a plurality of striations of high phase angle domains that extend across the surface of the carbon fiber, wherein the carbon fiber has an average phase angle depth of 5 nanometers or greater.
A carbon fiber having a tensile strength of at least 1000 ksi and modulus of elasticity of at least 50 Msi, and wherein the carbon fiber has a crystallite width value La of about 4 nm or greater and a resistivity value of about 14 μΩm or greater.
A carbon fiber having an atomic force microscopy surface image that is characterized by the presence of a plurality of striations of low phase angle domains and a plurality of striations of high phase angle domains that extend across the surface of the carbon fiber, and wherein the carbon fiber has a crystallite width value La of about 4 nm or greater.
A carbon fiber that is prepared by:
Dependencies are inferred from the claim text.