Carbon fiber is generally considered non-magnetic, exhibiting a weak diamagnetic response.
Here's a more detailed explanation:
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Diamagnetism: Carbon fiber possesses diamagnetic properties. Diamagnetic materials create an induced magnetic field in opposition to an externally applied magnetic field, causing a repulsive force. This effect is very weak in carbon fiber.
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Electrical Conductivity: Carbon fiber is electrically conductive. This conductivity is key to understanding its interaction with magnetic fields.
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Static Magnetic Fields: In a static (unchanging) magnetic field, carbon fiber's diamagnetic response is minimal and typically undetectable with common magnets. This is why it's considered effectively non-magnetic in most practical applications.
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Dynamic Magnetic Fields: When exposed to high-frequency alternating electromagnetic waves, carbon fiber composites can exhibit a stronger dynamic diamagnetic response, especially if the skin depth (the depth to which the electromagnetic wave penetrates) is greater than the fiber diameter.
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Carbon Fiber Composites: It's important to note that carbon fiber is often used in composites with other materials. The magnetic properties of the composite will depend on the properties of all the constituent materials. If the matrix material (the material holding the carbon fibers together) is magnetic, then the composite may exhibit some magnetic properties.
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Fiber Orientation: The orientation of the carbon fibers within a composite material can also affect the overall magnetic response.
In summary, while carbon fiber is technically diamagnetic, its response is so weak that it's practically considered non-magnetic for most applications involving static magnetic fields. Its behavior can change under exposure to dynamic electromagnetic fields.