Effects of heat treatment and coatings on the infrared emissivity properties of carbon fibers

The infrared emissivity properties of carbon fibers with different treatments were investigated in the wave length range 6–15 μm from 1273 to 1873 K. The heat treatment affected the infrared emissivity of carbon fibers through the microstructure evolution. The Raman investigation about the microstructure indicated that the increase of the graphitization degree in carbon fibers degenerated the infrared emissivity of carbon fibers, especially under high temperatures. For the coated carbon fibers, the infrared emissivity properties were decreased for carbon fibers coated pyrolytic carbon (PyC) due to the lamellar structure of PyC and increased for carbon fibers deposited carbon nanotubes (CNTs) owing to the skeleton-like structure of CNTs. The study also illustrated that the PyC coating thickness from 0.5 to 1.0 μm had few effects on the infrared emissivity properties of carbon fibers.