Carbon fibers three-step process

Pyrolysis can be considered as a three-step process. The first step (stabilization) takes place when poly(acrylonitrile) fibers are heated at 200-300 °C in air. This initiates oxidation and the formation of cross-finks. The second phase (known as carbonization)... 

Fabrication by LPI A carbon-fiber preform infiltrated with resin (e.g., PCS) is pyrolyzed to form SiC. Infiltration and pyrolyzation are repeated a number of times until the pores are narrow enough so that further infiltration ceases. Finally, the body is heated to temperatures between 1000 and 1500 °C for crystallization of the SiC matrix. Densification takes less time and costs less than densification by CVI. Fabrication by LSI The LSI/MI processes can generally be subdivided in three main steps ... 

The strength and tensile behavior, at room and high temperatures, as well as the structure of three dimensional earbon fiber/SiC composites, fabricated by the slurry pulse/CVI combined process, were eharacterized by Suzuki et al [207-209]. Carbon fiber preforms, constructed with 4-step braid, 4-step/axial braid, 2-step braid and orthogonal weave, were used as reinforcements of the composites. The composites were fabrieated by a process consisting of slurry and dissolved organosilicon polymer infiltrations, followed by the application of pulse CVI. 

Copper can be coated on carbon fibers [47] and Zhu and workers have used a three-step electrodeposition process for the fabrication of Cu composites [48]. 

The synthesizing of this catalyst consists of three process steps which are construction of carbon nanotubes (CNTs) on carbon fibers support, coating of polymer-derived silicon carbonitride (SiCN) on CNTs and finally decoration of transition metal on surface. The rate of hydrogen generation has been reported as 75 L mim g" [100]. 

Japan. Shindo recognized the importance of an oxidative heat treatment step prior to carbonization in reducing the processing time and improving the carbon yield from PAN. He demonstrated good tensile strengths and moduli over 20 million psl, about three times those available from rayon precursor carbon fibers of that time. Shlndo s work was quickly taken up... 

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