The effect of carbonization temperature of PAN fiber on the properties of activated carbon fiber composites

Air oxidation of SiC fibers prepared from carbon fibers and SiO vapor

“…In Fig. 4, SiO 2 peaks were not seen because of its amorphous nature, while residual carbon was not seen probably due to the small amount, otherwise it gives a diffuse pattern at 2θ = 20~30 o [3,4]. As oxidation progressed, the SiC peaks became weaker owing to the formation of amorphous silica from the surface.…”

“…But the oxidation of carbon and the subsequent evolution of CO and CO 2 seemed to decrease the net weight gains. Numerous pores, mostly of 2~10 nm in size, were found to exist inside the sample, when pore size distribution was determined with the multi-point BJH method using a nitrogen desorption isotherm [3,4].…”

“…The porous ACFC reacted with the SiO vapor generated from a powder mixture of Si and SiO 2 at 1400 o C for 2 hr under vacuum in order to produce SiC fiber composites. The experimental procedure is described elsewhere in more detail [3,4]. The oxidation tests of the SiC samples obtained were done using a thermogravimetic analyzer (TGA) in air up to 1000 o C. The structure of the unoxidized and oxidized samples was examined with an X-ray diffractometer (XRD) with Cu-K α radiation.…”

“…Lee et al [3,4] recently extended the work of Kennedy and North to produce porous SiC-bonded SiC fiber composites by reacting activated carbon fiber composites (ACFCs) with SiO vapor at 1400 o C for various times under vacuum. Besides forming SiC, part of the SiO vapor generated condensed on the converted carbon fiber surface as amorphous silica.…”

“…It was also found that a small amount of residual carbon still existed in the converted ACFSs. Though their physical and mechanical properties have been studied in detail [3,4], the oxidation property of converted ACFSs, i.e., porous SiC fibers has not yet been studied. The oxidation of SiC, which is an important factor for actual applications, can be simply expressed by Eq.…”