| Summary: | 碩士 === 國立中正大學 === 化學工程研究所 === 84 === The thesis is to study synthesis of silicon carbide by the
method of Self-Propagating High -Temperature Synthesis(SHS).
Becaues of low heat of formationand low adiabatic combustion
temperature of Si/C reaction, it is difficult forcombustio wave
to be self-sustained. In this study, we adopt two approachs
tosynthesize SiC by direct synthesis and using ignitors.
Experimental results of direct synthesis : SiC was
successfully obta but the reactant pellet was broken and
thecombustion wave can not be self-sustained. Thus the
reactivity in this situation was lower than that of using oxy-
acetylene torch. Because the small particle size of carbon
black, the crystallization of SiCwas small and the size was near
10 um with a spherical shape. Results of using ignitors are as
follows : For different ignitors, 1. Fe2O3+2Al 2. Cr2O3+2Al 3.
TiO2+4/3Al+C 4. Ti+Cwere studied. The reactivity and
separability of ignitors 1 and 2 were foundto be good, as
compared to ignitors 3 and 4. Among these two ignitors,
reactivity of Ti+C ignitor os better than TiO2 thermite ignitor.
For the Ti+C ignitor, we find the minimum molar ratio Ti+C/Si+C
was 1.75 suchthat the conversion of SiC was higher than 95% .
Because larger particle size of graphite was used, the
crystallization of SiC surface was also large and size was near
40~50 um with an irrgular shape.
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