|
|
Journal of the Korean Ceramic Society 1987;24(5): 453. |
이연에 의한 $beta$$-사이알론의 열분해 |
최상흘, 이희철1, 이종진, 서규식 |
인하대학교 무기재료공학과 1인하대학교 화학공학과 |
Thermal Decomposition of $beta$$-Sialon by Graphite |
|
|
|
|
|
ABSTRACT |
β'-sialon(Z=2.7) specimens with <30%wt. graphite as a reducing agent were decomposed at 1350°up to 1,450℃ under the atmosphere of 90% N2-10%H2. The decomposition of β'-sialon was calculated from the change in Z-value, and the formation of new minerals was identified from X-ray diffraction patterns. The decomposition reactions of sialon were considered to yield a stable sialon close to β-silicon nitride and some aluminum compounds according to the following equations; β'-sialon(s)+C(s)+N2(g)→β2-sialon(metastable)+β3-sialon(stalbe phase) β2-sialon(s)+C(s)+N2(g)→β3-sialon(s)+AlN(s)+α-Al2O3(s)+15R(s)+SiO(g)+Al2O(g)+CO(g) Z-value; β2( 3.5)>β'( 2.7)>β3( 0.5) The decomposition rate of sialon was controlled by two mechanisms ; One was characterized by the interface area of contact, corresponding to an apparent activation energy of 50.5Kcal/mol in the initial stage, and the other by the diffusion, corresponding to that of 104.3Kcal/mol in the final stage of the decomposition. |
|
|
|