HWAHAK KONGHAK, Vol.13, No.2, 73-78, April, 1975
TGA에 의한 BaCO3-TiO2계 고상반응의 속도론적 해석
Kinetics of Solid Phase Reaction of BaCO3-TiO2 System by a Thermogravimetric Method
초록
일정승온율로 승온시킬 수 있는 TGA를 이용하여 고상반응의 속도론적 해석을 보다 간편하게 할 수 있는 이론적 방법을 제시하였다. 여러 가지 승온율（β）에 대하여 실험적으로 T. C. D. 곡선을 얻어 이 곡선이 극대가 되는 점에 상당하는 온도(Tm)를 구하고 ln(Tm2/β)+ln(41Rk0)/E=(E/RTm)의 관계식으로부터 ln(Tm2/β) 대 Tm-1를 도시하여 얻은 직선의 기울기와 절편으로부터 활성화에너지 및 frequency factor를 계산하였다. BaTiO3의 합성반응에 대하여 활성화에너지를 구하였고 그 값이 이미 발표된 문헌상의 값과 잘 일치하는 것으로 보아 본 연구에서 제시한 방법이 유효함을 알았다. 일반적으로 이 방법은 반응 중 생성가스가 생성 즉시 방출되어 없어지는 경우와 특히 다단계반응, 예로서 촉매에 흡착된 흡착질의 열탈착 연구 등에 잘 적용될 것으로 생각된다.
A more convenient theoretical approach is developed, which can be applied to the study of solid-phase reaction by using a thermogravimetric apparatus with temperature programmer. The method proposed by the present authors to estimate the kinetic data and probable mechanism of the reaction is as follows. The temperature （Tm） corresponding to the peak of T. C. D. curve is determined experimentally for various linear heating rate (β), and then a graph of ln(Tm2/β) vs. Tm-1 is plotted following the relation, ln(Tm2/β)+ln(41Rk0)/E=(E/RTm).
If a linear relationship is obtained, the activation energy and frequency factor can be calculated from the slope and intercept of the straight line. The validity of this method is confirmed by the good agreement between the value of activation energy obtained in this work and that due to previous workers for the formation reaction of barium titanate. In general, the present method may be well applied where the products of reaction are gases which eacape immediately, and particularly for step by step reaction, such as thermal desorption processes of adsorbate from adsorbent.
If a linear relationship is obtained, the activation energy and frequency factor can be calculated from the slope and intercept of the straight line. The validity of this method is confirmed by the good agreement between the value of activation energy obtained in this work and that due to previous workers for the formation reaction of barium titanate. In general, the present method may be well applied where the products of reaction are gases which eacape immediately, and particularly for step by step reaction, such as thermal desorption processes of adsorbate from adsorbent.