Abstract
Isothermal gravimetric curves of the thermal decomposition of Mg(OH)2 have been examined from the standpoint of kinetics and mechanisms. A new kinetic model is proposed; the decomposition occurs successively from the particles in which nuclei have been formed, and a single-particle decomposition once initiated proceeds according to a contracting disk model. The present model combining nucleation and two dimensional interface growth satisfactorily accounts for the thermal decomposition of Mg(OH)2 prepared by different methods and thus having different crystallite sizes. Temperature dependences of the nucleation rate constant and the rate constant of interface growth is separately evaluated and related to the nature of sample.
