Table 3. Reaction Mechanism Function for Each Stage.

reaction stage	reaction temperature (°C)	f(α)	function name	reaction mechanism
1	67–114	f = 1 – α	Maple one-line rule, first order	stochastic nucleation and subsequent growth
2	220–286	f = 2 × (1 – α)0.5	shrinking cylinder (area)	phase boundary reaction (cylindrical symmetry)
3	417–432	f = (1 – α)2	second order	chemical reaction, deceleration shape α–t curve
4	455–484	3 × (1 – α)2/3	constricted globose	phase boundary reaction (spherical symmetry)