Equations and Tables for Analyzing Solid-state Reaction Kinetics

The Jander, Dünwald‐Wagner, and Ginstling‐Brounshteǐn equations for isothermal reaction kinetics are discussed and compared directly. A table of α (fraction of total material reacted) versus Kt (product of isothermal reaction constant and time) is given for each of the three equations. In order of decreasing relative speed of reaction predicted up to α= 0.94, the equations are: Ginstling‐Brounshteǐn, Dünwald‐Wagner, and Jander. The equations are further compared with the aid of the Arrhenius expression assuming the Ginstling‐Brounshteǐn to be correct for a rate process having an E (activation energy) of 2 ev per molecule. It is demonstrated that analyzing data at constant α, rather than at constant t, is a general method which will give the same E for any equation wherein α is a function of Kt.