New method to analyze data on overall crystallization kinetics

One of the most difficult tasks in analyzing the results of the overall crystallization kinetics, controlled by the equation alpha = 1 - e(-Ktn), is the determination of power n. Usually, this is done in double logarithmic coordinates, i.e. plotting In[-In(1-alpha)] against lnt. Because of the property of the logarithmic function, ln0 -> -infinity, this method exaggerates the role of initial stages (alpha -> 0) as well as the role of the stages near the end of the process Unfortunately, these are just the ranges where most grave experimental errors appear. The present contribution proposes suitable coordinates for presentation of experimental data. In this coordinates the importance of the contribution of the initial stages alpha -> 0 as well as that of the stages near the end of the process, alpha -> 1, is suppressed as compared to the importance of the more trusty data at about alpha approximate to 0.5. Therefore, the power n is determined in a more reliable way. The theoretical derivation is confirmed by analyzing some existing experimental data. (c) 2005 Elsevier B.V. All rights reserved.