Useful method to analyze data on overall transformation kinetics

• Published in: Journal of non-crystalline solids Vol. 356; no. 23; pp. 1201 - 1203
• Main Authors: Avramov, I., Avramova, K., Rüssel, C.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 15.05.2010; Elsevier
• Subjects: Cross-disciplinary physics: materials science; rheology; Crystallization; Exact sciences and technology; Glass-ceramics; Growth from solid phases (including multiphase diffusion and recrystallization); Materials science; Methods of crystal growth; physics of crystal growth; Physics; Relaxation; Relaxation; Glass-ceramics; Crystallization; Kinetic equations; Glass ceramics
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2010.03.004

The aim of this article is to demonstrate the important source of errors when overall crystallization kinetics data are plotted in coordinates ln [ − ln (1 − α)] against ln t (in isothermal case), respectively ln [ − ln (1 − α( T))] against ln q (in the case of linear temperature change at a rate q). Due to the specific properties of the logarithmic function, (in particular because ln 0 → − ∞), this plot exaggerates the role of both the initial stage ( α → 0) and the stage near the end of the process ( α → 1). Unfortunately, these are just the ranges where most grave experimental errors appear. In case the double logarithmic scale is used, data outside the limits − 2 < ln ( − ln (1 − α)) < 1, respectively 0.1 < α < 0.9 are not reliable and should not be taken into account. Instead, we propose suitable coordinates for presentation of experimental data, so that the power n in the Kolmogorov–Johnson–Mehl–Avrami equation is determined in a more reliable manner.