Thermal Transformation of Fired Clay Ceramics by Dilatometric Analysis

L. Beddiara, b, F. Sahnouneb, c, M. Heraizb, D. Redaouib aDepartment of Science of Materials, University Mohamed Khaiddar Beskra, Algeria bPhysics Department, Faculty of Science, University Mohamed Boudiaf of M'sila, 28000 M'sila, Algeria cResearch Unit on Emerging Materials (RUEM), Ferhat Abbas of Setif 01, 19000 Setif, Algeria

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In the present study the mechanism and kinetic parameters of allotropic transformation (α→β) of the quartz of Algerian clay from Al-maathed was studied by dilatometric analysis technique. The activation energies measured by both isothermal (Johnson-Mehl-Avrami theory using Ligero method) and non-isothermal (Kissinger methods) treatments were 980 and 1050 kJmol-1, respectively. The growth morphology parameters n (Avrami parameter) which indicates the crystallization mode were found to be almost equal to 1.5, using non-isothermal treatments, and equal to 1.4 using isothermal (Ligero method). The numerical factor which depends on the dimensionality of crystal growth m obtained by Matusita et al. equation was 1.50. Analysis of the results shows that the bulk nucleation is the dominant mechanism in β-quartz crystallization and the three-dimensional growth of β-quartz crystals with polyhedron-like morphology occurs, controlled by diffusion from a constant number of nuclei.

DOI:10.12693/APhysPolA.134.86 topics: ceramics, thermal analysis, powders