Formation Kinetics and Cation Inversion in Mechanically Activated MgAl₂O₄ Spinel Ceramics

Abstract

Solid-state mechanical activation of MgO and α-Al2O3 powders was used to produce MgAl2O4. The cation site occupancy in the resulting MgAl2O4 spinel was investigated using different methods. Differential thermal analysis and thermal gravimetry showed that mechanical activation reduced the spinel formation temperature by around 200°C, and the corresponding activation energy by about 25%. In addition, characteristic temperatures for evaporation of physisorbed water and decomposition of Mg(OH)2 shifted to lower values, and peaks were more pronounced. Raman spectra were used to characterize the degree of inversion as a function of the sintering temperature for all of the sintered specimens, indicating that the breaking point for ordering of the crystal structure was around 1500°C for non-activated samples, and 1400°C for activated samples.

Department(s)

Materials Science and Engineering

Comments

This investigation was supported by the Serbian Ministry of Education, Science and Technological Development of the Republic of Serbia, and it was conducted under the OI 172057 project.

Published online: 25 Sep 2019

Keywords and Phrases

DTA; Mechanical Activation; Raman Spectroscopy; Sintering Kinetics; Spinel

International Standard Serial Number (ISSN)

1388-6150; 1572-8943

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2019 Akadémiai Kiadó, All rights reserved.

Publication Date

01 Apr 2020

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