Effect of Yb2O3 and TiO2 on reaction sintering and properties of magnesium aluminate spinel

Magnesium aluminate spinel with an initial MgO: Al2O3 molar ratio of 2:1 was prepared from its constituent oxides through a solid-state sintering process at temperatures ranging from 1550 to 1700 °C in a normal air atmosphere. The effect of varying amount (0.25–1.0 wt%) of TiO2 and Yb2O3 on densific...

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Bibliographic Details
Published inCeramics international Vol. 47; no. 19; pp. 27372 - 27385
Main Authors Sinhamahapatra, Somnath, Ghosh, Chandrima, Tripathi, Himansu Sekhar, Mukhopadhyay, Sunanda
Format Journal Article
LanguageEnglish
Published Elsevier Ltd 01.10.2021
Subjects
Magnesium aluminate spinel
Mechanical properties
Microstructure
Reaction-sintering
Refractories
Reaction-sintering
Mechanical properties
Microstructure
Refractories
Magnesium aluminate spinel
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Summary:Magnesium aluminate spinel with an initial MgO: Al2O3 molar ratio of 2:1 was prepared from its constituent oxides through a solid-state sintering process at temperatures ranging from 1550 to 1700 °C in a normal air atmosphere. The effect of varying amount (0.25–1.0 wt%) of TiO2 and Yb2O3 on densification, phase assemblage, mechanical, thermo-mechanical properties and microstructure of magnesia-rich spinel were investigated under static heating condition. The addition of TiO2 and Yb2O3 favours the densification of magnesia-rich spinel, which is discernible up to 1650 °C. This beneficial effect may be attributed to the development of the secondary phase and formation of solid solution due to the dissolution of the additive ions in the spinel structure. A marginal increase in the average grain size of the samples along with a narrower grain size distribution occurred with the incorporation of both the additives. Both the additives improved the mechanical properties of the magnesia-rich spinel; however, better room temperature flexural strength was achieved with Yb2O3 as compared to TiO2 addition. For the samples sintered at 1550 °C, 1.0 wt% Yb2O3 addition resulted in 30% increase in flexural strength; however, same amount of TiO2 addition increased the strength by 20%. In case of thermal shock resistance, 1.0 wt% TiO2 and 0.25 wt% Yb2O3 addition demonstrated promising result among all the samples.
ISSN:0272-8842
1873-3956
DOI:10.1016/j.ceramint.2021.06.159