The impact of heat treatment on the microstructure of a clay ceramic and its thermal and mechanical properties

Abstract : This paper presents the results of an experimental study on the microstructure, the thermal and the mechanical properties of a clay-based ceramic used in building applications. The X-ray tomography analysis showed a layered microstructure of clay with 200 mu m sheets of porosity after the extrusion process. The gas release from the dehydration, dehydroxylation and decarbonation induced a 7 vol% formation of porosity during the heat treatment of the clay-based ceramic up to 850 degrees C. The porosity increase and the development of metakaolin led to a 38% decrease in the thermal conductivity. On the other hand, the Young's modulus of the clay-based ceramic was conserved due to the formation of smaller pores than the 200 mu m sheets of porosity. The densification and the crystallization of amorphous phases also led to a 110% increase of the Young's modulus from 850 degrees C to 1050 degrees C. The Young's modulus of the clay-based ceramic was only decreased by the 13 Kt quartz inversion of the cooling due to sand addition. Hence, this study provided a useful insight into how the microstructure of fired clay bricks can be specifically transformed by the porosity during the heat treatment to control the thermal and mechanical properties.
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Ceramics International, Elsevier, 2017, 43 (2), p.1747-1754. 〈10.1016/j.ceramint.2016.10.084〉
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https://hal.archives-ouvertes.fr/hal-01619238
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Soumis le : mardi 6 novembre 2018 - 16:32:51
Dernière modification le : mardi 13 novembre 2018 - 13:44:01

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P. M. Nigay, Thierry Cutard, Ange Nzihou. The impact of heat treatment on the microstructure of a clay ceramic and its thermal and mechanical properties. Ceramics International, Elsevier, 2017, 43 (2), p.1747-1754. 〈10.1016/j.ceramint.2016.10.084〉. 〈hal-01619238〉

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