Fine needles of mullite grains were obtained successfully in a compact and low porous matrix using solid state sintering. We treated high-grade kaolin and sand-rich kaolin at 750 °C to amorphous metakaolins, and bauxite at 1,000 °C to metastable alumina. By designing a stochiometric composition of mullite, each amorphous metakaolin was added to metastable alumina. Fine grains of mullite with almost complete crystallization were obtained from 1,350 °C in a case of amorphous metakaolin from high-grade kaolin and at 1,550 °C in the other case where amorphous metakaolin is from sand-rich kaolin. The difference in the temperatures of mullitization was linked to the late dissolution of silica from the cristobalite and quartz phases which were still present in the sand-rich metakaolin sample at 1,350 °C. The use of metastable alumina and metakaolin instead of kaolin to design the mullite matrix allows the increase in number of mullite nucleation sites. This results to high densification and crystallization, fine grain size, and high mechanical properties of the final matrix. © 2014 Akadémiai Kiadó, Budapest, Hungary.

Reaction sintering and microstructural evolution in metakaolin-metastable alumina composites / Djangang, Chantale Njiomou; Tchamba, Arlin Bruno; Kamseu, Elie; Melo, Uphie Chinje; Elimbi, Antoine; Ferrari, Anna Maria; Leonelli, Cristina. - In: JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY. - ISSN 1388-6150. - ELETTRONICO. - 117:(2014), pp. 1035-1045. [10.1007/s10973-014-3937-6]

Reaction sintering and microstructural evolution in metakaolin-metastable alumina composites

KAMSEU, Elie;FERRARI, Anna Maria;LEONELLI, Cristina
2014

Abstract

Fine needles of mullite grains were obtained successfully in a compact and low porous matrix using solid state sintering. We treated high-grade kaolin and sand-rich kaolin at 750 °C to amorphous metakaolins, and bauxite at 1,000 °C to metastable alumina. By designing a stochiometric composition of mullite, each amorphous metakaolin was added to metastable alumina. Fine grains of mullite with almost complete crystallization were obtained from 1,350 °C in a case of amorphous metakaolin from high-grade kaolin and at 1,550 °C in the other case where amorphous metakaolin is from sand-rich kaolin. The difference in the temperatures of mullitization was linked to the late dissolution of silica from the cristobalite and quartz phases which were still present in the sand-rich metakaolin sample at 1,350 °C. The use of metastable alumina and metakaolin instead of kaolin to design the mullite matrix allows the increase in number of mullite nucleation sites. This results to high densification and crystallization, fine grain size, and high mechanical properties of the final matrix. © 2014 Akadémiai Kiadó, Budapest, Hungary.
117
1035
1045
Reaction sintering and microstructural evolution in metakaolin-metastable alumina composites / Djangang, Chantale Njiomou; Tchamba, Arlin Bruno; Kamseu, Elie; Melo, Uphie Chinje; Elimbi, Antoine; Ferrari, Anna Maria; Leonelli, Cristina. - In: JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY. - ISSN 1388-6150. - ELETTRONICO. - 117:(2014), pp. 1035-1045. [10.1007/s10973-014-3937-6]
Djangang, Chantale Njiomou; Tchamba, Arlin Bruno; Kamseu, Elie; Melo, Uphie Chinje; Elimbi, Antoine; Ferrari, Anna Maria; Leonelli, Cristina
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11380/1117557
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