Synthesis and sintering at low temperature of a new nanostructured beta-Eucryptite dense compact by spark plasma sintering

The solid state reaction between kaolin and Li2CO3 with a 1:1 M composition has been studied in the temperature range 380°C-550 °C. The role played by Li2CO3 (basic medium) in the thermal transformation of the kaolin has been investigated by X-Ray diffraction, FESEM, TEM, MAS-NMR and XPS techniques. For the first time, a nanostructured high density β- Eucryptite (<10 nm) has been obtained by Spark Plasma Sintering (SPS) at 550 °C in high vacuum. The atmosphere used in sintering treatments has a determinant role in lithium migration and crystallization of β- Eucryptite. In the case of low vacuum treatments, an amorphous LiAlSiO4 geopolymer type material was obtained. Due to exclusive properties and performances of β- Eucryptite based materials, the results reported in the present investigation open new perspectives for new nanostructured and amorphous functional materials with null thermal expansion, ionic conduction and remarkable mechanical properties.The authors acknowledge the Principado de Asturias (Spain) for funding through the projects GRUPIN IDI/2018/000232 and MAT2016-78362-C4-2. A. Borrell acknowledges the Spanish Ministry of Economy and Competitiveness for her RyC contract (RYC-2016-209.15).Peer reviewe

Synthesis and sintering at low temperature of a new nanostructured beta- Eucryptite dense compact by spark plasma sintering

[EN] The solid state reaction between kaolin and Li2CO3 with a 1:1 M composition has been studied in the temperature range 380 degrees C-550 degrees C. The role played by Li2CO3 (basic medium) in the thermal transformation of the kaolin has been investigated by X-Ray diffraction, FESEM, TEM, MAS-NMR and XPS techniques. For the first time, a nanostructured high density beta-Eucryptite ( < 10 nm) has been obtained by Spark Plasma Sintering (SPS) at 550 degrees C in high vacuum. The atmosphere used in sintering treatments has a determinant role in lithium migration and crystallization of beta-Eucryptite. In the case of low vacuum treatments, an amorphous LiAlSiO4 geopolymer type material was obtained. Due to exclusive properties and performances of beta-Eucryptite based materials, the results reported in the present investigation open new perspectives for new nanostructured and amorphous functional materials with null thermal expansion, ionic conduction and remarkable mechanical properties.The authors acknowledge the Principado de Asturias (Spain) for funding through the projects GRUPIN IDI/2018/000232 and MAT201678362-C4-2. A. Borrell acknowledges the Spanish Ministry of Economy and Competitiveness for her RyC contract (RYC-2016-209.15).Suárez, M.; Fernández, A.; Díaz, L.; Sobrados, I.; Sanz, J.; Borrell Tomás, MA.; Palomares, F.... (2020). Synthesis and sintering at low temperature of a new nanostructured beta- Eucryptite dense compact by spark plasma sintering. Ceramics International. 46(11):18469-18477. https://doi.org/10.1016/j.ceramint.2020.04.1521846918477461