Amorphous and nanostructured silica and aluminosilicate spray-dried microspheres

作者：Todea M; Turcu R V F; Frentiu B; Tamasan M; Mocuta H; Ponta O; Simon S^*

来源：Journal of Molecular Structure, 2011, 1000(1-3): 62-68.

DOI：10.1016/j.molstruc.2011.05.053

• Microspheres
• Sol-gel
• Nanostructures
• Microscopy
• NMR

Amorphous silica and aluminosilicate microspheres with diameters in the 0.1-20 mu m range were produced by spray drying method. SEM, TEM and AFM images showed the spherical shape of the obtained particles. Based on thermal analysis data, several heat treatments have been applied on the as-prepared samples in order to check the amorphous state stability of the microspheres and to develop nanosized crystalline phases. As-prepared microspheres remain amorphous up to 1400 degrees C. By calcination at 1400 degrees C, cristobalite type nanocrystals are developed on silica sample, while in aluminosilicate sample first are developed mullite type nanocrystals and only after prolonged treatment are developed also cristobalite type nanocrystals. Si-29 and Al-27 MAS NMR results show that the local order around aluminum and silicon atoms strongly depend on the thermal history of the microspheres.

• 出版日期2011-8-10