In:
Journal of the American Ceramic Society, Wiley, Vol. 102, No. 5 ( 2019-05), p. 2316-2324
Abstract:
Si OCN ceramic aerogels with lightweight, high surface areas, and macro‐meso pores have been synthesized by a facile method combining freeze‐drying technique and polymer‐derived ceramic route. The wet gels are synthesized via the hydrosilylation reaction between polysilazane and divinylbenzene with cyclohexane as solvent. The solvent is then removed by a freeze‐drying process to form pre‐ceramic aerogels. The Si OCN ceramic aerogels are finally obtained by pyrolyzing the pre‐ceramic aerogels at 1000°C in ultrahigh purity N 2 . The thermogravimetric and mass spectrometry system ( TG / DSC ‐ MS ) is used to investigate the polymer‐to‐ceramic conversion process during pyrolysis. The phase composition, structure, and morphology of the Si OCN ceramic aerogels are investigated by XRD , FT‐IR , XPS , and SEM . The results show that Si OCN ceramic aerogels are composed of amorphous matrix phase and “free carbon” phase. The Si OCN aerogels possess three‐dimensional (3D) network porous structure with low density (0.19 g/cm 3 ), high specific surface area (134 m 2 /g), large pore volume (0.49 cm 3 /g), and hierarchical pore structures of both macro and meso pores. The formation mechanism and evolution process of Si OCN ceramic aerogels are discussed.
Type of Medium:
Online Resource
ISSN:
0002-7820
,
1551-2916
DOI:
10.1111/jace.2019.102.issue-5
Language:
English
Publisher:
Wiley
Publication Date:
2019
detail.hit.zdb_id:
2008170-4
detail.hit.zdb_id:
219232-9
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