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Synthesis of cubic silicon nitride

Riedel, Ralf ; Zerr, Andreas ; Miehe, Gerhard ; Serghiou, George ; Schwarz, Marcus ; Kroke, Edwin ; Fueß, Hartmut ; Kroll, Peter ; Boehler, Reinhard (1999):
Synthesis of cubic silicon nitride.
In: Nature, 400 (6742), pp. 340-342. NPG, ISSN 00280836,
[Article]

Abstract

Silicon nitride (Si3N4) is used in a variety of important technological applications. The high fracture toughness, hardness and wear resistance of Si3N4-based ceramics are exploited in cutting tools and anti-friction bearings1; in electronic applications, Si3N4 is used as an insulating, masking and passivating material2. Two polymorphs of silicon nitride are known, both of hexagonal structure: alpha- and beta-Si3N4. Here we report the synthesis of a third polymorph of silicon nitride, which has a cubic spinel structure. This new phase, c-Si3N4, is formed at pressures above 15 GPa and temperatures exceeding 2,000 K, yet persists metastably in air at ambient pressure to at least 700 K. First-principles calculations of the properties of this phase suggest that the hardness of c-Si3N4 should be comparable to that of the hardest known oxide (stishovite3, a high-pressure phase of SiO2), and significantly greater than the hardness of the two hexagonal polymorphs.

Item Type: Article
Erschienen: 1999
Creators: Riedel, Ralf ; Zerr, Andreas ; Miehe, Gerhard ; Serghiou, George ; Schwarz, Marcus ; Kroke, Edwin ; Fueß, Hartmut ; Kroll, Peter ; Boehler, Reinhard
Title: Synthesis of cubic silicon nitride
Language: English
Abstract:

Silicon nitride (Si3N4) is used in a variety of important technological applications. The high fracture toughness, hardness and wear resistance of Si3N4-based ceramics are exploited in cutting tools and anti-friction bearings1; in electronic applications, Si3N4 is used as an insulating, masking and passivating material2. Two polymorphs of silicon nitride are known, both of hexagonal structure: alpha- and beta-Si3N4. Here we report the synthesis of a third polymorph of silicon nitride, which has a cubic spinel structure. This new phase, c-Si3N4, is formed at pressures above 15 GPa and temperatures exceeding 2,000 K, yet persists metastably in air at ambient pressure to at least 700 K. First-principles calculations of the properties of this phase suggest that the hardness of c-Si3N4 should be comparable to that of the hardest known oxide (stishovite3, a high-pressure phase of SiO2), and significantly greater than the hardness of the two hexagonal polymorphs.

Journal or Publication Title: Nature
Journal volume: 400
Number: 6742
Publisher: NPG
Divisions: 11 Department of Materials and Earth Sciences
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences > Material Science > Dispersive Solids
11 Department of Materials and Earth Sciences > Material Science > Structure Research
Date Deposited: 08 Jun 2012 06:57
Official URL: http://dx.doi.org/10.1038/22493
Identification Number: doi:10.1038/22493
Funders: This work was supported by the Deutsche Forschungsgemeinschaft, Bonn, Germany, and the Fonds der Chemischen Industrie, Frankfurt, Germany.
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