Dissolution and Deagglomeration of Silicon Nitride in Aqueous Medium

Silicon nitride undergoes hydrolysis and dissolution when subjected to an aqueous environment. Molecular dynamics simulations suggest that hydrolysis proceeds through nucleophilic attack of water with the formation of an intermediate molecular complex involving a pentacoordinated silicon. We found t...

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Published inJournal of the American Ceramic Society Vol. 83; no. 10; pp. 2394 - 400
Main Authors Laarz, Eric, Zhmud, Boris V., Bergström, Lennart
Format Journal Article
LanguageEnglish
Published Westerville, Ohio American Ceramics Society 01.10.2000
Blackwell
Wiley Subscription Services, Inc
Subjects
agglomerates
Chemistry
Colloidal state and disperse state
Exact sciences and technology
General and physical chemistry
Powders
silicon nitride
Hydrolysis
Transmission electron microscopy
Simulation
Aqueous medium
Silicon Nitrides
Molecular dynamics
Temperature effect
pH
Dissolution
Activation energy
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Summary:Silicon nitride undergoes hydrolysis and dissolution when subjected to an aqueous environment. Molecular dynamics simulations suggest that hydrolysis proceeds through nucleophilic attack of water with the formation of an intermediate molecular complex involving a pentacoordinated silicon. We found that the dissolution of an oxidized silicon nitride powder resembles that of silica; the dissolution rate could be described using a simple kinetic equation with a dissolution activation energy of 52 kJ·mol−1. The deagglomeration of a fine silicon nitride powder under mild agitation was evaluated; we show that the peptization kinetics at room temperature is dominated by the breakup of particle–particle bonds due to hydrodynamic friction and cluster attrition. For breakup of hard agglomerates of small particles the dissolution of interparticle necks will play an important role.
Bibliography:ArticleID:JACE2394
istex:73CE2F253610013098970FE41C596476CADF1A49
ark:/67375/WNG-JN5GMD08-J
Member, American Ceramic Society.
The work performed within “The Brinell Centre‐Inorganic Interfacial Engineer‐ing” was supported by the Swedish National Board for Industrial and Technical Development (NUTEK) and the following industrial partners: Erasteel Kloster AB, Ericsson Cables AB, Höganäs AB, Kanthal AB, OFCON Optical Fiber Consultants AB, Sandvik AB, Seco Tools AB, and Uniroc AB. The work of B.V.Z. was supported by a grant from the Wenner‐Gren Foundation (Sweden).
V. A. Hackley—contributing editor
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ISSN:0002-7820
1551-2916
1551-2916
DOI:10.1111/j.1151-2916.2000.tb01567.x