Dissolution and Deagglomeration of Silicon Nitride in Aqueous Medium

Abstract

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 kJ⅐mol ؊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.

Mechanical and tribological behavior of silicon nitride and silicon carbon nitride coatings for total joint replacements

“…Furthermore, silicon nitride particles dissolve in aqueous media (Laarz et al, 2000). This, in turn, suggests that wear particles can dissolve in vivo, which may reduce the negative body response from the debris, and potentially increase the longevity of the implant.…”

SiNx Coatings Deposited by Reactive High Power Impulse Magnetron Sputtering: Process Parameters Influencing the Nitrogen Content

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The Sophistication of Ceramic Science Through Silicon Nitride Studies

“…Because SiCl 4 is an inexpensive, high purity by-product formed when removing silica from different ores, with the exception of its oxygen content Ĭ1.5 weight!, more than likely introduced during the pyrolysis of the diimide , the a-Si 3 N 4 powder produced by this method was very pure, relative to other synthesis routes. Laarz et al 20 showed that much of the oxygen within the powder was in the form of SiO 2 that bonded primary crystallites together with a size ranging between 50 to 200 nm forming agglomerates with a size ranging between 500 and 1000 nm. They showed that the agglomerates could be broken into their primary particles by dissolving the SiO 2 in water, buffered at pH 8.7 by the release of HN 3 produced during the oxidation of Si 3 N 4 during the dissolution of the SiO 2 .…”