Improved Aqueous Dispersion of Silicon Nitride with Aminosilanes

Buchta, M.; Shih, Wei‐Heng

doi:10.1111/j.1151-2916.1996.tb08729.x

Cited by 15 publications

(5 citation statements)

References 9 publications

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“…36 It was also observed that the addition of amino and diaminosilanes buffers the pH around 10.6 as is characteristic for adsorbed amines. 15 The PEG-silane molecule is essentially an aminosilane in which one amino group is replaced with a poly(ethylene glycol) chain, leaving one free proton bound to nitrogen (NH). It may bind to the surface through the hydrogen bonding between the nitrogen proton and the silanol groups on the silicon nitride surface.…”

Section: The Data Reported Above Show That N-[(triethoxysilyl)propyl]mentioning

confidence: 99%

“…[12][13][14][15][16] Organofunctional silanes seemed to bond particularly strong with the silanol groups from silica or silicon nitride surfaces. [13][14][15][16] In the present study, silicon nitride powders were coated with different silane molecules to achieve high packing density, low viscosity, high sedimentation stability, and a powder that was relatively nonreactive with water. Some of these silanes can also yield aqueous Si 3 N 4 slurries that consolidate to bodies that exhibit claylike plasticity.…”

Section: Introductionmentioning

confidence: 99%

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Chemisorption of Organofunctional Silanes on Silicon Nitride for Improved Aqueous Processing

Čolić

Franks

Fisher

et al. 1998

Journal of the American Ceramic Society

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Different chem-adsorbed silane molecules have been used to produce weakly attractive silicon nitride particle networks for aqueous colloidal processing. Silanes with diamino and poly(ethylene glycol) hydrophilic heads yielded slurries with the lowest viscosity, longest sedimentation stability, and highest packing density. Chem-adsorbed silane molecules protected silicon nitride and yttrium oxide, a common processing aid, from hydrolysis at pHs between 5.5 and 11. A novel approach was used to produce shortrange repulsive potentials necessary to yield the weakly attractive networks. Addition of salt to dispersed silicon nitride slurries with particles coated with poly(ethylene glycol)-silane caused the collapse of the 22-atom-long chains and residual electrical double layer. This produced a weakly attractive network which persisted during consolidation to yield a plastic body with a flow stress that was dependent on the counterion size. When 0.5M tetramethylammonium chloride was used at pH 10, plastic bodies had a flow stress similar to clay, whereas lithium counterions produced bodies with a much higher flow stress.

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Section: The Data Reported Above Show That N-[(triethoxysilyl)propyl]mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Chemisorption of Organofunctional Silanes on Silicon Nitride for Improved Aqueous Processing

Čolić

Franks

Fisher

et al. 1998

Journal of the American Ceramic Society

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“…Other authors propose the usage of short-chain organic compounds for building up stable and homogeneous aqueous dispersions of non-oxidic powders. Among these compounds, guanidine propionic acid or alkoxysilanes such as 3-aminopropyltriethoxysilane or 3-(triethoxysilyl)-2-methylpropylsuccinic acid were found. The silanes were proposed to bind chemically to the surface of a silicon nitride powder by condensation with surface-bound hydroxyl groups of the oxide layer.…”

Section: Introductionmentioning

confidence: 99%

Protecting Nanoscaled Non-oxidic Particles from Oxygen Uptake by Coating with Nitrogen-Containing Surfactants

et al. 2004

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To suppress the reactivity of nanoscaled non-oxidic powders of titanium nitride (TiN) and silicon carbonitride (SiCN) against hydrolysis and oxidation, chemical surface modification with nitrogen-containing surfactants was investigated. Among these surfactants, long-chain primary amines, ethylenediamines, guanidines, nitriles, isocyanates, and succinimides were examined. Thermogravimetry, elemental analysis, and behavior against the water-vapor adsorption of the modified particles were used as methods to estimate the protective capacity of the organic coating material. The best results were obtained by using the long-chain amines and octadecylisocyanate, which were indicated by a significant shift of the powder oxidation toward the higher temperatures and an increase of the particle hydrophobicity. A long-chain succinimide was found to be the most effective in dispersing nanoscaled TiN in organic media. Preparation of a stable aqueous dispersion without significant changes in the elemental composition of the powder was achieved by the application of an ionic surfactant to the surface-modified particles.

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“…To manipulate the rheological behavior, several investigations were undertaken to alter the depth of the secondary potential well, either by increasing the concentration of counterions added to dispersed slurries, 4,6,11,12 changing the size of the counterions used to collapses the double layer, 9 or using short-range steric barriers of different sizes. [13][14][15][16][17] Colic et al 17 used a different approach to produce short-range repulsive potentials for Si 3 N 4 powders. Different aminosilane molecules were chemadsorbed on Si 3 N 4 powder to develop a short-range repulsive potential that persists during consolidation and leads to plastic bodies.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Interparticle Pair Potential on the Rheological Behavior of Zirconia Powders: I, Electrostatic Double Layer Approach

Klein

Fisher

Franks

et al. 2000

Journal of the American Ceramic Society

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Aqueous slurries containing 20 vol% ZrO 2 powder doped with 3 mol% Y 2 O 3 were prepared by first dispersing the powder at pH 11, then adding 0.1M to 1.0M tetramethylammonium chloride (TMACl), or 1.0M of TPACl, CsCl, and LiCl to produce different, weakly attractive particle networks. The particle pair potentials in the slurries were investigated by viscosity versus shear rate measurements. Slurries exhibited increasing viscosities (at a given shear rate) with increasing salt concentration and decreasing (unhydrated) counterion size. The viscosities for these weakly attractive networks were intermediate to dispersed (pH 11 without added salt) and flocced (isoelectric point, pH 7.5) slurries. Cylindrical bodies were consolidated from these slurries by pressure filtration at different applied pressures. The bodies consolidated from slurries formulated with TMACl had the highest packing densities relative to those consolidated from a flocculated slurry, but the relative densities were much lower than those achieved from bodies consolidated from a dispersed slurry. The plastic or brittle nature of these bodies was determined in uniaxial compression. Powder compacts consolidated from flocced slurries and slurries coagulated with 1M TMACl, CsCl, and LiCl showed plastic behavior for filtration pressures <7.5 MPa. Results for ZrO 2 will be compared with those previously obtained for Al 2 O 3 , which produces plastic, consolidated bodies over a much broader range of slurry conditions.

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Improved Aqueous Dispersion of Silicon Nitride with Aminosilanes

Cited by 15 publications

References 9 publications

Chemisorption of Organofunctional Silanes on Silicon Nitride for Improved Aqueous Processing

Chemisorption of Organofunctional Silanes on Silicon Nitride for Improved Aqueous Processing

Protecting Nanoscaled Non-oxidic Particles from Oxygen Uptake by Coating with Nitrogen-Containing Surfactants

Effect of the Interparticle Pair Potential on the Rheological Behavior of Zirconia Powders: I, Electrostatic Double Layer Approach

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