Synthesis of Silicon Nitride Ceramic Fibers and the Effect of Nitrogen Atmosphere on their Morphology

Sotaro Baba; Tomoyo Goto; Sung Hun Cho; Tohru Sekino

doi:10.4028/www.scientific.net/MSF.922.92

Paper Titles

Effect of the Addition of ZrO₂ Having Different Crystal Structures on the Mechanical Properties of Al₂O₃
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High Emissivity of Ca²⁺/Fe³⁺-Doped LaAlO₃ Based Ceramic Materials
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Optical Properties Evaluated According to the Different Thickness Sapphire under the Same Polishing Conditions
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Solvothermal Synthesis of TiO₂-Modified Hydroxyapatite Using Water-Isopropanol Solution
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Synthesis of Silicon Nitride Ceramic Fibers and the Effect of Nitrogen Atmosphere on their Morphology
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Effects of Characteristic of Green Body on the Microstructure and Properties of Reaction Bonded Silicon Carbide
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Oxidation Resistance and Bending Strength at High Temperatures of Ni/(ZrO₂+Al₂O₃) Hybrid Materials
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Torsion Strength Measurement of Engineering Ceramics
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Mechanical Properties of MgO-Doped Transparent Crystalline Alumina Fabricated by Two-Step Pressureless Sintering
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HomeMaterials Science ForumMaterials Science Forum Vol. 922Synthesis of Silicon Nitride Ceramic Fibers and...

Synthesis of Silicon Nitride Ceramic Fibers and the Effect of Nitrogen Atmosphere on their Morphology

Abstract:

The effect of nitrogen gas flow rate on the morphology of silicon nitride fibers obtained via carbothermal nitridation heat treatment method was investigated. A precursor containing silicon, oxygen and carbon was obtained by a sol-gel method from a mixture of tetraethyl orthosilicate, polyvinyl alcohol, H₂O and ethanol. A white wool-like product was obtained by heat treating the precursor placed in an alumina crucible under a 0.5 MPa nitrogen gas pressure at 1500oC with different nitrogen gas flow rates. The mass-based production rates of the samples obtained from the precursor powder were 20-30% for the different nitrogen gas flow rates. X-ray diffraction analysis revealed that the samples contained α-Si₃N₄ as the major phase along with β-Si₃N₄, Si₂N₂O and a small amount of amorphous product as minor phases. Unique twisted fibers with diameters of several hundreds of nanometers were found among the straight fibers by SEM observation. Elemental analysis using energy dispersive X-ray spectroscopy indicated that silicon and nitrogen were contained in the twisted fibers along with approximately 68 at.% of oxygen and several at.% of aluminum, which might have come from the crucible material. The SiAlON-like structures might have been formed by the partial dissolution of Al and O in the Si₃N₄ fibers. It was considered that the twisted morphology of some fibers might be formed by co-existing of β-SiAlON and/or amorphous phase regions in the Si₃N₄ fiber and resultant distortion of the fibers.

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Periodical:

Materials Science Forum (Volume 922)

Pages:

92-97

DOI:

https://doi.org/10.4028/www.scientific.net/MSF.922.92

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Online since:

May 2018

Authors:

Sotaro Baba, Tomoyo Goto, Sung Hun Cho, Tohru Sekino*

Keywords:

Carbothermal Nitridation, Ceramic Fibers, Silicon Nitride, Sol-Gel Method

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