α-Sialon ceramics synthesised from a clay precursor by carbothermal reduction and nitridation

Ekström, Thommy; Shen, Zhijian-j.; MacKenzie, Kenneth J.D.; Brown, I. W. M.; White, G. V.

doi:10.1039/a707729g

Cited by 42 publications

(22 citation statements)

References 12 publications

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“…To make fine powders, it is essential to pulverize the as-synthesized powders, which can easily damage the particle surfaces. Therefore work has shown that a-SiAlON powders can be prepared from oxide precursors by simultaneous carbothermal reduction and nitridation (CRN) in a flow of nitrogen gas [9][10][11][12]. However, except for the report of Mitomo et al [10], there have been few papers on the synthesis of pure a-SiAlON powders by this process.…”

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confidence: 98%

Fine yellowα-SiAlON:Eu phosphors for white LEDs prepared by the gas-reduction–nitridation method

Hirosaki

Xie

et al. 2007

Science and Technology of Advanced Materials

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Yellow-emitting a-SiAlON:Eu 2+ phosphors were synthesized by the gas reduction and nitridation of a homogeneous oxide precursor in a CaO-Al 2 O 3 -SiO 2 -Eu 2 O 3 system at 1400-1450 1C using an NH 3 -CH 4 mixture gas as a reduction-nitridation agent. The precursor was prepared by a sol-gel process using a low-cost nitrate, tetraethyl orthosilicate and citric acid as the starting materials. The effects of reaction parameters such as heating rate, temperature, holding time and CH 4 content on the composition, microstructure and photoluminescence of the prepared powders were investigated. Nearly single-phase a-SiAlON was successfully synthesized by the onestep gas reduction and nitridation without the need for post-annealing at a higher temperature. The prepared powders consisted of relatively well-dispersed and uniform crystals with a hexagonal shape. The photoluminescence spectra of Eu-doped Ca-a-SiAlON phosphors excited by near-ultraviolet or blue light showed a broad, yellow emission band at 500-700 nm, which agrees well with that obtained from phosphors prepared by the conventional solid-state reaction. r

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confidence: 98%

Fine yellowα-SiAlON:Eu phosphors for white LEDs prepared by the gas-reduction–nitridation method

Hirosaki

Xie

et al. 2007

Science and Technology of Advanced Materials

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“…1,2 Because sialon was prepared using clay minerals as raw materials via the in situ carbothermal reduction nitridation (CRN) technique, 3 new methods, including rare earth element doping, have been carried out to improve its properties. 4 Rare earth elements, which have been classified as critical materials due to their specific properties and difficult direct material substitution, are enablers for a wide range of technologies.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Sialon-SiC Composites from Kyanite Tailings by Carbothermal Reduction Nitridation

Min

Fang

Huang

et al. 2015

JOM

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Sialon-SiC composites were synthesized from kyanite tailings via the carbothermal reduction nitridation (CRN) technique. The phase composition, morphology, and microstructure of the CRN samples were investigated by x-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, and elected-area electron diffraction. A brief discussion on the synthesis mechanism of CRN process was investigated based on the thermodynamic analysis of the SiO 2 -Al 2 O 3 -C-N 2 system. The results show the phase compositions depended on the synthesis temperature. With the increasing heating temperature, SiO 2 was first changed into Si 2 N 2 O and then transformed into Si 3 Al 3 O 3 N 5 through reacting with N 2 , Al 2 O 3 , and C. At the same time, the excess SiO 2 changed into SiC by a carbothermal reduction reaction. The optimized synthesis temperature for the CRN reaction was found to be at 1550°C for 4 h. The Si 3 Al 3 O 3 N 5 and SiC phases were proved coexisting in the same CRN particle. This transformation provided a feasible utilization route of kyanite tailings for high-temperature application.

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“…In order to improve the reliability of a-SiAlON ceramics, it is important to develop homogeneous and fine a-SiAlON powders. a-SiAlON powders have been prepared by carbothermal reductionnitridation (CRN) from SiO 2 -Al 2 O 3 -(Ca-or Y-) oxides [8,9], clay-metal compounds [10], talc-halloysite clay minerals [11,12] and slag-clay mixtures [13,14] mixing with carbon in flowing N 2 gas.…”

Section: Introductionmentioning

confidence: 99%

Ca-α SiAlON hollow spheres prepared by carbothermal reduction–nitridation from different SiO2 powders

Hotta

Tatami

Zhang

et al. 2010

Ceramics International

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α-Sialon ceramics synthesised from a clay precursor by carbothermal reduction and nitridation

Cited by 42 publications

References 12 publications

Fine yellowα-SiAlON:Eu phosphors for white LEDs prepared by the gas-reduction–nitridation method

Fine yellowα-SiAlON:Eu phosphors for white LEDs prepared by the gas-reduction–nitridation method

Synthesis of Sialon-SiC Composites from Kyanite Tailings by Carbothermal Reduction Nitridation

Ca-α SiAlON hollow spheres prepared by carbothermal reduction–nitridation from different SiO2 powders

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