α′-Sialon ceramics

Hampshire, Stuart; Park, H. K.; Thompson, D. P.; Jack, K. H.

doi:10.1038/274880a0

Cited by 432 publications

(208 citation statements)

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“…The charge discrepancy introduced by the former substitution is counterbalanced by the introduction of metal ions Me p+ with x ¼ m/p (p is the valency of the metal cation Me). There are two interstitial sites per unit cell in the a-Si 3 N 4 structure that can be occupied by Me p+ metal ions, which limits the maximum value of x to 2 in formula (1), because each unit cell contains four formula units. The Me elements that have been reported to stabilize the a-SiAlON structure are Li, Mg, Ca, Y and the rare-earth metals except for Ce, La, Pr and Eu [1][2][3][4].…”

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confidence: 99%

“…There are two interstitial sites per unit cell in the a-Si 3 N 4 structure that can be occupied by Me p+ metal ions, which limits the maximum value of x to 2 in formula (1), because each unit cell contains four formula units. The Me elements that have been reported to stabilize the a-SiAlON structure are Li, Mg, Ca, Y and the rare-earth metals except for Ce, La, Pr and Eu [1][2][3][4]. Generally, it is impossible to stabilize the a-SiAlON structure for rare-earth metals with a large ionic size such as Eu 2+ and Ce 3+ , but it is possible if they are codoped with calcium [5,6].…”

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confidence: 99%

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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: 99%

mentioning

confidence: 99%

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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“…The so-called o/-sialons have the structure of ol-Si3N 4 (space group P31c) and the general formula MexSii2_(m+~)Alm+~OnN16_~, with x ~< 2 [1]. If the valency of the metal Me is v, electroneutrality requires x = m/v.…”

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confidence: 99%

Neutron diffraction study of yttrium ?'-sialon

1993

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“…Since no data is available for the oxygen content of the SiC powder, it was believed that the incorporation of surface oxygen originated from the SiO2 phase had decreased the liquid phase formation temperature and affected the viscosity of the liquid phase which consequently accelerated the  SiAlON phase transformation. This additional SiO2 increases the diffusion paths between reactive Si 4+ and Al 3+ species during sintering that restricts the formation of desired amount of β-SiAlON phase [26].…”

Section: Phase and Microstructural Developmentmentioning

confidence: 99%

Mechanical, Electrical and Thermal Properties of α/β SiAlON-SiC Composites Fabricated by Gas Pressure Sintering Method

Ayas¹

2016

ANADOLU UNIVERSITY JOURNAL OF SCIENCE AND TECHNOLOGY a - Applied Sciences and Engineering

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ABSTRACTα/β SiAlON-SiC composites were produced by coating SiAlON based spray dried granules with varying amounts of SiC (0-10 vol % SiC) following gas pressure sintering technique. A two step sintering schedule between 1940-1990°C under 10 MPa N2 gas pressure was adopted in order to achieve high densification rate. All the composites and the reference SiAlON material were densified up to 99 %. α/β SiAlON -10 vol. % SiC composite had the highest hardness value (Hv10: 16.33 GPa) due to the formation of α-SiAlON phases promoted with the increasing SiC content. No significant changes in the fracture toughness values of composites were observed. 3D segregated network of SiC particles along granules to establish electrical and thermal conductivity in the composites was successfully achieved with incorporation of 10 vol. % SiC. α/β SiAlON -10 vol. % SiC composite exhibited the semiconductor characteristic and high thermal conductivity with the electrical resistivity of 10 2 Ω.m and thermal diffusivity of ~11 mm 2 /s measured at room temperature.

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α′-Sialon ceramics

Cited by 432 publications

References 4 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

Neutron diffraction study of yttrium ?'-sialon

Mechanical, Electrical and Thermal Properties of α/β SiAlON-SiC Composites Fabricated by Gas Pressure Sintering Method

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