Self-Reinforced Nitrogen-Rich Calcium-α-SiAlON Ceramics

Nitrogen‐rich Ca–α‐SiAlON ceramics with nominal compositions CaxSi12−2xAl2xN16 and 0.2≤x≤2.6, extending along the Si3N4–1/2Ca3N2:3AlN tie line, were prepared from Si3N4, AlN, and CaH2 precursors by hot pressing at 1800°C. The x values attained were determined by energy‐dispersive X‐ray (EDX) microan...

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Bibliographic Details
Published in:Journal of the American Ceramic Society 2007-02, Vol.90 (2), p.608-613
Main Authors: Cai, Yanbing, Shen, Zhijian, Grins, Jekabs, Esmaeilzadeh, Saeid, Höche, Thomas
Format: Article
Language:English
Subjects:
Applied sciences
Building materials. Ceramics. Glasses
Ceramic industries
Chemical industry and chemicals
Exact sciences and technology
Miscellaneous
Technical ceramics
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Summary:Nitrogen‐rich Ca–α‐SiAlON ceramics with nominal compositions CaxSi12−2xAl2xN16 and 0.2≤x≤2.6, extending along the Si3N4–1/2Ca3N2:3AlN tie line, were prepared from Si3N4, AlN, and CaH2 precursors by hot pressing at 1800°C. The x values attained were determined by energy‐dispersive X‐ray (EDX) microanalysis and X‐ray powder diffraction (XRPD) data using the Rietveld method. The results show that Ca–α‐SiAlONs form continuously within the compositional range x=0 to at least x=1.82. Phase assemblages, lattice parameters, Vickers hardness, and fracture toughness were determined and correlated to the calcium content, x. Owing to a high sintering temperature and the use of CaH2 as a precursor, grain growth was kinetically enhanced, resulting in self‐reinforced microstructures with elongated grains. The obtained Ca–α‐SiAlON ceramics demonstrate a combination of both high hardness ∼21 GPa, and high fracture toughness ∼5.5 MPa·m1/2.
ISSN:0002-7820
1551-2916
DOI:10.1111/j.1551-2916.2006.01451.x