Premium
Self‐Reinforced Nitrogen‐Rich Calcium–α‐SiAlON Ceramics
Author(s) -
Cai Yanbing,
Shen Zhijian,
Grins Jekabs,
Esmaeilzadeh Saeid,
Höche Thomas
Publication year - 2007
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2006.01451.x
Subject(s) - sialon , fracture toughness , materials science , ceramic , vickers hardness test , microstructure , sintering , rietveld refinement , microanalysis , mineralogy , powder diffraction , analytical chemistry (journal) , composite material , crystallography , metallurgy , crystal structure , chemistry , organic chemistry , chromatography
Nitrogen‐rich Ca–α‐SiAlON ceramics with nominal compositions Ca x Si 12−2 x Al 2 x N 16 and 0.2≤ x ≤2.6, extending along the Si 3 N 4 –1/2Ca 3 N 2 :3AlN tie line, were prepared from Si 3 N 4 , AlN, and CaH 2 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 CaH 2 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·m 1/2 .