Microstructural investigation of alpha-beta yttrium sialon materials

Chatfield, C.; Ekström, Thommy; Mikus, Magdalena

doi:10.1007/bf01114271

Cited by 53 publications

(6 citation statements)

References 14 publications

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“…A summary of the XRD phase analysis (lattice parameters) of the materials investigated is given in Table III sible to determine from the knowledge of ␤-Si 3 N 4 cell parameters the z value in the formula Si 6-z Al z O z N 8-z by assuming that it is a linear function of the shift of the a-and c-axes of the hexagonal unit cell (at z ‫ס‬ 0, the cell parameters were set to a ‫ס‬ 0.7603 nm and c ‫ס‬ 0.2909 nm). 31 The z value was ∼0.25 (materials 1-3) and 0.36 (materials 4-6) for the two SiAlON compositions, and it was almost independent of the raw materials used.…”

Section: Resultsmentioning

confidence: 84%

High‐Temperature Properties of Mixed α′/β′‐SiAlON Materials

Klemm

Herrmann

Reich

et al. 1998

Journal of the American Ceramic Society

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The mechanical behavior of mixed ␣/␤-SiAlON materials was studied at elevated temperatures. Two different ␣/␤-SiAlON compositions along the Si 3 N 4 -Y 2 O 3 ؒ9AlN composition line in the Si 3 N 4 -Al 2 O 3 ؒAlN-YNؒ3AlN plane (␣-SiAlON plane) were prepared using three different raw-material mixtures. Six different materials were obtained with significantly lower values in ␣-SiAlON than expected. The high-temperature properties of the materials studied were influenced strongly by the chemical composition (␣ content and grain-boundary phase) of the SiAlONs. A high content of ␣-SiAlON was beneficial in terms of creep behavior of the materials. The same materials, however, were characterized by a considerably degradated fracture behavior at elevated temperatures in air because of a crack-growth process enhanced by the poor oxidation resistance of these materials. It was concluded that, despite some superior features of the materials studied, a long-term application of mixed ␣/␤-SiAlON materials at 1400°C in air is problematical. A combination of all properties required for such applications was not observed. For that reason, it is suggested that the real high-temperature potential of these materials in air should be limited to temperatures <1300°C.

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Section: Resultsmentioning

confidence: 84%

High‐Temperature Properties of Mixed α′/β′‐SiAlON Materials

Klemm

Herrmann

Reich

et al. 1998

Journal of the American Ceramic Society

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“…Aspect ratio of ␣-SiAlON grains was found to be similar with ␤-SiAlON grains in SB1 and SB2 samples. Previous studies 18,27 indicate that nucleation and growth of a ␤-SiAlON grain generally proceed from ␤-Si 3 N 4 seeds. Rosenflanz 20 studied sintering of ␣-SiAlON ceramics using ␤-Si 3 N 4 powder with 1 and 3 m average particle sizes.…”

Section: Samplementioning

confidence: 98%

“…The aspect ratio of grains during precipitation depends primarily on the viscosity of the liquid phase and the diffusion rate, high viscosity of the liquid phase leads to a slow reduction of supersaturation and a higher final aspect ratio. 27 Apart from viscosity, grain size is a critical factor for grain growth. Smaller grains have smaller radius of curvature and more driving energy to move, change shape and even to be consumed by larger grains.…”

Section: Samplementioning

confidence: 99%

Influence of β-Si3N4 particle size and heat treatment on microstructural evolution of α:β-SiAlON ceramics

Açıkbaş

Kumar

Kara

et al. 2011

Journal of the European Ceramic Society

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“…A core/shell structure is observed in large elongated ␤-Si 3 N 4 grains, and they were both identified as ␤-Si 3 N 4 . 31,32 The observations of nucleation sites, here identified as incorporating ␤-Si 3 N 4 seed, were made possible because of the compositional difference between the ␤-Si 3 N 4 core and shell. The concentration of Al and Si in the core were close to those of the ␤-Si 3 N 4 seeds.…”

Section: Microstructural Characterizationmentioning

confidence: 99%

Microstructure in silicon nitride containing β-phase seeding: Part I

Huang

1999

J. Mater. Res.

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A proper powder preparation technique was used to develop elongated ␤-Si 3 N 4 particles as seeds from raw materials. The phase transformation and development of microstructure in Si 3 N 4 ceramics containing ␤-Si 3 N 4 seeds were investigated. The specimens of seeded silicon nitride had higher phase transformation rates than the specimens without seed. A core/shell structure was observed by transmission electron microscopy in seeded specimens owing to the difference in aluminum concentration in Si 3 N 4 grains. The misfit between the core and the shell was accommodated by interfacial dislocation that has a rotation character. The growth mode was epitaxial, although there was some compositional difference between the core and the shell. A relatively larger grain size and wider grain size distribution in seeded Si 3 N 4 specimens was due to the amount of ␤-phase seeds that could act as the nuclei, and the final modification of the microstructure was due to the coalescence process. The crack wake process characterized the mechanism of toughening.

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Microstructural investigation of alpha-beta yttrium sialon materials

Cited by 53 publications

References 14 publications

High‐Temperature Properties of Mixed α′/β′‐SiAlON Materials

High‐Temperature Properties of Mixed α′/β′‐SiAlON Materials

Influence of β-Si3N4 particle size and heat treatment on microstructural evolution of α:β-SiAlON ceramics

Microstructure in silicon nitride containing β-phase seeding: Part I

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