Microstructural Evolution and Mechanical/Thermal Properties of Silicon Nitride Ceramics

Silicon nitride ceramics were fabricated with Yb2O3 as the sintering additive. The effects of the amount of Yb2O3 on the microstructure and the mechanical properties such as the flexural strength and the fracture toughness were investigated. Almost fully densified Si3N4 was obtained when only 4 wt% Yb2O3 was added. Both the flexural strength and the fracture toughness increased steadily with the Yb2O3 content. The transgranular fracture mode was observed in the specimen containing 4 wt% Yb2O3, however, the intergranular fracture mode was observed in the specimen containing 10 wt% Yb2O3.

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Observations on the Influence of Secondary Me Oxide Additives (Me=Si, Al, Mg) on the Microstructural Evolution and Mechanical Behavior of Silicon Nitride Ceramics Containing RE2O3(RE=La, Gd, Lu)

Journal of the American Ceramic Society ◽

10.1111/j.1551-2916.2009.03435.x ◽

2010 ◽

Vol 93 (2) ◽

pp. 570-580 ◽

Cited By ~ 34

Author(s):

Paul F. Becher ◽

Naoya Shibata ◽

Gayle S. Painter ◽

Frank Averill ◽

Klaus van Benthem ◽

...

Keyword(s):

Silicon Nitride ◽

Mechanical Behavior ◽

Microstructural Evolution ◽

Nitride Ceramics

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Effect of β-Seed Addition on the Microstructural Evolution of Silicon Nitride Ceramics

Journal of the American Ceramic Society ◽

10.1111/j.1151-2916.2001.tb01134.x ◽

2001 ◽

Vol 84 (12) ◽

pp. 3040-3042 ◽

Cited By ~ 6

Author(s):

Sang-Hoon Rhee ◽

Jae Do Lee ◽

Doh-Yeon Kim

Keyword(s):

Silicon Nitride ◽

Microstructural Evolution ◽

Seed Addition ◽

Nitride Ceramics

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Direct Observation of Microstructure Change During Densification of Silicon Nitride Ceramics with A Novel Characterization Method

MRS Proceedings ◽

10.1557/proc-287-435 ◽

1992 ◽

Vol 287 ◽

Cited By ~ 2

Author(s):

Y. Iwamoto ◽

H. Nomura ◽

I. Sugiura ◽

J. Tsubaki ◽

H. Takahashi ◽

...

Keyword(s):

Silicon Nitride ◽

Spray Drying ◽

Microstructural Evolution ◽

Direct Observation ◽

Microscopic Examination ◽

Sintered Body ◽

Immersion Liquid ◽

Fracture Origin ◽

Microstructure Change ◽

Nitride Ceramics

ABSTRACTA novel characterization method is applied to study the evolution of microstructures during densification of silicon nitride ceramics. This characterization method involves an immersion liquid for making green and sintered bodies transparent, and a subsequent direct optical microscopic examination. Granules were prepared with the spray drying processand formed into green bodies by CIP. After sintering at various temperatures, the specimens were examined for microstructural evolution. Large pores were located at the center and boundary regions of granules left in the green bodies; they were not removed by densification and resulted in large pores in the sintered body, possibly forming fracture origin in ceramics.

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