scholarly journals Quantitative Estimation of Intergranular Glassy Phase of Silicon Nitride Ceramics

1993 ◽  
Vol 101 (1172) ◽  
pp. 480-483
Author(s):  
Kazumasa TAKATORI ◽  
Shigetaka WADA ◽  
Nobuo KOBAYASHI
Keyword(s):  
Silicon Nitride ◽  
Glassy Phase ◽  
Quantitative Estimation ◽  
Nitride Ceramics

Corrosion of Silicon Nitride Ceramics by Nitric Acid

1992 ◽  
Vol 287 ◽  
Author(s):  
Kunihiko Kanbara ◽  
N. Uchida ◽  
K. Uematsu ◽  
T. Kurita ◽  
K. Yoshimoto ◽  
...  
Keyword(s):  
Weight Loss ◽  
Nitric Acid ◽  
Silicon Nitride ◽  
Glassy Phase ◽  
Strength Loss ◽  
Ionic Species ◽  
Corrosion Layer ◽  
Nitride Ceramics ◽  
Conventional Drying ◽  
Icp Analysis

ABSTRACTCorrosion of silicon nitride was studied in boiling nitric acid to examine its feasibility as a drying pan material in the reprocessing of nuclear fuel. Unlike stainless steel (a conventional drying pan material), the weight loss and strength degradation were negligible in the concentration of nitric acid. The corrosion increased with decreasing concentration of nitric acid. At the concentration of 1-6N, the maximum losses of weight and strength were 0.8% and over 40%, respectively, in 200 h. Ionic species dissolved in nitric acid were determined by ICP analysis and were found to be accurately correlated to the weight loss and thickness of the corrosion layer determined by micrography. In the corrosion layer, grain boundary glassy phase was selectively dissolved. Strength loss was correlated to the weight loss and was ascribed to the reduced load bearing area due to corrosion.

Hot-Pressed Silicon Nitride Ceramics With Rare-Earth Oxides Additives

1985 ◽  
Author(s):  
Xu Youren ◽  
Huang Liping ◽  
Fu Xiren ◽  
Yen Tungsheng
Keyword(s):  
Fracture Toughness ◽  
Rare Earth ◽  
Silicon Nitride ◽  
Room Temperature ◽  
Glassy Phase ◽  
Rare Earth Oxides ◽  
Bend Strength ◽  
Silicon Nitride Ceramic ◽  
X Ray ◽  
Nitride Ceramics

A hot-pressed silicon nitride ceramic material with rare-earth oxides additive has been processed, its bend strength maintains 800–900 MPa up to 1300°C and measures 680 MPa at 1400°C, its fracture toughness at room temperature is 4.38–4.96 MPam. X-ray, SEM, EDS and electron probe analyses reveal that the microstructure of this material is composed of fine β-Si3N4 grains, α-Si3N4 whiskers, small tetragonal lanthanide crystals and La-containing glassy phase. Observation on fracture surface shows that the fracture path is mainly transcrystalline up to 1400°C. The effects of additives on strength and fracture toughness of HPSN obtained are also discussed.

Grain boundary glassy phase and abnormal grain growth of silicon nitride ceramics

2001 ◽  
Vol 27 (5) ◽  
pp. 603-605 ◽  
Author(s):  
Haitao Yang ◽  
Lin Gao ◽  
Gangqin Shao ◽  
Runze Xu ◽  
Peiyun Huang
Keyword(s):  
Silicon Nitride ◽  
Grain Boundary ◽  
Grain Growth ◽  
Glassy Phase ◽  
Abnormal Grain Growth ◽  
Nitride Ceramics

Microstructure, toughness and flexural strength of self-reinforced silicon nitride ceramics doped with yttrium oxide and ytterbium oxide

2001 ◽  
Vol 201 (2) ◽  
pp. 238-249 ◽  
Author(s):  
Y. S. Zheng ◽  
K. M. Knowles ◽  
J. M. Vieira ◽  
A. B. Lopes ◽  
F. J. Oliveira
Keyword(s):  
Silicon Nitride ◽  
Flexural Strength ◽  
Yttrium Oxide ◽  
Ytterbium Oxide ◽  
Nitride Ceramics

Effect of α/β phase ratio on microstructure and mechanical properties of silicon nitride ceramics

2001 ◽  
Vol 16 (8) ◽  
pp. 2264-2270 ◽  
Author(s):  
Hirokazu Kawaoka ◽  
Tomohiko Adachi ◽  
Tohru Sekino ◽  
Yong-Ho Choa ◽  
Lian Gao ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Silicon Nitride ◽  
Phase Ratio ◽  
Phase Content ◽  
Sintering Process ◽  
Β Phase ◽  
Nitride Ceramics ◽  
Pulse Electric ◽  
Sintering Condition ◽  
Sintered Materials

Highly densed silicon nitride ceramics with various α/β phase ratios were produced by pulse electric current sintering process. The β-phase content of Si3N4 in sintered materials varied from 20 to 100 wt% depending on the sintering condition. The microstructure was observed by scanning electron microscopy and investigated by image analysis. Young's modulus, hardness, fracture toughness, and strength were strongly dependent on the α/β phase ratio. The fracture toughness increased from 4.6 MPa m1/2 for 20-wt% b-phase content to 8.2 MPa m1/2 for 95-wt% β-phase content, and the fracture strength showed a maximum value of about 1.6 GPa at 60-to-80-wt% β-phase content.

Metallizing of silicon nitride ceramics

1986 ◽  
Vol 2 (3) ◽  
pp. 241
Author(s):  
Akio Sayano ◽  
Shun-ichiro Tanaka ◽  
Kazuo Ikeda
Keyword(s):  
Silicon Nitride ◽  
Nitride Ceramics
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