Cyclic fatigue behavior and fracture toughness of silicon nitride ceramics sintered with rare-earth oxides

1994 ◽  
Vol 42 (9) ◽  
pp. 3055-3064 ◽  
Author(s):  
B.E. Cornelissen ◽  
R.H. Dauskardt ◽  
R.O. Ritchie ◽  
G. Thomas
Keyword(s):  
Fracture Toughness ◽  
Rare Earth ◽  
Silicon Nitride ◽  
Fatigue Behavior ◽  
Cyclic Fatigue ◽  
Rare Earth Oxides ◽  
Nitride Ceramics

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.

Effect of rare earth oxides addition on the mechanical properties and coloration of silicon nitride ceramics

2020 ◽  
Vol 40 (4) ◽  
pp. 1132-1138 ◽  
Author(s):  
Ning Liu ◽  
Jingxian Zhang ◽  
Yusen Duan ◽  
Xingbang Li ◽  
Shaoming Dong
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Silicon Nitride ◽  
Rare Earth Oxides ◽  
Nitride Ceramics

Fracture Toughness of Si3N4 Based Ceramics with Rare-Earth Oxide Sintering Additives

2009 ◽  
Vol 409 ◽  
pp. 377-381 ◽  
Author(s):  
Peter Tatarko ◽  
Štefánia Lojanová ◽  
Ján Dusza ◽  
Pavol Šajgalík
Keyword(s):  
Fracture Toughness ◽  
Rare Earth ◽  
Silicon Nitride ◽  
Aspect Ratio ◽  
Rare Earth Oxide ◽  
Rare Earth Oxides ◽  
Crack Deflection ◽  
Indentation Fracture ◽  
Toughening Mechanisms ◽  
Sintering Additives

Fracture toughness of hot-pressed silicon nitride and Si3N4+SiC nanocomposites prepared with different rare-earth oxides (La2O3, Sm2O3, Y2O3, Yb2O3, Lu2O3) sintering additives have been investigated by Chevron Notched Beam, Indentation Strength and Indentation Fracture techniques. The fracture toughness values of composites were lower due to the finer microstructures and the lack of toughening mechanisms. In the Si3N4 with higher aspect ratio (Lu or Yb additives) crack deflection occurred more frequently compared to the Si3N4 doped with La or Y, which was responsible for the higher fracture toughness.

High-Resolution Interface Atomic Structure Analysis in Silicon Nitride Ceramics

2004 ◽  
Vol 839 ◽  
Author(s):  
A. Ziegler ◽  
J. C. Idrobo ◽  
M. K. Cinibulk ◽  
C. Kisielowski ◽  
N. D. Browning ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Electronic Structure ◽  
Rare Earth ◽  
Silicon Nitride ◽  
High Resolution ◽  
Rare Earth Elements ◽  
Structure Analysis ◽  
Atomic Structure ◽  
Nitride Ceramics ◽  
Ionic Size

ABSTRACTIn this study we examine the immediate interface between matrix grains and the amorphous intergranular film in a Si3N4 ceramic doped with rare-earth oxides La2O3, Sm2O3, Er2O3, Yb2O3 and Lu2O3, extracting unique structural and atomic bonding information. In particular, we relate the structure of the interface to the ionic size and electronic structure of the rare-earth elements and the presence of oxygen in the intergranular film. We relate these results to the measured fracture toughness.

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.

Correlation between fracture toughness and microstructure of seeded silicon nitride ceramics

2007 ◽  
Vol 42 (18) ◽  
pp. 7920-7926 ◽  
Author(s):  
D. Bučevac ◽  
S. Bošković ◽  
B. Matović ◽  
Lj. Živković ◽  
M. Vlajić ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Silicon Nitride ◽  
Nitride Ceramics

Effects of Sintering Additives on the Microstructure and Mechanical Properties of Silicon Nitride Ceramics by GPS

2010 ◽  
Vol 105-106 ◽  
pp. 27-30 ◽  
Author(s):  
Wei Ru Zhang ◽  
Feng Sun ◽  
Ting Yan Tian ◽  
Xiang Hong Teng ◽  
Min Chao Ru ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Phase Transformation ◽  
Silicon Nitride ◽  
Porous Silicon ◽  
Flexural Strength ◽  
Relative Density ◽  
Sintering Additives ◽  
Microstructure And Mechanical Properties ◽  
Nitride Ceramics

Silicon nitride ceramics were prepared by gas pressure sintering (GPS) with different sintering additives, including La2O3, Sm2O3 and Al2O3. Effect of sintering additives on the phase-transformation, microstructure and mechanical properties of porous silicon nitride ceramics was investigated. The results show that the reaction of sintering additives each other and with SiO2 had key effects on the phase-transformation, grain growing and grain boundaries. With 9MPa N2 atmosphere pressure, holding 1h at 1850°C, adding 10wt% one of the La2O3, Sm2O3, Al2O3, porous silicon nitride was prepared and the relative density was 78%, 72%, 85% respectively. The flexural strength was less than 500MPa, and the fracture toughness was less than 4.8MPam1/2. Dropping compounds sintering additives, such as La2O3+Al2O3, Sm2O3+Al2O3 effectively improves the sintering and mechanical properties. The relative density was 99.2% and 98.7% with 10wt% compounds sintering additives. The grain ratio of length to diameter was up to 1:8. The flexural strength was more than 900MPa, and the fracture toughness was more than 8.9MPam1/2.

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