Microstructure of silicon nitride ceramics sintered with rare-earth oxides

1995 ◽  
Vol 43 (3) ◽  
pp. 923-930 ◽  
Author(s):  
Y. Goto ◽  
G. Thomas
Keyword(s):  
Rare Earth ◽  
Silicon Nitride ◽  
Rare Earth Oxides ◽  
Nitride Ceramics

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

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.

Rare-earth adsorption at intergranular interfaces in silicon nitride ceramics: Subnanometer observations and theory

2005 ◽  
Vol 72 (14) ◽  
Author(s):  
N. Shibata ◽  
G. S. Painter ◽  
R. L. Satet ◽  
M. J. Hoffmann ◽  
S. J. Pennycook ◽  
...  
Keyword(s):  
Rare Earth ◽  
Silicon Nitride ◽  
Nitride Ceramics

Mechanical and Thermal Properties of Silicon Nitride Hot Pressed with Adding Rare-Earth Oxides

2005 ◽  
Vol 486-487 ◽  
pp. 181-184 ◽  
Author(s):  
Dae Ho Choi ◽  
Byung Kyu Moon ◽  
Rak Joo Sung ◽  
Seung Ho Kim ◽  
Koichi Niihara
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Rare Earth ◽  
Silicon Nitride ◽  
Flexural Strength ◽  
Grain Growth ◽  
Rare Earth Oxides ◽  
Lattice Oxygen ◽  
Mechanical And Thermal Properties ◽  
Si3n4 Ceramics

Mechanical and thermal properties of Si3N4 ceramics with various rare-earth oxides (La2O3, CeO2, Lu2O3, Dy2O3, Sm2O3, Nd2O3, Yb2O3, and RuO2) were investigated. Flexural strength of silicon nitride with addition of 5vol% Nd2O3, CeO2, Dy2O3, and Sm2O3 showed higher value than that of silicon nitride with Lu2O3 and La2O3 added because they form denser microstructure and smaller elongated grain. Thermal conductivity of silicon nitride with an addition of 5vol% RuO2 was more enhanced than that of silicon nitride added with Nd2O3, Sm2O3, and Dy2O3 because the addition of RuO2 depressed grain growth. It is also associated with lattice oxygen governing thermal conductivity of Si3N4 when added rare-earth oxides.

Oxynitride Glasses and Their Properties - Implications for High Temperature Performance of Silicon Nitride-Based Ceramics

2006 ◽  
Vol 317-318 ◽  
pp. 419-424 ◽  
Author(s):  
Stuart Hampshire ◽  
Michael J. Pomeroy
Keyword(s):  
Glass Transition ◽  
Rare Earth ◽  
High Temperature ◽  
Silicon Nitride ◽  
Elastic Moduli ◽  
Aluminosilicate Glass ◽  
Temperature Behaviour ◽  
Intergranular Films ◽  
Nitride Ceramics ◽  
Earth Cation

Oxynitirde glasses are found at triple point junctions and as intergranular films in silicon nitride based ceramics. The glass chemistry, particularly the content of modifyer,usually Y or a rare earth (RE) ion, and the volume fractions of these oxynitride glass phases within the ceramic control the properties of silicon nitride, in particular, creep at high temperature. It is known that, as nitrogen substitutes for oxygen in silicate and aluminosilicate glass networks, increases are observed in glass transition and softening temperatures, viscosities (by two to three orders of magnitude), elastic moduli and microhardness. If changes are made to the RE:Si:Al ratios or different rare earth cation are substituted, properties such as viscosity can be increased by a further two to three orders of magnitude. These effects have implications for the high temperature properties of silicon nitride based ceramics, especially creep resistance. This paper provides an overview of oxynitride glasses and outlines the effect of composition on properties such as glass transition temperature and viscosity and discusses the effects on high temperature behaviour of silicon 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.

Strength and Creep Behavior of Rare-Earth Disilicate-Silicon Nitride Ceramics

1992 ◽  
Vol 75 (8) ◽  
pp. 2050-2055 ◽  
Author(s):  
Michael K. Cinibulk ◽  
Gareth Thomas ◽  
Sylvia M. Johnson
Keyword(s):  
Rare Earth ◽  
Silicon Nitride ◽  
Creep Behavior ◽  
Nitride Ceramics
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