Thermal Conductivity and Mechanical Property of Si3N4 Ceramics Sintered with CeF3/LaF3 Additives

2010 ◽  
Vol 105-106 ◽  
pp. 171-174 ◽  
Author(s):  
Bai Bing ◽  
Teng Fu ◽  
Xiao Shan Ning
Keyword(s):  
Thermal Conductivity ◽  
Mechanical Property ◽  
Rare Earth ◽  
Rare Earth Oxides ◽  
Sintering Additives ◽  
Rare Earth Fluoride ◽  
Earth Fluoride ◽  
Si3n4 Ceramics ◽  
Rare Earth Fluorides

In this paper, rare-earth fluorides were used as sintering additives instead of rare-earth oxides, the influence of the type and the amount of the fluoride on the thermal conductivity, hardness and strength of Si3N4 ceramics was studied. Results show that the thermal conductivity of a sample sintered with CeF3 is nearly 10% higher than that of the sample sintered with Ce2O3, while the samples sintered with LaF3 increases further 15% as comparing with the samples sintered with CeF3. The strength of the samples changes reversely. These results express that the thermal conductivity of Si3N4 ceramics can be improved by using rare-earth fluoride additives instead of the oxides, and the type of rare-earth fluorides has a significant impact on the properties of Si3N4 ceramics.

Characterization of Rare-Earth Fluoride Anti-Stokes Phosphors by Scanning arid Transmission Electron Microscopy

1971 ◽  
Vol 29 ◽  
pp. 142-143
Author(s):  
N. M. P. Low ◽  
L. E. Brosselard
Keyword(s):  
Electron Microscopy ◽  
Rare Earth ◽  
Elevated Temperatures ◽  
Stoichiometric Composition ◽  
Rare Earth Ions ◽  
Crystalline Solid ◽  
Precipitation Process ◽  
Rare Earth Fluoride ◽  
Earth Fluoride ◽  
Rare Earth Fluorides

There has been considerable interest over the past several years in materials capable of converting infrared radiation to visible light by means of sequential excitation in two or more steps. Several rare-earth trifluorides (LaF3, YF3, GdF3, and LuF3) containing a small amount of other trivalent rare-earth ions (Yb3+ and Er3+, or Ho3+, or Tm3+) have been found to exhibit such phenomenon. The methods of preparation of these rare-earth fluorides in the crystalline solid form generally involve a co-precipitation process and a subsequent solid state reaction at elevated temperatures. This investigation was undertaken to examine the morphological features of both the precipitated and the thermally treated fluoride powders by both transmission and scanning electron microscopy.Rare-earth oxides of stoichiometric composition were dissolved in nitric acid and the mixed rare-earth fluoride was then coprecipitated out as fine granules by the addition of excess hydrofluoric acid. The precipitated rare-earth fluorides were washed with water, separated from the aqueous solution, and oven-dried.

High-pressure Syntheses and Characterization of the Rare-earth Fluoride Borates RE2(BO3)F3 (RE=Tb, Dy, Ho)

2013 ◽  
Vol 68 (11) ◽  
pp. 1198-1206 ◽  
Author(s):  
Ernst Hinteregger ◽  
Michael Enders ◽  
Almut Pitscheider ◽  
Klaus Wurst ◽  
Gunter Heymann ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Rare Earth ◽  
Monoclinic Space Group ◽  
Rare Earth Fluoride ◽  
Earth Fluoride ◽  
Structure Determinations ◽  
New Compounds ◽  
Rare Earth Fluorides

The new rare-earth fluoride borates RE2(BO3)F3 (RE=Tb, Dy, Ho) were synthesized under highpressure/ high-temperature conditions of 1:5 GPa=1200 °C for Tb2(BO3)F3 and 3:0 GPa=900 °C for Dy2(BO3)F3 and Ho2(BO3)F3 in a Walker-type multianvil apparatus from the corresponding rareearth sesquioxides, rare-earth fluorides, and boron oxide. The single-crystal structure determinations revealed that the new compounds are isotypic to the known rare-earth fluoride borate Gd2(BO3)F3. The new rare-earth fluoride borates crystallize in the monoclinic space group P21/c (Z = 8) with the lattice parameters a=16:296(3), b=6:197(2), c=8:338(2) Å , b =93:58(3)° for Tb2(BO3)F3, a= 16:225(3), b = 6:160(2), c = 8:307(2) Å , b = 93:64(3)° for Dy2(BO3)F3, and a = 16:189(3), b = 6:124(2), c = 8:282(2) Å , β= 93:69(3)° for Ho2(BO3)F3. The four crystallographically different rare-earth cations (CN=9) are surrounded by oxygen and fluoride anions. All boron atoms form isolated trigonal-planar [BO3]3- groups. The six crystallographically different fluoride anions are in a nearly planar coordination by three rare-earth cations.

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.

Thermal conductivity of rare earth fluoride crystals

1976 ◽  
Vol 30 (1) ◽  
pp. 99-101
Author(s):  
B. M. Mogilevskii ◽  
V. F. Tumpurova ◽  
A. F. Chudnovskii
Keyword(s):  
Thermal Conductivity ◽  
Rare Earth ◽  
Rare Earth Fluoride ◽  
Earth Fluoride ◽  
Fluoride Crystals

A general strategy for the synthesis of rare earth fluoride nano(micro)crystals

CrystEngComm ◽  
2018 ◽  
Vol 20 (45) ◽  
pp. 7293-7300 ◽  
Author(s):  
Songtao Liu ◽  
Gejihu De ◽  
Xian Wang ◽  
Yueshan Xu ◽  
Yuanyuan Liu ◽  
...  
Keyword(s):  
Rare Earth ◽  
Environmentally Friendly ◽  
General Strategy ◽  
Solvothermal Route ◽  
Rare Earth Fluoride ◽  
Earth Fluoride ◽  
Environmentally Friendly Method ◽  
Rare Earth Fluorides

A simple, and environmentally friendly method to synthesize rare earth fluorides of REF3 (RE = La, Y), and AREF4 (A = Li, Na, K; RE = La, Gd, Y) nano(micro)crystals via a solvothermal route.

Thermal Decomposition of Rare Earth Fluoride Hydrates

Science ◽  
1959 ◽  
Vol 129 (3352) ◽  
pp. 842-842 ◽  
Author(s):  
W. W. WENDLANDT ◽  
B. LOVE
Keyword(s):  
Thermal Decomposition ◽  
Rare Earth ◽  
Rare Earth Fluoride ◽  
Earth Fluoride

In situ high temperature NMR and EXAFS experiments in rare-earth fluoride molten salts

2004 ◽  
Vol 7 (12) ◽  
pp. 1135-1140 ◽  
Author(s):  
Anne-Laure Rollet ◽  
Catherine Bessada ◽  
Aïdar Rakhmatoulline ◽  
Yannick Auger ◽  
Philippe Melin ◽  
...  
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Molten Salts ◽  
Rare Earth Fluoride ◽  
Earth Fluoride

One-step synthesis of carboxyl-functionalized rare-earth fluoride nanoparticles for cell imaging and drug delivery

RSC Advances ◽  
2015 ◽  
Vol 5 (43) ◽  
pp. 33999-34007 ◽  
Author(s):  
Zhiyang Zhang ◽  
Xiaoyan Ma ◽  
Zhirong Geng ◽  
Kuaibing Wang ◽  
Zhilin Wang
Keyword(s):  
Drug Delivery ◽  
Rare Earth ◽  
Hydrothermal Treatment ◽  
Cellular Uptake ◽  
Cell Imaging ◽  
Rare Earth Fluoride ◽  
Earth Fluoride ◽  
One Step ◽  
Fluoride Nanoparticles

CDDP was loaded onto the surface of carboxyl polymer-coated NaYF4:Yb3+/Tm3+ nanoparticles prepared by hydrothermal treatment in the form of Pt–O bonds, and delivered through cellular uptake of the NaYF4–CDDP composite.

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