Synthesis and Characterization of Mg2Si Thermoelectric Material

2013 ◽  
Vol 802 ◽  
pp. 213-217 ◽  
Author(s):  
Chalida Nakhowong ◽  
Teerawut Sumpao ◽  
Tosawat Seetawan
Keyword(s):  
Crystal Structure ◽  
Single Phase ◽  
Solid State Reaction Method ◽  
Argon Atmosphere ◽  
Synthesis And Characterization ◽  
Mixed Powder ◽  
Reaction Method ◽  
Cubic Structure ◽  
Structure And Microstructure

The Mg2Si compound was synthesized by the solid state reaction method. The powder precursors of Mg and Si were thoroughly mixed in ballmilling for 24 hr in an argon atmosphere. Mixed powder was pressed at 170MPa and sintered at 800 °C for 6 hr in an argon atmosphere. The sinter powder was crushed in mortar for 1 hr. The crystal structure and microstructure were measured and observed by using XRD and SEM. The microstructure and the crystal structure were analyzed. TheMg2Si shows single phase, cubic structure and particle size about 1-10 mm.

scholarly journals Thermoelectric Study of La2Ti2-xNbxO7 (0≤x≤0.25) Ceramic Materials

2020 ◽  
pp. 38-47
Author(s):  
A. C. Iyasara ◽  
F. U. Idu ◽  
E. O. Nwabineli ◽  
T. C. Azubuike ◽  
C. V. Arinze
Keyword(s):  
Crystal Structure ◽  
Thermal Conductivity ◽  
Solid State ◽  
Single Phase ◽  
Ceramic Materials ◽  
Solid State Reaction Method ◽  
Reaction Method ◽  
Reducing Atmosphere ◽  
High Seebeck Coefficient ◽  
Porous Microstructures

La2Ti2-xNbxO7 (x = 0.00, 0.05, 0.10, 0.15, 0.20, 0.25) powders were synthesised via solid state reaction method, followed by sintering at 1673 K in a reducing atmosphere of 5% H2/N2 gas. The crystal structure, microstructure and thermoelectric (TE) properties of the pure and Nb-doped La2Ti2O7 ceramics were investigated. All compositions were single phase with porous microstructures consistent with their low experimental densities. Thermoelectric results of Nb-doped compositions showed improved properties in comparison to pure La2Ti2O7, suggesting that cation doping has the potential to improve the thermoelectric properties. Generally, the TE results obtained are not suitable for thermoelectric applications. However, the high Seebeck coefficient (≥190 μV/K) and glass-like thermal conductivity ( ≤2.26 w / m.k )  values achieved have opened a new window for exploring the thermoelectric potentials of La2Ti2O7 and other related oxides.

Effects of Various Fluxes on Synthesis of Deep Red Emitting CaAl12O19:Mn4+ Phosphors

2016 ◽  
Vol 852 ◽  
pp. 454-460 ◽  
Author(s):  
Qiu Hong Zhang ◽  
Hai Yong Ni ◽  
Ling Li Wang ◽  
Fang Ming Xiao
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Solid State Reaction ◽  
Single Phase ◽  
Luminescent Properties ◽  
Solid State Reaction Method ◽  
Luminescent Intensity ◽  
Reaction Method ◽  
Structure Morphology ◽  
Forming Temperature

Deep red emitting CaAl12-xO19:xMn4+ phosphors were synthesized by solid state reaction method. Various fluxes (BaF2, H3BO3, Na2CO3 and NH4Cl) were added in preparation of the phosphors. The influences of the various fluxes on the crystal structure, morphology and luminescent properties of CaAl12O19:Mn4+ phosphors were studied. The results show that the obtained phosphors with fluxes possessed better luminescent intensity than that of the phosphors without fluxes. The maximum luminescent intensities were found with the following order: H3BO3 (2.0 wt%) > Na2CO3 (0.5 wt%) > NH4Cl (0.3 wt%) > BaF2 (0.1 wt%) > no flux. The H3BO3 flux can decrease the single phase forming temperature of CaAl12O19:Mn4+ phosphors by about 150°C.

Synthesis and Characterization of Delafossite CuLaO2 for Thermoelectric Application

2007 ◽  
Vol 534-536 ◽  
pp. 1081-1084 ◽  
Author(s):  
Yuhsuke Takahashi ◽  
Hiroaki Matsushita ◽  
Akinori Katsui
Keyword(s):  
Seebeck Coefficient ◽  
Single Phase ◽  
Metallic Copper ◽  
Solid State Reaction Method ◽  
X Ray Diffraction ◽  
Mixed Powder ◽  
X Ray ◽  
Type Semiconductor ◽  
P Type

The preparation of single-phase CuLaO2 with delafossite-type structure by means of the solid-state reaction method was investigated using X-ray diffraction. The results showed that notwhistanding the fact that there was a trace of metallic copper, nearly single-phase CuLaO2 was obtained by using La(OH)3 as a lanthanum source and by firing the mixed powder with nonstoichiometric composition ratio of La(OH)3:Cu2O =1:1.425 in a vacuum at 1273 K for 10 h. The measurement of electrical conductivity and Seebeck coefficient showed that CuLaO2 thus obtained was a p-type semiconductor and had a Seebeck coefficient of approximately 70 /V/K.

scholarly journals Thermoelectric Study of La2Ti2-xNbxO7 (0 ≤ x ≤ 0.25) Ceramics

2020 ◽  
Author(s):  
Adindu Cyril Iyasara ◽  
Felix U Idu
Keyword(s):  
Crystal Structure ◽  
Thermal Conductivity ◽  
Solid State ◽  
Seebeck Coefficient ◽  
Single Phase ◽  
Solid State Reaction Method ◽  
Reaction Method ◽  
Reducing Atmosphere ◽  
High Seebeck Coefficient ◽  
Porous Microstructures

Abstract La2Ti2 − xNbxO7 (x = 0.00, 0.05, 0.10, 0.15, 0.20, 0.25) powders were synthesised via solid state reaction method, followed by sintering at 1673 K in a reducing atmosphere of 5% H2/N2 gas. The crystal structure, microstructure and thermoelectric (TE) properties of the pure and Nb-doped La2Ti2O7 ceramics were investigated. All compositions were single phase with porous microstructures consistent with their low experimental densities. Thermoelectric results of Nb-doped compositions showed improved properties in comparison to pure La2Ti2O7, suggesting that cation doping has the potential to improve the thermoelectric properties. Generally, the TE results obtained are not suitable for thermoelectric applications. However, the high Seebeck coefficient ( \ge 190 µV/K) and glass-like thermal conductivity ( \le 2.26 \text{W}/\text{m}.\text{K}) values achieved have opened a new window for exploring the thermoelectric potentials of La2Ti2O7 and other related oxides.

scholarly journals Novel Orange Color Pigments Based on La3LiMnO7

Molecules ◽  
2021 ◽  
Vol 26 (20) ◽  
pp. 6243
Author(s):  
Ryohei Oka ◽  
Jun-ichi Koyama ◽  
Takuro Morimoto ◽  
Toshiyuki Masui
Keyword(s):  
Crystal Structure ◽  
Optical Properties ◽  
Toxic Elements ◽  
Single Phase ◽  
Solid State Reaction Method ◽  
Orange Pigment ◽  
Phase Form ◽  
B Values ◽  
Reaction Method ◽  
Orange Color

La3LiMn1−xTixO7 (0 ≤ x ≤ 0.05) samples were synthesized by a solid-state reaction method, and a single-phase form was observed for the samples in the range of x ≤ 0.03. Crystal structure, optical properties, and color of the La3LiMn1−xTixO7 (0 ≤ x ≤ 0.03) samples were characterized. Strong optical absorption was observed at a wavelength between 400 and 550 nm, and a shoulder absorption peak also appeared around 690 nm in all samples; orange colors were also exhibited. Among the samples synthesized, the most brilliant orange color was obtained at La3LiMn0.97Ti0.03O7. The redness (a*) and yellowness (b*) values of this pigment were higher than those of the commercially available orange pigments. Therefore, the orange color of this pigment is brighter than those of the commercial products. Since the La3LiMn0.97Ti0.03O pigment is composed of non-toxic elements, it could be a new environmentally friendly inorganic orange pigment.

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