On improving the phase stability and thermal expansion coefficients of lanthanum cerium oxide solid solutions

2006 ◽  
Vol 54 (8) ◽  
pp. 1505-1508 ◽  
Author(s):  
Wen Ma ◽  
Shengkai Gong ◽  
Huibin Xu ◽  
Xueqiang Cao
Keyword(s):  
Thermal Expansion ◽  
Cerium Oxide ◽  
Solid Solutions ◽  
Phase Stability ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

Investigation of Strontium-Niobium Oxides for Application to Thermal Barrier Coatings

2006 ◽  
Vol 317-318 ◽  
pp. 517-520 ◽  
Author(s):  
Masato Shida ◽  
Katsunori Akiyama ◽  
Ichiro Nagano ◽  
Yuichiro Murakami ◽  
Satoshi Ohta
Keyword(s):  
Thermal Expansion ◽  
Thermal Barrier Coatings ◽  
Solid Solutions ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Niobium Oxides ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
Thermal Conductivities

We have been trying to find new oxide compounds with large thermal expansion coefficients and low thermal conductivities by means of a material calculation technique. Among thousands of compounds in the databases, we found that there were some materials with low thermal conductivities and large thermal expansion coefficients in the group of strontium-niobium oxides. For example, Sr4Nb2O9 has a thermal expansion coefficient of 14.510-6 / and thermal conductivity of 1.0 W/mK, although a slight amount of other phases appear during long-term annealing. These thermal properties are better than those of yttria-stabilized zirconia, which is the standard material for thermal barrier coatings. To prevent the precipitation of other phases, we prepared the solid solutions, Sr4Nb2-xMxO9. In this study, the thermal conductivities and thermal expansion coefficients of these solid solutions were measured, and their thermal stabilities were evaluated by long-term annealing.

Nitrate-Citrate Combustion Synthesis and Properties of Ce1-xGdxO2-x/2 Solid Solutions

2007 ◽  
Vol 336-338 ◽  
pp. 401-404
Author(s):  
Cheng Peng ◽  
Zhen Zhang
Keyword(s):  
Thermal Expansion ◽  
Solid Solutions ◽  
Combustion Method ◽  
Thermal Expansion Coefficients ◽  
Gel Combustion ◽  
Dense Ceramic ◽  
Maximum Conductivity ◽  
Expansion Coefficients ◽  
Lower Temperature ◽  
Gel Combustion Method

The structure, thermal expansion coefficients, and electric conductivity of Ce1-xGdxO2-x/2 (x = 0 ~ 0.6) solid solutions, prepared by gel-combustion method, were investigated. The uniform small particle size of the gel-combustion prepared materials allows sintering of the samples into highly dense ceramic pellets at 1300°C, a significantly lower temperature, compared to that of 1600~1650°C required for ceria solid electrolytes prepared by traditional solid state techniques. XRD showed that single-phase solid solutions have been formed in all investigated range. The maximum conductivity, σ600°C = 5.26×10-3S/cm, was found at x = 0.2. The thermal expansion coefficient, determined from high-temperature X-ray data is 8.125×10-6 K-1 at x = 0.2.

scholarly journals High-pressure synthesis and thermal expansivity investigation of carbonate solid solutions Mg1-xMnxCO3

2020 ◽  
Vol 48 (4) ◽  
pp. 367-380
Author(s):  
RUI LI ◽  
WEN LIANG ◽  
HANQI HE ◽  
YONG MENG ◽  
HONGFENG TANG
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Solid Solutions ◽  
Thermal Expansivity ◽  
X Ray Diffraction ◽  
Thermal Expansion Coefficients ◽  
High Temperature Xrd ◽  
Pressure Synthesis ◽  
Expansion Coefficients ◽  
Cubic Function

Using synthesized MgCO3 and reagent-grade MnCO3 as starting materials, a series of Mg1-xMnxCO3 carbonate solid solutions were synthesized by a simple solid reaction under high-temperature-pressure conditions of 3 GPa and 800°C for 4 h. The phase compositions of as-synthesized Mg1-xMnxCO3 samples were investigated by powder X-ray diffraction (XRD); no impurities were observed. The lattice parameters were refined and showed a linear relationship as a function of the Mn2+ content, which is expected to be in accordance with the ideal solution model. Based on this, high- temperature XRD measurements were carried out to further study the thermal expansivity of Mg1-xMnxCO3. The axis thermal expansion coefficients (αa and αc) and the volumetric thermal expansion coefficient αV for Mg1-xMnxCO3 were quantified as αa =7.41×10-6/°C, αc=2.37×10-5/°C and αV=3.86×10-5/°C for x=0.0; αa =6.67×10-6/°C, αc=2.31×10-5/°C and αV=3.67×10-5/°C for x=0.1; αa=6.61×10-6/°C, αc=2.35×10-5/°C and αV=3.59×10-5/°C for x=0.3; αa=5.91×10-6/°C, αc=2.40×10-5/°C and αV=3.58×10-5/°C for x=0.5; αa=5.47×10-6/°C, αc=2.53×10-5/°C and αV=3.61×10-5/°C for x=0.7; αa=4.76×10-6/°C, αc=2.55×10-5/°C and αV=3.52×10-5/°C for x=0.9; αa=4.18×10-6/°C, αc=2.50×10-5/°C and αV=3.35×10-5/°C for x=0.3. The thermal expansion coefficients (αa, αc and αV) can be fitted with a symmetric cubic function of the Mn2+ content as αa=7.34×10-6 -7.06×10-6x+1.21×10-5x2-8.19×10-6x3; αc=2.37×10-6-7.94×10-6x+2.57×10-5x2-1.64×105x3; αV=3.85×10-5-2.08×10-5x+4.59×10-5x2-3.01×10-5x3.

Influence of Cr deficiency on sintering, thermal expansion and electrical properties of La0.75Sr0.25Cr1−xO3−δ as a SOFC interconnect material

2016 ◽  
Vol 30 (11) ◽  
pp. 1650127 ◽  
Author(s):  
Yi Ren ◽  
Wen Ma ◽  
Xiaoying Li ◽  
Jun Wang ◽  
Yu Bai ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Electrical Properties ◽  
Perovskite Phase ◽  
Ignition Process ◽  
Thermal Expansion Coefficients ◽  
Auto Ignition ◽  
Pure Perovskite Phase ◽  
Maximum Conductivity ◽  
Expansion Coefficients ◽  
Interconnect Material

The SOFC interconnect materials La[Formula: see text]Sr[Formula: see text]Cr[Formula: see text]O[Formula: see text] [Formula: see text]–[Formula: see text] were prepared using an auto-ignition process. The influences of Cr deficiency on their sintering, thermal expansion and electrical properties were investigated. All the samples were pure perovskite phase after sintering at 1400[Formula: see text]C for 4 h. The cell volume of La[Formula: see text]Sr[Formula: see text]Cr[Formula: see text]O[Formula: see text] decreased with increasing Cr deficient content. The relative density of the sintered bulk samples increased from 93.2% [Formula: see text] to a maximum value of 94.7% [Formula: see text] and then decreased to 87.7% [Formula: see text]. The thermal expansion coefficients of the sintered bulk samples were in the range of [Formula: see text]–[Formula: see text] (30–1000[Formula: see text]C), which are compatible with that of YSZ. Among the investigated samples, the sample with 0.02 Cr deficiency had a maximum conductivity of 40.4 Scm[Formula: see text] and the lowest Seebeck coefficient of 154.8 [Formula: see text]VK[Formula: see text] at 850[Formula: see text]C in pure He. The experimental results indicate that La[Formula: see text]Sr[Formula: see text]Cr[Formula: see text]O[Formula: see text] has the best properties and is much suitable for SOFC interconnect material application.

Novel Silicon-Elastomers for Advanced Soft Lithography

2006 ◽  
Vol 947 ◽  
Author(s):  
Kyung Choi
Keyword(s):  
Thermal Expansion ◽  
High Resolution ◽  
Soft Lithography ◽  
Materials Properties ◽  
Nano Scale ◽  
Thermal Expansion Coefficients ◽  
High Thermal Expansion ◽  
Expansion Coefficients

ABSTRACTHigh resolution pattern transfers in the nano-scale regime have been considerable challenges in ‘soft lithography’ to achieve nanodevices with enhanced performances. In this technology, the resolution of pattern integrations is significantly rely on the materials' properties of polydimethylsiloxane (PDMS) stamps. Since commercial PDMS stamps have shown limitations in nano-scale resolution soft lithography due to their low physical toughness and high thermal expansion coefficients, we developed stiffer, photocured PDMS silicon elastomers designed, specifically for nano-sized soft lithography and photopatternable nanofabrications.

Thermal expansion coefficients of NH4ReO4and NH4IO4down to 58 K

1985 ◽  
Vol 82 (3) ◽  
pp. 1611-1612 ◽  
Author(s):  
Stanley L. Segel ◽  
H. Karlsson ◽  
T. Gustavson ◽  
K. Edstrom
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients
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