scholarly journals Novel Materials through Non-Hydrolytic Sol-Gel Processing: Negative Thermal Expansion Oxides and Beyond

Materials ◽  
2010 ◽  
Vol 3 (4) ◽  
pp. 2567-2587 ◽  
Author(s):  
Cora Lind ◽  
Stacy D. Gates ◽  
Nathalie M. Pedoussaut ◽  
Tamam I. Baiz
Keyword(s):  
Thermal Expansion ◽  
Sol Gel ◽  
Negative Thermal Expansion ◽  
Novel Materials ◽  
Gel Processing

Synthesis of ZrW2O8 Ceramics and Composites from Aqueous Sol-Gel Precursors

2006 ◽  
Vol 45 ◽  
pp. 218-222
Author(s):  
Klaartje de Buysser ◽  
Serge Hoste ◽  
Isabel Van Driessche
Keyword(s):  
Phase Transition ◽  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Sol Gel ◽  
Negative Thermal Expansion ◽  
Oxide Mixture ◽  
Stability Range ◽  
Cubic Symmetry ◽  
Geometrical Effect

The thermal expansion of a ceramic material in general leads to a positive thermal expansion coefficient (α). In the last decennium, several families of materials which exhibit negative thermal expansion, arising from a specific geometrical effect in their so-called open framework structures, have been discovered. Usually, this negative thermal expansion coefficient is small, anisotropic and the phenomena occur in a very small temperature interval. ZrW2O8 is an exception because of its large and isotropic negative thermal expansion coefficient (NTE) in a temperature range from 0.5K to 1050K. A cubic symmetry is found over the entire stability range with a phase transition from α-ZrW2O8 to β-ZrW2O8 near 430K. This phase transition is noticed by a change in α. The aqueous citrate-gel method is a suitable synthesis route for negative thermal expansion ceramics and will give a fine, pure and homogenous oxide mixture, well suitable for the preparation of ZrW2O8. The expansion coefficient of α–ZrW2O8 is -11 μm/m K whereas for the β- ZrW2O8 a value of -3 is obtained.

Effects of Heat-Treatment Temperature on the Properties of Negative CTE Eucryptite Ceramics

2010 ◽  
Vol 105-106 ◽  
pp. 123-125 ◽  
Author(s):  
Yong Li ◽  
Qi Hong Wei ◽  
Ling Li ◽  
Chong Hai Wang ◽  
Xiao Li Zhang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Heat Treatment Temperature ◽  
Bending Strength ◽  
Sol Gel ◽  
Negative Thermal Expansion ◽  
Treatment Temperature ◽  
Heat Treated

In this paper, negative thermal expansion coefficient eucryptite powders were prepared by sol-gel method using silica-sol as starting material. The raw blocks were obtained by dry pressing process after the powder was synthesized, and then the raw blocks were heat-treated at 600º, 1150º, 1280º, 1380º, 1420º and 1450°C, respectively. Variations of density, porosity and thermal expansion coefficient at different heat treatment temperatures were investigated. Phase transformation and fracture surface morphology of eucryptite heat-treated at different temperatures, respectively, were observed by XRD and SEM. The results indicate that, with the increasing heat- treatment temperature, the grain size and the bending strength increased, porosity decreased, thermal expansion coefficient decreased continuously. Negative thermal expansion coefficient of -5.3162×10-6~-7.4413×10-6 (0~800°C) was obtained. But when the heat-treatment temperature was more than 1420°C, porosity began to increase, bending strength began to decrease, which were the symbols of over-burning, while the main crystal phase didn’t change.

Ceramic thin films by sol-gel processing as novel materials for integrated humidity sensors

1996 ◽  
Vol 31 (1-2) ◽  
pp. 59-70 ◽  
Author(s):  
Enrico Traversa ◽  
Guglielmina Gnappi ◽  
Angelo Montenero ◽  
Gualtiero Gusmano
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Humidity Sensors ◽  
Novel Materials ◽  
Ceramic Thin Films ◽  
Gel Processing

scholarly journals Preparation and Thermal Expansion Behavior of Pollucite Powders by Sol-Gel Processing

1991 ◽  
Vol 99 (1152) ◽  
pp. 686-691 ◽  
Author(s):  
Hidehiko KOBAYASHI ◽  
Toshihiro TERASAKI ◽  
Toshiyuki MORI ◽  
Chihiro ISHIHARA ◽  
Shoshichi SAITO ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Sol Gel ◽  
Thermal Expansion Behavior ◽  
Expansion Behavior ◽  
Gel Processing

Ceramic thin films by sol-gel processing as novel materials for integrated humidity sensors

1996 ◽  
pp. 59-70 ◽  
Author(s):  
Enrico Traversa ◽  
Guglielmina Gnappi ◽  
Angelo Montenero ◽  
Gualtiero Gusmano
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Humidity Sensors ◽  
Novel Materials ◽  
Ceramic Thin Films ◽  
Gel Processing

scholarly journals Sol–gel synthesis of doped Cu2V2O7 fine particles showing giant negative thermal expansion

AIP Advances ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 075207 ◽  
Author(s):  
M. Sato ◽  
V. Warne-Lang ◽  
Y. Kadowaki ◽  
N. Katayama ◽  
Y. Okamoto ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Fine Particles ◽  
Sol Gel ◽  
Negative Thermal Expansion ◽  
Sol Gel Synthesis

Fabrication of negative thermal expansion ZrMo2O8 film by sol–gel method

2012 ◽  
Vol 177 (2) ◽  
pp. 263-268 ◽  
Author(s):  
Qinqin Liu ◽  
Xiaonong Cheng ◽  
Juan Yang ◽  
Xiujuan Sun
Keyword(s):  
Thermal Expansion ◽  
Sol Gel ◽  
Negative Thermal Expansion ◽  
Gel Method ◽  
Sol Gel Method
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