Structural evolution and effects of calcium doping on nanophasic LaCoO3 powders prepared by non-alkoxidic sol–gel technique

2005 ◽  
Vol 15 (20) ◽  
pp. 2020 ◽  
Author(s):  
Venkata Krishnan ◽  
Gregorio Bottaro ◽  
Silvia Gross ◽  
Lidia Armelao ◽  
Eugenio Tondello ◽  
...  
2010 ◽  
Vol 148-149 ◽  
pp. 1016-1020
Author(s):  
Li Ren Han ◽  
Wei Guo Fu ◽  
Xiang Yun Deng ◽  
Xiao Fen Guan ◽  
Zhong Wen Tan ◽  
...  

(Ba0.7Ca0.3)TiO3 (BCT) powders and ceramics have been prepared by sol-gel technique. Structural evolution of the BCT dry gels are investigated by thermal gravimetric analysis–differential scanning calorimetry. It is found that BCT crystallites can be formed before 800 . Well-sintered samples are synthesized at 1260 for 2h. The crystal structure of the BCT powders is studied by XRD and ferroelectric properties of the ceramics are characterized by TF analyzer 2000. The Curie temperature Tc of the BCT ceramics is at about 125 . The maximum dielectric constant (εr) reaches about 4851 at 125 and hysteresis loops are measured with the temperature range from 25 to 150 .


1996 ◽  
Vol 430 ◽  
Author(s):  
Y. Zhou ◽  
O. Van der Biest ◽  
C. Groffils ◽  
P. J. Luypaert

AbstractGels in the CaO-A12O3-SiO2 (CAS) system were successfully converted into glass in a single mode, tuneable, cylindrical microwave applicator, operating at 2.45 GHz in the TM012 mode. Transparent glasses were formed as a result of the direct microwave heating of homogeneous CAS gels to well above their melting temperature (1170°C). The effect of processing parameters, such as incident power level, sample mass and location, and thermal insulation has been investigated. The excellent coupling of the CAS gel with microwave can be understood from the structural evolution during sol-gel processing.


2013 ◽  
Vol 1 (2) ◽  
pp. 59-69 ◽  
Author(s):  
Sarbjit Kaur ◽  
Niraj Bala ◽  
Charu Khosla
Keyword(s):  
Sol Gel ◽  

2011 ◽  
Vol 4 (3) ◽  
pp. 224-237 ◽  
Author(s):  
Aurica P. Chiriac ◽  
Loredana E. Nita ◽  
Iordana Neamtu ◽  
Manuela T. Nistor
Keyword(s):  
Sol Gel ◽  

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1263
Author(s):  
Elvira Mahu ◽  
Cristina Giorgiana Coromelci ◽  
Doina Lutic ◽  
Iuliean Vasile Asaftei ◽  
Liviu Sacarescu ◽  
...  

A mesoporous titania structure has been prepared using the ultrasound-assisted sol-gel technique in order to find out a way to tailor its structure. The TiO2 obtained was compared to the same version of titania but synthesized by a conventional sol-gel method with the objective of understanding the effect of ultrasound in the synthesis process. All synthesis experiments were focused on the preparation of a titania photocatalyst. Thus, the anatase photocatalytic active phase of titania was proven by X-ray diffraction. Additionally, the ultrasonation treatment proved to increase the crystallinity of titania samples, being one of the requirements to having good photocatalytic activity for titania. The influence of surfactant/titania precursor weight ratio on the structural (XRD), textural (N2-sorption measurements), morphological (TEM), surface chemistry (FTIR) and optical properties (UVDR) was investigated. It was observed that the crystallite size, specific surface area, band gap energy and even photocatalytic activity was affected by the synergism occurring between cavitation effect and the surfactant/titania precursor weight ratio. The study yielded interesting great results that could be considered for further application of ultrasound to tailor mesoporous titania features via sol-gel soft template synthesis, against conventional sol-gel process.


2021 ◽  
Vol 127 (5) ◽  
Author(s):  
M. M. El-Desoky ◽  
Ibrahim Morad ◽  
Mohamed. A. Ali ◽  
Atif Mossad Ali ◽  
M. A. Sayed ◽  
...  

2000 ◽  
Vol 341-348 ◽  
pp. 2459-2460 ◽  
Author(s):  
A. Sin ◽  
P. Odier ◽  
F. Weiss ◽  
M. Núñez-Regueiro
Keyword(s):  
Sol Gel ◽  

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