scholarly journals Electrical Behavior of Electric Field-Assisted Pressureless Sintered Ceria-20 mol% Samaria

Ceramics ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 385-392
Author(s):  
Shirley L. Reis ◽  
Sabrina G.M. Carvalho ◽  
Eliana N.S. Muccillo ◽  
Reginaldo Muccillo

CeO2:20 mol% Sm2O3 green ceramic pellets were sintered conventionally at 1500 °C/2 h and flash sintered by applying a 200 V cm−1 electric field at 800 °C, 1000 °C and 1200 °C. The thickness shrinkage of the pellets was followed bythe specimen being positioned inside a dilatometer adapted with platinum electrodes and terminal leads connected to a power supply for application of the electric voltage. The microstructure of the surfaces of the sintered samples were observed in a scanning electron microscope. The electrical properties were evaluated by the impedance spectroscopy technique in the 5 Hz–13 MHz frequency range from 210 °C to 280 °C. The main results show that (i) the final shrinkage level is nearly independent of the temperature when the electric field is applied and slightly better than that of the 1500 °C sintered pellet, and (ii) the bulk conductivity of the sample flash sintered at 1200 °C is similar to that of the sample sintered at 1500 °C. The availability of a pathway for the electric current pulse derived from the applied electric field is proposed as the reason for the achieved shrinkages. Scavenging of the grain boundaries by Joule heating is proposed as the reason for the improved oxide ion bulk conductivity.

2015 ◽  
Vol 804 ◽  
pp. 55-58 ◽  
Author(s):  
Thanapong Sareein ◽  
Panakamon Deeyai ◽  
Bundit Putasaeng ◽  
Naphat Chathirat

In this work, impedance spectroscopy technique was used in order to investigate the electric properties of double perovskites of the Y2NiMnO6 ceramics, which were prepared by thermal decomposition technique at 800°C for 6 hours and then sintered at a high temperature of 1400°C for 6, 12, 18, and 24 hours. Consequently, the electric characterization of the Y2NiMnO6 ceramics was performed at 30°C °C in the frequency range from 102 Hz to 108 Hz. The results in the Rg with 10,000, 9,990, 6,400, and 1,700 (Ω) at sintering time, respectively. Dispersion was observed in the variation of impedance values with frequency. Possible reason for all the above observation was discussed.


RSC Advances ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 3809-3815 ◽  
Author(s):  
Huaibo Yi ◽  
Yun Lv ◽  
Yanhui Wang ◽  
Xue Fang ◽  
Victoria Mattick ◽  
...  

The bulk conductivity of Ca12Al14O33 can be apparently enhanced by Ga-doping on the Al sites.


2015 ◽  
Vol 8 (2) ◽  
pp. 179-184 ◽  
Author(s):  
Valeria Nocella ◽  
Luca Pelliccia ◽  
Paola Farinelli ◽  
Roberto Sorrentino ◽  
Mario Costa ◽  
...  

A robust and tuneless micromachined waveguide diplexer operating in the frequency range 71–86 GHz is here presented. The diplexer is based on multiple coupled cavities and it is manufactured using micromachining technology on two staked silicon layers. The diplexer consists of two filters combined to a common waveguide port via an E-plane T-junction. The two eight-order band-pass filters are centered at 73.5 and 83.5 GHz. The fractional bandwidths for two bands are 8.8 and 7.8% at higher- and lower-band, respectively. The measured insertion loss is below 0.7 dB for both the filters and the diplexer isolation is better than 55 dB, as required. The proposed technology allows for a very compact device (<20 × 20 × 1.5 mm) and the first prototypes were proved to be very robust to manufacturing tolerances and environmental tests, thus leading to an excellent tuneless manufacturing yield in future production. The diplexer will be employed in next generation terrestrial radio-link communications front-ends.


2021 ◽  
Vol 19 (3) ◽  
pp. 217-226
Author(s):  
G. Domínguez ◽  
E. Cardiel ◽  
J.L Reyes ◽  
E. Sánchez ◽  
P.R. Hernández

Purpose: The development of an electric impedance meter based on the impedance spectroscopy technique, for in vitro and in situ experimentation, with cellular epithelia submitted to extremely low frequency magnetic fields in a controlled environment. Unlike other reported systems, a strength of the one presented here is that it avoids the influence of external factors on the experiment. Materials and methods: The designed system employs the electrical impedance values obtained by the impedance spectroscopy technique to determine the parameters of the simple equivalent electrical model of a cellular monolayer. The Madin-Darby Canine Kidney (MDCK) cell cultures were used as subjects of study in the experimental protocol. Results: The validation was carried out by comparing the transepithelial electrical impedance data of the cell cultures obtained with the developed system and those of the Cellzscope® commercial system used as the standard. Non-significant differences were obtained. Conclusion: It was confirmed that the developed system provides reliable values of transepithelial electrical impedance to experiment with cell cultures and take advantage of the controlled environment to reduce the effects of experimental management.


Author(s):  
Nikolai S. Pshchelko ◽  
Ekaterina G. Vodkailo ◽  
Vladimir V. Tomaev ◽  
Boris D. Klimenkov ◽  
Veniamin L. Koshevoi ◽  
...  

Some results are provided confirming that modifying of the zinc films fabricated on glass substrates by a resulting effect of heat treatment in an atmosphere of dry air and action of cross electric field is possible. Using scanning electron microscopy (measured with the Zeiss Merlin microscope) the surface morphology of the films was studied. Also, the elemental composition of the films by micro-X-ray spectral analysis was studied. On the glass substrates, by the method of vacuum thermal evaporation, zinc films (Zn) with thickness of ~ 500 nm were obtained. In order to form ZnO films, the original films were treated at 250 °C in a dry air atmosphere, and in another case - in addition to the sample a transverse electric field with a potential of 300 V was applied. Platinum films on the silicon dioxide layer were obtained using the method of the ion-plasma sputtering. These layers were investigated by X-ray phase analysis, electron and atomic force microscopy. The thickness of platinum layers was 50 and 100 nm. During the deposition (deposition temperature – 300 °C, deposition rate - 5 nm / min), applied voltage between the platinum film and the silicon plate was 5 V. The films, obtained by applying a biasing, showed a more homogeneous fine-grained structure and a higher rate of growth than the original samples.  In this way ZnO films can be manufactured with the extended surface. The possibility of significant changes caused by electric field use in adhesion, structure and conductive properties of the coatings is discussed. The method of depositing platinum on a dielectric substrate with an additional electrostatic field is also substantiated. It is shown that the application of an electric voltage to the film leads to a significant change in the structure of the resulting coating.Forcitation:Pshchelko N.S., Vodkailo E.G., Tomaev V.V., Klimenkov B.D., Koshevoi V.L., Belorus A.O. Influence of electric field on adhesion and structure of conducting films on dielectric substances. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 8. P. 100-104.


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