Conductive Metakaolin Geopolymer with Steel Microfibres​

2021 ◽  
Vol 321 ◽  
pp. 59-64
Author(s):  
Cecílie Mizerová ◽  
Ivo Kusák ◽  
Pavel Rovnaník ◽  
Patrik Bayer

Research of alkali-activated materials and geopolymers suggests their increased ability to transfer the electric charge thus indicating their suitability for self-sensing and other multifunctional composites. In this paper, the electrical properties of metakaolin geopolymer are enhanced by the incorporated steel microfibres that also improve the mechanical and fractural properties of the composite. Selected electrical properties of metakaolin geopolymer mortars with steel microfibres (up to 30 % of metakaolin wt.) were assessed via impedance spectroscopy analysis and followed by testing their compressive and flexural strength. Mercury intrusion porosimetry and SEM imaging enabled to characterize the binder microstructure and quality of fibre-matrix bonding.

RSC Advances ◽  
2020 ◽  
Vol 10 (47) ◽  
pp. 28007-28018
Author(s):  
Amine Bendahhou ◽  
Karim Chourti ◽  
Rachid El Bouayadi ◽  
Soufian El Barkany ◽  
Mohamed Abou-Salama

In this work, Zn co-doped tungsten bronze having nominal formula Ba5CaTi1.94Zn0.06Nb8O30 has been synthesized and systematically studied for structure, dielectric and electrical properties.


2014 ◽  
Vol 46 (2) ◽  
pp. 235-245 ◽  
Author(s):  
D.L. Sekulic ◽  
Z.Z. Lazarevic ◽  
C. Jovalekic ◽  
A. Recnik ◽  
M. Romcevic ◽  
...  

Nano spinel ferrites MFe2O4 (M=Ni, Mn, Zn) were obtained by soft mechanochemical synthesis in a planetary ball mill. The appropriate mixture of oxide and hydroxide powders was used as initial compounds. All of this mixture of powders was mechanically activated, uniaxial pressed and sintered at 1100?C/2h. The phase composition of the powders and sintered samples were analyzed by XRD and Raman spectroscopy. Morphologies were examined by SEM. In this study, the AC-conductivity and DC-resistivity of sintered samples of MFe2O4 (M= Ni, Mn, Zn) ferrites were measured at different frequencies and at room temperature. The values of the electrical conductivities show an increase with increasing temperature, which indicated the semiconducting behavior of the studied ferrites. The conduction phenomenon of the investigated samples could be explained on the basis of hopping model. The complex impedance spectroscopy analysis was used to study the effect of grain and grain boundary on the electrical properties of all three obtained ferrites


2010 ◽  
Vol 405 (17) ◽  
pp. 3564-3571 ◽  
Author(s):  
K. Prasad ◽  
S. Bhagat ◽  
Priyanka ◽  
K. AmarNath ◽  
K.P. Chandra ◽  
...  

Author(s):  
D. J. Bailey ◽  
M. C. Stennett ◽  
J. Heo ◽  
N. C. Hyatt

AbstractSEM–EDX and Raman spectroscopy analysis of radioactive compounds is often restricted to dedicated instrumentation, within radiological working areas, to manage the hazard and risk of contamination. Here, we demonstrate application of WetSEM® capsules for containment of technetium powder materials, enabling routine multimodal characterisation with general user instrumentation, outside of a controlled radiological working area. The electron transparent membrane of WetSEM® capsules enables SEM imaging of submicron non-conducting technetium powders and acquisition of Tc Lα X-ray emission, using a low cost desktop SEM–EDX system, as well as acquisition of good quality μ-Raman spectra using a 532 nm laser.


Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4374
Author(s):  
Wu-Jian Long ◽  
Xuanhan Zhang ◽  
Biqin Dong ◽  
Yuan Fang ◽  
Tao-Hua Ye ◽  
...  

Reduced graphene oxide (rGO) has been widely used to modify the mechanical performance of alkali activated slag composites (AASC); however, the mechanism is still unclear and the electrical properties of rGO reinforced AASC are unknown. Here, the rheological, mechanical, and electrical properties of the AASC containing rGO nanosheets (0, 0.1, 0.2, and 0.3 wt.%) are investigated. Results showed that rGO nanosheets addition can significantly improve the yield stress, plastic viscosity, thixotropy, and compressive strength of the AASC. The addition of 0.3 wt.% rGO nanosheets increased the stress, viscosity, thixotropy, and strength by 186.77 times, 3.68 times, 15.15 times, and 21.02%, respectively. As for electrical properties, the impedance of the AASC increased when the rGO content was less than 0.2 wt.% but decreased with the increasing dosage. In contrast, the dielectric constant and electrical conductivity of the AASC containing rGO nanosheets decreased and then increased, which can be attributed to the abundant interlayer water and the increasing structural defects as the storage sites for charge carriers, respectively. In addition, the effect of graphene oxide (GO) on the AASC is also studied and the results indicated that the agglomeration of GO nanosheets largely inhibited the application of it in the AASC, even with a small dosage.


2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Naokazu Murata ◽  
Naoki Saito ◽  
Kinji Tamakawa ◽  
Ken Suzuki ◽  
Hideo Miura

Effects of crystallographic quality of grain boundaries on mechanical and electrical properties were investigated experimentally. A novel method using two parameters of image quality (IQ) and confidence index (CI) values based on electron back-scattering diffraction (EBSD) analysis was proposed in order to evaluate crystallographic quality of grain boundaries. IQ value was defined as an index to evaluate crystallinity in region irradiated with electron beam. CI value determined existence of grain boundaries in the region. It was found that brittle intergranular fatigue fracture occurred in the film without annealing and the film annealed at 200 °C because network of grain boundaries with low crystallinity remained in these films. On the other hand, the film annealed at 400 °C caused only ductile transgranular fatigue fracture because grain boundaries with low crystallinity almost disappeared. From results of measurement of electrical properties, electrical resistivity of copper interconnection annealed at 400 °C with high crystallinity (2.09 × 10−8 Ωm) was low and electron migration (EM) resistance was high compared with an copper interconnection without annealing with low crystallinity (3.33 × 10−8 Ωm). It was clarified that the interconnection with high crystallinity had superior electrical properties. Thus, it was clarified that the crystallographic quality of grain boundaries has a strong correlation of mechanical and electrical reliability.


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