The Influence of Ion Beam Implantation on Electrical Properties of Polycrystalline MnNiCuFeO

1992 ◽  
Vol 279 ◽  
Author(s):  
Li Binbin ◽  
Tan Hui ◽  
Han Ying ◽  
Tao Wei ◽  
Lin Chenglu
Keyword(s):  
Electrical Properties ◽  
Grain Boundaries ◽  
Boundary Effect ◽  
Ion Beam ◽  
Low Frequency ◽  
Bulk Properties ◽  
Spreading Resistance ◽  
Impedance Analyzer ◽  
Ion Beam Implantation ◽  
Grain Boundary Effect

ABSTRACTPolycrystalline MnNiCuFeO was implanted by B+, P+ and Si+ ion beams and thermally annealed. The structure and electrical properties of the sample were measured using SEM, Microprobe (MP), Low Frequency Impedance Analyzer (LFIA) and Spreading Resistance Probe (SRP). The results show that the resistance of grain boundaries is much higher than that of grains. The spreading resistance of the implanted samples is lower by factor of 2 than that of the unimplanted ones. The ratio of the real part Rs (grain effect) to imaginary part Xs (grain boundary effect) decreases with ion beam implantation. From these results, we came to the conclusion that the behavior of the grain boundaries is important to the bulk properties of polycrystalline MnNiCuFeO.

scholarly journals Electrical properties of mechanically activated zinc oxide

2006 ◽  
Vol 38 (2) ◽  
pp. 131-138 ◽  
Author(s):  
K. Vojisavljevic ◽  
M. Zunic ◽  
G. Brankovic ◽  
T. Sreckovic
Keyword(s):  
Zinc Oxide ◽  
Electrical Properties ◽  
Grain Boundaries ◽  
Arrhenius Equation ◽  
Electrical Response ◽  
High Energy ◽  
Microstructural Properties ◽  
Impedance Analyzer ◽  
Zinc Oxide Powder ◽  
Zno Ceramics

Microstructural properties of a commercial zinc oxide powder were modified by mechanical activation in a high-energy vibro-mill. The obtained powders were dry pressed and sintered at 1100?C for 2 h. The electrical properties of grain boundaries of obtained ZnO ceramics were studied using an ac impedance analyzer. For that purpose, the ac electrical response was measured in the temperature range from 23 to 240?C in order to determine the resistance and capacitance of grain boundaries. The activation energies of conduction were obtained using an Arrhenius equation. Donor densities were calculated from Mott-Schottky measurements. The influence of microstructure, types and concentrations of defects on electrical properties was discussed.

scholarly journals Grain boundary effects on piezoelectric properties of the core–shell-structured BaTiO3@TiO2 ceramics

2018 ◽  
Vol 08 (06) ◽  
pp. 1850044 ◽  
Author(s):  
Xixi Li ◽  
Zhonghua Yao ◽  
Juan Xie ◽  
Zongxin Li ◽  
Hua Hao ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Grain Boundary ◽  
Boundary Effect ◽  
Ferroelectric Properties ◽  
Critical Role ◽  
Impedance Analysis ◽  
Ferroelectric Materials ◽  
Boundary Effects ◽  
Grain Boundary Effects ◽  
Grain Boundary Effect

Grain boundary effect on BaTiO3 has been widely investigated for several decades. However, all of them tailored the grain boundary by grain size of BaTiO3. In this case, a direct way was introduced to modify the grain boundary by coating technique to investigate the role of grain boundary in ferroelectric materials. Nonferroelectric phase TiO2 was employed to investigate grain boundary effects on the electrical properties of BaTiO3 piezoelectric ceramics. TiO2 coating can result in the reduction of piezoelectric and ferroelectric properties and the annealing process in oxygen can increase piezoelectric behavior of pure BaTiO3 due to valence state of Ti ions while that remains for Ti-modified composition possibly due to the increased grain boundary effect by impedance analysis. Compared with ferroelectric grain, grain boundary plays a critical role to impact the electrical properties of perovskite-type ferroelectric materials.

Nanopore Imaging in Vaca Muerta Mudrocks To Evaluate Controls on Complex Resistivity Spectra in Unconventional Reservoirs

2017 ◽  
Vol 20 (04) ◽  
pp. 1028-1044 ◽  
Author(s):  
Jan H. Norbisrath ◽  
G. Michael Grammer ◽  
Beth Vanden Berg ◽  
Max Tenaglia ◽  
Gregor P. Eberli ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Ion Beam ◽  
Low Frequency ◽  
Hydrocarbon Exploration ◽  
Unconventional Reservoirs ◽  
Rock Properties ◽  
Pore Geometry ◽  
Carbonate Content ◽  
Complex Resistivity ◽  
Vaca Muerta

Summary Nanopore geometry and mineralogy are key parameters for effective hydrocarbon exploration and production in unconventional reservoirs. This study describes an approach to evaluate relationships between low-frequency complex resistivity spectra (CRS), nanopore geometry, and mineralogy to use CRS to provide estimates of reservoir parameters concerning hydrocarbon saturation, storage, and producibility. For this purpose, the frequency dispersion of CRS was analyzed in 56 mudrock core plugs from the Vaca Muerta Formation (VMF) (Jurassic/Cretaceous) in Argentina, along with cementation factors (m), carbonate content (CO3), and total organic carbon (TOC). To quantify the nanoporosity, a subset of 23 samples was milled with broad ion beam (BIB) and imaged with scanning electron microscopy (SEM); the image grids of these samples were stitched together into high-resolution BIB-SEM mosaics and analyzed with digital image analysis (DIA) techniques. Results show that porosity is the dominant control on electrical properties in the mudrocks analyzed as part of this study. There is no conclusive evidence that pore geometry influences the electrical properties in the analyzed mudrocks. Pore-geometry parameters [dominant pore size (DOMsize) and perimeter over area (PoA)] do not correlate with electrical properties. Instead, mineralogy shows a first-order correlation with electrical properties, where cementation exponents are higher in rocks with high TOC and low CO3 content. CRS can be used to estimate porosity and cementation factors with high correlation coefficients of R2 = 0.71 and R2 = 0.95, respectively. Estimates of the 2D interfacial surface area (ISA2D), which is a function of both pore geometry and porosity, achieve an R2 = 0.59. The results of this study suggest that low-frequency dielectric rock properties, if measured downhole, could be useful to identify primary producing intervals in unconventional reservoirs, and to accurately determine cementation factors independent of formation fluids and porosity.

Scale invariance of the low‐frequency electrical properties of inhomogeneous materials

Geophysics ◽  
1981 ◽  
Vol 46 (7) ◽  
pp. 1057-1059 ◽  
Author(s):  
Morrel H. Cohen
Keyword(s):  
Dielectric Constant ◽  
Electrical Properties ◽  
Scale Invariance ◽  
Low Frequency ◽  
Inhomogeneous Material ◽  
Inhomogeneous Materials ◽  
Low Frequencies ◽  
Bulk Properties ◽  
Grain Sizes

We show that the electrical properties of an inhomogeneous material are invariant to the scale of the inhomogeneity at low frequencies when they are determined solely from local bulk properties, Thus the pore and grain sizes of rocks cannot be ascertained by low‐frequency conductivity and dielectric constant measurements.

Evaluation of Grain Boundary Effect on the Strength of Fe-C Martensitic Steels through Nanoindentation Technique

2005 ◽  
Vol 475-479 ◽  
pp. 4113-4116 ◽  
Author(s):  
Takahito Ohmura ◽  
Kaneaki Tsuzaki
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Boundary Effect ◽  
Martensitic Steels ◽  
Tempering Temperature ◽  
Nanoindentation Technique ◽  
The Matrix ◽  
Grain Boundary Effect ◽  
Grain Boundary Strengthening

Nanoindentation measurements were performed for Fe-C based martensitic steels, and then the strengthening factors such as grain boundary effect were evaluated. Nanohardness of the matrix of the martensite is lower than that expected from macroscopic hardness, indicating that the grain boundary effect is significant for the macroscopic strength of the Fe-C martensite. A remarkable decrease of the grain boundary effect was found at the tempering temperature of 673 K, which is due to a disappearance of film-like carbides on grain boundaries. These results will be discussed in light of the interpretations of grain boundary strengthening.

scholarly journals Grain Boundary Evolution of Cellular Nanostructured Sm-Co Permanent Magnets

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5179
Author(s):  
Wei Zhang ◽  
Hongyu Chen ◽  
Xin Song ◽  
Tianyu Ma
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Permanent Magnets ◽  
Boundary Effect ◽  
Boundary Region ◽  
Energy Product ◽  
Transmission Electron ◽  
Grain Boundary Effect ◽  
Treated State ◽  
Boundary Microstructure

Grain boundaries are thought to be the primary demagnetization sites of precipitate-hardening 2:17-type Sm-Co-Fe-Cu-Zr permanent magnets with a unique cellular nanostructure, leading to a poor squareness factor as well as a much lower than ideal energy product. In this work, we investigated the grain boundary microstructure evolution of a model magnet Sm25Co46.9Fe19.5Cu5.6Zr3.0 (wt. %) during the aging process. The transmission electron microscopy (TEM) investigations showed that the grain boundary region contains undecomposed 2:17H, partially ordered 2:17R, 1:5H nano-precipitates, and a Smn+1Co5n−1 (n = 2, 1:3R; n = 3, 2:7R; n = 4, 5:19R) phase mixture at the solution-treated state. After short-term aging, further decomposition of 2:17H occurs, characterized by the gradual ordering of 2:17R, the precipitation of the 1:5H phase, and the gradual growth of Smn+1Co5n−1 compounds. Due to the lack of a defect-aggregated cell boundary near the grain boundary, the 1:5H precipitates are constrained between the 2:17R and the Smn+1Co5n−1 nano-sheets. When further aging the magnet, the grain boundary 1:5H precipitates transform into Smn+1Co5n−1 compounds. As the Smn+1Co5n−1 compounds are magnetically softer than the 1:5H precipitates, the grain boundaries then act as the primary demagnetization sites. Our work adds important insights toward the understanding of the grain boundary effect of 2:17-type Sm-Co-Fe-Cu-Zr magnets.

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