Cobalt oxide addition effects on the microstructure and electronic properties of CuZn ferrites

The effects of cobalt oxide addition on the microstructure and electrical properties of CuZn ferrites were investigated. CuZn ferrites with compositions of (CuO)0.2(ZnO)0.8(Co3O4)x/3 (Fe2O3) 0.986-2x; x = 0 , 0.02, 0.04, 0.08, 0.1 were synthesized using a solid state reaction. It was observed that the addition of cobalt will change the amounts and distribution of Cu2+, Cu+, Fe2+, and Fe3+ in the grain and grain boundary. The segregation of copper ions at the grain boundary was observed as the substitution of cobalt was increased. Moreover, as the x value was increased above 0.04, second phases of CuO and ZnO were found. The different amounts and distribution of Cu2+, Cu+, Fe2+, and Fe3+ in the bulk and grain boundary for samples added with different amounts of cobalt changed the conductivity activation energies of the bulk and grain boundary, and hence affected the space polarization and dielectric properties.

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Method of High Active Preparation and Electrical Properties of CuFeO2 Delafossite-Type

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.979.302 ◽

2014 ◽

Vol 979 ◽

pp. 302-306 ◽

Cited By ~ 2

Author(s):

Chalermpol Rudradawong ◽

Aree Wichainchai ◽

Aparporn Sakulkalavek ◽

Yuttana Hongaromkid ◽

Chesta Ruttanapun

Keyword(s):

Crystal Structure ◽

Electrical Conductivity ◽

Solid State ◽

Electrical Properties ◽

Grain Boundary ◽

Solid State Reaction ◽

Solid State Reaction Method ◽

Lattice Parameter ◽

Metal Powders ◽

High Power Factor

In this paper, the CuFeO2compound were prepared by classical solid state reaction (CSSR) and direct powder dissolved solution (DPDS) method from starting material metal oxides and metal powders. Preparation of two methods shows that, direct powder dissolved solution faster recover phases than classical solid state reaction method. The fastest method gets from starting materials Cu and Fe metal powders, the electrical conductivity, Seebeck coefficient, carrier concentration and mobility are 10.68 S/cm, 244.59 μV/K, 12.86×1016cm-3and 494.96 cm2/V.s, respectively. In addition, each CuFeO2compounds were investigated on crystal structure and electrical properties. From XRD and SEM results, all samples have a crystal structure delafossite-typeand a large grain boundary more than 15 μm by electrical conductivity corresponds to grain boundary and lattice parameter: a increases. Within this paper, from above results exhibit that preparation CuFeO2from Cu and Fe by direct powder dissolved solution method most appropriate for thermoelectric oxide materials due to high active for preparation else high lattice strain and high power factor are 0.00052 and 0.64×10-4W/mK2, respectively.

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The Effect CuO Additive on the Microwave Dielectric Properties of Mg(Zr0.05Ti0.95)O3 Ceramics

Materials Science Forum ◽

10.4028/www.scientific.net/msf.687.199 ◽

2011 ◽

Vol 687 ◽

pp. 199-203 ◽

Cited By ~ 1

Author(s):

Ching Fang Tseng

Keyword(s):

Dielectric Constant ◽

Dielectric Properties ◽

Solid State ◽

Liquid Phase ◽

Solid State Reaction ◽

Microwave Dielectric Properties ◽

Solid State Reaction Method ◽

Reaction Method ◽

Microwave Dielectric ◽

Second Phases

The microwave dielectric properties of the Mg(Zr0.05Ti0.95)O3ceramics with CuO addition were investigated. All specimens were prepared by solid-state reaction method and sintered at 1270-1420°C for 4 h. When CuO was added, the second phases of MgTi2O5, TiO2and liquid phase were produced. For specimens with 1.5 wt% CuO sintered at 1300°C, the dielectric constant,Q´fand tfvalues are 18.2, 223000 GHz and -2 ppm/°C, respectively.

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Effects of Charge Compensation on Colossal Permittivity and Electrical Properties of Grain Boundary of CaCu3Ti4O12 Ceramics Substituted by Al3+ and Ta5+/Nb5+

Molecules ◽

10.3390/molecules26113294 ◽

2021 ◽

Vol 26 (11) ◽

pp. 3294

Author(s):

Jakkree Boonlakhorn ◽

Jedsada Manyam ◽

Pornjuk Srepusharawoot ◽

Sriprajak Krongsuk ◽

Prasit Thongbai

Keyword(s):

Dielectric Properties ◽

Electrical Properties ◽

Grain Boundary ◽

Grain Boundaries ◽

Barrier Height ◽

Potential Barrier ◽

Charge Compensation ◽

Solid State Reaction Method ◽

Wide Frequency Range ◽

Potential Barrier Height

The effects of charge compensation on dielectric and electrical properties of CaCu3Ti4-x(Al1/2Ta1/4Nb1/4)xO12 ceramics (x = 0−0.05) prepared by a solid-state reaction method were studied based on the configuration of defect dipoles. A single phase of CaCu3Ti4O12 was observed in all ceramics with a slight change in lattice parameters. The mean grain size of CaCu3Ti4-x(Al1/2Ta1/4Nb1/4)xO12 ceramics was slightly smaller than that of the undoped ceramic. The dielectric loss tangent can be reduced by a factor of 13 (tanδ ~0.017), while the dielectric permittivity was higher than 104 over a wide frequency range. Impedance spectroscopy showed that the significant decrease in tanδ was attributed to the highly increased resistance of the grain boundary by two orders of magnitude. The DFT calculation showed that the preferential sites of Al and Nb/Ta were closed together in the Ti sites, forming self-charge compensation, and resulting in the enhanced potential barrier height at the grain boundary. Therefore, the improved dielectric properties of CaCu3Ti4-x(Al1/2Ta1/4Nb1/4)xO12 ceramics associated with the enhanced electrical properties of grain boundaries. In addition, the non-Ohmic properties were also improved. Characterization of the grain boundaries under a DC bias showed the reduction of potential barrier height at the grain boundary. The overall results indicated that the origin of the colossal dielectric properties was caused by the internal barrier layer capacitor structure, in which the Schottky barriers at the grain boundaries were formed.

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Effect of Nd3+ substitution for Bi3+ on the dielectric properties and conduction behavior of Aurivillius NdBi4Ti3FeO15 ceramics

RSC Advances ◽

10.1039/c5ra27821j ◽

2016 ◽

Vol 6 (25) ◽

pp. 21254-21260 ◽

Cited By ~ 10

Author(s):

Fida Rehman ◽

Hai-Bo Jin ◽

Lin Wang ◽

Abbas Tanver ◽

De-Zhi Su ◽

...

Keyword(s):

Dielectric Properties ◽

Solid State ◽

Solid State Reaction ◽

Conduction Behavior

NdBi4Ti3FeO15 and Bi5Ti3FeO15 ceramics were prepared by solid state reaction.

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Effect of Sintering Temperature on Electrical Properties of SFN Ceramics Doped with Al Prepared by a Solid-State Reaction Technique

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.675-676.527 ◽

2016 ◽

Vol 675-676 ◽

pp. 527-530

Author(s):

Thanatep Phatungthane ◽

Kachaporn Sanjoom ◽

Denis Russell Sweatman ◽

Buagun Samran ◽

Chamnan Randorn ◽

...

Keyword(s):

Solid State ◽

Electrical Properties ◽

Solid State Reaction ◽

Sintering Temperature ◽

Perovskite Phase ◽

Dielectric Behavior ◽

Orthorhombic Symmetry ◽

X Ray Diffraction ◽

Solid State Reaction Technique ◽

Pure Perovskite Phase

In the present work, strontium iron niobate SrFe0.5Nb0.5O3 ceramics doped with aluminum were synthesized by a solid-state reaction technique. Phase formation investigation by X-ray diffraction technique (XRD) revealed that all ceramics exhibited pure perovskite phase with orthorhombic symmetry. Grain size observed by electron microscopy (SEM) was found to increase with increasing sintering temperature. The electrical properties and related parameters of the ceramics were also measured. The ceramics exhibit very good dielectric behavior and have a significant potential for dielectric applications.

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Tribological and electrical behavior of Cu-based composites with addition of Ti-doped NbSe2 nanoplatelets

Industrial Lubrication and Tribology ◽

10.1108/ilt-10-2016-0259 ◽

2018 ◽

Vol 70 (3) ◽

pp. 560-567 ◽

Cited By ~ 1

Author(s):

Jian Feng Li ◽

Qin Shi ◽

HeJun Zhu ◽

ChenYu Huang ◽

Shuai Zhang ◽

...

Keyword(s):

Electron Microscopy ◽

Solid State ◽

Friction Coefficient ◽

Electrical Properties ◽

Tribological Properties ◽

Solid State Reaction ◽

Electrical Contact ◽

Solid State Reaction Method ◽

Content Type ◽

Reaction Method

Purpose This paper aims to clarify the size and morphology of transition metal dichalcogenides has an impact on lubrication performance of Cu-based composites. This study is intended to show that Cu-based electrical contact materials containing Nb0.91Ti0.09Se2 have better electrical and tribological properties than those containing NbSe2. The tribological properties of Cu-based with different Ti-dopped NbSe2 content were also discussed. Design/methodology/approach The NbSe2 and Nb0.91Ti0.09Se2 particles were fabricated by thermal solid state reaction method. The powder metallurgy technique was used to fabricate composites with varying Nb0.91Ti0.09Se2 mass fraction. The phase composition of Cu-based composites was identified by X-ray diffraction, and the morphology of NbSe2/Nb0.91Ti0.09Se2 and the worn surface of composites were characterized by scanning electron microscopy and transmission electron microscopy. In addition, the tribological properties of composites were appraised using a ball-on-disk multi-functional tribometer. The data of friction coefficient and resistivity were analyzed and the corresponding conclusion was drawn. Findings In comparison with the pure copper, Cu-based composites containing Nb0.91Ti0.09Se2/NbSe2 had a lower friction coefficient, illustrating the Nb0.91Ti0.09Se2 with nano-size particles prepared in this work is a perfect choice for the fabrication of excellent electrical contact composites. Compared to composites with NbSe2, composites containing Nb0.91Ti0.09Se2 have better tribological and electrical properties. Research limitations/implications Because of the use of thermal solid state reaction method, the size of NbSe2 and Nb0.91Ti0.09Se2 is relatively large. Therefore, the fabrication of finer particles of Nb0.91Ti0.09Se2 is encouraged. Originality/value In this paper, the authors discuss the tribological and electrical properties of Cu-based composites, and the value of optimum obtained as Nb0.91Ti0.09Se2 content is 15 Wt.%.

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Novel Mg Sensors for Application in Molten Al

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.368-372.265 ◽

2008 ◽

Vol 368-372 ◽

pp. 265-267 ◽

Cited By ~ 1

Author(s):

Hui Zhu Zhou ◽

Lei Dai ◽

Yue Hua Li ◽

Yin Lin Wu ◽

Ling Wang ◽

...

Keyword(s):

Solid State ◽

Electrical Properties ◽

Solid State Reaction ◽

Electrochemical Sensors ◽

Activation Energies ◽

Refining Process ◽

Molten Aluminium ◽

On Line ◽

Mg Content

Mg ion conductors, MgAl2O4 and MgZr4(PO4)6, were prepared by solid state reaction. Their electrical properties were measured and their application in electrochemical sensors for on-line determination of Mg in molten Al in the refining process and alloying process was examined. The activation energies for Mg ion conduction in MgAl2O4 and MgZr4(PO4)6 are 2.08 eV and 1.7 eV, respectively. The sensors have been found to respond rapidly to the change of Mg content in molten aluminium around 1000 K.

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