Co-firing process using conventional and microwave sintering technologies for MnZn- and NiZn-ferrites

Tsay, Chien-Yih; Liu, Kuo‐Shung; Lin, I‐Nan

doi:10.1016/s0955-2219(01)00146-7

Cited by 30 publications

(10 citation statements)

References 12 publications

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“…Tsay et al [15] have used a porous Al 2 O 3 -SiO 2 crucible with SiC rods as susceptors which lead to uneven absorption of microwave energy, while others [17,29] used SiC plates as susceptors. However, they have reported cracks in the samples due to rapid heating.…”

Section: Susceptor Assemblymentioning

confidence: 99%

“…The ferrites, in powder, pillets or in thin film forms, were prepared by the high-temperature solid state reaction method [7], coprecipitaion [8], sol-gel method [9], pulsed laser deposition [10], high-energy ball milling [11], hydrothermal technique [12], and flash combustion technique [13]. Several workers have successfully prepared Ni-Zn ferrites by the microwave sintering technique [14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

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Magnetic properties of Ni-Zn ferrites prepared by microwave sintering method

et al. 2011

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The effect of zinc ion substitution for nickel on structural and magnetic properties of NiZn ferrites is reported. The spinel ferrite system Ni 1-x Zn x Fe 2 O 4 with x0 0.2, 0.3, 0.4 and 0.5 was prepared by microwave sintering method. The uniaxially pressed samples were sintered at various temperatures such as 900°C, 1000°C and 1100°C for 30 min. X-ray diffraction patterns of the samples indicate the formation of single-phase cubic spinel structure. SEM micrographs show that grain size increases with increasing zinc content and sintering temperature. The elemental composition of these ferrites was analyzed by EDS. Lattice constant increases with increase in zinc content, obeying Vegard's law. The effect of composition and sintering temperature on initial permeability as the function of frequency and temperature was studied. The initial permeability of NiZn ferrite increases greatly with increasing Zn content and sintering temperature. The dependence of initial permeability with respect to temperature shows the decrease in the Curie point with increase in zinc content, is the normal behavior of ferrites. The relative loss factor ðtan d μ i = Þ of the order of 10 −2 to 10 −5 in the frequency range from 100 Hz to 1 MHz indicates that the prepared ferrites have relatively high purity.

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Section: Susceptor Assemblymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Magnetic properties of Ni-Zn ferrites prepared by microwave sintering method

et al. 2011

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“…Shrinkage mismatches of the constituent powders cause interface debinding due to incompatibility in cofiring behavior but show high dependence upon process parameters. Both dielectric and magnetic (Ni based ferrite) constituents’ electromagnetic material properties such as dielectric permittivity and permeability show primary dependence on the processing parameters such as sintering time and temperature resulting in microstructural changes, density variations, and defect formations . As a result, microstructural effects play a crucial role and need to be investigated in optimizing the process to deliver the improved performance and miniaturization of electromagnetic devices demanding such large FGM based composite substrates.…”

Section: Introductionmentioning

confidence: 99%

Optimization of dry powder deposition parameters for production of large substrates using functionally graded ceramics

Berkun

Kızıltaş

2018

Int J Applied Ceramic Tech

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The ability to control the spatial variation in three dimensions of dielectric properties is known to play a crucial role in achieving novel electromagnetic performance such as miniaturization and high gain of broadband antennas. To address this need, the objective in this paper is to use earlier proposed Dry Powder Deposition to produce large substrates of Functionally Graded Materials with spatially controlled CaTiO3‐MgTiO3‐Mg2TiO4 dielectrics. We present an in‐depth analysis and optimization of critical processing parameters such as compaction pressure, sintering temperature, and dwell time. Using the optimized compaction and co‐sintering process, spatially varying large (8.2 cm × 8.2 cm) substrates were produced without the presence of any significant cracks and warping. In addition to these structural functionalities, sintered ceramic constituents of the designed substrate display targeted dielectric permittivity values of a miniaturized broadband Satellite Communication Ultra High Frequency antenna at the optimized conditions. This optimized route opens up possibilities for multifunctional metrics to be addressed for other applications calling for different spatial distributions of large Functionally Graded Materials possibly with the same family of ceramic constituents.

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“…Generally, Microwave processing microstructures possess smaller grain size in comparison with conventional process [6,7]. Many ferrites have been microwave heated and their dielectric and magnetic properties with respect to microstructures have also been studied [8][9][10][11][12]. Another method for reducing eddy current loss is, modifying the grain boundary region by adding suitable additives which promote liquid phase sintering and forms as an insulating layer at the grain boundaries.…”

Section: Introductionmentioning

confidence: 99%

Influence of additives on the structural, electrical and elastic properties of nanocrystalline MgCuZn ferrites

2015

Appl. Sci. Lett.

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Lead oxide (PbO) and Tantalum pentoxide (Ta2O5) added Mg0.2Cu0.3Zn0.5 Fe2O4 spinel ferrites are prepared by the microwave hydrothermal method. The prepared powders are characterized by powder X-ray diffraction (XRD), Infrared spectroscopy (IR), Transmission electron microscopy (TEM) and Differential scanning calorimeter (DSC). Monophase nanocrystalline ferrites of ~10 to 20nm size are prepared at a lower processing temperature of 160°C/1hour. The ferrites are sintered to a temperature of 900°C using microwave sintering (MW) method. The influence of additives on structure, densification, microstructure and electrical resistivity is studied. The addition of PbO to ferrite improves sintered density and resistivity compared to Ta2O5. The ultrasonic pulse transmission method is used to determine the elastic properties of the sintered ferrites. Elastic moduli such as Young's modulus (E), bulk modulus (B), modulus of rigidity (G), Poisson's ratio (σ) and Debye temperature (θD) are computed from the measured ultrasonic wave velocities. The elastic moduli of ferrite materials increase with PbO and decrease with Ta2O5 content, whereas Poisson's ratio almost remains constant. A linear relationship between Debye temperature and average sound velocity is observed.

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Co-firing process using conventional and microwave sintering technologies for MnZn- and NiZn-ferrites

Cited by 30 publications

References 12 publications

Magnetic properties of Ni-Zn ferrites prepared by microwave sintering method

Magnetic properties of Ni-Zn ferrites prepared by microwave sintering method

Optimization of dry powder deposition parameters for production of large substrates using functionally graded ceramics

Influence of additives on the structural, electrical and elastic properties of nanocrystalline MgCuZn ferrites

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