Comparison between Powders of Strontium Hexaferrite Processed by Dynamic Gas Heat Treatment and Re-Calcination

Tudorache, Florin; Brinza, Florin; Popa, P.D.; Petrila, Iulian; Grigoraş, Mircea; Tascu, Sorin

doi:10.12693/aphyspola.121.92

Cited by 12 publications

(7 citation statements)

References 3 publications

(3 reference statements)

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“…Furthermore, the presence of Fe 2 O 3 was possibly due to the solubility rates of oxide, which are generally low, while that of carbonates is high [14,15,30,46]. Besides, it was observed from the spectra that the intensity of the peaks for samples having ratios of 1:5 and 1:6 were relatively lower than the other samples.…”

Section: Resultsmentioning

confidence: 99%

“…The AC conductivity increased with the frequency as the temperature increased. It was highly temperature-dependent [13,14,15]. According to Johnscher’s universal power law, the frequency independence plateau from 40 Hz to 10 kH was attributed to DC-like conductivity.…”

Section: Resultsmentioning

confidence: 99%

“…The real and imaginary parts of the permeability have a peak near 50 GHz, which is determined by the level of diamagnetic substitution [7]. BaFe 12 O 19 ferrites are used in many aspects of technology, such as high frequency microwaves [8,9,10], magnetic recording media [11], permanent magnets, magnetic sensor applications [12], sensors [13,14,15], etc. Apart from that, BaFe 12 O 19 ferrites are also used in water purifiers to separate the paramagnetic minerals and to eliminate some of metallic impurities in water [16].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Ratio in Ammonium Nitrate on the Structural, Microstructural, Magnetic, and AC Conductivity Properties of BaFe12O19

et al. 2018

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This paper investigates the effect of the ratio of ammonium nitrate (AN) on the structural, microstructural, magnetic, and alternating current (AC) conductivity properties of barium hexaferrite (BaFe12O19). The BaFe12O19 were prepared by using the salt melt method. The samples were synthesized using different powder-to-salt weight ratio variations (1:3, 1:4, 1:5, 1:6 and 1:7) of BaCO3 + Fe2O3 and ammonium nitrate salt. The NH4NO3 was melted on a hot plate at 170 °C. A mixture of BaCO3 and Fe2O3 were added into the NH4NO3 melt solution and stirred for several hours using a magnetic stirrer under a controlled temperature of 170 °C. The heating temperature was then increased up to 260 °C for 24 hr to produce an ash powder. The x-ray diffraction (XRD) results show the intense peak of BaFe12O19 for all the samples and the presence of a small amount of the impurity Fe2O3 in the samples, at a ratio of 1:5 and 1:6. From the Fourier transform infra-red (FTIR) spectra, the band appears at 542.71 cm−1 and 432.48 cm−1, which corresponding to metal–oxygen bending and the vibration of the octahedral sites of BaFe12O19. The field emission scanning electron microscope (FESEM) images show that the grains of the samples appear to stick each other and agglomerate at different masses throughout the image with the grain size 5.26, 5.88, 6.14, 6.22, and 6.18 µm for the ratios 1:3, 1:4, 1:5, 1:6, and 1:7 respectively. From the vibrating sample magnetometer (VSM) analysis, the magnetic properties of the sample ratio at 1:3 show the highest value of coercivity Hc of 1317 Oe, a saturation magnetization Ms of 91 emu/g, and a remnant Mr of 44 emu/g, respectively. As the temperature rises, the AC conductivity is increases with an increase in frequency.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Ratio in Ammonium Nitrate on the Structural, Microstructural, Magnetic, and AC Conductivity Properties of BaFe12O19

et al. 2018

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“…Current developments include the synthesis of barium and strontium hexaferrites in carbon monoxide reductive gas followed by recalcination [22], or from glass crystallization using a mixture of antimony and boron oxides [23]. An important task is to find a solvent or flux capable of both lowering the melting point, and ensuring the crystallization of barium hexaferrite phases.…”

Section: Introductionmentioning

confidence: 99%

Magnetic and Structural Properties of Barium Hexaferrite BaFe12O19 from Various Growth Techniques

et al. 2017

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Barium hexaferrite powder samples with grains in the μm-range were obtained from solid-state sintering, and crystals with sizes up to 5 mm grown from PbO, Na2CO3, and BaB2O4 fluxes, respectively. Carbonate and borate fluxes provide the largest and structurally best crystals at significantly lower growth temperatures of 1533 K compared to flux-free synthesis (1623 K). The maximum synthesis temperature can be further reduced by the application of PbO-containing fluxes (down to 1223 K upon use of 80 at % PbO), however, Pb-substituted crystals Ba1–xPbxFe12O19 with Pb contents in the range of 0.23(2) ≤ x ≤ 0.80(2) form, depending on growth temperature and flux PbO content. The degree of Pb-substitution has only a minor influence on unit cell and magnetic parameters, although the values for Curie temperature, saturation magnetization, as well as the coercivity of these samples are significantly reduced in comparison with those from samples obtained from the other fluxes. Due to the lowest level of impurities, the samples from carbonate flux show superior quality compared to materials obtained using other methods.

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“…Investigation of electrical properties of pellets sample provides important information about the behavior of this material as gas sensors. The electrical measurements under gas vapors influence were performed in a closed enclosure with known gas concentration (200 ppm) and controlling temperature using a Cromel–Alumel thermocouple located in the close proximity of the sample . The electric capacitance and electric resistance of the sample were recorded at fixed temperatures, both in air and in the presence of the test gas using a digital LCR meter (Wayne Kerr 6500P) at 20 Hz.…”

Section: Resultsmentioning

confidence: 99%

Self‐doped N‐propansulfonic acid polyaniline‐polyethylene terephthalate film used as active sensor element for humidity or gas detection

Solonaru¹,

Grigoraş²,

Petrila

et al. 2019

J of Applied Polymer Sci

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In this work, we report the fabrication of sensors’ element for humidity or gases, prepared by in situ polymerization of aniline N‐propansulfonic acid using ammonium persulfate in acidic medium. The polymer is being used in the form of powder or deposited in multiple layers onto the PET film. Various techniques including Fourier Transform infrared (FTIR), ultraviolet‐–visible spectroscopy (UV–vis), X‐ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to characterize the as‐prepared sensing materials. The film has been tested for humidity influence, where the significant variations in electrical characteristics were observed, suggesting its usefulness for humidity sensors. Also, for different organic and inorganic gases, a relatively low operating temperature and important sensitivity were observed that indicate its applicability as an active element for general gases sensors. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47743.

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Comparison between Powders of Strontium Hexaferrite Processed by Dynamic Gas Heat Treatment and Re-Calcination

Cited by 12 publications

References 3 publications

Effect of Ratio in Ammonium Nitrate on the Structural, Microstructural, Magnetic, and AC Conductivity Properties of BaFe12O19

Effect of Ratio in Ammonium Nitrate on the Structural, Microstructural, Magnetic, and AC Conductivity Properties of BaFe12O19

Magnetic and Structural Properties of Barium Hexaferrite BaFe12O19 from Various Growth Techniques

Self‐doped N‐propansulfonic acid polyaniline‐polyethylene terephthalate film used as active sensor element for humidity or gas detection

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