Preparation Of Mn-Zn Ferrites Research Articles

Co-precipitation method for the preparation of Mn-Zn Ferrite and study their Structural and Magnetic properties

"Ferrite nanoparticles were synthesized using the co-deposition method with pH = 12. This paper discusses the differences in composition and magnetic properties that contribute to the MnZn ferritic's properties. Samples were prepared, fabricated and annealed at two temperatures (600°C, 900°C). The crystal structure of the prepared samples was obtained using X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy (FTIR) and field emitting electron microscopy (FESEM), respectively. The magnetic properties of the samples prepared by assay (VSM) were obtained and the magnetic and structural properties were discussed based on the changing temperature."

Manganese Zinc Ferrites: a Short Review on Synthesis and Characterization

Manganese zinc ferrites are technically and scientifically a very important class of ferrite materials because they possess a very high magnetic permeability and low core losses. These materials have been broadly used in electronic applications such as transformers, choke coils, noise filters, and memory devices. Extensive research has taken place and still going in this field of science and technology. Applications of Mn-Zn ferrites in last 10 years are reviewed. General features, properties, and applications are discussed. Also, the various synthesis techniques used for the preparation of Mn-Zn ferrites are also considered such as normal ceramic technique, sol-gel method, hydrothermal method, co-precipitation method, and citrate precursor method. As the field is quite large, a reasonable effort has been made to include some of the original references discussing in details the specific outcome of the papers published.

Direct Preparation of the Nanocrystalline MnZn Ferrites by Using Oxalate as Precipitant

Oxalate was generally used as a precipitant for synthesis of MnZn ferrites during the co-precipitation process. However, the MnZn ferrite couldn’t be directly obtained and a calcination process was needed. In this research, we reported a direct preparation of the MnZn ferrite nanoparticles by using co-precipitation method, together with refluxing process. XRD measurements proved that crystallite size of the obtained samples increased with an increase in pH value of the co-precipitation solution, and that the crystallite size of about 25 nm was obtained for the sample at a pH of 13. This sample showed the maximum Ms of 58.6 emu/g, which was about one times larger than that of 12 (pH value). Calcination to the obtained samples result in an enlargement in their crystal size and an improvement in their magnetic properties with an increase in temperatures. The samples calcinated in CO2 + H2 atmosphere presented good stability, and the maximum Ms value of 188.2 emu/g was obtained for the 1100。C-heated sample. Unfortunately, precipitation of some Fe2O3 at 800。C suggested poor stability of the nanocrystalline MnZn ferrite in N2 atmosphere.

Preparation of Mn-Zn Ferrite from Spent Zinc-Carbon Batteries by Alkali Leaching, Acid Leaching and Co-Precipitation

The treatment of spent zinc-carbon batteries for the recovery of valuable metals followed by conversion to Mn−Zn ferrite has been conducted employing two-stage alkali and acid leaching and co-precipitation method. In the first stage, leaching process was carried out with 4 M NaOH, which resulted in a recovery of 63.4 %Zn and 0.1% Mn. Electrowinning of alkali leaching solution containing 12.75 g/L Zn at a current density of 0.2 A/cm2 produced Zn metal of 15 nm to 30 nm size and 99.9% purity. The second stage leaching of residue with 3 M H2SO4 and 6 vol.% H2O2 at a solid/liquid ratio of 1∶10 indicated the leaching efficiency of 98.0% Zn, 97.9% Mn and 55.2% Fe. The obtained leaching solution was finally adjusted to suitable mole ratios of Mn∶Zn∶Fe (1∶1∶4) by the addition of Zn and Fe sulfate salts followed by pH control to produce Mn−Zn ferrite powder. The characterization of the ferrite powder showed uniform nano-crystalline particles of about 20 nm size with spinel structure.

Preparation of Fine Grained Mn–Zn Ferrites by Hot Pressing

The preparation of Mn-Zn ferrites composed of fine grains has been carried out by hot pressing under various conditions. The results obtained are summarized as follows. (1) α-Fe 2 O 3 was more liable to form in the specimen prepared by hot pressing than in that prepared by the conventional sintering under ordinary pressure due to the remaining O 2 in the specimen. Therefore, it was confirmed that the hot pressing process in vacuum was more suitable than in 1%O 2 or N 2 . (2) Mn-Zn ferrites whose grain size is about 2 μm was obtained by the process where the specimen was heated to 1248 K at the heating rate of 0.028 K/s, and isothermally held under 0 MPa for 1.8 ks and hot pressing under 40 MPa in the vacuum of 1.33 x 10 -2 Pa for the subsequent 1.8 ks at the same temperature of 1248 K, using coprecipitated Mn-Zn ferrites powders. (3) Mn-Zn ferrites powder whose grain size is extremely fine of about 10-20 nm was obtained by the MG process in Ar, and it was confirmed that using these powders, Mn-Zn ferrites specimen whose grain size is finer than 1 μm was prepared by the above mentioned hot pressing process.

特集 金属間化合物の粉末冶金と諸持性 微細結晶を有するＭｎ‐ＺｎフェライトおよびＮｉ‐Ｚｎフェライト作製におよぼすＭＧ効果

The preparation of Mn-Zn ferrites and Ni-Zn ferrites composed of fine grains has been carried out by hot pressing under various conditions. The results obtained are summarized as follows. α-Fe2O3 was more liable to form in the Mn-Zn ferrrites specimen prepared by the hot pressing than that prepared by the conventional sintering under ordinary pressure due to the remaining O2 in the specimen. Therefore, it was confirmed that the hot pressing process in vacuum was more suitable than in 1%O2 or N2. Mn-Zn ferrites whose grain size is about 2μm was obtained by the process where the specimen was heated to 1248K at the heating rate of 0.028K/s, and isothermal holding under OMPa for 1.8ks and hot pressing under 40MPa in the vacuum of 1.33 × 10-2Pa for the subsequent 1.8ks at the same temperature of 1248K, using coprecipitated Mn-Zn ferritcs powders. Extremely fine grains of about 10-20nm were obtained in both of Mn-Zn ferrites powders and Ni-Zn ferrites powders by MG process, and it was confirmed that using these powders, both specimens of Mn-Zn ferrites and Ni-Zn ferrites prepared by the above-mentioned hot pressing process consist of finer grains than 1μm.

微細結晶粒を有するMn-Znフェライトのホットプレス法による作製

微細結晶粒を有するMn-Znフェライトのホットプレス法による作製