Effects of Calcination Conditions on Magnetic Properties in Strontium Ferrite Synthesized by the Molten Salt Method

Kim, Kyumin; Jeon, Kwang-Won; Moon, Ki Woong; Kang, Min Kyu; Kim, Jongryoul

doi:10.1109/tmag.2016.2531119

Cited by 17 publications

(11 citation statements)

References 10 publications

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“…[21][22][23][24] Moreover, the currently applied molten salts for the synthesis of ferrites generally include chlorine salt systems like NaCl and/or KCl. For example, Kim et al 21 used strontium carbonate and ɑ-hematite as raw materials and NaCl as molten salt to control the crystal orientation and shape of M-type strontium ferrite (SrFe 12 O 19 ) particles. By changing the calcination conditions, SrFe 12 O 19 particles with hexagonal plate shape and c-axis aligned to the normal direction of the plate were obtained.…”

Section: Raw Materialsmentioning

confidence: 99%

Sintering behavior of Ni–Zn ferrite powders prepared by molten‐salt synthesis

Yang

et al. 2021

Int J Applied Ceramic Tech

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Ni0.5Zn0.5Fe2O4 powders were prepared by a novel molten‐salt synthesis method. The effects of calcination processes of the powders on their sintering behaviors were investigated. Compared with the synthesis by traditional solid‐state reaction, the proposed molten‐salt method can significantly reduce the synthesis temperature of Ni0.5Zn0.5Fe2O4 from 800 to 550°C below, and the prepared powders have relatively high sintering activity at low temperature, which can thus decrease the sintering temperature. However, the abnormal growth of grains is easy to occur during sintering, thus resulting in uneven grain size. In particular, during the molten‐salt synthesis, the holding time for calcination is a dominant factor affecting the activity and crystallization degree of the resultant powders. From the point of view of increasing the density of sintered bodies, the optimal conditions for synthesizing Ni0.5Zn0.5Fe2O4 powder by the proposed molten‐salt synthesis is 400°C for 6 h. In addition, the saturate magnetization of the finally obtained ferrite ceramics has nothing to do with the preparation processes, while their coercivity depends on their densification and grain size caused by their different processing routes.

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Section: Raw Materialsmentioning

confidence: 99%

Sintering behavior of Ni–Zn ferrite powders prepared by molten‐salt synthesis

Yang

et al. 2021

Int J Applied Ceramic Tech

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“…B r /J s represents the degree of orientation of the sintered magnet, and the value of J is defined as the saturation magnetization J s on the J-H curve measured by BH Tracer when the applied magnetic field is 796kA/m. As indicated by Lotgering [7] and Kim [8], the magnetic anisotropy was quantitatively expressed by the relative intensity ratio (I 008 /I 107 ) between the (008) and (107) diffraction peaks. Fig.…”

Section: Effect Of Calcined Ferrites Stoichiometrymentioning

confidence: 99%

“…As mentioned above, due to too high weight ratio of the inter-additive CaO/SiO 2 , which leading to the excessive addition of CaCO 3 , the degree of degradation of i H c is therefore more significant than that of B r . destroyed during sintering process and has good uniformity of grain size; therefore, the magnetic grains are oriented and grown, resulting in the high properties of the sintering magnet, which is better than traditional La-Ca-Co ferrites [2], [4], [8]- [9], and help to achieve the purpose of large-scale industrial production.…”

Section: Effect Of Secondary Additives On Magnetic Propertiesmentioning

confidence: 99%

Development of optimum preparation conditions of Fe-deficient M-type Ca-Sr System hexagonal ferrites

Huang¹,

Chin-Chieh²,

Tsung-Han

et al. 2020

Preprint

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In this work, an experiment was carried out to investigate the preparation condition of anosotropic Fe-deficient M-type Ca-Sr system ferrite with optimum magnetic and physical properties using the raw material Fe2O3 from steel industrial iron oxide waste. The compositions of the calcined ferrites were chosen according to the stoichiometry Ca1 − x−yLaxSryFe10.9CozO19, where x was varied between 0.05 and 0.85, y between 0 and 0.18, and z = 0. The effect of CaO, SiO2 and Co3O4 inter-additives on the Ca-Sr system ferrite was also discussed in order to obtain low-temperature sintered magnets. The optimum condition of making magnets and some properties of a typical specimen are as follows. The preparation condition: condition: composition Ca0.37La0.45Sr0.18Fe10.9Co0O19, calcination condition 1240 °C × 1hr in atmosphere, low-temperature sintering condition 1210 °C × 1hr in atmosphere, inter-additives Co3O4 = 1.85 wt%, CaCO3 = 1.7 wt%, SiO2 = 0.6 wt%, CaO/SiO2 = 1.59. The magnetic properties of Br=5425 Gauss, bHc=4320 Oe, iHc=4602 Oe and (BH)max=5.26 MGOe were obtained for Ca-Sr system hard magnets with relatively low cobalt content. The unremarkable steel industrial iron oxide waste is recycled produce high-end permanent magnets under output power < 1 kW, which will eventually be used in high-efficiency motors. This is a specific manifestation of "garbage turning into gold" and is one of the best models of circular economy.

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“…After years of exploration and research, it has been discovered that simply by optimizing the process parameters of ferrite, such as the particle size and distribution after ball milling, the calcination temperature curve, the sintering temperature curve, and the compression molding process, some performance indexes of strontium ferrite can be optimized to a certain level. However, compared with its various theoretical values, there is still a big gap [4][5][6][7][8][9]. In a material, by doping a small amount of other elements or compounds, the material will produce specific optical, electrical and magnetic properties.…”

Section: Introductionmentioning

confidence: 99%

“…It ought to be noticed that the design of the formula requires the participation of valuable metal component cobalt to be used in the calcination formula in the form of oxide, such as Co 3 O 4 , which has a big hazard of mass production and greater cost. Previously, several literatures have been conducted with the goal of making Sr ferrite either with lower cobalt content or without cobalt [5,20]; however, such permanent materials possess lower magnetic characteristics. Furthermore, finer magnetic powder mill (<0.65 µm) and wet magnetic molding processes give magnets better performance due to a single magnetic domain grain size and higher alignment.…”

Section: Introductionmentioning

confidence: 99%

Investigation on the La Replacement and Little Additive Modification of High-Performance Permanent Magnetic Strontium-Ferrite

Huang

Chen

et al. 2021

Processes

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In this work, an experiment was carried out to investigate the preparation condition of anisotropic, Fe-deficient, M-type Sr ferrite with optimum magnetic and physical properties by changing experimental parameters, such as the La substitution amount and little additive modification during fine milling process. The compositions of the calcined ferrites were chosen according to the stoichiometry LaxSr1-xFe12-2xO19, where M-type single-phase calcined powder was synthesized with a composition of x = 0.30. The effect of CaCO3, SiO2, and Co3O4 inter-additives on the Sr ferrite was also discussed in order to obtain low-temperature sintered magnets. The magnetic properties of Br = 4608 Gauss, bHc = 3650 Oe, iHc = 3765 Oe, and (BH)max = 5.23 MGOe were obtained for Sr ferrite hard magnets with low cobalt content at 1.7 wt%, which will eventually be used as high-end permanent magnets for the high-efficiency motor application in automobiles with Br > 4600 ± 50 G and iHc > 3600 ± 50 Oe.

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Effects of Calcination Conditions on Magnetic Properties in Strontium Ferrite Synthesized by the Molten Salt Method

Cited by 17 publications

References 10 publications

Sintering behavior of Ni–Zn ferrite powders prepared by molten‐salt synthesis

Sintering behavior of Ni–Zn ferrite powders prepared by molten‐salt synthesis

Development of optimum preparation conditions of Fe-deficient M-type Ca-Sr System hexagonal ferrites

Investigation on the La Replacement and Little Additive Modification of High-Performance Permanent Magnetic Strontium-Ferrite

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