• Journal of the Korean Ceramic Society
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• v.35 no.8
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• pp.843-849
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• 1998

Fine powders of Mn-Zn ferrite were prepared by the alcoholic dehydration method and densification beha-vior of synthesized powder was investigated. The concentration and pH of solution for optimal precipitation was 0.4M and 2.5 respectively. The spinel single phase metastable state was formed by thermal decom-position of precipitate and then spinel phase was disintegrated into hematite and spinel {{{{ { { ZnFe}_{2 }O }_{4 } }} at 600$^{\circ}C$ With increase of temperature reaction of solid solution between hematite and spinel was proceeded and resulted in the spinel single phase (Mn, Zn Fe){{{{ { {Fe }_{2 }O }_{4 } }} On account of high reactivity of uncalcined powders densification started at 200$^{\circ}C$ lower and completed at 50$^{\circ}C$ lower in comparison with calcined powders.

• Resources Recycling
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• v.8 no.4
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• pp.45-56
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• 1999

The purpose of tlus sludy was to preparc raw material powder for Mn-Zn iclrile, h m mined mill scale and fero-Mn, usins a co-spray roasting process The mill scale and ferra-Mn uscd in this raalins process was rcf~nedb y mesn-ns of a slxc~apl rxcss ~nvolvinm~a te~ialsc ontalning imp~u-ltleso r less than 100 pprn In this study an effeclive spray roaster system. wllich produces fme complex oxide powder, collects produccd ~owder.,m d prcvel~tse ~~llssiooifi HCI gas. was also manufactured. By means of spray~ngp urifcd raw malerial solu~lionl nln a manufacued high tcmpervture rumace. &-ferrite powder and a comnpleu o ~ d e powder of Fe,O; and M,x203 were manufactured. The chmcterlstics of the composllion. surface urca, and p'miicle size dismbulion or the produced powder were exmined. ptoduced powdcr was then ~ m e dwi tli ZnO powder. aid olher addilives of defined cornposnion, and Mn-Zn femite cares werc praiuccil by meuns of Sorlning and closely controlled sintering processes. The magpelic p~oprlieso f c olo~ss, initlal permeability. mauin~u~mnn agnehc flux. coz~civcr orcc and residual magnccic flux for the above cores we,= measured, and fmm Il~ase I-csulls the eflicacy of lhe co-spray roasling pncess to pl.ellare raw material powder lor Mn-Zn ferntc was established

• Journal of the Korean Magnetics Society
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• v.11 no.5
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• pp.226-231
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• 2001

The effect of interface reaction between Mn-Zn ferrite single crystal and 61 SiO$_2$-23Pbo-6ZnO-8Na$_2$O-2K$_2$O (mol%) glass on the magnetic properties of the ferrite was investigated. After the reaction, the hump of Zn concentration appeared at the ferrite adjacent to the interface. The initial permeability of the ferrite bonded with the glass at 700 $^{\circ}C$ was 1766 at 100 KHz and reduced to 907 after reaction at 1000$^{\circ}C$. The permeability degradation with increasing reaction temperature was considered to be attributed not only to the sixe diminution of the ferrite due to the its dissolution into the glass but also to the residual stress due to the difference in expansion coefficient between the ferrite and the diffusion layer-the region of the hump of Zn concentration-adjacent to the interface.

• Journal of the Korean Ceramic Society
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• v.40 no.2
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• pp.146-152
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• 2003

The waste ferrites from magnetic core manufacturing process were used to $CO_2$gas decomposition to avoid the greenhouse effects. The waste ferrites are the mixed powder of Ni-Zn and Mn-Zn ferrites core. In the reduction of ferrites by 5% $H_2/Ar$ mixed gas, the weight loss of ferrites was about 14~16wt%. After the$CO_2$gas decomposition reaction, the weight of the reduced ferrites was increased up to 11wt%.$CO_2$gas was decomposed by oxidation of Fe and FeO in reduced compound and the phase of the waste ferrite was changed to spinel structure. A new technique capable of$CO_2$decomposition as low cost process through utilizing waste ferrite was development.

• Journal of the Korean Institute of Navigation
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• v.23 no.1
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• pp.15-22
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• 1999

In this paper, ferrite-rubber composite has been studied in order to apply to RF-A-PF in a super wideband electromagnetic absorber in RF-A-PF type, which can be used for a general purpose anechoic chamber. $Ni_x - Mn_0.1 - Zn_{(1-x-0.1)}ㆍFe_2O_4$ ferrite powder has been fabricated, then, using this, 〔$Ni_x - Mn_0.1 - Zn_{(1-x-0.1)}ㆍFe_2O_4$〕-Rubber composite for RF-layer in the RF-A-PF type absorber has been fabricated and it's characteristics have been analyzed. As a result, it has been clearly shown that the 〔$Ni_x - Mn_0.1 - Zn_{(1-x-0.1)}ㆍFe_2O_4$〕-Rubber composite has excellent electromagnetic wave absorbing properties.

• Journal of the Korean Ceramic Society
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• v.31 no.1
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• pp.55-61
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• 1994

Mn-Zn ferrite powder was obtained by wet method that was to be coprecipitated the metal ions of Fe2+, Mn2+ and Zn2+ with alkali solution. The target composition of the ferrite powder was 52 mol% Fe2O3, 24 mol% MnO, and 24 mol% ZnO, that was based on the region of high permeability. And the other ferrite powder was prepared by the dry method that was to be mixed the metal oxides as the above chemical composition. The wet method was compared with dry method for the powder properties and the electromagnetic characteristics of sintered cores. The synthesized powder by wet method was smaller particle size, narrower particle distribution, and higher purity than that of dry method. The initial permeability of sintered sample prepared by the wet method was 14000~28000, on the other side, 9000~15500 in case of the dry method.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1998.10b
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• pp.30-30
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• 1998

• Journal of the Korean Ceramic Society
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• v.32 no.8
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• pp.922-930
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• 1995

• Proceedings of the Korean Magnestics Society Conference
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• 1991.11a
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• pp.52-53
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• 1991

• Proceedings of the Materials Research Society of Korea Conference
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• 1999.05a
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• pp.42-42
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• 1999