| Summary: | 碩士 === 大同工學院 === 材料科學(工程)研究所 === 82 === To achieve high grain boundaries resistivity which results in a
reduction in eddy current loss of Mn-Zn ferrites,various
additives had been cooperated with a Mn0.705Zn0.213Fe2.082O4
ferrite.Those additives included CaO,Y2O3,CaO-Li2O,CaO-Na2O and
cordierite glass. Microstructure and physical properties of
ferrite, such as μ-T curve,DC and AC resistivity,lattice
constant, DC BH curve and power loss at various frequencies,
were examined. The results showed that combined additives of
CaO-Li2O and CaO-Na2O increased resistivity of the ferrite. The
respective optimum amounts were 400ppm Li2O+400ppm CaO and
100ppm Na2O+200ppm CaO. Due to the suppression of eddy current
loss ,samples with higher resistivity also exhibited lower
power loss at high frequency. On the other hand,additives of
cordierite and yttrium oxide in ferrite resulted in resolution
of additives in matrix and the detriment of power loss property
was observed.
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