JP3590454B2 - Oxide core material for high frequency - Google Patents

Description

【００３０】
【表２】

【００３１】
表１より、ｂ＋ｃ＋ｄ＋ｅ≦４７でｆ_Ｑｍａｘが３０ＭＨｚ以上となるとことがわかる。従って、ｂ＋ｃ＋ｄ＋ｅ≦４７の範囲が有用な組成であることがわかる。
【００３２】
以上、各実施例で示すように、μ_{３０ＭＨｚ}を１５程度確保しても、Ｑ_ｍａｘが約１５０から２００得られ、従来のこの系の材料に得られない特性が得られている。
【００３３】
なお、本実施例においては、ＮｉＯ，ＣｕＯ，ＺｎＯ，α−Ｆｅ_２Ｏ_３，Ｂｉ_２Ｏ_３，Ｃｏ_２Ｏ_３を原料として使用したフェライト焼結体のみについて述べているが、必ずしも、これら酸化物に限定されるものではなく、焼結体がスピネル型フェライトを形成するものであれば、本発明の範囲にある。
【００３４】
又、粉末の予備焼成、及び成形体の焼結を大気中で行っているが、焼結後の生成物がスピネル型フェライトであれば、成形用粉末の製造方法が予備焼成なし、共沈法、水熱合成法、噴霧焙焼法を適用しても、又、焼成雰囲気が大気中に比べ酸化性であっても、還元性であっても、本発明の範囲にある。
【００３５】
【発明の効果】
本発明によれば、３０ＭＨｚ以上でも、実効透磁率の温度変化が小さく、磁気損失が小さい高周波用酸化物磁芯材料を提供できた。
【図面の簡単な説明】
【図１】実施例１における化学組成比６０［Ｎｉ_{（１−ｘ）}・Ｃｕ_ｘ］Ｏ・５ＺｎＯ・３４Ｆｅ_２Ｏ_３・０．５Ｂｉ_２Ｏ_３・０．５ＣｏＯのｘと磁芯特性μ_{３０ＭＨｚ}，△μ_Ｔ，ｆ_Ｑｍａｘ，Ｑ_ｍａｘとの関係を示す図。
【図２】実施例２における化学組成比ａ（Ｎｉ_０．７・Ｃｕ_０．３）Ｏ・ｂＺｎＯ・２３Ｆｅ_２Ｏ_３・０．５Ｂｉ_２Ｏ_３・０．５ＣｏＯのｂと磁芯特性μ_{３０ＭＨｚ}，ｆ_Ｑｍａｘ，Ｑ_ｍａｘとの関係を示す図。
【図３】実施例３における化学組成比ａ（Ｎｉ_０．７・Ｃｕ_０．３）Ｏ・ｃＦｅ_２Ｏ_３・０．５Ｂｉ_２Ｏ_３・０．５ＣｏＯのｃと磁芯特性μ_{３０ＭＨｚ}，ｆ_Ｑｍａｘ，Ｑ_ｍａｘとの関係を示す図。
【図４】実施例４における化学組成比ａ（Ｎｉ_０．７・Ｃｕ_０．３）Ｏ・５ＺｎＯ・３４Ｆｅ_２Ｏ_３・ｄＢｉ_２Ｏ_３・０．５ＣｏＯのｄと磁芯特性μ_{３０ＭＨｚ}，△μ_Ｔ，ｆ_Ｑｍａｘ，Ｑ_ｍａｘとの関係を示す図。
【図５】実施例５における化学組成比ａ（Ｎｉ_０．７・Ｃｕ_０．３）Ｏ・５ＺｎＯ・３４Ｆｅ_２Ｏ_３・０．５Ｂｉ_２Ｏ_３・ｅＣｏＯのｅと磁芯特性μ_{３０ＭＨｚ}，△μ_Ｔ，ｆ_Ｑｍａｘ，Ｑ_ｍａｘとの関係を示す図。[0001]
[Industrial applications]
The present invention relates to a high frequency oxide core material, and more particularly to a spinel ferrite core material used in a high frequency range.
[0002]
[Prior art]
2. Description of the Related Art In recent years, with the advance of electronic device technology, the frequency band of a signal handled in the electronic device has been expanded to a higher frequency side, and the band extends from 10 MHz to several GHz.
[0003]
Conventionally, a soft magnetic material for an inductance element used in such a high-frequency region has a higher electric resistance than a metal, and has excellent frequency characteristics. Therefore, Mn-Zn-based ferrite, Ni-Zn-based ferrite, Spinel type ferrite represented by Mg-Mn type ferrite has been used.
[0004]
[Problems to be solved by the invention]
However, the conventional Ni-Zn, Ni-Zn-Cu ferrite used for the high frequency band inductance element is usually a magnetic core material intended for a frequency of about 10 MHz or less, and in a frequency band higher than that, the effective frequency is less than about 10 MHz. The temperature change and the loss of the magnetic permeability are extremely large, so that it has a drawback that it cannot be used as a magnetic core material. Therefore, it has been difficult to cope with a higher driving frequency of the electronic device.
[0005]
An object of the present invention is to provide a high-frequency oxide magnetic core material which eliminates these drawbacks, has a small change in effective magnetic permeability with temperature and loss, and can be applied at 30 MHz or higher.
[0006]
[Means for Solving the Problems]
As a result of repeated studies, the present inventors have found that the composition ratio of a spinel-type ferrite containing oxides of Ni, Zn, Cu, Fe, Bi, and Co as a main component is a [Ni _(1-x). Cu _x] and _{O · bZnO · cFe 2 O 3} · dBi 2 O 3 · eCoO, and its scope a + b + c + d + e = 100,0.1 ≦ x ≦ 0.8,0 ≦ b ≦ 14,23 ≦ c ≦ 46 , 0 <d ≦ 1, 0 <e ≦ 0.5, b + c + d + e ≦ 47, it has been found that a spinel ferrite magnetic core material applicable to a frequency band of 30 MHz or more can be industrially usefully manufactured.
[0007]
That is, the present invention provides a high-frequency oxide magnetic core material containing an oxide of Ni, Zn, Cu, Fe, Bi, and Co as a main component, the composition ratio of which is a [Ni _(1-x) .Cu _{x ] O · bZnO · cFe 2 O} 3 · dBi 2 O 3 · eCoO ( however, a + b + c + d + e = 100,0.1 ≦ x ≦ 0.8,0 ≦ b ≦ 14,23 ≦ c ≦ 46, 0 <d ≦ 1 , 0 <e ≦ 0.5, b + c + d + e ≦ 47).
[0008]
In the present invention, 30 MHz to evaluate material properties _mu, is carried out by _{Q max, f Qmax, △ μ} T. μ30 _MHz represents the effective magnetic permeability at 30 MHz, and this value is preferably higher because the inductance can be made higher. However, in general, if it is too high, the high-frequency characteristics are degraded. Q _max indicates the maximum value of Q (the reciprocal of the loss coefficient tan δ). f _Qmax indicates the frequency at which the Q _max is the maximum value, the frequency before and after the range that can operate effectively as a magnetic core material. Further, the △ mu _T, indicates the temperature change rate of the mu at 0 to 80 ° C. in the case relative to the mu value at 20 ° C., was determined from the following equation.
[0009]
_{△ μ T = (μ 80 -μ} 0) / μ 20/80 × 100
Here, μ ₀ , μ ₂₀ , and μ ₈₀ indicate the values of μ at 0 ° C., 20 ° C., and 80 ° C., respectively.
[0010]
[Action]
In the composition ratio of the oxide magnetic core material of the present invention _{a [Ni (1-x)} · Cu x] O · bZnO · cFe 2 O 3 · dBi 2 O 3 · eCoO ( however, a + b + c + d + e = 100), 0.1 The reason for limiting to ≦ x ≦ 0.8 is that, when the temperature exceeds this range, the temperature characteristic of μ is significantly deteriorated, and when an inductance element is manufactured using such a magnetic core material, the variation of the inductance with respect to the temperature is large. This is disadvantageous in terms of reliability.
[0011]
Also, the limitation of 0 ≦ b ≦ 14, 23 ≦ c ≦ 46 , b + c + d + e ≦ 47 is that if b = 14, c = 46 , and b + c + d + e = 47, f _Qmax becomes 30 MHz or less, which is an object of the present invention. This is because it will not be a high-frequency magnetic core material applicable to a certain 30 MHz or higher. On the other hand, if c is smaller than 23, _Qmax decreases, which is industrially disadvantageous.
[0012]
0 <had a d ≦ 1 is, in the range because there is △ mu _T decreases. Also, when d exceeds _{1.0, Q max} is decreased, because the industrial disadvantage. The reason why 0 <e ≦ 0.5 is set is that Q _max increases in that range. Also, when e exceeds 0.5, △ mu _T increases, because the industrial disadvantage.
[0013]
The effect of Bi ₂ O ₃ is generally recognized as improving △ μ _T and improving Q _max , and CoO also contributes to improving Q _max and increasing the frequency of f _Qmax. Although recognized, in the present invention, further improvement was observed by adding to the above composition.
[0014]
【Example】
Hereinafter, examples of the present invention will be described.
[0015]
(Example 1)
As raw materials, iron oxide (α-Fe ₂ O ₃ ), nickel oxide (NiO), cupric oxide (CuO), zinc oxide (ZnO), bismuth oxide (Bi ₂ O ₃ ), cobalt sesquioxide (Co ₂ O) _3), the chemical composition ratio of _{60 [Ni (1-x)} · Cu x] O · 5ZnO · 34Fe 2 O 3 · 0.5Bi 2 O 3 · 0.5CoO ( where, x = 0, 0.1, 0.2, 03., 0.4, 0.5, 0.6, 0.7, 0.8, 0.9) and wet-mixed in a ball mill for 20 hours. Here, the raw material powder used had a particle size of 0.5 μm or less.
[0016]
Next, these raw material mixed powders were calcined in air at 800 ° C. for 2 hours, and then wet-pulverized in a ball mill for 3 hours to obtain molding powder.
[0017]
Next, these molding powders were compression molded at a molding pressure of ² ton / cm ² using a mold having an outer diameter of 10 mm and an inner diameter of 2 mm so as to form a molded body having a height of 10 mm.
[0018]
Further, these compacts were sintered at 930 ° C. for 4 hours in the atmosphere, gradually heated, and furnace cooled. These sintered bodies had an outer diameter of about 8.5 mm, an inner diameter of about 1.7 mm, and a height of about 7.5 mm.
Next, the magnetic core characteristics of these sintered bodies were measured. The result is shown in FIG.
[0019]
As shown in FIG. 1, exceeds the range of x = 0.1~0.8, △ μ _T it can be seen that significantly increases. Therefore, it is understood that this range is a useful composition.
[0020]
(Example 2)
In the same manner as in Example 1, the chemical composition ratio of _{a (Ni 0.7 · Cu 0.3)} O · bZnO · 23Fe 2 O 3 · 0.5Bi 2 O 3 · 0.5CoO ( however, a + b = 52, A molding powder was prepared so that b = 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20) to obtain a molded body.
Next, these compacts were sintered at 930 ° C. for 2 hours, and the magnetic core characteristics were measured. The result is shown in FIG.
[0021]
As shown in FIG. 2, when b exceeds 14, f _Qmax becomes smaller than 30 MHz. Therefore, it is understood that the composition range of b = 0 to 8 is useful.
[0022]
(Example 3)
In the same manner as in Example 1, the chemical composition ratio of _{a (Ni 0.7 · Cu 0.3)} O · cFe 2 O 3 · 0.5Bi 2 O 3 · 0.5CoO ( however, a + c = 99, c = 22, 23, 24, 26, 28, 42, 44, 46, 47, 48), a molding powder was produced to obtain a molded body.
Next, these compacts were sintered at 930 ° C. for 2 hours, and the magnetic core characteristics were measured. The result is shown in FIG.
[0023]
As shown in FIG. 3, when c is smaller than 23, it can be seen that Q _max is significantly reduced. Also, it can be seen that when c exceeds 46 , f _Qmax becomes 30 MHz or less. Therefore, it is understood that the range of c = 23 to 46 is a useful composition.
[0024]
(Example 4)
In the same manner as in Example 1, the chemical composition ratio of _{a (Ni 0.7 · Cu 0.3)} O · 5ZnO · 34Fe 2 O 3 · dBi 2 O 3 · 0.5CoO ( however, a + d = 60.5, A molding powder was prepared so that d = 0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2) to obtain a molded body.
Next, these compacts were sintered at 930 ° C. for 2 hours, and the magnetic core characteristics were measured. The result is shown in FIG.
[0025]
As shown in FIG. 4, when d> 0, Δμ _T is significantly reduced. Further, if it exceeds d = _{1.0, Q max} is _{lowered, f Qmax} also has a 30MHz or less. Therefore, it is understood that the range of d = 0 to 1.0 (however, 0 is not included) is a useful composition.
[0026]
(Example 5)
In the same manner as in Example 1, the chemical composition ratio of _{a (Ni 0.7 · Cu 0.3)} O · 5ZnO · 34Fe 2 O 3 · 0.5Bi 2 O 3 · eCoO ( however, a + e = 60.5, e = 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6), a molding powder was produced to obtain a molded body.
Next, these compacts were sintered at 930 ° C. for 2 hours, and the magnetic core characteristics were measured. The result is shown in FIG.
[0027]
As shown in FIG. 5, when e> 0, an increase in Q _max is recognized. On the other hand, when e exceeds 0.5, △ μ _T becomes extremely large. Therefore, it is understood that the range of e = 0 to 0.5 (however, 0 is not included) is a useful composition.
[0028]
(Example 6)
In the same manner as in Example 1, the chemical composition ratio of _{a (Ni 0.7 · Cu 0.3)} O · bZnO · cFe 2 O 3 · dBi 2 O 3 · eCoO ( however, a + b + c + d + e = 100, b = 0, 2,4,6,8,10,12,14, c = 34,36,38,40,42,44,46,48, d = 0.5, e = 0.5) A powder was prepared to obtain a molded body.
Next, these compacts were sintered at 930 ° C. for 2 hours, and the magnetic core characteristics were measured. The results are shown in Tables 1 and 2.
[0029]
[Table 1]

[0030]
[Table 2]

[0031]
From Table 1, it can be seen that _fQmax becomes 30 MHz or more when b + c + d + e ≦ 47. Therefore, it is understood that the range of b + c + d + e ≦ 47 is a useful composition.
[0032]
As described above, as shown in each embodiment, even if about ₃₀ μm is secured, _Qmax is obtained from about 150 to 200, which is a characteristic that cannot be obtained by the conventional material of this type.
[0033]
In this embodiment, only ferrite sintered bodies using NiO, CuO, ZnO, α-Fe ₂ O ₃ , Bi ₂ O ₃ , and Co ₂ O ₃ as raw materials are described, but these oxides are not necessarily used. The present invention is not limited to a material, and is within the scope of the present invention as long as the sintered body forms a spinel type ferrite.
[0034]
In addition, pre-firing of the powder and sintering of the compact are performed in the air. If the product after sintering is a spinel-type ferrite, the manufacturing method of the compacting powder is no pre-firing, and the coprecipitation method is used. Even if a hydrothermal synthesis method or a spray roasting method is applied, and the firing atmosphere is oxidizing or reducing as compared with the atmosphere, it is within the scope of the present invention.
[0035]
【The invention's effect】
According to the present invention, even at 30 MHz or more, a high-frequency oxide magnetic core material having a small temperature change in effective magnetic permeability and a small magnetic loss can be provided.
[Brief description of the drawings]
[1] Example Chemical composition ratio ₆₀ at _{1 [Ni (1-x)} · Cu x] O · 5ZnO · 34Fe 2 O 3 · 0.5Bi 2 O 3 · 0.5CoO x and core properties _{mu 30 MHz} , Δμ _T , f _Qmax , Q _max .
FIG. 2 shows the chemical composition ratio a (Ni _0.7 · Cu _0.3 ) O · bZnO · 23Fe ₂ O ₃ · 0.5Bi ₂ O ₃ · 0.5CoO in Example ₂ and the magnetic core characteristics μ _{30 MHz.} , F _Qmax , and Q _max . FIG.
[3] The chemical composition ratio _{a (Ni} 0.7 · Cu _0.3) in Example _{3 O · cFe 2 O 3 ·} 0.5Bi 2 O 3 · 0.5CoO c and core properties _{mu 30 MHz,} f _Qmax, diagram showing the relationship between the _{Q max.}
FIG. 4 shows the d of the chemical composition ratio a (Ni _0.7 · Cu _0.3 ) O · 5ZnO · 34Fe ₂ O ₃ · dBi ₂ O ₃ · 0.5CoO and the magnetic core characteristics μ _{30 MHz} , △ in Example 4. μ _{T, f} Qmax, diagram showing the relationship between the _{Q max.}
[5] Example Chemical composition ratio in _{5 a (Ni 0.7 · Cu 0.3} ) O · 5ZnO · 34Fe 2 O 3 · 0.5Bi 2 O 3 · eCoO of e and core properties _{mu 30 MHz,} △ μ _{T, f} Qmax, diagram showing the relationship between the _{Q max.}

Claims (1)

Ni, Zn, Cu, Fe, Bi, in the high frequency oxide core material containing an oxide as the main component of Co, the composition ratio of _{a [Ni (1-x)} · Cu x] O · bZnO · cFe ₂ O ₃ · dBi ₂ O ₃ · eCoO (however, a + b + c + d + e = 100, 0.1 ≦ x ≦ 0.8, 0 ≦ b ≦ 14, 23 ≦ c ≦ 46 , 0 <d ≦ 1, 0 <e ≦ 0 .5, b + c + d + e ≦ 47).

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