JPH08259316A - Production of manganese-zinc-based ferrite - Google Patents

Abstract

PURPOSE: To improve the grain boundary strength and density of a manganese- zinc-based ferrite, uniformize the grain diameter of a crystal grains, prevent a material from breaking and improve the magnetic permeability. CONSTITUTION: A ferrite containing 0.005-0.1wt.% calcium oxide, 0.005-0.1wt.% chromium oxide, 0.005-0.2wt.% zirconium oxide, 0.001-3.0wt.% indium oxide and 0.001-0.1wt.% total amount of one or more metallic oxides selected from the group consisting of potassium oxide, molybdenum oxide, titanium oxide, nickel oxide, antimony oxide, thallium oxide, tin oxide, magnesium oxide, vanadium oxide, copper oxide, selenium oxide, cobalt oxide and aluminum oxide based on the fundamental composition comprising 40-70mol% iron oxide, 5-50mol% manganese oxide and 5-40mol% zinc oxide is produced. In the process, an iron oxide containing >=5wt.% of that having a spinel structure or a spinel structural history is used.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a manganese-zinc system ferrite.

[0002]

2. Description of the Related Art Manganese-zinc based ferrite has a wide range of uses as a magnetic material for manufacturing magnetic heads, communication devices and the like. Conventional studies have been conducted on the composition and the like of this magnetic material. For example, JP-A-48-519
In JP 07, by adding BaO, SrO, or CaO to a basic composition consisting of iron oxide, manganese oxide, and zinc oxide, detachment of crystals during processing of a magnetic head and during recording and reproduction is prevented. The technology is disclosed. In JP-A-59-50072, magnetic permeability and the like are improved by adding calcium oxide, cobalt oxide, zirconium oxide, vanadium oxide to a basic composition composed of iron oxide, manganese oxide and zinc oxide. Techniques for doing so are disclosed.

In JP-A-60-132301, calcium oxide and niobium oxide are added to the above basic composition, and further, silicon oxide, vanadium oxide,
A technique is disclosed in which, by containing one of aluminum oxide, cobalt oxide, copper oxide, and zirconium oxide, an abnormal crystal structure does not occur even at a high sintering temperature and magnetic loss characteristics are improved. JP-A-60
In Japanese Patent Laid-Open No. 132302, calcium oxide and tin oxide are added to the above basic composition, and further,
By containing one of silicon oxide, vanadium oxide, aluminum oxide, cobalt oxide, copper oxide, zirconium oxide and niobium oxide, an abnormal crystal structure does not occur even at a high sintering temperature and magnetic loss characteristics are improved. The technology is disclosed. In addition to this, as the material of the switching power source, Japanese Patent Laid-Open No. 5-243082,
There is JP-A-6-53023.

[0004]

The present inventor was engaged in research for manufacturing a magnetic head by machining manganese-zinc type ferrite. In this process,
At the stage of forming a magnetic head by subjecting a conventional manganese-zinc based ferrite material to precision polishing, the material may be chipped or chipped, which may reduce the yield of this processing step.

The present inventor has examined the reason for this, but in the crystal structure itself of the manganese-zinc ferrite material, there are portions where the grain boundary strength is weak, the density is not sufficiently high, and further the crystal grains It was found that the uneven distribution of coarse crystal grains is a cause of chipping or chipping of the material. The present inventor successively examined conventional manganese-zinc-based ferrites in order to solve this problem, but it was difficult to solve all of these problems. Further, depending on the additive, the magnetic permeability of the manganese-zinc system ferrite may decrease even if it has an effect of improving the density.

An object of the present invention is to sufficiently improve the grain boundary strength and density in the crystal structure of a manganese-zinc system ferrite, make the grain size of the crystal grains uniform, and prevent chipping or chipping of the material. And to prevent the decrease in magnetic permeability of the manganese-zinc ferrite.

[0007]

Means for Solving the Problems Manganese according to the present invention
The manufacturing method of zinc-based ferrite is iron oxide 40-70mo
1%, manganese oxide 5 to 50 mol% and zinc oxide 5
0.005 to 0.1% by weight of calcium oxide and 0.005 of chromium oxide with respect to the basic composition of -40 mol%
5 to 0.1 wt% and zirconium oxide 0.005
0.2 wt%, indium oxide 0.001-3.0 wt%, potassium oxide, molybdenum oxide, titanium oxide,
The total amount of one or more metal oxides selected from the group consisting of nickel oxide, antimony oxide, thallium oxide, tin oxide, magnesium oxide, vanadium oxide, copper oxide, selenium oxide, cobalt oxide and aluminum oxide is 0.00
A method for producing a manganese-zinc-based ferrite containing 1 to 0.1% by weight, wherein the iron oxide in the basic composition contains 5% by weight or more of iron oxide having a spinel structure or a spinel structure history. It is characterized by using iron oxide.

The present inventor, in the process of studying to solve the above-mentioned problem of chipping during processing, ferrous oxide having the composition of manganese-zinc ferrite as the above-mentioned specific composition and having a spinel structure or a spinel structure history. By using iron oxide containing 5% or more as a raw material, the denseness of the manganese-zinc ferrite, the homogeneity of the crystal grains and the grain boundary strength are improved, and the chipping when processing the ferrite is reduced, It has been found that the yield can be significantly improved. Moreover, the magnetic permeability of the manganese-zinc system ferrite could be improved at the same time.

In the present invention, iron oxide, manganese oxide,
If the proportion of zinc oxide deviates from the above-mentioned basic composition, the magnetic properties deteriorate, and it becomes unsuitable as a magnetic material for magnetic heads and the like. By setting the proportion of iron oxide having a spinel structure or a history of spinel structure to 5% or more, the grain boundary strength, relative density and homogeneity of crystal grains of ferrite are improved,
The magnetic permeability also increases. This is preferably 10% or more.

When the content of calcium oxide deviates from the above range, the grain boundary strength of ferrite decreases and the magnetic permeability decreases. When the content of chromium oxide deviates from the above range, the grain boundary strength of ferrite decreases. When the content of zirconium oxide deviates from the above range, the grain boundary strength of ferrite decreases and the homogeneity of crystal grains decreases. When the content of indium oxide deviates from the above range, the grain boundary strength of ferrite decreases, coarse crystal grains are likely to occur, and the magnetic permeability decreases. In addition, potassium oxide, molybdenum oxide, titanium oxide, nickel oxide, antimony oxide, thallium oxide, tin oxide, magnesium oxide, vanadium oxide, copper oxide, selenium oxide, which are the above-mentioned subcomponents,
When the content ratio of one or more metal oxides selected from the group consisting of cobalt oxide and aluminum oxide deviates from the above ratio, the grain boundary strength of ferrite decreases and the magnetic permeability also decreases.

[0011]

EXAMPLE When producing the manganese-zinc-based ferrite of the present invention, the compound of each metal, which is a raw material of each of the metal oxides described above, is mixed so that the content ratio of each metal atom is within the above range. Weigh and mix these. In this case,
Preferably, pure water is used as a dispersion medium for wet mixing, but dry mixing can also be used.

Then, the mixed powder is fired at a predetermined temperature. In this case, first, the mixed powder is dried and then calcined to obtain a calcined body, the calcined material is crushed, the powder obtained by this crushing is molded to obtain a molded body, and the molded body is fired. can do. The firing temperature of the ferrite of the present invention is 11
The temperature is preferably set to 00 to 1400 ° C. Further, in the step of firing the manganese-zinc ferrite, a hot isostatic pressing method can be adopted,
Further, the fired body can be annealed.

In the firing step, the temperature of the molded body is raised to a predetermined temperature of 800 to 1250 ° C., preferably under a reduced pressure condition, kept at this predetermined temperature for 2 to 4 hours, and then raised to the above firing temperature. Can be made. Further, the oxygen partial pressure in the firing atmosphere near this firing temperature is preferably 1 to 50. After holding at the firing temperature, it is preferable to lower the ambient temperature of the fired body to room temperature in an inert atmosphere. The manganese-zinc-based ferrite obtained by the present invention preferably has an average crystal particle size of 10 to 30 μm.

As a raw material of each metal oxide constituting the ferrite of the present invention, an oxide of each metal is preferable, but not limited to this, and a carbonate or nitrate of each metal atom may be used. Is also possible. Further, in the present invention, “iron oxide having a spinel structure or a spinel structure history”, which accounts for 5% or more of iron oxide as a raw material, can be produced as follows, and the remaining iron oxide is commercially available. You can use one.

In order to synthesize high-purity iron oxide having a spinel structure or a spinel structure history, for example, iron sulfate is obtained by a recrystallization method using electrolytic iron and sulfuric acid, and iron sulfate and aqueous ammonia are mixed. Used in hydrothermal synthesis, eg 80
When oxygen is blown in under conditions of ℃ and pH 7-9, magnetite (spinel structure) is obtained. When this magnetite is roasted at, for example, about 150 ° C., maghemite (spinel structure) is obtained. Also, this maghemite is about 580
When roasted at ℃, hematite (iron oxide having a spinel structure history) is obtained.

Hereinafter, more specific experimental results will be described. (Experiment 1) CaO, Cr ₂ O ₃ , and Zr were adjusted so that the content ratio of each metal oxide contained in the manganese-zinc ferrite was a value corresponding to each sample number shown in Table 1.
O ₂ , In ₂ O ₃ and K ₂ O were wet mixed, the mixed powder was calcined at 1000 ° C., the calcined body was crushed, and the powder thus obtained was molded to obtain 72 × 36 × 8. A 4t compact was obtained.

The molded body was placed in an electric furnace, and the temperature of the molded body was raised to 15 while vacuuming the atmosphere in the electric furnace.
The temperature was raised at 0 ° C./hour and kept at 1000 ° C. for 4 hours.
Next, the atmosphere inside the electric furnace was set to a mixed atmosphere of helium and oxygen, and the partial pressure of oxygen was set to 10%. The temperature of the molded body was increased at 150 ° C./hour, and the temperature was maintained at 1300 ° C. for 4 hours to perform firing. Then, the atmosphere in the electric furnace was set to a nitrogen atmosphere, and the temperature of the fired body was lowered to room temperature at 300 ° C./hour.

The porosity of the fired body of 60 × 30 × 7t thus obtained was measured with a microscope. Further, regarding the homogeneity of the crystal grains, the number of crystal grains having a diameter of 100 μm or more present per 0.54 mm ² was measured. When this number is 0 or more and less than 5, "homogeneity of crystal grains" is "○", and when it is 5 or more and less than 10, "homogeneity of crystal grains" is "△". In the case of the above, "homogeneity of crystal grains" was defined as "x".

Further, a workability test was conducted on each sintered body to produce a processed product having a shape as shown in FIG. FIG.
In the processed product shown in Fig. 2, two rows of flat plate-shaped feet 2 are formed on the main surface of the flat plate portion 1, and a groove 4 is formed between the two rows of feet 2.
Are formed, and grooves 3 are formed on the outside of each foot 2, respectively.

Here, 2.3 (D) × 2.
A sample of 7 (W) x 20 (L) was cut out and cut in the longitudinal direction to form the grooves 3 and 4. However, a slicing machine was used for cutting, and the rotation speed was 6000 rpm. p. m, the feed speed of the grindstone is 20 m
The grinding wheel used was resin type SD # 400. Next, the sample in which the formation of the groove was completed was cut in the direction of its cross section to obtain a processed product shown in FIG. In this step, the above slicing machine is used, and the rotation speed is 6000 rpm. p. m, the feed speed of the grindstone is 80 m
The grinding wheel used was a metal type SD # 400.

The dimension of each part of the processed product is a = 1.5 mm
, B = 0.8 mm, c = 2.7 mm, and d =
It was 0.5 mm. Then, 20 processed products were produced for each example, and the number of good products and defective products was investigated. However, a chipping having a size of 300 μm × 300 μm or less and a chipping having a length of more than 300 μm but having a width of 50 μm or less were regarded as good products. Further, the magnetic permeability at 1.0 MHz was measured for each manganese-zinc system ferrite. The results of these measurements are shown in Table 1.

[0022]

[Table 1]

In Table 1, sample Nos. 1 and 2 outside the present invention
, The proportion of iron oxide having a spinel structure or a history of spinel structure is 0% or 2%, but the porosity of ferrite is large, the homogeneity of crystal grains is poor, and the yield rate of the workability test is less than 80%. The magnetic permeability is also low. On the other hand, in Sample Nos. 3, 4, 5, 6, and 7 of the present invention, the proportion of iron oxide having a spinel structure or the like is 5% or more, but all have porosities of 0.10% or less, The crystal grains have good homogeneity and the magnetic permeability is 1600 or more.

(Experiment 2) In the same manner as in Experiment 1, manganese-zinc type ferrites having the respective compositions shown in the sample numbers shown in Table 2 were produced, and the characteristics of each ferrite were measured. The results are shown in Table 2.

[0025]

[Table 2]

Sample numbers 8, 9, 10, 11, 12 in Table 2
Does not contain subcomponents, and Sample Nos. 8, 9, 10 and 12 do not contain indium oxide or the like. Therefore, sample numbers 8, 9, 10, 1
In Nos. 1 and 12, the magnetic permeability was low and the yield rate of the workability test was low. Furthermore, in sample numbers 8, 9, and 10,
In all cases, the porosity exceeds 0.10, and the homogeneity of crystal grains is low.

(Experiment 3) In the same manner as in Experiment 1, manganese-zinc based ferrites having the respective compositions shown in the sample numbers shown in Table 3 were produced, and the characteristics of each ferrite were measured. However, CoO was used as the raw material containing cobalt. The results are shown in Table 3.

[0028]

[Table 3]

Sample Nos. 13, 14, and 15 other than the present invention did not contain indium oxide, Sample Nos. 13 and 14 did not contain calcium oxide, and Sample No. 13 further contained zirconium oxide. Does not contain. Therefore, in Sample Nos. 13, 14, and 15, the yield rate in the workability test is low, and the crystal grain homogeneity and porosity are also low. Further, in sample numbers 13 and 14, the magnetic permeability of ferrite is also low. In Sample No. 16 in the present invention, all the characteristics were good.

(Experiment 4) In the same manner as in Experiment 1, manganese-zinc type ferrites having the respective compositions shown in the sample numbers shown in Table 4 were produced, and the characteristics of each ferrite were measured. However, as a raw material of each metal shown in Table 4, MoO
₃ , TiO ₂ , NiO, Sb ₂ O ₃ , Tl ₂ O ₃ , Sn
O ₂ , MgO or V ₂ O ₅ was used. Table 4 shows the results.

[0031]

[Table 4]

Sample Nos. 17 to 24 are all in the present invention.
It is a sample of. And within the scope of the present invention,
The added metal is MoO as described above.₃, TiO
₂, NiO, Sb₂O₃, Tl₂O₃, SnO₂, Mg
O or V₂O_FiveEven if it is changed to
It turned out that sex is obtained. As such an accessory ingredient
Is also K₂O, CoO, TiO₂, NiO, Tl₂
O₃, SnO ₂, CuO, SeO₂, Al₂O₃Especially
preferable.

(Experiment 5) In the same manner as in Experiment 1, manganese-zinc based ferrites having the respective compositions shown in the sample numbers shown in Table 5 were produced, and the characteristics of each ferrite were measured. However, as a raw material of each metal shown in Table 5, Cu
O, SeO ₂ , Al ₂ O ₃ , K ₂ O and V ₂ O ₅ were used. The results are shown in Table 5.

[0034]

[Table 5]

Sample Nos. 25 to 27 are all within the scope of the present invention.
It is a sample of. And within the scope of the present invention,
Added as CuO, SeO₂, Al₂O ₃Strange
It was found that the same excellent characteristics can be obtained even if
Revealed

Sample Nos. 28 to 32 are all samples outside the present invention. In sample No. 28, K ₂ O which is an accessory component
Content of 0.15% by weight, the porosity increased, and both the homogeneity of crystal grains and the magnetic permeability decreased. In Sample No. 29, the content ratio of calcium oxide was 0.15
Although it is% by weight, the porosity becomes large, and both the homogeneity of the crystal grains and the magnetic permeability decrease. In Sample No. 30, the chromium oxide content was 0.12% by weight, but the porosity exceeded 0.10%, and the yield rate in the workability test was 80%.
Is less than%. In Sample No. 31, the content ratio of zirconium oxide was 0.21% by weight, but the porosity increased and the non-defective rate in the workability test also decreased. Sample number 3
In No. 2, the content ratio of indium oxide was 3.5% by weight, and although each characteristic was improved by this, the magnetic permeability was significantly reduced.

(Experiment 6) Similar to Experiment 1, the results are shown in Table 6.
The manganese-zinc-based ferrite of each composition listed in each sample number
Each light is manufactured and the characteristics of each ferrite are measured.
Was. However, as a raw material of each metal shown in Table 6, K
₂O, CoO, SnO₂, Tl₂O₃, Al ₂O₃, V
₂O_Five, SeO₂, TiO₂, CuO was used. this
Table 6 shows the results.

[0038]

[Table 6]

Sample Nos. 33 to 35 are all samples within the present invention, and all have good characteristics. As described above, even when two kinds or three kinds of metal oxides were used as the sub-components, the effects of the present invention could be well exhibited.

(Experiment 7) Similar to Experiment 1, the results are shown in Table 7.
The manganese-zinc-based ferrite of each composition listed in each sample number
Each light is manufactured and the characteristics of each ferrite are measured.
Was. However, as a raw material of each metal shown in Table 7, Ba
O, SrO, CoO, Nb₂O_Five, SiO ₂, Al₂O
₃, P₂O_FiveIt was used. The results are shown in Table 7.

[0041]

[Table 7]

Sample Nos. 36 to 41 are all samples outside the present invention. In sample numbers 36 to 41, iron oxide having a spinel structure or the like is not used. Also, sample number 3
6, 37, 38, 39, 40 did not use indium oxide, and sample numbers 36, 37, 38, 39 did not use chromium oxide. As a result, the porosities were all increased to 0.30 or more, the crystal grain homogeneity and the yield rate in the workability test were low, and the magnetic permeability was 1500 or less.

(Experiment 8) Experiments similar to Experiments 1 and 4 were performed. However, the molded body was subjected to a hot isostatic press method at a temperature of 1200 ° C. and a pressure of 1000 kg / cm ² . 1100 of the fired body thus obtained
Annealing was performed at 3 ° C. for 3 hours. Also for each of the obtained fired bodies, a tendency similar to the above-mentioned respective experimental results was observed.

(Experiment 9) Experiments similar to Experiments 1 and 4 were carried out on the single crystal ferrite, but the similar tendencies to the results of each experiment described above were observed.

[0045]

As described above, according to the present invention, in the crystal structure of manganese-zinc type ferrite, the grain boundary strength and density are sufficiently improved, the grain size of the crystal grains is made uniform, and the material lacks. Moreover, chipping can be prevented and the magnetic permeability of the manganese-zinc ferrite can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a shape of a processed product manufactured by a simulated processing test.

[Explanation of symbols]

 1 body part 2 legs 3, 4 groove

Claims (1)

[Claims] 1. A basic composition comprising 40 to 70 mol% of iron oxide, 5 to 50 mol% of manganese oxide and 5 to 40 mol% of zinc oxide, and 0.005 to calcium oxide.
0.1 wt% and chromium oxide 0.005-0.1 wt%
0.005 to 0.2% by weight of zirconium oxide, 0.001 to 3.0% by weight of indium oxide, potassium oxide, molybdenum oxide, titanium oxide, nickel oxide, antimony oxide, thallium oxide, tin oxide, oxidation Manganese-zinc containing 0.001 to 0.1% by weight in total of one or more metal oxides selected from the group consisting of magnesium, vanadium oxide, copper oxide, selenium oxide, cobalt oxide and aluminum oxide. In producing a ferrite system, iron oxide having a spinel structure or a spinel structure history is used as iron oxide in the basic composition in an amount of 5% by weight.
A method for producing a manganese-zinc ferrite, which comprises using the iron oxide contained above.