JPH03223401A - Flaky fe-ni series alloy fine powder and manufacture thereof - Google Patents

Abstract

PURPOSE:To mass-produce flaky Fe-Ni series alloy fine powder having excellent soft magnetism by executing annealing under non-oxidizing atmosphere to make the specific coercive force of powder after pulverizing the specific saturated magnetosriction constant of raw material to the specific particle diameter and thickness. CONSTITUTION:The raw material containing composition having the saturated magnetosriction constant Xs + or -15X10<-6> measured with bulky material is pulverized to make to 0.1-30mum average particle diameter and <=2mum average thickness. The composition of the above raw material is desirable to be 70-83% Ni, 2-6% Mo, 3-6% Cu, 1-2% Mn, <=0.05% C and if necessary, further 0.1-2% one or more kinds among B, P, As, Sb, Bi, S, Se and Te, and the balance of Fe with accompanying impurities. This raw material is desirable to use one obtd. with water atomizing method. This pulverization is desirably executed with mechanical pulverization under coexistence of pulverizing assist agent after executing heating treatment under low oxygen poten tial atmosphere. While fluidizing or shifting the powder obtd. with this under non- oxidizing atmosphere, the annealing is a executed under keeping the flaky fine powder state. By this method, the flaky Fe-Ni series alloy fine powder having <=400A/m coer cive force Hc, is obtd.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention has an average particle size of 0.1 to 30 μm and an average thickness of 2 μm.
Hereinafter, the present invention relates to a flat Fe-Ni alloy fine powder having preferably an average particle size of 0.1 to 20 μm and an average thickness of 1 μm or less and excellent soft magnetism, and a method for producing the same.

[Prior art] In recent years, in the field of magnetic cards related to personal secrets such as bank cards and credit cards, a coating film made of fine powder of a high magnetic permeability material is applied to the surface of the card for the purpose of magnetic shielding. Needs have increased. Such a coating powder is required to have high magnetic permeability, be a fine powder, and have a flat powder shape. This is not only necessary from the viewpoint of ease of application and surface smoothness of the coating film, but also because the shear force during application causes the flat fine powder to be aligned in the flat direction with the lowest demagnetizing field coefficient, that is, parallel to the card substrate direction. This is essential because alignment allows high magnetic permeability in the in-plane longitudinal direction to be obtained.

The specific characteristics of the powder required for this application are that the average particle size is o, i~30 μm, the thickness is 2 μm or less, and the coercive force of the powder in a random aggregation state ignoring the demagnetizing field is 400 μm.
A/m or less, preferably 240 A/m or less. The thickness of the powder is determined by embedding the powder in a resin powder and solidifying it while oriented in a flat direction in a magnetic field, and then examining the cross section of the embedded sample with a microscope.

As such a powder, an Fe--Ni alloy may be used which has a high magnetic permeability and is easily plastically deformed and flattened. However, a mass production method for obtaining the above-mentioned powder specifications and properties in Fe-Ni alloys has not yet been proposed.

JP-A-63-35701 and JP-A-63-3570
For No. 6, the thickness is 2 μm or less, and the ratio of thickness to diameter is 111.
It has been proposed to produce scale-like high magnetic permeability metal powder made of a pure metal or alloy material with a magnetic permeability of 0 or less using a wet ball milling method. Specifically, pure iron powder passed through a 44 μm sieve has been proposed. was ground for 96 hours to produce a scaly powder with a wall thickness of 1.0 μm that passed 98% through a 25 μm sieve, and Sendust alloy powder that had passed through a 44 μm sieve was ground for 96 hours and passed through a 25 μm white sieve. Meat that passes 96% $1.
A scaly powder with a size of 0 to 1.5 μm is obtained.

Although it is certainly possible to obtain magnetic material powder with a thickness of 2 μm or less using the above method, it requires pulverization for as long as 96 hours, and it is difficult to produce fine powder with an average particle size of 3 o or 20 Itta or less at a high rate. The interlayer point is difficult to obtain by distillation, and the coercive force of the obtained powder is significantly degraded by crushing strain, and the coercive force Hc is high. Above pure F
For e powder, 430e (3440A/+n) and for sendust alloy powder, 90e (720A/m) have been reported.

In the case of Sendust alloy, JP-A-62-238305
No. 1, a method is shown in which the powder is made into powder by water atomization so that the crystal grain size is 100 μm or less, and then ground into a single crystal flake powder with a major axis to minor axis ratio of 10 or more using a crusher with high energy density. . However, these flaky powders and flat powders are subjected to extremely large deformations due to pulverization, so they are provided with high coercive force due to pulverization strain. This method is insufficient as a method for producing powder for use.

As a method for removing crushing distortion, Japanese Patent Application Laid-Open No. 58-59268
The specification mentions that sendust powder, which is formed from an ingot into a flattened form through repeated crushing and grinding processes in multiple stages, is additionally annealed in a hydrogen atmosphere if necessary. However, the coercive force of the powder is not specified, and it does not provide knowledge about a specific annealing method to improve the coercive force, so it is still inappropriate as a powder manufacturing method for magnetic shielding of magnetic cards, etc., which is the subject of this application. It is enough.

Furthermore, none of the above disclosed examples makes any mention of the saturation magnetostriction constant.

Among Fe-Ni alloys, we have not been able to find anything specific about permalloy flat fine powder, and the present inventors have
No. 123494, average particle size 1 by water atomization
Mechanically pulverize Fe-Ni alloy powder with a diameter of 0μ or less,
We proposed a method for obtaining flat fine powder with an average particle size of 0.1 to 10 μm and a thickness of 1 μm or less. That is, here, Fe-
Ni-based alloys have high plastic deformability, are easily stretched, and are relatively easy to flatten, but are difficult to pulverize, and reducing the particle size of the initial powder improves pulverization efficiency. The method proposed above, which points out important points from the above, facilitates the flat pulverization of Fe-Ni alloys, but reducing the particle size of the initial powder is a mass production method from the perspective of atomization. The current situation is that there is no such thing. In other words, the water atomization method is the most mass-producible atomization process and is the process that makes it easier to reduce the particle size, but in order to achieve an average particle size of 1107z or less, molten metal must be sprayed at a water pressure of 100100O/ad or more. Therefore, installation of high-pressure supply pumps, equipment costs such as piping are enormous, maintenance is complicated, and the molten metal beam diameter has to be narrowed down to a few φ, so the amount of hot water delivered per unit time is small. There are also problems such as difficulty in obtaining a yield of <10 μm or less.
The methods of Nos. 3 to 123494 have limitations in mass production when considering the total raw material powder.

The flat fine powder with an average particle size of 0.1 to 30 μm and an average thickness of 2 μm or less, which is the subject of this application, is not only a fine powder but also has undergone severe distortion, and when annealed under the same conditions as normal bulk materials. , agglomeration or sintering phenomenon of powder particles occurs, and the flat shape obtained by crushing is lost. Therefore, actual annealing has to be done at a low temperature at which powder agglomeration does not occur, that is, the annealing temperature of normal bulk materials, which is around 1100°C, must be significantly lowered, and the coercive force of flat grains is a large value exceeding 500 A/m. was.

[Problem to be solved by the invention]

The present invention has been made in consideration of the problems of the prior art, and has an average particle size of 0.1 to 30 μm and an average thickness of 2 μm.
The present invention provides a flat Fe-Ni alloy fine powder having a coercive force Hc of 400 A/m or less and a method for mass-producing the powder.

[Means for Solving the Problems] The present invention has a saturation magnetostriction constant λs measured in a bulk material of ±1.
A Fe-Ni alloy raw material with a composition within 5 x 10' is crushed to obtain an average particle size of 0.1 to 30 μm and an average thickness of 2 μm.
m or less, and then annealed in a non-oxidizing atmosphere while maintaining the above-mentioned shape (flat fine powder shape) to obtain a fine powder with a coercive force of 400 A/m or less. Among them, especially Ni70~83%, Mo2~6%, Cu 3~
6%, Mn 1-2%, CO 0.05% or less, the balance consisting of iron and incidental impurities, and the method for producing the same. In particular, B, P, As, Sb, B
This includes adding 0.1 to 2% of one or more of the element group consisting of i, S, Se, and Te to improve the pulverizability.

That is, the present invention has a composition in which the saturation magnetostriction constant λs measured in the bulk material is within ±15×10′.

A flat Fe-Ni alloy fine powder having an average particle size of 0.1 to 30 μm, an average thickness of 2 pm or less, and a coercive force Hc of 400 A/m or less, among which the specified component range is By pulverizing raw materials suitable for use as PC permalloy and having a composition in which the saturation magnetostriction constant λs measured in the bulk material is within ±15X10', the average particle size is 0.1 to 30 μm and the average thickness is 2 μl. After that, the powder was annealed in a non-oxidizing atmosphere while maintaining the above-mentioned flat fine powder shape, and the coercive force Hc of the powder was increased to 4.
Flat Fe- characterized by having an OA/11 or less
This is a method for producing Ni-based alloy fine powder.

In the manufacturing method of the present invention, annealing of the pulverized powder is performed by
In order to perform the high-temperature treatment while preventing mutual agglomeration of particles, it is desirable to perform the treatment while flowing or moving the particles, such as in a fluidized bed.

In addition, as raw materials for grinding, B, P, As, Sb, Bi,
It is advantageous to use a material containing 0.1 to 2% of one or more of the element group consisting of S, Se%Te, and in this case, in particular, prior to pulverization, the raw material powder is suppressed. It is possible to oxidize by heating in an atmosphere with oxygen potential, that is, in a weakly oxidizing atmosphere, to use irregularly shaped powder obtained by water atomizing molten alloy as a raw material, and to coexist with a grinding aid for grinding. It is effective to improve the grinding efficiency by performing the grinding at the bottom.

[Effect]

In the present invention, the method for making the coercive force of the powder 40OA/1 or less in a randomly aggregated state ignoring the demagnetizing field with an average particle size of 0.1 to 30 μm and an average thickness of 2 μm or less is as follows. , the alloy composition is such that the saturation magnetostriction constant measured in the bulk material is within ±15
Selecting a Ni-based alloy; performing annealing at a high temperature in a non-oxidizing atmosphere to avoid agglomeration of powders after pulverization; and more specifically, performing high-temperature annealing while fluidizing or moving the powder. , is summarized in .

The flat fine powder that is the object of the present application requires a pulverization process. Although there is a method for producing flat grains directly from molten metal, there is a limit to the thickness of flat grains that can be produced directly from molten metal due to the surface tension of the molten metal, and the thickness is about 10 μm at the most.
It is necessary to reduce the wall thickness through some kind of processing, flatten it, and make the particle size finer. Therefore, the average particle size is 0.1~
The powder, which has a diameter of 30 μm and an average thickness of 2 μm or less, undergoes extremely large deformation and has large strains, and its original soft magnetic properties are severely impaired. That is, the coercive force of the powder in a randomly aggregated state ignoring the demagnetizing field exceeds 500 A/s at the minimum. In order to reduce the coercive force of fine powder with such large strain, powder annealing is essential, but in order to reduce the coercive force after annealing to 400 A/m or less, the saturation magnetostriction constant of the material component must be ± The present inventors have newly found that it is necessary that the distance be within 15 x 10'. In this case, the saturation magnetostriction constant is the wall thickness 2μ of the object of the present invention.
It is difficult to measure flat powder with a thickness of less than a layer, so the value measured is representative of the value measured on a plate material with a thickness greater than the thickness of a cabinet.

More specifically, the ordered lattice formation region of FeNi, a high magnetic permeability alloy with a composition near this region, so-called PA permalloy, and the F MOl in the e-N i system
The range includes multi-component permalloy to which Cr, Cu, Nb, Mn, etc. are added, so-called PC permalloy. It is known that these PA-based or PC-based permalloys have high magnetic permeability in ingotten bulk materials because the saturation magnetostriction constant is zero or close to zero, and the magnetic anisotropy constant K is close to zero. However, in the flat fine powder obtained by pulverization, which is the subject of this application, the saturation magnetostriction constant of its composition is ±1.
It has been found that within 5 x 10', significant residual strain due to crushing is released by subsequent annealing, and the target coercive force Hc becomes 40 OA/m or less.

Next, the reason for limiting the PC permalloy component recommended by this application will be described.

It is known that Fe-Ni alloy exhibits high magnetic permeability when Ni is around 80%, and Mo permalloy containing 4% Mo is particularly widely used. The alloy powder of the present invention contains Cu, Mn, and Mo as magnetism improving elements in the permalloy alloy.
It has a significantly increased magnetic permeability. The amount of Ni is 7
If 0% is left undropped, high magnetic permeability will not be exhibited, and if 83% is left undropped, the saturation magnetization will decrease, so it is set at 70 to 83%. C
U, Mn, and Mo are added for the purpose of improving soft magnetism. With 3% Cu powder droplets, the soft magnetism is improved, especially the coercive force Hc
The effect of reducing this is small. Moreover, when Cu exceeds 6%, the saturation magnetic flux density decreases and the magnetic permeability also decreases. M.O.
Also shows the same effect as Cu, and if Mo is less than 2%, the effect of improving soft magnetism, especially reducing coercive force Hc, is small, and if MO exceeds 6%, the saturation magnetic flux density and magnetic permeability decrease. do.

When Mn is less than 1%, the maximum magnetic permeability μm is low;
If it exceeds 1%, the coercive force Hc increases, and if it is between 1% and 2%, it is effective in increasing the maximum magnetic permeability. When C is dissolved in an alloy, it reduces the soft magnetic properties of the alloy, but its content up to 0.05% is permissible due to the soft magnetic properties of the powder.

The remainder is iron and accompanying impurities, but there is no problem in terms of properties even if Si, which is used as a deoxidizing agent during melting, is contained up to 1%.

In order to improve the crushability of the Fe-Ni alloy whose saturation magnetostriction constant λs is within ±15
, P, As, Sb, Bi, S, Se, Te, etc. Powder containing 0.1% or more and 2% or less of one or more of the element group consisting of P, As, Sb, Bi, S, Se, and Te is effective. was found to be more preferable. B, P, As, S
b, Bi, S, Se, and Te are the main composition of Ni-enriched Fe-
Since it has almost no solubility in the Ni system, the additives are M, B, M, P, M, Sb, M, Sb1,
M.B.I., M.S., M.S.

M, Se, MTe, MTe, and composite phases of these crystallize preferentially at grain boundaries as fragile intermetallic compound phases. Although each compound phase has a high or low melting temperature, it is extremely brittle, which makes the grain boundaries brittle and makes it easier to crush compared to normal Fe-Ni alloys in which these elements are not intentionally added. . In other words, the presence of the grain boundary embrittlement phase promotes the division of grain boundary units at the initial stage of crushing.
In particular, particle size refinement progresses quickly, improving pulverization efficiency.

In addition, most of the addition of the above element groups is spent in the compound phase at the grain boundaries and is hardly dissolved in the matrix, so basically the saturation magnetostriction constant of the matrix composition is ±
If it is within 15X10', the target coercive force Hc≦4
00A/m can be easily reached.

B, P, As, and Sb consumed in the formation of the grain boundary compound phase.
, Bi, S, Se, and Te may be added singly or in combination, but the appropriate total amount is 0.1% or more and 2% or less. At less than 0.1%, no visible effect on grinding efficiency is observed compared to when it is not intentionally added. Also, P, As, Sb, Bi, S.

Since the vapor pressure of Se, Te, etc. is particularly high at the melting temperature of the base composition, it is practically difficult to add more than 2% in total, and even B, which has a low vapor pressure, has a large coercive force Hc if it exceeds 2%. I don't like it. Therefore, the total amount added should be limited to 2% or less.

The compound phase at the grain boundary generated by the above element groups added in this way falls off from the grain boundary as the grain boundary units are divided during crushing, is mixed into the powder with the matrix composition, and is further crushed as the compound phase itself. Those with a low melting point melt and scatter due to frictional heat, or become extremely fine residues, which are melted and scattered during subsequent annealing, further reducing the amount, and do not remain to the extent that they deteriorate the magnetic properties.

When pulverizing the pulverized raw material to which the above-mentioned pulverization-promoting additive elements are added, heat treatment is performed in an atmosphere with suppressed oxygen potential.
The improvement in grinding efficiency is further promoted by the addition of the group consisting of Se and Te. The presence of the brittle grain boundary compound phase generated by the addition of the above element groups lowers the grain boundary energy, thereby reducing the
It is considered that the alloy is in a state where it is easily susceptible to selective grain boundary oxidation, which is difficult to recognize in i-based alloys. Although the oxidation state of the grain boundaries has not yet reached the stage where it is possible to quantify it, when preheating is performed at 600°C in wet hydrogen in an atmosphere with a suppressed oxygen potential, for example, as an atmosphere for pre-pulverization heating, but no heat treatment is performed. , and the grinding efficiency is improved compared to when heated in pure hydrogen. The atmosphere is not limited to wet hydrogen, and may be any weakly oxidizing atmosphere containing oxygen potential, such as nitrogen, inert gas such as Ar, NH, decomposed gas, etc., and is not particularly limited.

The temperature may be within a range where the powder to be pulverized begins to agglomerate, but if it exceeds 1000°C, the relative density will exceed 70% and a sintered body will be produced, which is not preferable because the pulverization efficiency will be reduced.

For mechanical pulverization, a stamp mill, a vibration mill, an attritor, etc. can be applied, but B, P, As, Sb, B of the present invention
In the case of Fe-Ni alloy powder containing 0.1 to 2% of one or more of the element group consisting of i, S, Se, and Te, it is It is possible to obtain flat powder with a target particle size and thickness within 10 hours with a yield of approximately 100%.

In the case of ordinary Fe--Ni based alloy powder without the addition of the above-mentioned powder, it is necessary to grind for a long time exceeding 10 hours in order to obtain the desired average thickness of 1 μm or less after grinding.

The above is a case using an attritor, and in crushers such as stamp mills and vibration mills that require lower input energy, the time factor shifts to the longer time side as a whole, but the tendency is the same.

In addition, the faster the solidification rate of the pulverized raw material during atomization, the
Since the crystal grain size of the powder becomes smaller and the grain boundary compound phase crystallizes uniformly and finely, pulverization progresses more easily.

Therefore, as the atomization method, the water atomization method with a high cooling rate is most suitable. Furthermore, according to water atomization, due to the shear force of the water in the atomizing medium.

Therefore, since the molten metal remains in an irregular shape with disordered interfaces, it is more likely to be pulverized due to its shape than the spherical shape produced by gas atomization, for example.

Flattening can be further promoted by performing the mechanical crushing in a medium to which a suitable crushing aid has been added.

The effectiveness of grinding aids is known, for example, in Japanese Patent Application No. 61-26213.
As shown in the case of amorphous alloy flakes in No. 4, the Fe of the present invention has the effect of adsorbing to the surfaces of activated powder particles as pulverization progresses, suppressing agglomeration of particles, and promoting flattening. -It was also observed in Ni-based alloys.

Effective solid aids include stearic acid, oleic acid,
Higher fatty acids such as lauric acid and valmitic acid, metal soaps such as zinc stearate, calcium stearate, zinc laurate and aluminum laurate, higher fatty alcohols such as stearyl alcohol, higher fatty acid amines such as ethanolamine and stearylamine, and polyethylene wax, and these may be used alone or in combination of two or more. The amount added is usually 0.1 to 500
Weight%. Moreover, organic solvents such as alcohols, glycols, and esters can also be used as liquid auxiliaries.

The crushed powder is classified as necessary to remove large particles. If there are large particles, it will be difficult to coat onto a substrate such as a card, and the coating will not be uniform, resulting in non-uniform properties. If the average particle size is 30 μm or less, there will be no problem in terms of characteristics.

Furthermore, if the average thickness is greater than 2 μm, the demagnetizing field coefficient in the flat direction increases, resulting in a decrease in soft magnetism after coating.

Next, if the flat fine powder that is the subject of this application is left as crushed, the
Since it has a coercive force exceeding A/m, an annealing process is an essential treatment.

When this highly strained fine powder Fe-Ni alloy is annealed under the same conditions as normal bulk materials, powder particles agglomerate,
That is, a problem arises in that a sintering phenomenon occurs and the flat shape obtained by mechanical crushing is lost. Therefore, annealing must be a treatment method that releases strain without causing agglomeration of powder particles and brings out soft magnetic properties.

In order to prevent agglomeration using conventionally known methods, the annealing temperature must be significantly lowered from around 1100°C for normal bulk materials, and it is impossible to reduce the coercive force of the powder to 400 A/m or less after annealing. It was possible. The method of annealing to release crushing strain and obtain soft magnetic properties is disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 58-59268.
However, it does not provide any concrete knowledge on how to overcome the above-mentioned agglomeration problem and improve soft magnetism.

In order to prevent agglomeration and improve soft magnetism, the present inventors have found that by setting specific component ranges, it is possible to prevent an increase in annealing temperature by increasing soft magnetism, and that flat F after crushing can be prevented by increasing soft magnetism.
High-temperature annealing is performed in a non-oxidizing atmosphere while flowing or moving the e-Ni alloy fine powder, suppressing agglomeration of the flat alloy fine powder during annealing and significantly reducing the high coercive force after crushing. I learned that it is possible.

For the latter annealing equipment, it is sufficient that the powder particles move in a soaking zone so that they do not agglomerate with each other, and the flat alloy fine powder is stirred and dispersed mechanically or with non-oxidizing gas until it reaches a predetermined temperature. A method of heating and annealing - including cutting.

For example, a cylindrical or groove-shaped container may be used in which powder is filled with a space at the top and continuously heated under stirring using rotating stirring blades installed in the width direction of the container.
Figure 1 is an example of this. Also, as shown in Figure 2,
A method may also be used in which the powder and the non-oxidizing gas are supplied countercurrently or cocurrently into an inclined rotating cylinder equipped with scraping blades inside. The powder is stirred up and annealed by repeated contact with heated non-oxidizing gas while falling in a curtain shape. Third
The figure shows a vibrating fluidized bed, in which non-oxidizing gas is blown in and powder is added to form a so-called fluidized bed, and the bottom of the fluidized bed is mechanically vibrated obliquely to promote fluidization. It transports powder in the direction of vibration. As the bottom plate, a perforated plate, a screen, etc. are used. In the examples in each figure, although the position of the heater is not particularly shown, the soaking zone is set by internal or external heating.

〔Example〕

Example 1 Various Fe--Ni base metal melts shown in Table 1 were water atomized to obtain powders with an average particle size of 30 to 37 μm.

The table also shows the saturation magnetostriction constant λs measured for the ingot bulk material of each composition. These six kinds of water atomized powders were pulverized using an attritor.

The pulverization conditions were such that the weight ratio of SUJ 2 steel balls and water atomized powder was 3:1, the same weight of isopropyl alcohol as the water atomized powder was added as a pulverization aid, and pulverization was carried out at 300 revolutions per minute for 10 hours. The obtained powder has an average particle size of 13
It is flat with a thickness of ~16 μm and an average thickness of 0.7 to 0.9 μm,
The apparent density was 3-6% of the true density of the corresponding component.

After measuring the coercive force Hc of the as-pulverized powder, the change in Hc and the shape of the powder after annealing in a hydrogen stream were observed.

FIG. 4 shows six results using a co-current rotary cylinder type annealing apparatus as shown in FIG. 2. In the figure, ○ indicates that the shape as crushed was maintained, and . indicates that agglomeration has occurred.

In other words, there is a tendency that the greater the deviation of the saturation magnetostriction constant from zero, the louder the as-pulverized Hc and the greater the Hc after annealing. When annealing is performed at 600°C within a range where agglomeration does not start, Hc is desirable 24
0A/m or less is limited to powder No. 3.6.5, and in this case, the saturation magnetostriction constant λs of each is 5x
10'', 3X10', lX10=.

Table 1 Example 2 In exactly the same manner as in Example 1, powders having compositions No. 1 to 6 were pulverized using an attritor, and then annealed in a vibrating fluidized bed type furnace as shown in FIG. In the case of Example 1, the powder was rotated, but in this case, since a uniform fluidized state was generated, Hc could be further reduced without agglomeration even at 700°C. That is, No, 2.4, 3, 6.5
An Hc of 240 A/m or less was obtained with the powder. However, no
, I could not achieve HC≦400A/w.

In this case, each saturation magnetostriction constant λs is 15XIO
'-12X10', 5X104.3X10', I
It is X104. Therefore, ±15 X 10”
If λs is, the target Hc can be obtained.

Example 3 Various Fe--Ni thread metal alloy melts shown in the column of Example 3 in Table 2 were water atomized to obtain powders with an average particle size of 31 to 39 μm.

These powders are pulverized with an attritor, and then H
It was annealed in two air currents to reduce the coercive force Hc. In the attritor pulverization, the weight ratio of 5UJZ steel balls and water atomized powder was 3:1, ethanol was added in the same weight as the water atomized powder as a pulverization aid, and the powder was pulverized at 300 revolutions per minute.

While sampling every 5 hours, the average thickness was 1 μm.
Stop grinding when it reaches 350 LIles.
The yield of -350mesh and its average particle size were measured. Also, 600℃X in a hydrogen atmosphere with a dew point of -60℃
Ibr annealing was performed, and the coercive force Hc was measured. The shape of the flat fine powder before and after annealing was compared, and it was confirmed that there was no change in shape due to annealing.

The annealing apparatus used was a tilted rotary inner cylinder type equipped with scraping blades inside as shown in Fig. 2, and a furnace in which hydrogen gas and powder were flowed in parallel.

The column of Example 3 in Table 2 lists the main components of the sample material excluding unavoidable impurities, the saturation magnetostriction constant λs measured in the melted bulk material, and the time required for pulverization to reach an average thickness of 1μ. ,−
The yield of 350 mesh, the average particle size at -350 mesh, and the coercive force Hc of the flat fine powder after annealing are shown.

From the perspective of the saturation magnetostriction constant λs, it can be seen that if the saturation magnetostriction constant λs is within ±15 26X10″&, Hc≦400A/m
cannot be reached.

From the perspective of pulverization efficiency, No. 14.18, 19, 20, 21.22, 25, which generates the brittle grain boundary compound phase of the present invention,
, 26, 27°, 28.30, 10 hr is sufficient under 5-mill grinding conditions, the yield of -350 esh exceeds 75%, and the average particle size is 20 μm or less. In particular, the difference in pulverizability between the composition of the present invention and the usual Fe--Ni alloy composition is remarkable for alloys with the same λs.

On the other hand, in No. 16.17, in which only a small amount of the crushing promoting element was added, the crushing time was 15 hours.

In addition, No. 11.13゜15 which does not contain these elements
．． No. 23.29 is somewhat unsatisfactory in terms of yield after grinding time -350+5esh.

Example 4 In the same manner as in Example 3, water atomized powders having compositions No. 18 and No. 25 of the present invention were pulverized. The powder was incubated at 700°C in wet hydrogen with a dew point of 30°C before attritor milling.
After one hr heat treatment, the powder became aggregates that could be loosened by hand. The apparent particle size is approximately 300μ.

When the above aggregated powder was pulverized using an attritor under the same conditions as in Example 3, the results shown in the column of Example 4 in Table 2 were obtained. That is, compared to Example 1 in which the heat treatment was not performed, the yield of -350mesb after the same 10-hour grinding increased by 9% and 3%, respectively, and the average particle size reached was 3 μm in both cases.
Reduced. In addition, the Hc after annealing is the same level as that without the heat treatment, that is, 200.140 A/
It was m.

Example 5 Among multi-element permalloy (PC permalloy) added with MO + Cu + Mn, a molten metal of an alloy with a composition having a high magnetic permeability that is expected to be applied in the field of magnetic shielding was water atomized to reduce the average grain size. A powder with a diameter of 29 to 35 μm was obtained. These powders were pulverized using an attritor in the same manner as in Example 3, and then annealed in an H8 air stream to reduce the coercive force Hc. Attritor pulverization is carried out by setting the weight ratio of 5UJZ steel balls and water atomized powder to 3:1, adding isopropanol as a grinding aid in the same weight as the water atomized powder,
It was pulverized at 300 revolutions per minute. The grinding time was as same as in Example 3, with sampling every 5 hours, and the average thickness was 1.
Grinding was stopped when the particle size became .mu.m or less, and the yield and average particle size were measured. Further, annealing was performed under the same conditions as in Example 3, and the coercive force Hc was measured. In the column of Example 5 in Table 2,
The main components of the sample material excluding unavoidable impurities and the measurement results are shown.

In this alloy composition, as in Example 3, in No. 32, 33, and 35, which produce brittle grain boundary compound phases, flattening progresses in a short time, and the yield of -350 mesh exceeds about 90% or more. It can be seen that the average particle size is 20 μm or less.

Example 6 Molten metals of various soft magnetic alloys shown in Table 3 were water atomized,
A powder with an average particle size of 25 to 36 μm was obtained.

These powders were pulverized with an attritor, and then H8
It was annealed in an air flow to reduce the coercive force Rc. The attritor powder was pulverized at 300 revolutions per minute with the weight ratio of 5UJZ steel balls and water atomized powder being 10:1, and the same volume of isopropyl alcohol as the steel balls added as a pulverizing aid. The grinding time was 5 hours. After crushing, it was sieved with 500 mesh and the average particle size was measured.
Measured by laser diffraction method.

In addition, if the battery is kept stationary in a hydrogen atmosphere with a dew point of -60°C,
Annealing was performed at 0° C. and IHr, and the coercive force Hc was measured. The shape of the flat fine powder before and after annealing was compared, and it was confirmed that there was no change in shape due to annealing.

Next, the annealed powder was mixed with a binder containing acrylic acid and urethane resins in a ratio of 2:3, and the mixture was applied onto a polyester substrate to a thickness of 12 to 14 μm. The coercive force Hc and maximum magnetic permeability μm in the substrate surface direction of the coated substrate were measured.

Table 3 lists the main components of the sample material excluding unavoidable impurities,
The saturation magnetostriction constant λs, coercive force Hc, maximum magnetic permeability μm, magnetic flux density B1 when applying a magnetic field of 8A/(2), average grain size at -500mesh, measured in the ingot bulk material,
The coercive force Hc of the flat fine powder after annealing, the coercive force (coercive force in the in-plane direction of the substrate after coating on a polyester substrate) 1c, and the maximum magnetic permeability μm are shown.

Comparing the magnetic properties of the bulk material with the magnetic properties after being applied to the flat fine powder and the substrate, it can be seen that the soft magnetic properties after being applied to the flat fine powder and the substrate are considerably reduced. This is due to the fact that the shape magnetic anisotropy effect was achieved by creating a flat fine powder, and the strain during the crushing process was 500°C.
This is due to the fact that it is difficult to completely remove it by low-temperature annealing.

However, it is clear from Table 3 that the magnetic properties in the bulk material are reflected in the magnetic properties after being applied to the flat fine powder and the substrate. That is, the composition of the alloy of the present invention that exhibits excellent soft magnetic properties in bulk material also exhibits superior soft magnetic properties compared to other compositions even after being applied to a flat fine powder and a substrate.

From Table 3, it is possible to satisfy the coercive force of Hc≦240A/m depending on the composition even when annealing in a static state at a low temperature (500°C), and that both Hc≦400A/i can be satisfied. Recognize. In addition, from No. 45.46, the maximum magnetic permeability μm is slightly lower when the Ni amount is outside the range of 70 to 83%, both in the bulk material and after coating. From No. 48, when the Cu amount is less than 3%, the bulk material No. 47 shows that the coercive force Hc becomes high regardless of the material, powder, or after coating, and the maximum magnetic permeability slightly deteriorates.No. It can be seen that each decreases. Further, from No. 49, when the Mn amount is less than 1%, the maximum magnetic permeability μ is low and the coercive force is high, and from No. 50, when the Mn amount is more than 2%, the coercive force Hc is large. The maximum magnetic permeability μm is also low, and according to No. 51, without Cu addition, μm is low in any state, and this low temperature annealing cannot satisfy the preferred target Hc≦240A/m of the coercive force Hc of the present invention. I understand that. However, if Hc≦400A/m, it is necessary to add drops.

From the above, flat fine powder N with the component range recommended by the present invention.
o, 41 to 44, even after coating on the substrate, the coercive force Hc,
It has excellent soft magnetic properties such as maximum permeability μl,
It can be seen that it exhibits good magnetic shielding characteristics.

Example 7 The same water atomized powder as No. 41 of Example 6 was pulverized with an attritor.

The attritor powder was pulverized at 300 revolutions per minute with the weight ratio of SUJ Z steel balls and water atomized powder being 10:l, and the same volume of isopropyl alcohol as the steel balls added as a pulverizing aid. The grinding time was set to 1, 3, and 5.20 hours in order to change the wall thickness and average particle size of the powder. After pulverization, the powder was crushed through 350 mesh or 500 mesh, and the particle size distribution and powder wall thickness were measured.

The obtained powder was annealed in H1 under the same conditions as in Example 6, then the coercive force Hc was measured, and after being coated on a substrate, the coercive force Hc and maximum magnetic permeability μm in the direction of the substrate surface were measured. did.

Table 4 shows the time of attritor crushing, -350IIes
h, average particle size at 500 mesh, average wall thickness, coercive force Hc of the flat fine powder after annealing, coercive force Hc in the in-plane direction of the substrate after coating on a polyester substrate, and maximum magnetic permeability μm.

From Table 4 No. 52, when the wall thickness is thicker than 1 μm, the demagnetizing field coefficient in the flat direction is large, so the coercive force Hc after coating is high, the maximum magnetic permeability μm is also low, and the preferable coercive force Hc of the powder is It can be seen that ≦240 A/m also tends to become unsatisfactory.

No. 54, which had an average particle size larger than 30 μm, had good average magnetic properties, but it was difficult to uniformly coat the substrate, and the coated film also became non-uniform.

〔Effect of the invention〕

As shown in the examples above, the saturation magnetostriction constant λs is ±
If it is a Fe-Ni alloy within 15 x 10', even if it is a very flat fine powder with an average particle size of 0.1 to 30 μl and an average thickness of 2 μm or less, the coercive force Hc can be increased to 400 A by annealing. /I11 or less is possible. Furthermore, by stirring and dispersing the powder (fluidization, movement) to prevent agglomeration of the powder during this annealing, the annealing temperature can be increased and the effect of the -layer can be increased. Furthermore, by specifying the components, the required magnetic properties of the powder and coating film can be satisfied even during low-temperature annealing that does not cause agglomeration.

As described above, according to the present invention, it is possible to obtain a flat fine powder with excellent soft magnetic properties, which has great industrial value.

Furthermore, as shown in the examples, B, P,
As% F containing 0.1% or more and 2% or less of one or more of the element group consisting of Sb, Bi, S, Se, and Te.
By subjecting e-Ni alloy powder to pulverization, flat soft magnetic fine powder with an average particle size of 0.1 to 30 μm, an average thickness of 2 μm or less, and a coercive force Hc of 400 A/+ or less can be efficiently produced. It can be manufactured and has great industrial value.

[Brief explanation of drawings]

1 to 3 are diagrams showing an example of an annealing apparatus for carrying out the present invention, and FIG. 4 is a diagram showing the relationship between coercive force and annealing temperature of pulverized powder related to the present invention. 2: Powder supply port, 3: Gas inlet, 5: Powder outlet, Figure Annealing degree (0C) Figure 4 Procedural amendment (voluntary) February 1998. Display of the July 17 incident, 1990. Patent Application No. 89705: Detailed description of the invention of the specification to be amended by the person making the amendment. Contents of the Amendment The Detailed Description of the Invention column of the specification is amended as follows. (1) The statement "thickness 2μ or less" on page 4, line 4 of the specification is corrected to "average thickness 2μ or less." (2) “No specifics found” on page 6, line 18 of the specification
The statement in the following is corrected to "No specific example found." (4) On page 18, line 9 of the specification, the statement "desirably 1 μm or less" should be changed to "desirably 2 μm or less"
Correct. (5) The description of "Improper Tool J" on page 30, line 8 of the specification is corrected to [isopropyl alcohol]. (6) Replace Table 3 on page 35 of the specification with the attached Table 3. that's all

Claims (1)

[Claims] 1. The saturation magnetostriction constant λs measured in bulk material is ±15×
It has a composition within 10^-^5 and an average particle size of 0.1~
30 μm, average thickness is 2 μm or less, and coercive force Hc is 4
00A/m or less flat Fe-N
I-based alloy fine powder. 2 Ni70-83%, Mo2-6%, Cu3-6%,
2. The flat Fe-Ni alloy fine powder according to claim 1, characterized in that Mn is 1 to 2%, C is 0.05% or less, and the balance is iron and incidental impurities. 3 Saturation magnetostriction constant λs measured in bulk material is ±15×
A raw material having a composition within 10^-^5 is pulverized into an average particle size of 0.1 to 30 µm and an average thickness of 2 µm or less, and then crushed into approximately the above flat fine powder form in a non-oxidizing atmosphere. Annealing is performed while maintaining the coercive force Hc of the powder to 40
Flat-shaped Fe-Ni characterized by being 0A/m or less
A method for producing alloy fine powder. 4 The raw material to be crushed has a saturation magnetostriction constant λs measured as a bulk material within ±15×10^-^5, and contains B, P, and As.
, Sb, Bi, S, Se, Te,
1. A method for producing a flat Fe--Ni alloy fine powder, characterized in that it contains one or more kinds in an amount of 0.1% or more and 2% or less. 5. The method for producing a flat Fe-Ni alloy fine powder according to claim 4, characterized in that, prior to pulverization, the raw material powder to be pulverized is subjected to heat treatment in an atmosphere having a suppressed oxygen potential. 6. The method for producing flat Fe-Ni alloy fine powder according to claim 3, 4 or 5, wherein the annealing is performed while the powder is fluidized or moved. 7. The flat Fe-Ni according to claim 3, 4, 5 or 6, wherein the raw material to be crushed is an irregularly shaped alloy powder obtained by spraying a molten alloy by a water atomization method. A method for producing alloy fine powder. 8. The method for producing a flat Fe-Ni alloy fine powder according to claim 3, 4, 5, 6 or 7, characterized in that the mechanical crushing is carried out in the coexistence of a crushing aid.