JPH01119620A - Manufacture of sheet metal of fe-ni magnetic alloy - Google Patents

Abstract

PURPOSE:To manufacture a material having superior D.C. magnetic properties and reduced in high frequency loss by cold-rolling an Fe-Ni alloy to a specific thickness, applying magnetic annealing to the resulting cold-rolled sheet, and then subjecting the above to cold working and annealing treatment under respectively specified conditions to form a sheet metal of a specific thickness. CONSTITUTION:An Fe-Ni alloy is refined and cast into an ingot, which is cold- rolled to <=100mu thickness and then subjected to magnetic annealing consisting of holding in a nonoxidizing atmosphere of dry oxygen, etc., at >=about 1,000 deg.C for >=about 10min and cooling down to room temp. Subsequently, the above sheet is subjected to slight-degree cold working at <=10% draft and then to annealing treatment consisting of holding in a nonoxidizing atmosphere of dry oxygen, etc., at >=700 deg.C for >=5min and cooling down to room temp. The above slight-degree working and annealing treatment are alternately applied once or plural times, respectively, to form a sheet metal of <50mu thickness. By this method, an extra thin magnetic sheet metal (foil) material increased in average crystalline grain size and remarkably improved in D.C. and A.C. magnetic properties can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to an iron-clad material particularly suitable for use under high frequency magnetic fields.
The present invention relates to a method for manufacturing a nickel (Fe-Ni) based magnetic alloy thin plate.

(Technical Background and Problems of the Invention) Permalloy is a typical magnetic alloy of Fe-Ni alloys.
), B grade (40-50% Ni, balance Fe), C grade (70
- Contains special components in addition to ~80% Ni, residual Fe), D class (
35-40% Ni, balance Fe), E grade (45-55% Ni
There are various types of ferrite, such as ferrite, residual Fe), and these are used in relays, magnetic pole pieces, transformers, transformers, magnetic shields, magnetic heads, magnetic amplifiers, etc., depending on their characteristics.

Since permalloy as described above has a regular lattice transformation, its magnetism changes very sensitively by heat treatment. Furthermore, magnetism changes significantly depending on the crystal grain size.

Among such Fe--Ni magnetic materials, a magnetic material used under a high-frequency magnetic field is required to have high effective magnetic permeability and small core loss. In particular, there is a strong demand for smaller size, higher performance, and higher reliability in various electronic devices these days, and one of the solutions is to increase the frequency of magnetic materials used in inductors and transformers (KHz-MH).
z) is considered.

Recently, research and development has been carried out on amorphous metals manufactured by the molten metal quenching method, but this manufacturing method has problems such as high production costs and changes in magnetic permeability over time due to relaxation of the amorphous structure. Therefore, there are problems in practical application.

For this reason, rolled magnetic thin plates have traditionally been used as magnetic cores used in high-frequency magnetic fields.
In order to reduce the eddy current loss of this magnetic thin plate, measures have been taken to reduce the thickness of the magnetic thin plate as much as possible. However, when the thickness of the plate is reduced beyond a certain level, the DC hysteresis loss increases, which poses a problem in the effectiveness of reducing the eddy current loss by making the plate thinner. To explain this point in more detail, in metal magnetic cores manufactured by magnetically annealing conventional rolled materials, as the plate thickness becomes thinner, particularly when it becomes 50 μm or less, the coercive force increases and the maximum magnetic permeability decreases. , a phenomenon in which the DC magnetic characteristics deteriorated was observed. On the other hand, the average grain size of a rolled thin plate is approximately proportional to the thickness of the plate.

From the above, the deterioration of DC magnetic properties due to thinning of the plate is as follows:
This is thought to occur because the crystal grains become finer as the plate thickness decreases, and the number of grain boundaries that pin the motion of the domain wall increases. Therefore, in order to improve the DC and AC magnetic properties of an ultra-thin Fe-Ni alloy (permalloy) with a thickness of less than 50 μm, the crystal grain size should be made as large as possible (preferably larger than the plate thickness). ) It was found that it was necessary to make an ultra-thin plate (foil).

[Structure of the invention]

The present inventors have arrived at the present invention in view of this point. That is, in the present invention, a Fe-Ni alloy of 100μ
After cold rolling to a plate thickness of 1.0 m or less, magnetic annealing is performed, and the first cold working is performed with a working degree of 10% or less and in a non-oxidizing atmosphere.
A method for producing a Fe-Ni magnetic alloy thin plate, characterized in that a thin plate having a thickness of less than 50 μm is obtained by performing an annealing treatment at a temperature of 00° C. or higher for 5 minutes or more, one time or a plurality of times, and the above-mentioned method. The present invention provides a method for producing the Fe--Ni magnetic alloy thin plate described above, characterized in that cold working and annealing are performed alternately once or a plurality of times to reduce the plate thickness to 20 μm or less.

[Detailed description of the invention]

Next, the reasons for limiting the conditions in the present invention will be described in detail below.

In the present invention, first, the material Fe-Ni alloy (
Permalloy) is melted and cast into an ingot, which is then forged, hot rolled, pickled, and then cold rolled and annealed as necessary to achieve the required thickness. The target plate thickness in this cold rolling is 100 μm or less. After this, magnetic annealing is performed. Magnetic annealing is performed by holding the material at a temperature of 1000° C. or higher for 10 minutes or more in a non-oxidizing atmosphere such as dry hydrogen, and then cooling it to room temperature at an appropriate cooling rate. After magnetic annealing, further light processing and annealing treatment is performed to improve the DC and AC magnetic properties. That is, when the material after magnetic annealing is subjected to mild cold working with a working degree of 10% or less and recrystallization annealing is performed, crystals grow and the structure is dominated by coarse crystal grains. The necessary conditions for the growth of coarse grains are that the applied cold working energy is sufficient for crystal growth, and that the degree of working is low so that nucleation is minimized. Further, in the heat treatment during light processing and annealing treatment, it is desirable to maintain the temperature at 700° C. or higher for 5 minutes or more in a non-oxidizing atmosphere such as dry hydrogen, and cool it to room temperature at an appropriate cooling rate. This heat treatment
If necessary, it can be performed under the same conditions as the magnetic annealing described above to serve as complementary magnetic annealing. By performing the above light processing and annealing treatments once or multiple times, the Fe-Ni sheet (foil) can be made into an ultrathin sheet (foil) with a large average crystal grain size, preferably larger than the sheet thickness. system alloy (permalloy) can be obtained. In this way, an ultra-thin sheet (foil) magnetic material with significantly improved DC and AC magnetic properties can be produced.

The Fe-Ni alloy of the present invention includes permalloy as described above, but in order to improve magnetic properties, corrosion resistance, wear resistance, etc., alloy components (such as Cr, Mo, W,
Co, Ca, Mn, Cu, V, Nb, Ta, Ti, AI
, Si%Mg, rare earth elements, etc.) in a total amount of 10% or less are naturally included in the above-mentioned Fe-Ni alloys.

In addition, in the present invention, what is described as a thin plate or an extremely thin plate includes foil, and the plate thickness also means the thickness of the foil. This is obvious from the description that the plate thickness is 100 μm or less or 20 μm or less.

〔Effect of the invention〕

The present invention makes it possible to obtain a material with excellent DC magnetic properties and low high-frequency loss that cannot be obtained through the normal manufacturing process of magnetically annealing a cold-rolled material as it is. This can significantly contribute to the improvement of optimization and performance.

〔Example〕

Next, examples of the present invention will be described.

The plate thickness is 100 μm or less (50 μm to 10 μm) by cold rolling.
0 μm, preferably more than 20 μm to 100 μm)
After performing magnetic annealing on the e-Ni-based permalloy alloy, the light working and annealing treatments were each repeated one or more times alternately to obtain a plate thickness of 20 μm. The magnetic annealing conditions were heating at 1100° C. for 1 hour in a dry hydrogen atmosphere, followed by furnace cooling.

The heat treatment for light processing and annealing was also carried out under the same conditions as the magnetic annealing conditions. From the material thus produced, a 10φ-6φ ring sample for measuring magnetic properties was fabricated by photoetching. The Fe-Ni alloy used in this example is
45Ni-Fe permalloy B alloy, 8ON, i5
Mo-Fe and 78Ni-4Mo-5Cu-F
It is a permalloy C-based alloy of e.

Table 1 shows the chemical composition and manufacturing process of the ultra-thin permalloy plate according to the present invention. Table 1 also lists the measurement results of their magnetic properties, average crystal grain size, and core loss per cycle at excitation frequencies of 1 kHz and LookHz. Also,
FIG. 1 shows an example of the frequency dependence of the core loss of the present invention example and the comparative example.

As is clear from Table 1, the C-based permalloys 1 to 2 of the examples of the present invention are superior to the C-based permalloys 0 to 2 of the comparative examples in direct current and alternating current magnetic properties. As shown in Figure 1,
The core loss of the example of the present invention is lower than that of the comparative example over the entire measurement frequency range. Similarly, the B-based permalloy [phase] to 0 of the present invention example is the B-based permalloy [phase] of the comparative example.
~[Phase] Excellent DC and AC magnetic properties.

Inventive examples ■, ■~■, and ■~◎ are those in which the light working and annealing treatment was repeated twice, and the average The crystal grain size is coarse, and the DC and AC magnetic properties are excellent.

Therefore, by repeating light processing and annealing multiple times,
Further improvements in DC and AC magnetic properties can be obtained. Comparative examples [phase], O2 [phase] and [phase] have a working degree of 50%
Because of the large size, the crystal grains do not coarsen due to heat treatment, and the effect of improving DC and AC magnetic properties is not obtained.

The limitations on the degree of processing in light processing and annealing are shown below. 78Ni-4Mo-5C subjected to magnetic annealing
For permalloy C-based alloys of u - Fe.

Cold rolling is performed with a working degree of 2 to 95%, and the final thickness is 50%.
FIG. 2 shows the relationship between the working degree and the average grain size of the material which was magnetically annealed after being reduced to μm. From Figure 2, the processing degree is 10.
%, coarse grains larger than the plate thickness cannot be obtained, and crystal growth exceeding the plate thickness occurs in the annealed material after light rolling with a workability of 10% or less.

[Brief explanation of the drawing]

FIG. 1 is a graph showing frequency dependence of core loss in the present invention example and comparative example, and FIG. 2 is a graph showing the frequency dependence of core loss in the present invention example and comparative example.
It is a graph showing the relationship between the workability of a permalloy C-based alloy of -4Mo-5Cu-Fe and the average grain size of the material after annealing. 0.1 1 10 100 10
00 frequency to Hz) Figure 1

Claims (2)

[Claims] (1) After cold rolling the Fe-Ni alloy to a thickness of 100 μm or less, magnetic annealing is performed, and then cold working with a workability of 10% or less and a temperature of 700°C or more in a non-oxidizing atmosphere. 1. A method for producing a thin Fe--Ni magnetic alloy sheet, characterized in that a thin sheet having a thickness of less than 50 .mu.m is obtained by performing annealing treatment for 5 minutes or more, one time or a plurality of times. (2) The Fe-Ni film described in claim 1 is characterized in that the cold working and annealing treatments are each performed once or multiple times alternately to reduce the plate thickness to 20 μm or less.
A method for manufacturing a magnetic alloy thin plate.