JPS60228684A - Annealing method of amorphous magnetic steel strip - Google Patents

Abstract

PURPOSE:To improve the magnetic characteristic of an amorphous magnetic steel strip by subjecting said strip to a surface treatment including a phosphate treatment and/or chromate treatment to stick an insulating film thereon then annealing the strip in an oxidative atmosphere. CONSTITUTION:The amorphous magnetic steel strip is subjected to the surface treatment in an aq. soln. consisting essentially of phosphoric acid and water soluble metallic salt and/or an aq. soln. consisting essentially of chromic anhydride and chromate. The insulating film consisting of the mixed film composed of the phosphate film and chromate film is thereby stuck onto said strip at a ratio of 10-1,000mg/cm<2> in terms of dry film weight. Methods such as roll coating and treating method and electrolytic treating method are adequately used for the surface treating method. The thickness of the above-mentioned film is 30- 5,000Angstrom . The above-mentioned steel strip stuck with the film is annealed in the oxidative atmosphere, for example, an atmosphere of air or a gaseous mixture composed of air and inert gas by which the insulating film having necessary interlayer resistance is obtd. without spoiling the max. effect in the magnetic characteristics, i.e., a small iron loss.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method of annealing an amorphous magnetic steel strip as a magnetic material used in transformer cores, motor cores, etc. The present invention relates to a method of annealing a treated amorphous magnetic copper strip.

(Prior art and problems) In recent years, non-crystalline metal strips made of amorphous metals such as Fe-81-B series and Fe-81-B-C series have been used as copper strips with excellent magnetic properties to be used as magnetic core materials. As crystalline magnetic copper strips began to attract attention, for example, the three temples described in the 1975 Japan Institute of Metals Autumn Conference Lecture Abstracts, pages 341-342.
Fe75-81B8~15 S'5~1 shown in Masumoto et al.'s paper or Japanese Patent Application Laid-Open No. 56-33453, etc.
5, B8-17 SI2-8C1-8 remainder F0, and other materials are known.

Such an amorphous magnetic steel strip is generally used as a magnetic core in the form of a wound iron core, which is wound, or a laminated iron core, which is punched into a predetermined shape and laminated.

After being formed into a wound iron core or stacked iron core in this way, annealing is usually performed, but the purpose is to control the magnetic domains by stress relaxation and annealing in a magnetic field, and the annealing atmosphere used is is an inert atmosphere N2. Ar, H
Dry N2 gas is usually used.

Further, as the annealing conditions, an annealing temperature within a range in which the amorphous metal does not crystallize and an annealing time in which optimum characteristics are obtained within that temperature range are selected.

In this case, the reason why the annealing atmosphere is an inert atmosphere is because it is said that when an amorphous magnetic copper strip is annealed in an oxidizing atmosphere, the oxide film on the surface of the copper strip becomes too thick and the magnetic properties deteriorate. In order to prevent the formation of an oxide film, annealing is generally performed in an inert atmosphere.

In addition, there has been little study on the surface coating treatment of amorphous magnetic steel strips, and the reason for this is that the currently considered applications for amorphous magnetic materials are iron cores for transformers, iron cores for motors, etc. It is said that it has a relatively small b capacitance and that it has a certain degree of specific resistance compared to crystalline metals.

Also, IEEE, Transactlons on
Magneticm, VOL, MAG-19, A5
(1983) P. 1943, entitled "Effect of Coating on Power Loss of Amorphous Wound Iron Core," was published, and it was reported that the coating of amorphous IJ gun had no beneficial effect.

However, due to the deterioration of magnetic properties (deterioration over time) that occurs over time when used for storage, the decrease in magnetism due to rust, and the need for an insulating film due to the high capacity, the present inventors have decided not to We have been intensively studying the surface treatment of crystalline magnetic steel strips, and have already published, for example, Japanese Patent Application Laid-Open No. 59-25998 and Japanese Patent Application No. 1983.
No. 8-84505, etc., have proposed novel surface treatment methods.

When these surface-treated amorphous magnetic copper strips are annealed in N2, which is the usual method, it has been observed that the magnetic properties, especially the iron loss, become worse than untreated materials. Improvement in this point was necessary.

(Objective of the Invention) The object of the present invention is to improve the magnetic properties of an amorphous magnetic steel strip treated with an insulating film.

In the present invention, annealing is performed in an oxidizing atmosphere, and for amorphous magnetic steel strips that have been previously treated with an insulating film as in the present invention, annealing in an oxidizing atmosphere may improve the magnetic properties.
In particular, the iron loss is improved, and the present invention has been achieved based on the discovery that the properties are equal to or better than those obtained when an untreated copper strip is annealed in N2.

(Structure and operation of the invention) That is, the present invention performs a surface treatment of phosphate treatment and/or chromate treatment on an amorphous magnetic copper strip, and has a dry film amount of 10 to 1000 da/-. This is a method of annealing an amorphous magnetic steel strip, which is characterized by annealing in an oxidizing atmosphere after depositing an insulating film.

The present invention will be explained in detail below.

First, the surface treatment liquid used in the present invention will be described. First, the phosphate treatment liquid is an aqueous solution containing phosphoric acid and a water-soluble metal salt as main components, and it is also possible to add 5IO2 sol, At203 sol, etc.

Further, the chromate treatment solution is an aqueous solution containing anhydrous chromic acid or chromate as a main component, and may also contain a small amount of metal ions such as zinc and aluminum, an organic reducing agent, and a fluorine compound.

Furthermore, the phosphate-chromate treatment solution is a treatment solution whose main components are chromic acid anhydride or chromate, phosphoric acid, and a metal compound of phosphoric acid, and some organic reducing agents and fluorine compounds. It is also possible to add salts, 5i02(5) sols, At203 sols.

In addition, the phosphate-chromate treatment in the present invention is
Phosphate treatment and chromate treatment are carried out simultaneously, and the resulting film is a mixed film of phosphate film and chromate film.

Next, as a surface treatment method, various methods such as a roll coating method, a spray coating method, a dip coating method, or an electrolytic treatment method can be used as appropriate. Note that pickling before treatment can be performed as necessary.

Next, regarding the dry adhesion amount of the surface treatment film, in the present invention, the adhesion amount of the treated film as a dry film is 1
Although it needs to be between 0 m9/d and 1000 Da/-, there is a reason for this limitation on the amount of adhesion. In other words, the upper and lower limits of the adhesion amount are determined by the relationship between interlayer resistance, magnetic properties, and the effect of annealing in an oxidizing atmosphere. This is because this is the minimum amount of adhesion required to maintain the minimum resistance and at the same time suppress deterioration of magnetic properties during annealing in an oxidizing atmosphere.
(6) Also, the upper limit was set at 1000■/- because this is the maximum adhesion necessary to not cause significant deterioration of magnetic properties, especially iron loss, and to exhibit the effect of annealing in an oxidizing atmosphere. This is because it is a quantity. In addition, the film thickness in this case is 3
It becomes extremely thin, about 0X to 5ooo1.

Next, the oxidizing atmosphere in the present invention refers to an atmosphere such as air, a mixed gas of air and an inert gas, a mixed gas of oxygen and an inert gas, or an inert gas containing moisture. , N2 gas, inert gas such as Ar gas, or N
This does not include an atmosphere containing reducing gas such as 2 gas.

In this case, the reason why the amorphous magnetic steel strip treated with the insulating film is annealed in an oxidizing atmosphere in the present invention is that by carrying out such annealing, deterioration of magnetic properties, especially iron loss, is significantly suppressed. This is because it will be done.

The reason why this happens is not clear at present, but it is probably due to the above-mentioned surface treatment solution that after the oxidized film disappears, an oxidizing atmosphere acts through the treated film, and as a result, the surface of the copper strip is re-applied to the surface of the copper strip. An oxide film is formed,
This is thought to be due to the fact that this acts as tension.

(Example) Hereinafter, the effects of the present invention will be illustrated more specifically by Examples.

Example 1 Fe 89.8%, Si 8.2L16, B2.0 (chemical composition is weight %, hereinafter all chemical compositions of amorphous metals in the examples are heavy) and Fe 93.1%, st4.
Chromic anhydride 501// on an amorphous steel strip with a thickness of 25 μm ± 2 μm (the former is referred to as steel strip 1 and the latter is referred to as steel strip 2) with a chemical composition of x%, B 2.7%, CO, 1 m l, phosphoric acid 1o p/t s diphosphoric acid ht 251//l, ethylene glycol 0.51/11 potassium fluorosilicide 2
．． A treatment solution consisting of 5 fl/l was appropriately diluted with water to adjust the amount of adhesion, and after roll coating, each was dried at 200° C. for 3 seconds in a hot air drying oven. The thus obtained amorphous copper strip with an insulating film was heated at 390°C for 120 minutes for steel strip 1.
Steel strip 2 was annealed in a magnetic field at 370°C for 30 minutes in an N2 gas atmosphere, an air atmosphere, and an N2 gas atmosphere containing water passed through hot water at a temperature of 50°C, and then iron loss W1
315o (iron loss value Wa t t /11 at frequency 50 Hz, magnetic flux density 1.3 Tesla) and magnetic flux density B
. , a (magnetic flux density when a magnetic field of 80 A/m 2 is applied, Tesla) was measured on a single plate.

The results are shown in Table 1 for steel strip 1 and in Table 2 for steel strip 2.

(9) As can be seen from Tables 1 and 2, the magnetic properties of the amorphous copper strip with an insulating film obtained by the method of the present invention are
The iron loss value is significantly lower than that in the case of medium annealing, and the performance is the same or better than that of an untreated material annealed in N2 up to a bonding piece of 1000 m9/-. Also, the decrease in magnetic flux density
smaller than when annealed in N2.

Example 2 460 g of water was added to the amorphous copper band (copper band 2) used in Example 1.
250 Ii of phosphoric acid, 20 Jil of calcium hydroxide.

Boric acid 15 y, 5to2 sol (20%) 10 I
A treatment liquid (treatment liquid 1) consisting of 450 # of water, 50 g of chromic anhydride, 10,11 l of phosphoric acid, and 40 Ii of zinc hydroxide.

A treatment solution consisting of 4 g of boric acid (91) reethanolamine (
Treatment liquid 2) and chromic anhydride 7011/l, ethylene glycol 0.51/l, potassium fluorosilicide 5/l/l
After appropriately diluting the treatment liquid (treatment liquid 3) with water to adjust the adhesion amount and rolling each,
Processing solution 1 was dried at 350°C for 3 seconds, processing solution 2 was dried at 250°C for 3 seconds, and processing solution 3 was dried at 200°C for 3 seconds in a hot air drying oven. The thus obtained amorphous copper strip with an insulating film was
After magnetic field annealing for 60 minutes at °C in N2, air, or a mixed gas of N2 and oxygen, the iron loss W1375 was obtained as in Example 1.
0% magnetic flux density B. , 8 was examined on a single plate.

The results are shown in Table 3 for treatment liquid 1, Table 4 for treatment liquid 2, and Table 5 for treatment liquid 3. As can be seen from Table 5, the magnetic properties, especially the core loss, of the amorphous copper strip with an insulating coating obtained by the method of the present invention are significantly improved compared to the copper strip obtained by the conventional annealing in N2. Also, the properties shown in Table 2 of Example 1 are equivalent to or greater than the properties obtained by annealing in N2 of the untreated material shown in Table 2 of Example 1.

(Effects of the Invention) As explained above, the amorphous magnetic steel strip obtained by the method of the present invention can be used as an iron core material for electric power and motors, and has the greatest effect on magnetic properties such as low iron loss. An insulating film having the necessary interlayer resistance without impairing the resistance can be obtained.

In addition, for example, since annealing in the atmosphere is possible, restrictions on annealing equipment, inert gas, etc. are relaxed, and there are great economic advantages.

(17)

Claims (1)

[Claims] Surface treatment of phosphate treatment and/or chromate treatment is performed on the amorphous magnetic copper strip, resulting in a dry film weight of 10/-
A method for annealing an amorphous magnetic steel strip, which comprises depositing an insulating film of ~1000~/- and then annealing in an oxidizing atmosphere.