JPH03126889A - Production of amorphous alloy - Google Patents

Abstract

PURPOSE:To obtain amorphous alloy foil having superior soft magnetism and satisfactory workability by electrodepositing an amorphous alloy having a specified ratio of Fe to Co+Fe and a specified P content with an acidic plating bath contg. Co ions, Fe ions and phosphorous acid. CONSTITUTION:An acidic plating bath contg. at least divalent Co ions, divalent Fe ions and phosphorous acid or phosphite is prepd. Electrolysis is carried out with the plating bath to electrodeposit an amorphous Fe-Co-P alloy having 0.1-20 atomic ratio of Fe to Co+Fe and 3-30 atomic% P content on a working electrode and the resulting electrodeposited film is exfoliated. The large amt. of P can be incorporated into the alloy with satisfactory film forming property, film thickness is advantageously reduced and amorphous alloy foil having superior magnetic characteristics and satisfactory workability is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a magnetic material, particularly an amorphous alloy that has excellent soft magnetism and is thinner and has better workability than conventional amorphous alloys.

[Conventional technology]

Amorphous alloys have irregular arrangement of metal atoms, lack long periodicity, and have structural specificities compared to crystalline alloys, such as the absence of grain boundaries and lattice defects. There is. Due to these factors, amorphous alloys have excellent magnetic properties.

In particular, applications as low hysteretic loss materials and high magnetic permeability materials are seen as promising. For example, Fe-based amorphous alloys have a high saturation magnetic flux density and are being considered for application as transformer iron cores by taking advantage of their low hysteresis loss characteristics. It is said that the loss can be significantly reduced compared to conventional transformers mainly made of silicon steel plates, and that it can have good characteristics. Furthermore, CO-based amorphous alloys have the characteristic of having a low coercive force over a wide frequency band, and are usefully used as magnetic core materials for magnetic amplifiers.

The most common method for producing amorphous alloys is to rapidly cool a molten alloy. This method involves directing molten metal to cooled rotating rolls,
By rapidly cooling at g/s, the alloy is solidified without giving any time for crystallization to form an amorphous alloy. However, at present, the amorphous alloy produced by this rapid cooling method can only have a thickness of several tens of microns or more due to its manufacturing method, and cannot be made to have good smoothness.

Other methods for producing amorphous alloys include sputtering,
Vacuum deposition methods and ion blating methods are being considered. But with these methods.

The productivity of the amorphous alloy is poor, the manufacturing equipment is expensive, and it is difficult to isolate the amorphous alloy in the form of a foil or film.

On the other hand, Japanese Patent Publication No. 63-10235 discloses p)1 containing divalent cobalt ions and hypophosphorous acid or hypophosphite.
Using a plating bath of 1.2 to 2.2, the bath temperature is 30 to 60°C,
An invention is disclosed in which an amorphous alloy containing cobalt and phosphorus as main components is produced by electroplating at a current density of 5 to 20 mA/d+y+2.

[Problem to be solved by the invention] In order to use an amorphous alloy thin film as an industrial product, it is necessary that it can be easily and precisely processed into the desired shape and size, and that it has good productivity. required. For example, considering the use of these amorphous alloys in magnetic heads, the future technological direction for magnetic heads is perpendicular magnetic recording, and the magnetic heads used for this will require further thinning and transparency. High magnetic flux is required. In addition, there is a demand for the development of magnetic cores used in switching regulators, etc. that have high magnetic properties such as coercive force and soft magnetism in the high frequency excitation region, but nothing that can meet this demand has yet been developed. Not yet reached. This is because, in general, when a high-frequency excitation current flows through the magnetic core, eddy currents flowing in the magnetic layer increase, resulting in increased loss. Since the eddy current is proportional to the thickness of the magnetic layer, it is necessary to make the magnetic material used for this as thin as possible, but with conventional technology it has not been possible to create a soft magnetic material with an extremely thin film thickness.

Furthermore, when winding or laminating amorphous alloy tape into a toroidal core shape, it is desired that the volume ratio, that is, the space factor occupied by the amorphous alloy tape is actually high, but conventionally developed Since an amorphous alloy film lacks surface smoothness, its space factor is only about 80 to 85%, and an amorphous alloy thin film with good surface smoothness that can increase this space factor to 90% or more is needed. development is desired.

Furthermore, the development of precision electronic equipment has generated a lot of electromagnetic interference, which has become a cause of noise and has become a problem. To eliminate this obstacle, it is desired to develop magnetic materials with high magnetic permeability.

[Means to solve the problem]

Therefore, the present inventors are currently considering developing a method for producing a thin amorphous alloy thin film with excellent surface smoothness and soft magnetic properties, using electroplating, which has traditionally been used as a source of amorphous elements. The present invention was completed by discovering that the desired amorphous alloy thin film could be produced by using phosphorous acid or its salts, which had been thought to be impossible.

The gist of the present invention is to electrolytically deposit Fe/(
Co+Fa) is 0.1 to 20 at%, P content is 3 to 30
The present invention provides a method for producing an amorphous alloy characterized by electrodepositing an amorphous alloy of at%.

Examples of salts for supplying divalent cobalt ions used in carrying out the present invention include salts that are water-soluble and have high solubility, such as cobalt sulfamate, cobalt sulfate, cobalt chloride, cobalt birophosphate, cobalt acetate, and cobalt benzoate. That's fine. Salts for supplying divalent iron ions include salts that are water-soluble and have high solubility, such as iron phosphate, iron chloride, and iron nitrate. Phosphite and/or phosphite are added to the plating bath as a phosphorus source to amorphize the iron-cobalt alloy. As the phosphite, potassium phosphite, ammonium hydrogen phosphite, sodium hydrogen phosphite, sodium phosphite, magnesium phosphite, etc. can be used.

In the present invention, divalent iron ions are oxidized to trivalent iron ions during electrolytic plating. Trivalent iron ions tend to form precipitates in the plating bath as hydroxides. This can be prevented by adding a reducing agent that reduces trivalent iron ions to divalent iron ions and/or a complex ion that forms a stable complex compound with trivalent iron ions. Examples of reducing agents include:
Examples include hydrazine, dimethylamine borane, sodium hydride, hydroquinone, and hydroxylamine hydrochloride. These reducing agents are thought to reduce trivalent iron to divalent iron without reducing phosphorous acid to hypophosphorous acid. This was confirmed by ion composition analysis using electrophoresis.

Examples of complexing agents include hydroxycarboxylic acids, polycarboxylic acids, citric acid, gluconic acid, BDTA and metal salts thereof.

The divalent cobalt ion in the plating bath is O81~5mol
/f, divalent iron ion is 0.01-1 mol/i, phosphorous acid and/or phosphite is 0.001-5, Omo
l/j! It is possible to form an amorphous alloy thin film.

In particular, the pH value of the plating bath for electrodeposition with good film forming properties is 1.
It has been confirmed that a value of around 5 is best. In order to adjust the plating bath to this pH range, it was necessary to add a large amount of acid using hypophosphorous acid according to the prior art, Japanese Patent Publication No. 63-10235, but when using phosphorous acid in the present invention, There is no need to use large amounts of acid. The film formability of an amorphous alloy film is an important characteristic for forming an amorphous alloy into foil or tape, or depositing it on a conductor. Furthermore, film formability is closely related to magnetic properties, and thin films obtained from amorphous alloy films that are free of pinholes, cracks, etc. and have a glossy surface tend to have better soft magnetic properties. Since the method of the present invention uses phosphorous acid, it can be provided with such characteristics, and the pH of the plating bath can be adjusted at the same time. In addition, special public service No. 63-10235
In the method of the publication, the concentration of hypophosphorous acid in the plating bath was set to 0.3.
When the ratio is mol/1 or more, the film formability of the amorphous alloy film is extremely reduced. The hypophosphorous acid concentration in the plating bath is Q,
3 mol/i', the phosphorus content in the alloy is 15 at%, which is the limit of the phosphorus content ratio in the alloy in Japanese Patent Publication No. 63-10235.

On the other hand, in the method of the present invention, the phosphoric acid concentration in the plating bath is 0.3 mol/I! Even with the above, no deterioration in the film formability of the amorphous alloy film obtained is observed, and even alloys with a very high phosphorus content of 20% or more can be made into thin films. The crystallization temperature of the resulting amorphous alloy can be increased, the thermal stability is also excellent, and heat treatment for improving magnetic properties can be effectively performed.

In the method of the present invention, the film thickness of the amorphous alloy can be freely controlled. That is, the film thickness depends on the plating time. By shortening the plating time, it is possible to obtain an amorphous alloy of 1 (1- or less), which cannot be produced by the liquid quenching method, and conversely, by taking a longer plating time, it is also possible to obtain an amorphous alloy of 3001- or more. When an acid and/or a phosphite is used, the film forming property is very good, and a thin film of 5 μm or less can be easily isolated.

The soft magnetic properties of a magnetic material, particularly its magnetic permeability, are largely dependent on the magnetostriction of the magnetic material. Furthermore, magnetostriction is generally a function of alloy composition, and among iron-cobalt alloys, cobalt-based alloys have excellent soft magnetic properties. Preferably, the atomic ratio of iron and cobalt in the alloy is 80% or more, particularly 90% or more of cobalt. More preferably, it contains 94% cobalt. According to the method of the present invention, it is possible to easily produce an amorphous alloy foil containing iron and cobalt, in which the atomic ratio of cobalt is 90% or more and the thickness is 10 or less. You can get something excellent. In our experiments, phosphorous acid and/or
It has also been found that when phosphite is used, the magnetic permeability is about twice as high as when hypophosphorous acid is used.

The amorphous alloy of the present invention can be cut into a desired shape and size and used as it is or in a layered manner depending on the purpose. For example, when used in a magnetic head, it can be produced by cutting a foil-like amorphous alloy of 10- or less into a horseshoe shape and winding it into a coil. Furthermore, when used as a magnetic core for a magnetic amplifier, it can be produced by winding an amorphous alloy foil with long slits into a toroidal shape. Further, according to the manufacturing method of the present invention, it is easy to attach an amorphous alloy foil onto a conductor such as copper or silver by direct plating. It is also possible to electrodeposit on a plastic film on which a conductive layer is formed. When such a support is used, it is theoretically possible to reduce the thickness of the amorphous alloy foil to several tens of layers. By making the film much thinner than the amorphous alloy produced by the rapid cooling method, it is possible to suppress the generation of eddy currents in the high frequency range and reduce the coercive force.

Furthermore, it is expected that the switching regulator body can be made significantly smaller.

Furthermore, since the method of the present invention is a plating method, it is possible to coat the surface of an object of any shape with a highly permeable magnetic material in the form of a thin film, so it can be expected to be used as a magnetic shielding material.

〔Effect of the invention〕

According to the manufacturing method of the present invention, an amorphous alloy foil can be obtained which has excellent soft magnetism, is thinner than conventional amorphous alloys, and has good workability.

In particular, compared to the case of using hypophosphorous acid or hypophosphite, it has the following characteristics.

(1) A large amount of phosphorus can be contained in the alloy with good film forming properties.

(2) It has very good film forming properties and is advantageous for thinning the film.

(3) Excellent magnetic properties.

〔Example〕 Examples will be explained below.

(Example 1) Film formation of amorphous alloy film A Iron chloride (I) 11.9 g/f, cobalt sulfate (II)
)264,3 g/1, an aqueous solution containing 3.3 g/L of sulfurous acid/6.2 g/L of boric acid was prepared to pH 1.3, and electrolytic deposition was performed at a current density of 0.05 A/ci. Ta. The power source used was HCP-3018 manufactured by Hokuto Electric Works.

An aqueous plating solution having the above composition is placed in a plating bath, and a voltage is applied between a counter electrode made of platinum and a working electrode to deposit metal etc. on the working electrode. The working electrode surface has a center line surface roughness of 0. It has a mirror finish below IIs and is further finished with hard chrome plating.

The deposited film is immediately peeled off, washed and dried.

The thickness of the electrodeposited film depends on the residence time of the working electrode in the plating solution, and the thickness of the amorphous alloy foil obtained after 7 minutes of electrodeposition is 7.
It was μ. Moreover, it had no pinholes and had excellent flexibility.

Observation of sample quality An X-ray analysis chart of amorphous alloy A is shown in FIG.

In Figure 1, the horizontal axis is the X-ray scattering angle from the sample,
The vertical axis is the scattering intensity. In this way, no peaks due to crystals peculiar to metals are observed, and the material is completely amorphous.

Measurement of alloy composition Nitric acid 5rd of amorphous alloy A! It was dissolved in water and distilled water was added to give a total concentration of 1.00 d. This liquid was collected using an ICP emission spectrometer (ICAP-575MK-n type manufactured by Jarrell Ash Japan).
Quantitative analysis was carried out by As a result, the atomic ratio is Fe:C
o:P=4.8:83.2:12. O(at%)
I got the result. The atomic ratio of iron and cobalt at this time is about 6:94.

(Example 2) Quantitative analysis of ions To a bath having the same composition as the plating bath for amorphous alloy A, 0.2 g/f of hydroquinone (reducing agent) was further added.

Regarding this plating bath, quantitative analysis of ions was carried out using a capillary isokinetic electrophoresis analyzer IP-3 model manufactured by Shimadzu Corporation. This plating bath (a) and after electrodeposition of this plating bath (
The results of b) are shown in quantitative analysis in Table 1 and measurement charts in FIGS. 2 and 3. The results show that this plating bath is free of hypophosphorous acid and trivalent iron ions.

Blank space below (Example 3) Film production of amorphous alloy film B Iron (II) chloride 11.9 g/f, Cobalt (II) sulfate
) 264, 3 g/1, phosphorous acid 164 g/i'
(pfl
Electrodeposition was performed at a current density of 0.05 A/cat. The electrodeposition time was 2 minutes, and a thin film of approximately 2 μm was peeled off from the electrode.

A foil with excellent flexibility and no pinholes was obtained.

The results of X-ray diffraction showed that it was amorphous.

As a result of quantitative analysis of the obtained amorphous alloy film B in the same manner as A, the atomic ratio was Fe:Co:P=4.5 near 5.2:20.3
(at%) results were obtained. The atomic ratio of iron and cobalt at this time was approximately 6:94, and the film contained more phosphorus than the amorphous alloy film A.

<Example 4) Amorphous alloy film Cty)T! Add 23.2 g of nickel sulfate to the plating bath for M film amorphous alloy film B.
1, and electrodeposition was performed under the same conditions.

As a result of quantitative analysis of the obtained product, the atomic ratio was Fe:Co:Ni:P=4J:69.1:1
A result of 0.1:16.5 (at%) was obtained.

(Example 5) Formation of amorphous alloy film Iron (II) chloride 11.9 g/A, cobalt (II) sulfate
)264.3g/j! , boric acid et, 2 g/It, and sodium phosphite 1.26.0 g/R were adjusted to pH 1.3, and the current density was 0.05 A/R.
Electrodeposition was performed using cnf. As a result of X-ray diffraction, it was found to be amorphous. The quantitative analysis results show that the atomic ratio is Fe:Co:P=4.9 near 8.1:17.0
(at%) results were obtained.

(Comparative Example 1) Iron(II) chloride 11.9g/l, cobalt(II) sulfate
) 264, 3 g/II, boric acid 6.2 g/II
, and sodium hypophosphite 31.8g/j! (0
, 3 mol/A) was adjusted to pH 1.3, and electrodeposition was performed at a current density of 0°05 A/caf. FIG. 4 shows a photograph of the surface of the deposit on the electrode.

Film forming properties were poor and it could not be taken out as an isolated film.

The precipitated pieces were peeled off from the electrode and quantitatively analyzed. The atomic ratio was Fe:Co:P=4.7 near 5.8:15.0
(at%) results were obtained.

(Comparative Example 2) Film production of amorphous alloy film E Iron chloride (formerly 11.9 g/f, cobalt (II) sulfate) 26
4.3g/j! , boric acid 6.2g/I! , and sodium hypophosphite 10.6g/j! (0.1 mol/:
Adjust the pH to 1.3, and adjust the current density to 0.05A/cr.
Electrodeposition was performed with l. The electrodeposition time was 8 minutes, and a thin film with a thickness of '7' was obtained.

As a result of quantitative analysis, the atomic ratio is Fe:Co:P=4.4:84.1:11.5
(at%).

(Example 6) Measurement of Magnetic Permeability A hollow plastic bobbin 1 with a diameter lOφ and a length of 2 cm was wound with 0.2φ enamelled wire 80 times each, with the secondary coil 3 being wound on the inside and the primary coil 2 being wound on the outside. After making four of them and wiring them in series, they were arranged as shown in Figure 5. Also,
In order to eliminate the induced electromotive force of the air core, a separate coil was wound and wired. An alternating current of I KHz was passed through the primary coil from an oscillator (4), and the induced electromotive force in the secondary coil was measured using a voltmeter (oscilloscope) 5. Note that the magnetic permeability was calculated using the following formula.

B μ= (G/○e) where, H
: magnetizing force, B: magnetic flux density, μ: magnetic permeability, N: number of coil turns (80x4), I: primary coil current, L: magnetic path length (12 cm), E: secondary coil induced voltage (peak value), f: Frequency (1000Hz), A: Sample cross-sectional area (CIII) Sample 6 has a width of 5III for amorphous alloy films A and E.
I11, cut into lengths of 4 cm, and heated at 200°C in a nitrogen atmosphere.
, heat treated for 5 minutes. These four samples were each inserted into a plastic bobbin, and the ends were overlapped to form a closed magnetic path.

The results are shown in Table 2. Amorphous alloy film A using phosphorous acid has high magnetic permeability.

Table 2

[Brief explanation of the drawing]

Figure 1 is an X-ray diffraction chart of amorphous alloy A in Example 1. Figures 2 and 3 are capillary isokinetic electrophoresis charts (b) after electrodeposition in Example 4 (each analysis of phosphorous acid). Fig. 4 is a photograph of the metallographic structure of the electrodeposited surface from a plating bath using sodium hypophosphite, and Fig. 5 is a schematic diagram of the magnetic permeability measurement circuit. 1... Bobbin, 2... Primary coil, 3
... Secondary coil, 4... Oscillator, 5... Voltmeter, 6... Sample. Figure 1: X-ray diffraction chart of amorphous alloy A

Claims (1)

[Claims] 1. Electrodeposited in an acidic plating bath containing at least divalent cobalt ions, divalent iron ions, and phosphorous acid and/or phosphite, and Fe/(Co+Fe) is 0. .1~20a
A method for producing an amorphous alloy, which comprises electrodepositing an amorphous alloy having a P content of 3 to 30 at% as a main component. 2. The method for producing an amorphous alloy according to claim 1, wherein the plating bath contains at least one of a reducing agent and a complexing agent.