JPH02301593A - Production of thin amorphous alloy film - Google Patents

Abstract

PURPOSE:To improve the smoothness and soft magnetism of a thin amorphous alloy film by electrodepositing the thin film having a specified ratio of Fe/(Co+ Fe) and a specified P content with an acidic plating soln. contg. divalent Co ions, divalent Fe ions and phosphorous acid. CONSTITUTION:An acidic plating soln. contg. divalent Co ions, divalent Fe ions and phosphorous acid is prepd. at 30-90 deg.C. A reducing agent and a completing agent are added to the plating soln. as required. A thin amorphous alloy film based on Fe and Co in 0.1-20 atomic ratio of Fe/(Co+Fe) and having 3-30% P content is electrodeposited with the plating soln. The thickness of the film can freely be controlled. The film has satisfactory workability.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing a magnetic material, particularly an amorphous alloy foil 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. ing. 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, an amorphous alloy based on Fel has a high saturation MJ magnetic flux density, and its application as a transformer iron core is being considered by taking advantage of its low hysteresis loss characteristics. It is said that the loss can be significantly reduced compared to the conventional transformer made of silicon steel sheet metal 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 and
By rapidly cooling at 0 to 10 deg/s, the alloy is solidified without giving time for crystallization, and an amorphous alloy is formed. However, at present, the amorphous alloy produced by this rapid cooling method can only have a thickness of several tens of micrometers or more due to its manufacturing method, and cannot be made to have good smoothness.

Other methods for producing amorphous alloys are being considered, such as a direct sputtering method, a vacuum evaporation method, and an ion grating method. However, these methods have poor productivity of amorphous alloys, expensive manufacturing equipment, and difficulty in isolating amorphous alloys in the form of foils or films.

On the other hand, Japanese Patent Publication No. 65-10235 discloses -1, containing divalent cobalt ions and hypophosphorous acid or hypophosphite.
To 2.2.2 An invention is disclosed in which electroplating is performed using a plating bath at a bath temperature of 30 to 60 C and a current density of 5 to 20 mA/dm21 to produce an amorphous alloy whose main components are cobalt and phosphorus. has been done.

[Problems to be Solved by the Invention] When the Ministry of the Invention and others studied the above-mentioned light 8A, it was found that a simple plating bath with the above composition has a difficult value in the range of 6.5 to 4.
Even if electroplating is carried out at this value, it is not possible to create an amorphous alloy mainly composed of cobalt and phosphorus with good properties, and by adding a large amount of acid, the value of the plating bath can be reduced to the above value. It is necessary to adjust the value within this range, but if the plating bath has a - value of less than 1.0, the formation of an amorphous alloy thin film will be poor, and the magnetic permeability of the resulting amorphous alloy will be low, resulting in poor magnetic properties. It cannot be assumed that the In addition, if the plating bath value exceeds 165, the hydroxide ion concentration in the plating bath will increase, and the iron components in the plating bath will precipitate as hydroxide. It is not possible to create an amorphous alloy with Therefore, in the present invention, it is necessary to accurately adjust the value of the plating bath within the range of t-1.3 to 1.5, and a large amount of acid must be added.

Furthermore, if the plating bath contains hypophosphorous acid or its derivatives, the total concentration of hypophosphorous acid in the plating bath for precipitating an amorphous alloy is higher than 0.2 mol/m. The precipitation properties of the amorphous alloy film deteriorate rapidly. Ninth, the phosphorus content in a cobalt-iron-phosphorus alloy made using a plating bath with a hypophosphorous acid concentration of 0.2 mol/-e or less is within a narrow range of 10 to 12 at%. It is extremely difficult to control the content of phosphorus, which acts to make the alloy amorphous, and it is extremely difficult to create a thin amorphous alloy film that has excellent magnetic properties.

When performing full electroplating in a plating bath containing hypophosphorous/acid, sodium hypophosphite is NaHpo −+Na”+Hpo; +1) HP
O'''' → H++ PO2'''' (22) Although it undergoes electrolysis, the dissociation of (2) is slow to progress, and the reverse reaction progresses near the electrode, resulting in a local decrease in the hydrogen ion concentration near the electrode, resulting in homogeneous characteristics. It is thought that it may be difficult to make an amorphous alloy thin film with such characteristics.

Nine, in order to use amorphous alloy thin films as industrial products,
It is required to be able to be easily and precisely processed into the desired shape and size, and to have good productivity. For example, considering the use of these amorphous alloys in magnetic heads, the future technology direction for magnetic heads is perpendicular magnetic recording, and the magnetic heads used for this will require even thinner films. be done. 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. Generally speaking, when a high-frequency excitation current flows through a magnetic core, a vortex flows in the magnetic layer.
This is because the tortoise current increases and the loss increases. Since the eddy current is proportional to the thickness of the magnetic N, it is necessary to make the magnetic material used for this as thin as possible, but with conventional technology, it is not possible to make a soft magnetic material with a thin film of less than 20 μm.

Furthermore, when an amorphous alloy tape is wound or laminated into a troignal core shape, it is desired that the volume ratio, that is, the space factor occupied by the amorphous alloy tape is actually high.
The amorphous alloy films that have been developed so far lack surface smoothness, resulting in a space factor of only about 80 to 85%. Development of amorphous alloy thin films is desired.

[Next means to solve the problem]

Therefore, the present inventors are currently considering developing a method for producing a thin amorphous alloy thin film of 20 μm or less that is resistant to surface smoothness and has excellent soft magnetic properties. The present invention was completed by using phosphorous acid or its salt, which was previously thought to be unusable, to obtain the desired amorphous alloy thin film.

The gist of the present invention is that divalent cobalt ions,
30~? Contains divalent iron ions and substinum rRwo? Fe/(Co + Fe) was electrodeposited using a DC acidic plating bath.
) is 0.1 20 at%, P content 3-30 at
% of the amorphous alloy thin film is electrodeposited.

Invention? Examples of the salt for supplying divalent cobalt ions used in carrying out the method include cobalt sulfamino acid, cobalt sulfate, cobalt chloride, cobalt hyrophosphate, cobalt acetate, and cobalt benzoate. In addition, examples of salts for supplying all divalent iron ions include iron sulfate, iron chloride, iron nitrate, and the like. The phosphorous acid is added to the plating bath as a source of oxygen to amorphize the iron-cobalt alloy.

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.

Further, examples of the complexing agent include hydroxycarboxylic acid, polycarboxylic acid, citric acid, gluconic acid, gDTA and its kanetou salt.

In the plating bath, divalent cobalt ions are reduced to 0.1 to 5 mo
l/i, divalent iron ion is 0.01” 1 mol
However, it is possible to form an amorphous alloy thin film with 0.001 to 1.0 mol/j of aphrous acid.

In particular, the ratio value of a friend plating bath that deposits well is 1.5.
It has been found that it is best to do it before and after. In the prior art, it was necessary to add a large amount of acid to adjust the plating bath to this range, but in the present invention, since phosphorous acid is used, there is no need to use a large amount of acid. The film forming properties of amorphous alloy films are as follows:
This is an important property for depositing on conductors. Film formability is also 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 excellent soft magnetic properties. Since the method of the present invention uses phosphorous acid, it can be provided with such characteristics, and the plating bath can be adjusted at the same time. The method of Japanese Patent Publication No. 65-10255 was used to reduce the concentration of hypophosphorous acid in the plating bath! : 0.
3 mol/J! Above this value, the film formability of the amorphous alloy film is extremely degraded. The hypochlorous acid concentration in the plating bath is 0.
When it is 5 mol/Z, it is the limit of the production rate. On the other hand, in the method of the present invention, the concentration of zincite in the plating bath increases, and 3 mo
1i of amorphous alloy film obtained even when l/j or more! No deterioration in film properties is observed, and it is possible to produce alloys with a very high silver content of 20% or more. In addition, the crystallization temperature of the obtained amorphous alloy can be increased, and an amorphous alloy foil with excellent thermal stability can be provided.

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 total plating time, it is possible to obtain an amorphous alloy foil with a thickness of 10 μm or less, which cannot be produced by the liquid quenching method, and by increasing the plating time, it is also possible to obtain an amorphous alloy foil with a thickness of 300 μm or more.

The soft magnetic properties of a magnetic material, especially the coercive force, greatly depend on the magnetostriction of the magnetic material. Furthermore, magnetostriction is generally a function of alloy composition, and in iron-cobalt systems, cobalt-based alloys have excellent soft magnetic properties. Preferably, the atomic ratio of iron and cobalt in the alloy is 8% 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 having a thickness of 10 μm or less, which contains iron and copal (t), and has cobalt in an atomic ratio of 90% or more.

The amorphous alloy film of the present invention can be cut into a desired shape and size and used as is or in a layered manner depending on the application. For example, when used in a magnetic head, a foil-like amorphous alloy of 10 μm or less can be cut into a horseshoe shape and wound with 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. Furthermore, according to the manufacturing method of the present invention, it is also easy to deposit the amorphous alloy W3 directly onto a conductor such as copper or silver by plating. It is also possible to electrodeposit on a glass film with a conductive layer formed on its surface. When such a support is used, the thickness of the amorphous alloy foil is a1
In principle, it is possible to reduce the thickness to 0χ. The film is much thinner than the amorphous alloy produced by the rapid cooling method, and it is also 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.

Examples will be explained below.

(Example 1) Production of iron chloride of amorphous alloy film A (phantom 11.rp&/L, cobalt sulfate (1) 26
An aqueous solution containing 4.31/z, 5.5 J/L s of phosphorous acid and 6.217 tt of swinous acid (adjusted to pH 1j, electrolytically deposited at a current density o, o s A7t:nl) went.

The power source used was HCP-301H manufactured by Hokuto Denko.

゛A plating water bath with 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 surface of the working electrode has a mirror finish with a total centerline surface roughness of 0.1 μm or less, and is further plated with hard chrome. 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
μm Deatutora. Also, it has no pinholes and is highly flexible.

Observation of quality of sample An X-ray analysis chart of amorphous alloy A is shown in FIG. In FIG. 2, the horizontal axis is the X@disturbance angle from the sample, and 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.

Amorphous alloy Af: Dissolve in 5d of nitric acid and add distilled water to make 1
It was set as 00. This liquid was quantitatively analyzed using an IcP source analyzer (model ICAP-575MK-1 manufactured by Jarrell Ash Japan). As a result, the weight ratio was Fa:Co:P-4,8:812:12.0 (
at%) was obtained. The atomic ratio of iron and cobalt at this time was 6:94.

(Example 2) Film formation of amorphous alloy film B Iron chloride (1) 11.9.9/z, cobalt sulfate (
1) 264.3.9/12, cinous acid 164.9/i
(2 molA) 6.2 hydric acid! An aqueous solution h1.3 containing 0.21% and t' of hydroquinone was prepared, and electrolytic deposition was performed at a current density of 0.05 A/(II2).

The result of X-ray diffraction showed that it was amorphous. Also, the film forming properties are good, there are no pinholes, and the next layer is very flexible and can be obtained easily.

[Brief explanation of the drawing]

Figure 1 = Example 1 amorphous alloy AOX-ray diffraction chart

Claims (2)

[Claims] (1) Electrodeposited Fe in an acidic plating bath at 30 to 90°C containing divalent cobalt ions, divalent iron ions, and phosphorous acid.
/(Co+Fe) is 0.1 to 20 at%, P content is 3 to 20 at%
A method for producing an amorphous alloy thin film, which comprises electrodepositing an amorphous alloy thin film containing 30 at% as a main component. (2) at least one reducing agent or complexing agent as a plating bath;
2. The method for producing an amorphous alloy foil according to claim 1, wherein a plating bath containing seeds, divalent iron ions, and phosphorous acid is used.