DE2105529A1 - Process for the electrolytic deposition of a Ni Fe alloy - Google Patents

Description

DA-4193

description
to the patent application

of the company
HITACHI LIMITED
1-5-1 Marunouchi, Chiyoda-ku,
Tokyo / Japan

.concerning

Electrolytic deposition method a Ni-Fe alloy

Priority: February 6, 1970, No. 9929/70, Japan

The present invention relates to a method for electrodeposition of a Ni-Fe alloy on a non-magnetic metal substrate, being a memory element in the form of an electrodeposited magnetic film.

In the case of Ni-Fe alloy, used as an electrodeposited magnetic film for a memory element is used, the magnetostriction of the electrodeposited film becomes an important factor.

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Namely, when a magnetic substance has magnetostriction, the magnetic properties may change when external forces such as mechanical tension, twisting and the like are applied. Thus, the closer the coefficient of magnetostriction of an electrolytically deposited magnetic film approaches zero, the more suitable it is for a memory element. The coefficient of magnetostriction is variable according to the composition of the alloy and it approaches almost zero when the composition is around 80 # nickel and 20 56 iron in the case of permalloy (Ni-Fe alloy 78.5 ^ Ni - 21.5 % Fe ) is.

In the case of Ni-Fe alloy electrodeposition, however, iron ions become lighter than nickel ions deposited so that an iron-rich layer is formed at the beginning of the electrodeposition. That's why it is difficult to make the magnetostriction of the electrodeposited layer completely zero.

With an electrolyte having a nickel concentration of about 0.2 to 1.0 mol, which has heretofore been generally used for the electrodeposition of permalloy, a change in composition occurs in the direction of the thickness of the film even if the magnetostriction of the electrolytic deposited layer can be made zero on average. Therefore, if a magnetic wire,

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which was electrolytically applied to a non-magnetic metal wire with Permalloy, a mechanical tension of about 50 to 100 g is imparted, the storage properties deteriorate. There is therefore a there is a marked need to solve the problem related to the magnetostriction of a magnetic Wire to which a permalloy pile is electrolytically applied became.

1 shows the change in the curve of a critical magnetic field for switching when an Ag-Cu substrate wire of 0, 1 mm in diameter, a mechanical tension is imparted. Curve 1 corresponds to the situation in which there is no tension, while curve 2 shows mechanical tension on a wire which has been electrolytically coated with the alloy containing more than 80 $> nickel; curve 3 shows the mechanical stress which corresponds to a wire which is electrolytically applied with the alloy and which contains less than 80 % nickel. It can be seen that the curves of the critical magnetic field for switching change in both cases in opposite directions when there is a mechanical stress, while almost no change is observed in an alloy with zero magnetostriction and about 80 # nickel.

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ten is. It is therefore seen that the best magnet wire for an electrodeposited film for a memory element is that which corresponds to the conditions of curve 1 when no mechanical stress is applied has been; this is still true even after tension has been applied; namely, it has a composition exhibiting magnetostriction in the direction of the thickness of an electrodeposited film of uniform Shows zero.

In the case of electrolytically applied permalloy, an electrolyte with a content of iron and nickel sulfate, chloride or sulfamate as the main component in a Nickel concentration of about 0.2 to 1.0 mole and with a ratio of nickel to iron between 4: 1 and 20: 1 in

the electrolyte used.

However, if one uses permalloy for a storage element in an electrolyte of such a usual concentration electrolytically wants to deposit, there is the disadvantage that it is impossible to approach zero magnetostriction of the film because of the change in composition in the direction of film thickness. Rather, the magnetic properties fluctuate considerable with mechanical tension or torsion.

The present invention avoids the above disadvantages in the case of a permalloy film for a memory element, which by

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conventional electrodeposition processes can be obtained; it relates to a method for electrodeposition of a Ni-Fe alloy, one being an electrodeposited permalloy film for a storage element is obtained which has a uniform composition in the direction of film thickness and has nearly zero magnetostriction.

The present invention thus relates to a method for the electrolytic deposition of a Ni-Fe alloy on a wire or a plate made of non-magnetic metal as a substrate with the help of an electrolyte, which consists of a mixed solution of iron (II) salts and nickel salts and is characterized in that one uses an electrolyte with a smaller amount of metal ions than in a conventional electrolyte.

Thus, the present invention also relates to an electrolyte, the iron (II) salts and nickel salts as Contains main ingredient. The electrodeposition of a Ni-Fe alloy on a non-magnetic metal takes place with a nickel concentration of the order of about 0.02 to 0.15 mol / l, preferably about 0.05 to 0.1 mol / l, with the ratio of nickel to iron in the electrolyte between about 4: 1 and 20: 1, preferably is between about 5: 1 and 10: 1.

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Fig. 1 shows a change in the critical magnetic field • of switching by mechanically tensioning one with Permalloy electrolytically coated magnet wire with various nickel content.

Fig. 2 illustrates an apparatus for producing one that is electrolytically coated with permalloy Magnet wire.

Fig. 3 shows the current density and the current efficiency im

Case of a permalloy film with a ratio of Fe: Ni = 1: 4, made of an electrolyte with different concentrations was applied electrolytically.

Fig. 4 shows the changes in a critical magnetic field of switching by mechanically tensioning a Permalloy magnet wire, which is applied electrolytically with different electrolyte concentrations has been.

Fig. 5 shows the relationship of the mechanical stress to the output power of a magnet wire applied electrolytically from permalloy with different Electrolyte concentrations,

Fig. 6 shows the change in output power due to a mechanical tension applied to a magnet wire that is electrolytically applied from Permalloy obtained with a range of electrolyte concentrations will.

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The invention is defined by 'the following information and' same experiments explained in more detail.

The magnet wire with an electrolytically applied Permalloy pilm for the mentioned magnetic properties was made with the apparatus and method described below.

Figure 2 is a schematic view of a continuous electrolytic cell that can be used for the electrolytic deposition of a Ni-Fe alloy. In the drawing, the reference number 1 denotes an electrolyte bath and 2 denotes the anode made of permalloy. The bath 1 is arranged to daP a substrate wire 3 runs as silver or copper wire with O,} mm diameter through the center of the bath 1, with a cylindrical stirrer 4 rotates eccentric rings around the wire. Furthermore, there is provided: a feed device 5 for the substrate wire 3; a pretreatment device 6j electrical contacts 7 and 7 ¹ ; Cleaning devices 8 and 8 ¹ ; a post-treatment device 9 for heat treatment and the like; a device 10 for observing the magnetic properties, a winding device 11 for the electrolytically applied wire 12; a DC power source 13 for electrolytic deposition; a DC ammeter 14; a power source 15 for the magnet

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size to generate a magnetic field in the circumferential direction of the substrate wire 3 after the electrolytic treatment and an AC ammeter 16 therefor.

The composition of the electrolyte was as follows:

NiSO ₄ . 6H ₂ O. 52.6-5.3 g / l

H ₅ BO ₅ 40 g / l

Sodium 1,5-naphthalene disulfonate 10 g / l FeSO ₄ . 7H ₂ O. 10.0 - 1.0 g / l

6-n H ₀ SO- 1 ml

2 4

To produce this electrolyte, the iron (II) salt and the nickel salt were dissolved independently of one another. This means that the iron (H) salt was dissolved in the acidic solution of 6-n H ₂ SO ₄ and then mixed with the other solution. About 2 liters of the electrolyte was adjusted to a pH of 2.8 for use at various Fe: Ni concentrations of 1: 6.3.

About 2 liters of this electrolyte were put into the electrolyte cell 1 and kept at 50 ° C. The cylindrical stirrer 4 was set at 120 rpm to stir the electrolyte set in motion. The aftertreatment device 9 (e.g. an electric furnace) was heated to 300 ° C to keep the electrolytically treated wire 12 in the heat can be treated to stabilize against aging.

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Thereafter, the power source 15 is switched on, so that a Direct current through the electrolytic cell 1 and an alternating current in the substrate wire 3 can flow. Simultaneously becomes the feeding device 5 and the winding device set in motion to feed the substrate wire 3 at a speed of 1.2 cm / second. To this. Way can be an electrolytically "treated permalloy magnet wire" with an axis of easy magnetizability in the circumferential direction of the substrate wire 3 on the winding device 11 can be obtained.

Fig. 3 shows the electrical current density (curve 1) and the electric current efficiency for an electrodeposited permalloy film with magnetostriction averaging zero at a range of nickel concentrations of the electrolyte, namely at an average ratio of Fe: Ni of 1: 4 · This result can be achieved using the apparatus described above. In this case, the thickness of the electrodeposited film 0.6 microns.

From the drawing it can be seen for the electric current density that if the concentration of the electrolyte becomes low, the electric current density required for the realization of the value zero for the magnefcoatriction is, becomes zero, although the ratio of iron is too

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Nickel is the same. As a result, one must have iron ions add to obtain a high current density. However, almost the same result was achieved with a limited one Preserve current density. (Below this current density, the surface of the electrolytically applied Film coarse-grained.) The current efficiency drops slightly when the concentration of the electrolyte becomes low.

In the following, using a series of tests with various Nickel concentrations in the electrolyte are the measurement results of various properties of the electrolytic applied magnet wire s shown at the current density shown in the above-mentioned Fig. 3.

4 shows the curve of a critical magnetic field for switching for a magnet wire. In the drawing curve 1 means that the mechanical stress is zero, while curves 2, 3 and 4 for a magnet wire apply electrolytically in an electrolyte with a concentration of 0.4; 0.2 and 0.1 moles, respectively, and was applied under a load of 50 g.

As can be readily seen from the drawing, curve 1 shows a large change for the wire without tension when the concentration of the electrolyte increases, while curve 4 when using the electrolyte with 0.1 Mo1 almost no change and eutob.

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Pig. 5 shows the ratio of the mechanical load to the output power, based on the test result of a Pulse characteristic of the magnet wire. In the drawing, curves 1, 2 and 3 represent the values obtained from an electrolyte of 0.2, 0.1 and 0.05 mol concentration, respectively.

You can see from the drawing that the output power of the Magnetic wire made of an electrolyte of 0.2 mol electrolytically was knocked down, suddenly decreased when the mechanical load rises above 30 g, while the output power of the magnet wire, the Electrolytically applied from an electrolyte of 0.1 or 0.05 moles, does not change much until the voltage load is about 70 g.

Pig. 6 shows the change in output power with no voltage load and under a tension load of 50 g for a magnet wire with different electrolyte concentrations was applied.

The drawing shows that the output changes greatly when the concentration of the electrolyte is over 0.15 Mole increases.

In summary, one can say that an electrolytically applied permalloy pile has a very low magnetostriction when the concentration of the electrolyte is less than 0.15 mol.

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The lower the electrolyte concentration, the lower and magnetostriction gets better. The test results also show that if the nickel concentration of the electrolyte becomes smaller than 0.01 mol, the limited current density becomes low and impractical. After that shows that the electrolyte should preferably have a concentration greater than 0.02 mol. In the above mentioned In the 2nd case, the ratio of Fe: Ni was about 1: 6.3. However, almost the same results can be obtained with an electrolyte can be obtained in which the ratio of Fe: Ni is between about 1: 4 and 1:20.

The experiments described above clearly show that the magnetic properties are mechanical Stresses or torsion in the thin magnetic film for memory elements do not change significantly, according to the invention * have been manufactured. Great effectiveness can be expected when the magnetic film memory element is used for a storage device such as an electronic computer, an electronic circuit system and the like are used will.

Claims

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Claims (8)

Claims M.) Process for the electrolytic application of a Ni-Fe alloy from an acidic electrolyte, which contains iron (II) and nickel salts as the main component, thereby characterized in that the acidic electrolyte with a nickel concentration of about 0.02 Ms 0.15 mol per liter and a ratio of nickel to iron between 4: 1 and 20: 1 and then the Ni-Fe alloy film is electrodeposited in the usual way. 2. The method according to claim 1, characterized in that a nickel concentration of about 0.05 to 0.1 mol / l applies. 3. The method according to claim 1 or 2, characterized in that there is a ratio of nickel to Apply iron at about 5: 1 to 10: 1. 4. The method according to claim 1 to 3, characterized in that the iron (H) salt is iron sulfate, chloride and / or sulfamate used. 5. The method according to claim 1 to 4, characterized in that g e k e η η ze Lehne t, that as nickel ore nickel sulphate, -chloride and / or suLfeunate wounded, 6. More suitable for depositing a magnetic Fe-Ni alloy Electrolyte, characterized in that it is approximately in an aqueous acidic solution Contains 0.02 to 0.15 mol / l nickel ions, the nickel: iron ratio being 4: 1 to 20: 1. 7. Electrolyte according to claim 6, characterized in that the nickel concentration is approximately Is 0.05 to 0.1 mol / l. 8. Electrolyte according to claim 6 or 7, characterized in that the nickel: iron ratio is about 5: 1 to 10: 1. - H 109838 / If, 1 3