JPS60217605A - Manufacture of rigid magnetic film - Google Patents

Abstract

PURPOSE:To stabilize a magnetic film up to the neighborhood of the melting point of a plating metal, and to make the film to enable to endure sufficiently even formation of a finely magnetized pattern according to projection of laser by a method wherein after rigid magnetic particles are adhered to a substrate, the substrate is immersed in the plating liquid of a metal, and electrolysis is performed using the substrate as a cathode. CONSTITUTION:A magnet 7 is made to come in contact with the back of a substrate 2, rigid magnetic particles having conductive films stable to a plating liquid 4 are adhered to the substrate 2, then by performing electrolysis using the substrate 2 as a cathode, and by immersing in the plating liquid 4, a metal film containing the rigid magnetic particles is formed on the substrate. For example, a permanent magnet 7 is made to come in contact with the inside of the cylindrical substrate 2 manufactured of copper, and gamma-Fe2O3 particles covered with conductive Ag thin films according to the sputtering method are adhered. Then immersed in a plating liquid 4 consisting of AgCn, KCN, K2CO3 to make to face with a roll 3, an anode 5 and an electric power source 6 for electrolysis are arranged, and electrolysis is performed using the substrate 2 as a cathode, and by rotating the substrate 2. Accordingly, a magnetic film 1 having 95vol% of content of gamma-Fe2O3 particles is obtained on the outside of the cylindrical substrate 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a hard magnetic film that has better heat resistance than a plastic magnet film and can also form a fine magnetized pattern by laser irradiation.

[Prior art and its problems]

When manufacturing a hard magnetic film, the magnet itself is brittle and easily cracked when cutting bulk materials made by casting or sintering, so it is usually done by applying a liquid mixture of magnetic particles and resin, or by cutting a bulk material made by casting or sintering. At the same time, molding into a film using resin as a binder was carried out at the school.

However, the characteristics of the magnetic film produced by such a molding method have the drawback of low heat resistance because it contains resin as a component, and cannot be applied at high temperatures.

For example, as a method for forming a fine magnetized pattern in a magnetic encoder, a magnetic film formed on the side surface of a cylinder or a disk is magnetized all at once, and then laser light is irradiated to locally heat the part to demagnetize and magnetize the minute part. There is a way to do both at the same time. In this method, 4
The problem is that conventional magnetic films using resin as a binder have a heat resistance of only 100 to 200°C, so they cannot be used at all for such fine laser magnetization. There is.

[Purpose of the invention]

The purpose of the present invention is to stabilize the magnetic film substantially to near the melting point of the plated metal by bonding magnetic particles with metal by electroplating, and to create a hard magnetic film that can sufficiently withstand the formation of fine magnetized patterns by laser irradiation. An object of the present invention is to provide a method for manufacturing a membrane.

[Structure of the invention]

The method of the present invention involves contacting the magnet from the back side of the substrate to generate γ-F
e20B, Ba ferrite, SmI Co5 +
After attaching hard magnetic particles such as Sm2Co17 and Nd-Fe to the substrate, NilCu, Ag+Au+
A magnetic film containing magnetic particles fixed by the plating metal is obtained on the substrate by immersing it in a plating solution of a metal with a high melting point, such as Co or Cr, and electrolyzing the substrate with the substrate as a cathode.

Furthermore, in addition to being able to obtain a magnetic film with good heat resistance, the method of the present invention also allows plating to be carried out after magnetic particles are first attached to the substrate, so the magnetic particles are dispersed in the plating solution. Another advantage is that the magnetic film can be formed at a faster rate than conventional methods.

Here, among the hard magnetic particles, Nd-Fe and SmI Co
5 or 5l112 C017-based fine particles are easily oxidized when discharged into the atmosphere, and when immersed directly in an aqueous solution, active rare earth metal components such as Nd and Sm react with water to generate hydrogen gas. Therefore, when carrying out the present invention, it is necessary to form a protective film on the surface. Also, B
When using magnetic particles that do not have electrical conductivity, such as a-ferrite or r-Fe20g particles, the method of the present invention cannot conduct electricity even if immersed in a plating solution, so such magnetic particles are coated with a conductive film. need to be formed. For the same reason, the protective film of Nd-Fe or Sm-Co hard magnetic particles must also be electrically conductive.

The type of conductive film is difficult to react with water and does not form a hydroxide film on the surface (Cu+Ni+^g).

Metal film such as Cr, Co+Au or Ti+Zr
+Nb, Ta nitride films are suitable. Suitable methods for forming these films on the surfaces of hard magnetic particles include dry brating methods such as vacuum evaporation, ion blating, CVD, ARE, and sputtering. For oxide particles such as Ba ferrite and γ-Fe208, NilCu, Ag
Electroless plating method can also be applied.

Furthermore, when a hard magnetic film for forming a fine magnetized pattern of a magnetic encoder is produced by the method of the present invention, the content of hard magnetic particles in the magnetic film is 70 to 95% by volume (
Unless otherwise specified below, % is volume %. )Must. This is because if the content of hard magnetic particles is less than 70%, the characteristics as a magnet will not be fully exhibited, whereas if the content exceeds 95%, the binding force between the magnetic particles will be weak, and the particles will easily peel off due to external force. be.

〔Example〕

Hereinafter, the method of the present invention will be explained based on Examples.

[Example 1] An electromagnet was brought into contact with the back surface of a copper substrate, the electromagnet was adjusted so that the magnetic flux density on the surface of the substrate was 1000 Gauss, and the surface of the substrate was coated with 0.3 μm conductive Ni electroless plating. Ba ferrite particles (average particle size 0.8 μm
) was attached. Adhesive film thickness of Ba ferrite particles is 60
After removing enough particles to make it μm, the substrate was coated with nickel sulfate 240g/C nickel chloride 45g/β. The substrate was immersed in a nickel plating solution of &30 g/l, and electrolyzed with the substrate as a cathode at a solution temperature of 40'C and a current density of I A/dm2 until the Ni plating film thickness reached 5 μm. As a result, a magnetic film with a Ba ferrite particle content of 92% and good magnetic properties was obtained.

After this magnetic film was magnetized, a fine magnetization pattern was formed by irradiation with a YAG laser, and a good magnetization pattern was obtained.

Further, a permanent magnet was used instead of an electromagnet, and the distance to the substrate was adjusted so that the magnetic flux density on the surface of the substrate was 1000 Gauss. When this substrate was plated with Ni using the above magnetic particles and plating solution under the same conditions, the same results as when using an electromagnet were obtained in this case as well.

[Example 2] An electromagnet was brought into contact with the back surface of an iron substrate, and the magnetic flux density on the substrate surface was adjusted to 500 Gauss. Next, SmI Co5 particles with an average particle size of 1 μm and a 0.4 μm Cu thin film vacuum-deposited on the substrate surface, and 0.3 μm conductive Z
Sm2 (
CoO,7,CuO,15,FeO,1,Mn
Particles of O, 05) and 17 compositions were respectively deposited. After removing excess particles so that the adhesion film thickness of these particles was 0.1III11, copper sulfate 200 g/β,
Sulfuric acid 50g/! The substrate was immersed in a copper plating solution consisting of 1 A, and electrolysis was carried out using the substrate as a cathode at a solution temperature of 40'C and a current density of IA/dn+2 until the Cu plating film thickness reached 40 μm. This allows Sn+I Co5 and Sm2(Co
0.7+Cu O,15,Fe 0.1. Mn O,0
5) A metal film containing 70% of magnetic particles having a composition of 17 and having good magnetic properties was obtained. After magnetizing these magnetic films, Δr
When a fine magnetized pattern was formed by laser irradiation, a good magnetized pattern was obtained.

[Example 3] As shown in Fig. 1, a copper cylindrical substrate with an outer diameter of 80 mm (
A permanent magnet (7) was brought into contact with the inside of the substrate (2), and the magnetic flux density on the surface of the substrate (2) was adjusted to be in the range of 500 to 600 Gauss. The surface of this substrate (2) was coated with a 0.4 μm conductive Ag thin film by sputtering.
0a particles (average particle size 0.06 μm, average length 0.6 μm
) and AgCN 36 g/j! ! , KCN
60 g/l.

It was immersed in a plating solution (4) consisting of 45 g/β of K2 COa. The gap between the opposing roll (3) is 50μ
m, the anode (5) and the electrolytic power source (6) were arranged, and the substrate (2) was rotated at 30rpo+ at a temperature of 30°C and a current density of 0.5 A/dII2, and the plating film thickness was 3 μm. Electrolysis was carried out using the substrate (2) as a cathode until . As a result, γ-Fe20 is placed on the outside of the cylindrical substrate (2).
A magnetic film (1) with a content of 3 particles of 95% by volume and good appearance and magnetic properties was obtained. After magnetizing this magnetic film (1),
Fine magnetization was performed by irradiation with a YAG laser, and a good magnetization pattern was obtained.

[Example 4] As shown in Fig. 2, a permanent magnet (7) is brought into contact with the inside of a copper cylindrical substrate (2) with an outer diameter of 50 mm, and the substrate (2) is
The magnetic flux density at the surface was adjusted to be in the range of 3'OO to 400 Gauss. 0.3μ on the surface of this substrate (2)
Nd-Fe hard magnetic particles (average particle size 1 μm) coated with a Cr thin film (average particle size 1 μm) were deposited, and
It was immersed in a chromium plating solution consisting of 50 g/It and 2.5 g/It of sulfuric acid.

Furthermore, a blade (8) is attached to a position facing the substrate (2), the gap with the substrate is set to 60 μm, and the temperature is 5.
Cr plating film thickness is 15 μm at 0°C, current density 15 A/dm2, using substrate (2) as a cathode and rotating at 20 rpm.
It was electrolyzed until As a result, a magnetic film (1) containing 80% Nd-Fe particles and having good magnetic properties and appearance was formed on the outside of the cylindrical substrate (2). After magnetizing this magnetic film.

When fine m@magnetization was performed by irradiating a YAG laser, a good magnetization pattern was obtained.

In addition, the shapes of the magnetic particles and the substrate (2) and the rotational speed of the plating device and the substrate (2) remained the same, and the plating solution was mixed with 30 g/l of potassium gold cyanide and 100 g/l of weak acid buffer.
, piperazine compound 25g/β, changed to PTTs gold plating solution, and the gap between the blade (8) and the substrate (2) was set to 20g/β.
Electrolysis was carried out at a temperature of 40° C. and a current density of 3 A/dm 2 until the gold plating thickness reached 5 μm. As a result, a magnetic film having an Nd-Fe particle content of 80% and excellent magnetic properties and corrosion resistance was obtained on the outside of the cylindrical substrate (2). The magnetic film obtained here was also finely magnetized using a YAG laser after magnetization, and a good magnetization pattern was obtained.

[Effects of the Invention] - As described above, according to the present invention, it is possible to fabricate a hard magnetic film that has good heat resistance and is optimal for forming fine magnetized patterns using a laser, and thereby can be used in magnetic encoders and pulse motors. This has the effect of achieving smaller size and higher performance.

[Brief explanation of drawings]

FIGS. 1 and 2 are schematic diagrams showing a plating apparatus for forming a magnetic film on a cylindrical substrate. ti> Magnetic film (2) Substrate (3) Roll (4) Plating solution (5) Anode (6) Power source for electrolysis (7) Permanent magnet (8) Blade

Claims (1)

[Claims] 1. Apply a magnet from the back of the substrate to attach hard magnetic particles with a conductive film that is stable against the plating solution to the substrate,
A method for producing a hard magnetic film, which comprises obtaining a metal film containing hard magnetic particles on a substrate by immersing the substrate in a plating solution and electrolyzing the substrate using the substrate as a cathode.