JPH04207005A - Sensor with magnetic film and its manufacture - Google Patents

Abstract

PURPOSE:To improve the reproduction output and coercive force of magnetic films by forming the magnetic films of a magnetic material which is capable of recording magnetic signals on the surface of a substrate and making the magnetic films to contain a nonmagnetic material by a specific amount in a scattered state. CONSTITUTION:Since magnetic films 3 and 3 formed of a magnetic material A around the surface of a turbine shaft 2 at a prescribed interval in the axial direction of a shaft 2 near the central part of the shaft 2 contain a nonmagnetic material B by specific amounts in scattered states, the magnetic walls of the films 3 and 3 are effectively increased by the nonmagnetic material B as compared with the case where the magnetic walls are increased by only using a magnetic material composed of fine crystalline particles. When magnetic fields are impressed upon the films 3 and 3, a large number of magnetic walls of crystalline particles move so as to increase magnetic domains spontaneously magnetized in nearly the same direction as that of the magnetic fields and the overall magnetization of the crystals is increased in the direction of the magnetic fields.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for manufacturing a sensor having a magnetic film, and more specifically, it is a method for measuring the torque, rotation speed, rotation angle, etc. applied to a shaft-shaped base material with high precision. Concerning something that can be measured.

(Prior Art) Conventionally, as a sensor having a magnetic film, a method is known in which a magnetic film is formed on the surface of a shaft-shaped base material and the applied torque is measured using the magnetic properties of the film.

For example, in Japanese Unexamined Patent Publication No. 61-53504, a magnetic film is formed on the surface of a rotating body shaft by spraying and coating a solution of a dissolved magnetic material.

By the way, when a magnetic material is used in the form of crystalline particles, when a magnetic field is applied to the crystal, the domain wall moves in a manner that increases the volume of the magnetic domain that is spontaneously magnetized in approximately the same direction as the magnetic field. As a result, the magnetization of the crystal increases in the direction of the magnetic field.

In that case, the finer the particles, the greater the number of domain walls in the crystal;
An extremely strong magnetic field is applied to the movement of the domain walls throughout the crystal. Therefore, even if the magnetic field becomes zero, a high residual magnetization is obtained due to the large number of domain walls that have moved once, increasing the reproduction output during measurement, and the reverse magnetic field, or coercive force, required to reduce the residual magnetization to zero be enhanced.

(Problem to be Solved by the Invention) However, there is a limit to increasing the domain wall using a magnetic material made of fine particles that remain crystalline as described above.
By increasing the domain wall of the magnetic film more effectively,
There is a demand to further improve reproduction output and coercive force by obtaining higher residual magnetization due to a large number of domain walls.

The present invention has been made in view of this point, and its purpose is to disperse and mix into the magnetic film a substance that effectively increases the domain wall of the crystal.
This is intended to further improve reproduction output and coercive force.

In addition, by specifying the magnetic material, a substance that effectively increases the domain wall is generated when forming a magnetic film, so that a magnetic film that further improves reproduction output and coercive force can be easily formed. The purpose is also to

(Means for Solving the Problem) In order to achieve the above object, the solving means taken by the invention according to claim (1) is to provide a sensor having a magnetic film on the surface of a base material with a magnetic film capable of recording magnetic signals. The structure is such that a magnetic film made of a material is formed and a predetermined amount of a non-magnetic substance is dispersed and contained in the magnetic film.

In addition, the solution taken by the invention according to claim ('2J) is
As a sensor having a magnetic film, the non-magnetic substance is at least IN selected from oxides, carbides, nitrides and borides, and the proportion of these non-magnetic substances to the magnetic material is 5 to 60% by weight. It is configured to do this.

In addition, the solution taken by the invention according to claim (3) is that a sensor having a magnetic film is made of at least titania, alumina, zirconia, magnesium oxide, or a non-magnetic material.
An oxide consisting of a single substance or a mixture of silicon dioxide and cobalt oxide, and the magnetic coating is formed by dispersing this oxide in a magnetic material and forming it on the surface of a base material by thermal spraying. be.

Moreover, the solution taken by the invention according to claim (4) is a sensor having a magnetic film, which is configured to use cobalt oxide as the non-magnetic substance.

Further, the solution taken by the invention according to claim (5) is to form a magnetic film made of a cobalt-based magnetic material capable of recording magnetic signals on the surface of a base material as a sensor having a magnetic film, and The magnetic film has a structure in which cobalt oxide is dispersed in an amount of 10 to 401 r% based on the magnetic material.

Furthermore, the solution taken by the invention according to claim (6) is:
The method for manufacturing a sensor with a magnetic film includes a first step of pulverizing cobalt oxide particles to a particle size of 1 to 10 μm, and a predetermined amount of cobalt oxide particles in the first step being dispersed and mixed into a magnetic material, followed by sintering. The second step is to spray the cobalt-based sintered powder from the second step onto the surface of the base material to form a magnetic material that can record magnetic signals. This configuration includes a third step of forming a film.

(Function) With the above configuration, in the invention according to claim (1), a predetermined amount of a non-magnetic substance is dispersed and contained in the magnetic film formed on the surface of the base material and made of a magnetic material capable of recording magnetic signals. Therefore, the domain wall of the magnetic film can be effectively increased by the non-magnetic material, compared to a method in which the domain wall is increased using only a magnetic material consisting of fine particles that are still crystalline. Due to this, when a magnetic field is applied to the magnetic film,
Many domain walls of the crystal move to increase the volume of magnetic domains that are spontaneously magnetized in almost the same direction as the magnetic field, and the magnetization of the entire crystal increases in the direction of the magnetic field. The magnetic coating is applied with an extremely strong magnetic field to move the domain walls of the entire body, and even when the magnetic field becomes zero, a high residual magnetization is obtained due to the large number of domain walls of the crystal that have been moved, improving the reproduction output during measurement. do.

Furthermore, in the invention according to claim (2), the nonmagnetic substance is at least one selected from oxides, carbides, nitrides, and borides, and these nonmagnetic substances are contained in the magnetic material. Since the ratio is 5 to 60% by weight, the non-magnetic substance is contained in the magnetic material. Depending on the content ratio to the material, the domain wall of the magnetic film can be effectively increased, and higher residual magnetization can be reliably obtained, thereby reliably improving the reproduction output during measurement.

Further, in the invention according to claim (3), the nonmagnetic substance is selected from at least an oxide of titania, alumina, zirconia, magnesium oxide, silicon dioxide, and cobalt oxide, or a mixture thereof, and the magnetic coating is teeth,
Since this oxide is dispersed in a magnetic material and thermally sprayed onto the surface of the base material, the oxide dispersed in the magnetic material will not be further oxidized by the flame during thermal spraying. A magnetic coating with extremely low unevenness is formed on the surface of the base material by thermal spraying.

Further, in the invention according to claim (4), since the non-magnetic substance is cobalt oxide, when cobalt is used as the magnetic material, cobalt oxide is easily generated by oxidizing cobalt by the flame during thermal spraying. In addition, since the non-magnetic material is cobalt oxide, which forms a magnetic film with very little unevenness by the flame during thermal spraying, the domain wall of the magnetic film is effectively increased by the cobalt oxide, and the domain wall is increased by this non-magnetic material. As a result, the residual magnetization properties are further enhanced, the writing frequency of the magnetic signals to the magnetic film is increased, the change in magnetic signals over time is prevented, and the coercive force properties are improved.
Improves playback output during measurement.

Further, in the invention according to claim (5), the magnetic film made of a cobalt-based magnetic material formed on the surface of the base material contains cobalt oxide dispersed in an amount of 10 to 40% by weight based on the magnetic material. Therefore, it can be obtained by including cobalt oxide in a magnetic material. The effect of increasing the domain wall by cobalt oxide is not hindered, and the content ratio of cobalt oxide to the magnetic material effectively increases the domain wall of the magnetic film, and in particular, reliably improves the residual magnetization property.

Furthermore, in the invention according to claim (6), the particle size is 1 to 10 μm.
A predetermined amount of cobalt oxide particles pulverized to 100 m is dispersed and mixed into a magnetic material, and sintered to form a cobalt-based sintered powder with a particle size of 10 to 75 μm. Since the magnetic coating is formed by thermal spraying, the cobalt-based sintered powder having a smaller particle size is oxidized by the flame during thermal spraying, and a predetermined amount of cobalt oxide is easily generated in the magnetic coating. Moreover, the cobalt oxide particles have a particle size of 1~
Since the cobalt oxide particles are pulverized to 10 μm in size, the production cost for pulverizing the cobalt oxide particles is lower than that of pulverizing the cobalt oxide particles to a particle size of less than 1 μm, and the cobalt oxide particles are This prevents oxidation and prevents cobalt oxide particles from being dispersed in a magnetic coating in an amount exceeding a predetermined amount due to oxidation of cobalt oxide particles during thermal spraying.

(Example) Embodiments of the present invention will be described below based on the drawings.

In FIG. 1 showing a sensor having a magnetic film, 1 is a well-known sensor having a magnetic film, and this sensor 1 is applied to an aluminum turbine shaft 2 (base material) in a torque converter device (not shown). be. At approximately the center of the surface of the turbine shaft 2, magnetic coatings 3.3 having a coating thickness of 100 μm are formed at predetermined intervals in the axial direction and extending over the entire circumference. The magnetic film 3.3 is a second magnetic film.
As shown in the figure, the proportion of the magnetic material A having a magnetic function and the magnetic material A is 5 to 60% by weight.
and a non-magnetic material B as a non-magnetic substance having a non-magnetic function.

The above-mentioned magnetic material A consists of magnetic primary particles pulverized to a particle size of 1 to 10 μm. On the other hand, non-magnetic material B has magnetic coating 3.
A predetermined amount is dispersed and mixed into 3.

The above magnetic primary particles are dispersed and contained, and by binding these magnetic primary particles, secondary particles C having a particle size of 10 to 75 μm are granulated as thermal spray powder, and this secondary particles C are applied to the turbine shaft 2. It is formed by spraying using a plasma spray method.

Further, a magnetic coating 3 is provided on the outside of the turbine shaft 2.
, 3, a pair of magnetic signal reading heads 4, 4 are arranged. In this case, a pair of magnetic signal recording heads (Fig. (not shown), a rectangular pulse signal (recording signal A and recording signal B) as shown in FIG. , 4 are arranged.

When torque is applied to the turbine shaft 2, the respective detection signals (recorded signals A and B) detected by the magnetic signal reading heads 4 and 4 are generated as shown in FIG.
is sent to the signal processing section 11. In this signal processing section 11, after the detection signals of the magnetic signal reading heads 4.4 are processed by individual signal processing means 12.12, the phase difference calculating means 13 performs signal processing between the magnetic signal reading heads 4.4 ( The phase difference signal (between the magnetic films 3, 3) is calculated, and then the torque required to eliminate the phase difference between the magnetic signal reading heads 4, 4 is calculated by the torque calculation means 14, and this torque is output. , to reduce torque shock during gear shifting.

Here, the magnetic material A is appropriately selected from cobalt powder, iron oxide powder, etc., which have magnetic functions. Also,
The above-mentioned magnetic material A is finely pulverized as magnetic primary particles having a particle size of 1 to 10 μm while remaining as a crystal.

On the other hand, as the non-magnetic material B, alumina (A120
3), titania (T t 02 ), zirconia (Zr
Oz), magnesium oxide (MgO).

Silicon dioxide (Sin;), cobal oxide h (C.

Cr3
'C2, Ti C, WC, B4 C, S i C,
Carbide such as ZrC, TiN, ZrN, 5i3Na.

Nitride such as BN, TiB2. MoB2. Only one type is appropriately selected from borides such as ZrB2. In addition, among the non-magnetic materials B, non-magnetic materials B excluding cobalt oxide are prepared by dispersing and mixing the above-mentioned primary particles and having a particle size of 10 to 75.
It is granulated as μm-sized secondary particles C by an atomization method, a granulation method, a pulverization method, or the like.

Next, an example of a method for manufacturing the magnetic film 3.3 will be described.

First, in the first step, magnetic primary particles made of the above-mentioned magnetic material are finely ground to a particle size of 1 to 10 μm while remaining as crystals. The method for crushing these magnetic primary particles is as follows:
Pulverization methods are used.

Next, in the second step, the above-mentioned non-magnetic material is dispersed and mixed into the fine magnetic primary particles crushed in the first step and granulated with a binder, and then the granulated powder is classified to determine the particle size. Secondary particles having a distribution of 10 to 75 μm are produced as thermal spray powder.

In addition, methods for granulating secondary particles include atomization method,
Granulation methods, pulverization methods, etc. are used.

Then, in the third step, the 2
Magnetic particles having crystalline particles are sprayed onto the entire circumference of the turbine shaft 2 at predetermined intervals in the axial direction at approximately the center of the surface of the turbine shaft 2.
3. A magnetic coating in which a large number of secondary particles are mixed and non-magnetic material B is dispersed in a ratio of 5 to 60% by weight based on the magnetic material.
form 3. Note that methods for forming the magnetic film on the surface of the turbine shaft include a plasma spraying method, a coating method, a plating method, and the like.

In this case, if cobalt-based primary particles are used as the magnetic material, there may be no need to disperse and mix a non-magnetic material into the cobalt-based primary particles. The resulting granulated powder is sintered to produce sintered granulated powder as 2-carbon particles C, and by plasma spraying this sintered granulated powder, the cobalt is oxidized by the flame and becomes a non-magnetic material. The cobalt oxide is dispersed and contained at a desired ratio of 10 to 40% by weight based on the magnetic material in the magnetic coating.

At that time, the particle size of the magnetic primary particles was set to 1 μm or more because
By reducing the magnetic primary particles to 1 μm or less, the number of magnetic primary particles dispersed in the secondary particles C is increased, the domain wall of the crystal is increased, and an extremely strong magnetic field is applied to increase the magnetic 1
By moving the domain walls of the crystals in the secondary particles, we can increase the residual magnetization of the magnetic film when the magnetic field is reduced to zero, increasing the reproduction output during measurement, and at the same time achieving the reversal required to reduce the residual magnetization to zero. This is to increase the magnetic field, or coercive force.

In addition, the size of the secondary carbon particles C is set to be 10 to 75 μm or more because if the secondary particles are less than 10 am, they are too light to be used as thermal spray powder used in the plasma spraying method, and are blown away by flames and cannot be used on the surface of the turbine shaft. On the other hand, if the diameter is 75 μm or more, there is too much difference in secondary particle size, making it difficult to form a magnetic film with a uniform thickness on the turbine shaft.

Further, the magnetic film 3 described above is widely used in the mechatronics field such as automobiles, machine tools, and industrial robots.

Therefore, according to the magnetic coatings 3, 3 as described above, the magnetic coating 3 made of the magnetic material A capable of recording magnetic signals is formed at a predetermined distance apart in the axial direction approximately at the center of the surface of the turbine shaft 2. Since .3 contains a predetermined amount of non-magnetic material B dispersed therein, the magnetic film 3,3 The domain wall of is effectively increased by the nonmagnetic material B. This results in a magnetic coating of 3°3
When a magnetic field is applied to the magnetic field, many domain walls of the crystal move to increase the volume of the magnetic domains that are spontaneously magnetized in almost the same direction as the magnetic field, and the magnetization of the entire crystal increases in the direction of the magnetic field. Therefore, in the magnetic film 3.3 in which an extremely strong magnetic field is applied to move the domain walls of the entire crystal, even if the magnetic field becomes zero, a high residual magnetization is obtained due to the large number of domain walls of the crystal that have been moved. Therefore, the reproduction output during measurement can be effectively improved.

Further, as the non-magnetic material, at least one type is selected from oxides, carbides, nitrides, and borides, and the ratio of the non-magnetic material B to the magnetic material A is 5 to 60.
% by weight, it can be obtained by containing the non-magnetic material B relative to the magnetic material A. The effect of increasing the domain wall by the non-magnetic material B is not hindered, and the content ratio of the non-magnetic material B to the magnetic material A increases the magnetic film 3.
The domain wall of No. 3 is effectively increased, higher residual magnetization is reliably obtained, and the reproduction output during measurement can be effectively and reliably improved.

Furthermore, an oxide consisting of at least a single substance or a mixture of titania, alumina, zirconia, magnesium oxide, silicon dioxide, and cobalt oxide is selected as the non-magnetic material B, and the magnetic film disperses this oxide in the magnetic material. When the oxide is formed by thermal spraying on the surface of the turbine shaft, the oxide dispersed in the magnetic material will not be further oxidized by the flame during thermal spraying.
A magnetic coating with very little unevenness is formed on the surface of the turbine shaft by thermal spraying, and detection accuracy can be improved due to the magnetic coating H3, 3 in which the domain walls are evenly and effectively increased.

Moreover, when cobalt is used as the magnetic material A, the cobalt oxide is oxidized by the flame during thermal spraying, and cobalt oxide as the non-magnetic material B can be easily produced. Furthermore, when cobalt is used as the magnetic material A, the non-magnetic material B forms a very even magnetic film 3.3 due to the flame during thermal spraying, and the domain walls of the magnetic films 3, 3 are formed by cobalt oxide. The remanent magnetization is further increased by the effect of increasing the domain wall due to cobalt oxide, and the writing frequency of the magnetic signal to the magnetic film 3.3 is increased, preventing the magnetic signal from changing over time and improving the coercive force characteristics. In addition to further improving the performance, it is possible to improve the reproduction output during measurement.

Furthermore, when cobalt is used as the magnetic material A and cobalt oxide is dispersed in the magnetic film made of the cobalt-based magnetic material in an amount of 10 to 40% by weight based on the magnetic material, cobalt oxide becomes magnetic. It can be obtained by adding it to the material. The domain wall increasing effect of cobalt oxide is not hindered, and the content ratio of cobalt oxide to the magnetic material effectively increases the domain wall of the magnetic film, and in particular, remanent magnetization characteristics can be reliably improved.

Moreover, a predetermined amount of cobalt oxide-based magnetic primary particles pulverized to a particle size of 1 to 10 μm is dispersed and mixed into a magnetic material, and sintered to granulate cobalt-based sintered powder with a particle size of 10 to 75 μm. If the cobalt-based sintered powder is thermally sprayed onto the surface of the turbine shaft to form a magnetic film, the flame during thermal spraying will oxidize the cobalt-based sintered powder, which has a smaller particle size, and form the desired coating on the magnetic material. Cobalt oxide having a ratio of 10 to 40% by weight is easily generated in the magnetic film, and a magnetic film that further improves reproduction output and coercive force can be easily formed. Moreover, since the cobalt oxide particles are pulverized to a particle size of 1 to 10 μm, the manufacturing cost for pulverizing the cobalt oxide particles can be lower than that of pulverizing the cobalt oxide particles to a particle size of less than 1 μm.
Sintering during granulation prevents the cobalt oxide particles from being oxidized, and it is possible to reliably prevent cobalt oxide particles from being dispersed in a magnetic coating in an amount exceeding a predetermined amount due to oxidation of the cobalt oxide particles during thermal spraying.

Next, a first test conducted to confirm the effects of the magnetic films 3, 3 will be described.

First, in iron oxide-based magnetic primary particles, non-magnetic materials A and B made of oxides of titania alone and alumina alone, and non-magnetic material C made of nitride of boron nitride (BN),
After appropriately dispersing and mixing and granulating jO, 20, 40, 60° and 70% by weight, this granulated powder was used to form a powder with a diameter of 30 mm by a plasma spraying method based on the spraying conditions shown in Table 1.
A coating thickness of 100 mm is applied to the surface of the aluminum shaft member.
A μm-thick magnetic film was formed. Thereafter, using a function generator (magnetic signal recording head), a rectangular wave is generated for 15 minutes while the magnetic signal recording head is in contact with the magnetic film of the shaft member rotating at 600 rpm.
Write in V.

Table 1 Then, instead of the magnetic signal recording head, a magnetic signal reading head was placed so as to correspond to the magnetic film, and the magnetic signal of the magnetic film was measured using this magnetic signal reading head based on the measurement conditions shown in Table 2. , the results shown in FIG. 5 were obtained.

Table 2 As can be seen, the reproduction output improvement rate of the magnetic coating using oxide as a non-magnetic material is highest in the order of titania and alumina, and the reproduction output improvement rate of the magnetic coating using nitride (boron nitride) is higher than the above two. It was confirmed that oxides are suitable as non-magnetic materials.

Furthermore, the ratio of oxides and nitrides dispersed and mixed as non-magnetic materials to the magnetic material is below 10% by weight, for example, from 5% by weight, the reproduction output improvement rate of the magnetic film starts to increase, and when it reaches 60% by weight. It was confirmed that when the value exceeds this value, the reproduction output improvement rate of the magnetic film decreases.

Next, a second test conducted to confirm the effect of the magnetic films 3, 3 will be explained.

First, in the same iron oxide-based magnetic primary particles as in the first test, non-magnetic materials A and B consisting of oxides of titania alone and alumina alone, and non-magnetic materials consisting of nitride of boron nitride (BN) were added. Add C to the granulated powder that has been appropriately dispersed and mixed at a ratio of 10°20.40.60.70% by weight,
Silicon nitride (Si3N4) is included in the iron oxide magnetic primary particles.
) non-magnetic material made of nitride, 10. 20.4
A magnetic film having a film thickness of 100 μm was formed on the surface of an aluminum shaft member having a diameter of 30 mm using a coating method using granulated powder that had been appropriately dispersed and mixed at a ratio of 0.60.70% by weight. In this case, the granulated powder is made by adding non-magnetic materials A, B, C, and D individually to iron oxide magnetic primary particles and dispersing and mixing an acrylic urethane binder in a ratio of 1 to 4. This granulated powder is sprayed onto the surface of the shaft member and then dried to form a magnetic film.

Then, using a function generator (magnetic signal recording head), the magnetic signal recording head is
A rectangular wave is written at 15 V while the shaft member is in contact with the magnetic film of the rotating shaft member. Then, instead of the magnetic signal recording head, a magnetic signal reading head is arranged to correspond to the magnetic film, and this magnetic signal reading head measures the magnetic signal of the magnetic film based on the measurement conditions shown in Table 2 above. , the results shown in FIG. 6 were obtained.

In this way, the reproduction output improvement rate of magnetic coatings using oxides as non-magnetic materials is highest in the order of titania and alumina, followed by the reproduction output improvement rate of magnetic coatings using nitrides compared to the above two. Similar to the first test, it was confirmed that oxides are suitable as small, non-magnetic materials.

In addition, when the ratio of nonmagnetic materials such as oxides and nitrides dispersed in the magnetic material is 10% by weight, the reproduction output improvement rate of the magnetic coating starts to increase, and when it exceeds 60% by weight, the reproduction output of the magnetic coating starts to increase. The first problem mentioned above is that the output improvement rate decreases.
It was confirmed in the same way as the test.

Next, a third test conducted to confirm the effects of the magnetic films 3, 3 will be described.

First, in sample A, using cobalt powder with a particle size of 177 μm or less granulated by the atomization method as a thermal spray powder, a vertical
A magnetic film with a thickness of 110 μm was formed on the surface of an aluminum plate measuring 0 mm x 2 mm wide x 1 mm thick.

Table 3 In addition, in sample B, cobalt powder with a particle size of 177 μm or less granulated by the atomization method was used as the thermal spray powder, and by plasma spraying based on the thermal spraying conditions (■) shown in Table 3 above,
A magnetic film B having a film thickness of 110 μm was formed on the surface of the same plate material as the sample A above.

In addition, in sample C, the particle size was 1 to 10 μm as a thermal spray powder.
Using cobalt powder with a particle size of 10 to 75 μm, which was sintered after granulating magnetic primary particles using a granulation method, the sample A
A magnetic film C having a film thickness of 110 μm was formed on the surface of the same plate material.

In addition, in the sample, the particle size of the thermal spray powder was 1 to 10 μm.
The above Sample A was obtained by plasma spraying based on the thermal spraying conditions ① shown in Table 3 above using cobalt powder with a particle size of 10 to 75 μm which was granulated by a granulation method (7)t and sintered magnetic primary particles of . A magnetic film with a film thickness of 110 μm was formed on the surface of the same plate material.

In addition, in sample E, magnetic primary particles with a particle size of 1 to 8 μm were granulated by a granulation method as thermal spray powder, and the particle size was 10 to 75 μm.
A magnetic film E having a film thickness of 110 μm was formed on the surface of the same plate material as the above sample A by plasma spraying using cobalt powder of 100 μm under the spraying conditions (1) shown in Table 3 above.

In addition, in sample F, magnetic primary particles with a particle size of 1 to 8 μm were granulated by a granulation method as thermal spray powder, and the particle size was 5 to 45 μm.
A magnetic film F having a film thickness of 110 μm was formed on the surface of the same plate material as Sample A by plasma spraying using the cobalt powder shown in Table 3 above under the spraying conditions (1).

Then, sample A was measured using a VSM device (vibrating magnetometer).
-F, the magnetic properties of each magnetic coating A to F, that is, the coercive force and residual magnetization characteristics, and the content of cobalt oxide as a non-magnetic material dispersed in each magnetic coating A to F were measured. The results shown in FIGS. 7 and 8 and Table 4 were obtained. Note that the magnetic field applied to the SM device is 5 kOe.

Table 4 Thus, it was confirmed that as the ratio of cobalt oxide as a non-magnetic material dispersed in the magnetic film (the amount of cobalt oxide) increased, the coercive force increased.

In addition, it was confirmed that the residual magnetization of the magnetic film starts to increase at a ratio of cobalt oxide dispersed in the magnetic film of 10% by weight, and that the residual magnetization of the magnetic film levels off when it exceeds 40% by weight. did it.

In addition, in the above examples and test examples, the turbine shaft 2 and shaft member made of aluminum were used, respectively.
Turbine shafts and shaft members made of magnetic materials such as iron may also be used. In this case, after forming a non-magnetic film of a non-magnetic material such as aluminum on the surface,
A magnetic film is formed on top of the non-magnetic film.

(Effects of the Invention) As described above, according to the sensor having a magnetic film of the invention according to claim (1), a magnetic film made of a magnetic material containing a predetermined amount of a non-magnetic substance dispersed on the surface of the base material is provided. As a result, the domain walls of the magnetic film are effectively increased by the non-magnetic material, and this increased domain wall is moved by applying an extremely strong magnetic field to obtain high residual magnetization due to the large number of domain walls, which results in a high remanent magnetization during measurement. It is possible to further improve the playback output.

Further, according to the sensor having a magnetic film of the invention according to claim (2), at least one non-magnetic substance selected from oxides, carbides, nitrides and borides is contained in the magnetic material. Since the ratio is set to 5 to 60% by weight, the domain wall of the magnetic film can be effectively increased without interfering with the domain wall increasing effect due to the content ratio of the non-magnetic substance to the magnetic material, and higher residual magnetization can be reliably obtained. , it is possible to more reliably improve the reproduction output during measurement.

Further, according to the sensor having a magnetic film of the invention according to claim (3), at least an oxide selected from the group consisting of a single substance or a mixture of titania, alumina, zirconia, magnesium oxide, silicon dioxide, and cobalt oxide is used. However, since a magnetic film was formed by dispersing a non-magnetic substance in a magnetic material and thermally spraying it onto the surface of the base material, the oxide dispersed in the magnetic material is protected against further oxidation by the flame during thermal spraying. It is possible to form a magnetic film with very little unevenness on the surface of the base material by thermal spraying while preventing the magnetic field from forming, and the detection accuracy can be improved by effectively increasing the magnetic domain walls evenly.

Further, according to the sensor having a magnetic film of the invention according to claim (4), cobalt oxide is used as the non-magnetic material, so if cobalt is used as the magnetic material, the flame during thermal spraying will oxidize the cobalt and turn it into cobalt oxide. can be easily generated. Moreover, since the non-magnetic material is cobalt oxide, which forms a magnetic film with very little unevenness by the flame during thermal spraying, the domain wall of the magnetic film is effectively increased by the cobalt oxide, and the domain wall is increased by this non-magnetic material. This effect further increases residual magnetization, increases the writing frequency of magnetic signals to the magnetic film, prevents changes in magnetic signals over time, improves coercive force characteristics, and further improves reproduction output during measurement.

Further, according to the sensor having a magnetic film of the invention according to claim (5), the magnetic film contains cobalt oxide dispersed in an amount of 10 to 40% by weight based on the cobalt-based magnetic material. On the other hand, the domain wall of the magnetic coating can be effectively increased by the content ratio of cobalt oxide to the magnetic material without impeding the effect of increasing the domain wall by the cobalt oxide contained, and in particular, the residual magnetization characteristics can be reliably improved.

Furthermore, in the invention according to claim (6), the particle size is 1 to 10 μm.
A predetermined amount of cobalt-based sintered particles pulverized to 500 μm is dispersed and mixed into a magnetic material and sintered to granulate cobalt-based sintered powder with a particle size of 10 to 75 μm, and this cobalt-based sintered powder is used as a base material. Since the magnetic coating was formed by thermal spraying on the surface of the magnetic coating, the cobalt-based sintered powder with a smaller particle size is oxidized by the flame during thermal spraying, and a predetermined amount of cobalt oxide is easily generated in the magnetic coating. , it is possible to easily form a magnetic film that further improves reproduction output and coercive force. Moreover, by pulverizing the cobalt oxide particles to a particle size of 1 to 10 μm, the manufacturing cost for pulverizing the cobalt oxide particles can be reduced, and
By preventing oxidation of cobalt oxide particles due to sintering during granulation, it is possible to reliably prevent the magnetic coating from containing more than a predetermined amount of cobalt oxide dispersed therein.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 shows a magnetic skin M.
2 is an explanatory diagram of the sprayed powder, FIG. 3 is a diagram showing the magnetic signals of the magnetic film recorded by a pair of magnetic signal recording heads, and FIG. FIG. 5 is a diagram showing the magnetic signal of the magnetic coating read by the magnetic signal reading head; FIG. Figure 6 is a characteristic diagram showing the characteristics of the reproduction output improvement rate with respect to the amount of non-magnetic material dispersed in the magnetic film formed by coating.
The figure shows the coercive force characteristics with respect to the amount of cobalt oxide.
FIG. 8 is a characteristic diagram showing residual magnetization characteristics with respect to the amount of cobalt oxide. 1...Sensor 2...Turbine shaft (base material) 3...Magnetic film A...Magnetic material B...Non-magnetic material Patent applicant: Tomiyo Mazda Motor Corporation
Before Rinto 1) Hiroshi
- Idiot 1 Knee sensor 2 - Turpino shaft (base material) 3 - Magnetic coating 8 - Magnetic material B...Non-magnetic material 1st m J 2 M Fig. 3 Fig. 4rI! J 20 l4o60 80 100 non,
da mio palmto Δshitoguchi iI (middle 11z) Fig. 5 non-TJm ('f7 o brushto m71 [] ((11iS) 6th
WJ Kasumi Shitaku P Zuzume

Claims (6)

[Claims] (1) A magnetic film characterized in that a magnetic film made of a magnetic material capable of recording magnetic signals is formed on the surface of a base material, and a predetermined amount of a non-magnetic substance is dispersed and contained in the magnetic material. A sensor with (2) The non-magnetic substance consists of at least one of oxides, carbides, nitrides, and borides, and the content of these non-magnetic substances with respect to the magnetic material is 5 to 60% by weight.
A sensor having a magnetic film according to claim (1). (3) The non-magnetic substance is an oxide consisting of at least one of titania, alumina, zirconia, magnesium oxide, silicon dioxide, and cobalt oxide, or a mixture thereof, and the magnetic film is formed by incorporating this oxide into the magnetic material. A sensor having a magnetic film according to claim 2, wherein the magnetic film is dispersed and formed on the surface of the base material by thermal spraying. (4) A sensor having a magnetic film according to claim (3), wherein the non-magnetic substance is cobalt oxide. (5) A magnetic film made of a cobalt-based magnetic material capable of recording magnetic signals is formed on the surface of the base material, and the magnetic film has cobalt oxide dispersed in an amount of 10 to 40% by weight based on the magnetic material. A sensor having a magnetic film containing a magnetic film. (6) A first step of pulverizing cobalt oxide particles to a particle size of 1 to 10 μm, and dispersing and mixing a predetermined amount of the cobalt oxide particles in the first step into a magnetic material, followed by sintering to a particle size of 10 to 7 μm.
A second step of granulating 5 μm cobalt-based sintered powder, and a third step of spraying the cobalt-based sintered powder of the second step onto the surface of the base material to form a magnetic film capable of recording magnetic signals. 1. A method for manufacturing a sensor having a magnetic film, characterized in that the sensor has a magnetic film.