JPH073469A - Amorphous coating body and formation thereof - Google Patents

Abstract

PURPOSE:To obtain the amorphous coating body in which an amorphous metal sticks on the surface of a base material as a covering layer. CONSTITUTION:The amorphous coating body forming the covering layer consisting of the amorphous metal on the surface of the base material is obtained by applying the high energy speed processing of 0.7-80GPa molding pressure to the amorphous metal powder of 0.01-200mum grain diameter. In this way, the coating body free from occurrence of peeling is formed on the surface of the base material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding an amorphous coating body in which an amorphous metal is formed as a coating layer on the surface of a base material.

[0002]

2. Description of the Related Art Amorphous metals have characteristics such as high mechanical strength, low thermal expansion coefficient, and excellent chemical corrosion resistance and abrasion resistance, and are being applied to various parts. . Further, it is being used in many products as a magnetic material by utilizing the porcelain characteristics of amorphous metal. For example, amorphous is used as the magnetic material of the torque sensor.

As a method for molding such an amorphous material, many methods have been conventionally considered. For example, Japanese Patent Application Laid-Open No. 57-21130 discloses a method in which an amorphous metal formed into a thin strip is adhered to the surface of a drive shaft with an adhesive (epoxy resin or the like) or soldering.

Further, Japanese Patent Application Laid-Open No. 58-90345 discloses a torque sensor having an amorphous metal ribbon fixed as a magnetostrictive material.

[0005]

However, according to the method disclosed in Japanese Patent Laid-Open No. 57-21310, it is not possible to obtain sufficient adhesive strength at the bonded portion between the drive shaft and the amorphous metal ribbon, and therefore, when the method is used for a long time. Peeling due to fatigue,
Alternatively, there arises a problem that porcelain characteristics are not sufficiently changed due to stress.

Furthermore, Japanese Patent Laid-Open No. 58-90345 does not disclose a specific method for fixing an amorphous metal. Therefore, in view of the above problems, an object of the present invention is to provide an amorphous coating layer in which an amorphous metal is firmly adhered to the surface of a base material as a coating layer, and a molding method thereof.

[0007]

Therefore, in the present invention, as a first invention, a molding pressure is 0.7 to 80 GPa for an amorphous metal powder having a particle diameter of 0.01 to 200 μm.
The present invention provides a method for forming an amorphous coating body, which comprises forming a coating layer of an amorphous metal on the surface of a base material by performing the high energy speed processing of 1.

As a second invention, an amorphous coating comprising a matrix and a coating layer of an amorphous metal formed by subjecting the surface of the matrix to a high energy velocity processing with a molding pressure of 0.7 to 80 GPa. It provides the body. Here, points to be particularly noted in forming the amorphous coating will be described. Generally, the inside of the base material is non-uniform due to various causes such as internal stress, grain boundaries, non-uniformity of components, lattice defects, and precipitation of impurities. Therefore, the magnetic permeability of the base material has different values depending on the location and the direction. Therefore, if the amorphous metal is simply placed on the surface of the base material and they are fixed by high energy velocity processing, lattice defects, grain boundaries, non-uniformity of components, impurities of impurities are present between the amorphous metal powder and atoms. Problems such as precipitation occur. These problems cause the two to not be firmly fixed.

Therefore, in the present invention, the amorphous coating is formed by paying attention to the following points. First, before the high-energy speed machining of both of them, the first point to be noted is that the first step in the production of the amorphous metal powder is performed in an atmosphere of argon (Ar) which is an inert gas. This is to prevent an oxide layer from being formed on the surface of the amorphous metal powder. Second, the particle size of the amorphous metal powder is 0.01 to 200 μm. This is because the amorphous metal ribbon and the base material are satisfactorily adhered to each other during high energy speed processing. Third, the surface of the base material on which the coating layer is formed and the surface of the amorphous metal powder are subjected to plasma treatment in a hydrogen atmosphere of 10 ^-2 to 10 Torr. This is because the oxide layer on the surface is removed and at the same time, the surface is activated so as to improve the adherence during high energy speed processing.

Fourth, at the time of high energy speed machining, a method in which energy per unit time is uniformly applied to the base material and the amorphous metal is used. This is because the amorphous metal powder and the powder, and the amorphous metal powder and the surface of the base material are evenly bonded and fixed at any part. Fifthly, the heat treatment for removing the strain at the boundary between the base metal and the amorphous metal or the strain in the amorphous metal particles, which is caused by the application of high energy after the high energy speed processing, is performed in an inert atmosphere. To do. The heat treatment temperature is set so that the non-quality amorphous metal does not crystallize.

With the above points in mind, the present invention can form an amorphous coating material in which an amorphous metal is firmly adhered to the surface of a base material.

[0012]

By adopting the above molding method,
As the coating layer, it is possible to obtain an amorphous coating body in which an amorphous metal is firmly adhered to the surface of the matrix.

[0013]

【Example】

 (First Example) When the amorphous metal is powder,
And explain. Here, the amorphous metal is a metal element
Iron (Fe), cobalt (Co), nickel (Ni),
At least one of chromium (Cr) and silicon (Si)
Amorphous metal powder as the main component. This amorph
Asus metal powder is composed of metal elements and metalloids (phosphorus (P), carbon
(C), boron (B), silicon (Si), etc.)
Gold or iron-based elements and rare earth metals (Gd, Tb, Dy
Etc.) can be used. Representative Amol
Fe as the fass metal powder₇₀Co₁₅B₁₅, Fe ₈₀B
₁₅Bi_Five, Fe₄₀Ni₄₀P₁₄B₆, Fe₇₀Co₁₅B₁₅,
Co₈₀B₁₅C₁₅, Ni₇₈B₂Si_Tenand so on. (here
Numerical values such as 70, 15, 5 and the like indicate atomic%. ) Amol
The particle shape of fass metal powder is spherical and fine with excellent symmetry.
Long gourds are good, but in some cases flakes and
It may be a bon shape or a linear shape.

In the present invention, an amorphous metal powder having a particle size of about 0.01 to 200 μm is used. Where 0.
The reason why the numerical value is limited to 01 to 200 μm is as follows. That is, if it is less than 0.01 μm, the volume of the powder particles becomes smaller than the surface area of the powder particles. Therefore, it becomes insufficient to deprive the heat generated on the surface of the particles of the amorphous metal powder to the inside of the particles when subjected to high energy velocity processing such as explosion molding. As a result, the amorphous property of the ultrafine amorphous metal powder existing on the surface of the particles is likely to be lost. On the other hand, if it exceeds 200 μm, the powder packing density becomes low and the bondability of the powder particles deteriorates.

Amorphous metal powder having a particle size of 0.01 to 200 μm can be produced by a commonly used method. For example, rotating roll method, atomizing method, spray method, spark method,
A cavitation method or the like can be used. Amorphous metal powder having spherical particles can be produced by a spark method or an atomizing method. A typical example of producing an amorphous metal powder by the rotating roll method will be described more specifically.
That, Fe65 parts, CO15 parts, B15 parts, a powder of particle size 1~1000μm having the composition Si5 parts were mixed in a ball mill at high-frequency heating of 13.56MH _Z 14
Dissolve above 00 ° C. After that, this molten metal is
It is formed in a rod shape of 0 mm. Next, this rod-shaped compact is placed in a quartz or ceramic container at 1350 ° C to 1400 ° C.
Dissolve by heating at the temperature of. High frequency melting is preferable for heat melting.
Next, the molten metal formed as described above is jetted from the nozzle of the container toward the rotating roll, and is pulverized on the water surface, and
Quench at 0 ⁴ to 10 ⁶ ° C / sec. As a result, an amorphous metal powder having a particle size of 0.01 to 200 μm is manufactured. Thus, during the production of the amorphous metal powder, an atmosphere of argon (Ar) gas is preferable so as not to form an oxide layer on the powder surface. The particles thus produced may have a spherical shape, a rugby ball shape, an elliptic spherical shape, a peanut shape, or the like.

Next, the case where the above-mentioned amorphous metal powder is coated as the magnetic material of the torque sensor will be described in more detail. In this embodiment, the above-mentioned powder is placed on the surface of the drive shaft, which is the base material on which the coating layer is formed, and then both are fixed by high-energy speed processing to form an amorphous coating.

FIG. 1 is a schematic view of a torque sensor using the amorphous coating body of the present invention as a drive shaft, FIG. 2 is a partial external view showing an arrangement state of exciting coils, and FIG. 3 is II of FIG.
Sectional drawing which follows the I-III line, FIG. 4 is a partially expanded view of FIG. As is clear from FIG. 4, in the state of high energy velocity processing, the amorphous metal powder is fixed to the surface of the drive shaft to form a coating. Here, high energy speed machining means extremely short time (generally 10 ⁻³
This means a processing method of instantaneously releasing energy in a very short time (about 10 to ⁸ seconds) to perform molding. When the high energy velocity processing is used, the energy per unit time, that is, the energy velocity, is extremely large, so that the energy can be consolidated without generating much heat. Therefore, it can be solidified without impairing the amorphous property. The molding pressure by high energy velocity processing is preferably 0.7 to 80 GPa. Here, if the molding pressure is less than 0.7 GPa, the pressure of the powder particles is low, so that it is difficult to integrally mold the powder particles.
If it is a or more, it is possible to perform integral molding, and more preferably to exceed 1.5 GPa to obtain a better and uniform coating material. Explosive molding processing is a typical high energy speed processing. Explosive molding is a method in which TNT explosive momentarily applies pressure by a shock wave or gas expansion generated by the explosion of dynamite. Explosive molding is generally performed by exploding explosive powder in water. The pressure for explosive molding can be adjusted depending on the depth from the water surface to the explosive, the distance from the explosive to the object to be molded, and the amount of explosive. The pressure when explosive molding is used is also preferably 0.7 to 80 GPa. If a higher pressure than that is applied, the amount of heat at the time of joining will become too large, and some of the amorphous metal will crystallize, making it easier to lose the amorphous property. Is.

Specifically, first, the above-mentioned amorphous metal powder is subjected to reduction treatment under plasma in a reducing atmosphere containing hydrogen of 10 ^-2 to 10 Torr for 10 to 30 minutes. The temperature at this time is lower than the temperature (450 ° C.) at which the amorphous metal is crystallized, and is 250 ° C. to 450 ° C. As a result, the surface of the amorphous metal powder is activated while the oxide layer is completely removed. Further, a drive shaft having a diameter of 20 mm and a length of 250 mm is similarly treated and activated under plasma. At this time, as the material of the drive shaft, one having a Vickers hardness of 100 to 300 Hv is suitable. It is an iron-based or Ni-based metal such as S4
5C, S55C, SUS416, SUS304, SUS
316 is good. 3 reasons to limit Vickers hardness
When it is equal to or more than 00 Hv, the surface of the base material is not deformed, and it is difficult for the powder to enter the inside of the base material, so that the fixing strength is poor. This is because if it is less than 100 Hv, the shape cannot be maintained because the base material is deformed during explosive compression.

Next, the drive shaft on which the above treatment has been carried out is arranged in the center of the cylindrical container of copper or iron-based material. Then, while applying vibration (5 to 100 Hz) to the space between the drive shaft and the cylindrical container, the treated amorphous metal powder is filled to about 50% of the theoretical density, and the container is sealed after vacuum deaeration. After that, the sheet explosive is exploded, and the amorphous metal powder in the container and the drive shaft are pre-pressed. Next, a container is placed in the center of the explosive in the molding chamber and explosion molding is performed. At this time, the point explosion by the detonator becomes a plane explosion wave by the explosive lens, and propagates to the upper surface of the main explosive at the same time to explode the main explosive. The powder in the container is simultaneously compressed radially and axially by the shock wave. The amorphous metal powder is fixed by the shock wave received through the container, and the powder and the powder and the surface of the drive shaft are securely fixed and joined. The explosive shock wave causes the powder to be impacted for about 10 ⁻⁶ seconds. The pressure at this time is 0.7 to 80 GPa.

The pressure exerted by this impact action is controlled as described below based on the ratio of the particle size of the amorphous metal powder as shown in FIG. When the particle size ratio of the powder is as shown in FIG. 5A (when the particle size of 50 to 200 μm is 100%), a pressure of about 10 to 80 GPa is applied. When the particle size ratio is as shown in FIG.
A pressure of about 8 to 50 GPa is applied when the thickness of 50 μm is 5 to 20% and the thickness of 50 to 130 μm is 80 to 95%. When the particle size ratio is as shown in FIG.
Ultra fine powder of ~ 0.08 μm is 0.1-0.5%,
5 to 30% of 10 to 40 μm, 50 to 130 μm
When the content of the material is 55 to 95%), a pressure of 0.7 to 10 GPa is applied. Then, the amorphous metal powder has a density of 90 to 99.9% of the theoretical density and is fixed on the surface of the drive shaft. Further, considering the deformation of the base material during the explosive forming process, the pressure should be small. Therefore, FIG. 5 (c)
It is preferable to use an amorphous metal powder having a particle size ratio shown in (1), and the pressure is appropriately 0.7 to 10 GPa.

The lower limit of the explosion pressure range is determined by the pressure at which the boundaries between particles are eliminated, and the upper limit is determined by the amorphous phase being maintained by the heat generated during the explosion. That is, at 90 GPa or more, the amorphous particles are heated by the heat generated between the powder particles at the time of explosion,
Therefore, the amorphous phase changes to a crystalline phase, and even if it is rapidly cooled, it does not return to the original amorphous phase.

Incidentally, the container of copper or iron-based material installed on the outer peripheral portion of the drive shaft is removed by grinding or cutting after the explosion formation.
The drive shaft from which this container has been removed exhibits remarkable magnetic characteristics when heat-treated for about 1 to 2 hours while applying magnetism (1000 to 2000 Oersted) at a temperature (100 ° C to 350 ° C) at which amorphous does not crystallize. Be improved.
The amorphous coating thus formed has a coating layer (100 to 500 μm) of amorphous metal firmly adhered to the surface of the drive shaft 4, as shown in FIG. At this time, the amorphous metal coating phase was a uniform layer in which the powder particles were well bound to each other. Inside the coating layer of amorphous metal, there are almost no boundaries between powder particles and defects, and defects. At the interface between the amorphous metal powder and the surface of the drive shaft, which is the base material, atoms of each other enter and the bond between the atoms is strong.
Furthermore, as a result of analyzing this by electron beam diffraction, a halo pattern was submitted, and all parts were in an amorphous state.

Next, the operation of the torque sensor using the amorphous coating material thus formed as a magnetic material will be described. As shown in FIG. 1, in the vicinity of the surface of the drive shaft 4 on which the coating layer is formed, a coil 2 for exciting the coating layer,
When the detection coil 3 for detecting the magnetostrictive characteristic of the coating layer is installed, the electromotive force due to the strain due to the torque transmitted to the drive shaft can be measured. The electromotive force is amplified and taken out as an electric signal. As a detection circuit, a signal output from the oscillator 11 is converted into a square wave by the drive circuit 12, and a current is added to the exciting coil 3. In the detection coil 2, the electromotive force generated by the distortion caused by driving is amplified by the AC amplifier 13, sampled by the sampling circuit 14, and further compared with the excitation square wave to detect the torque.

In the above-mentioned embodiments, the drive shaft of the torque sensor, that is, a cylindrical member is used as the base material. However, the shape of the base material is not limited to such a cylindrical shape, and may be any other shape as long as it has a surface on which the amorphous metal coating layer is formed. For example, it may be a prism, an ellipse, a flat plate, or the like. Further, the base material may have a complicated shape such as an electromagnetic clutch or a magnetic head. Needless to say, it is necessary to apply an impact pressure evenly to the surface of the base material having these shapes at high energy speed.

Further, since the amorphous metal of the above embodiment is a powder, it can be firmly fixed even if the impact pressure in high energy velocity processing or the like is small. Since this pressure may be small, the base material on which the coating layer is formed is not deformed. As a result, the dimensional accuracy of the formed amorphous coating is improved. The amorphous coatings formed in the above-mentioned examples have different coating layer thicknesses, but their characteristics do not change. Therefore, the measured values of the amorphous coatings formed in the examples are described below.

FIG. 6 is a diagram showing the relationship between the composition of the amorphous metal powder and the magnetostrictive characteristics of the resulting coated body.
According to this, the magnetostrictive property of the present invention is remarkably improved as compared with the reference example (conventional nickel-plated coating layer having a thickness of 10 μm). This is a value when the coating layer is 10 μm and 5 Kθe (oersted).

FIG. 7 shows No. 1 in FIG. 2 composition (Fe ₇₆
B ₈ Si ₁₆₎ the torque applied to the amorphous covering body which is formed from amorphous metal powder consisting of a diagram showing the relationship between the output. According to this, the torque applied to the amorphous coating, which is the drive shaft, and the output obtained from the amorphous coating layer as a result are the same as those of the conventional (N
A good proportional relationship is established as compared with i plating 20 μm). Further, the difference in hysteresis due to the rise and fall of the applied torque is smaller than that of the conventional one (Ni plating 20 μm), and the sensitivity (ratio of torque and output) is good. As described above, the magnetic property of the present invention is improved.

Next, the amorphous coating of the present invention (No. 2 in FIG. 6) and the conventional one (thickness: 25 to 30 μm)
The adhesive strength of the amorphous thin ribbon of m is adhered by an epoxy resin having a thickness of 5 to 15 μm for driving). When a torque of 14 kg · m was applied to the drive shaft and the conventional one was applied with a torque of about 100 times, the sensitivity decreased and the output decreased. However, the above-mentioned one of the present invention did not change even after being used 100,000 times, and the output did not decrease. From this, the one of the present invention has sufficient durability as compared with the conventional one.

Further, in FIG. 5 to No. Since No. 8 has corrosion resistance, it can be used in a corrosion resistant environment.
Next, Vickers hardness and magnetic characteristics (FIG. 8) when forming an amorphous coating pair in which different amorphous metal powders are fixed to the surface of the drive shaft (diameter 20 mm, material: S45C), and the thickness of the coating layer Relationship between Vickers hardness (FIG. 9) and relationship between coating layer thickness and peeling load (FIG. 1)
0) will be described.

FIG. 8 is a diagram showing magnetic characteristics (saturation magnetic flux density, magnetic permeability, coercive force) and Vickers hardness of the present invention.
Each amorphous coating pair is 100-500 μm thick. This is because it is difficult to strictly control the thickness of the coating layer formed on the surface of the drive shaft experimentally.
There is a range of up to 500 μm. However, as is clear from FIG. 9, the Vickers hardness is saturated when the thickness of the coating layer is 100 μm or more. Therefore, as data for comparing the Vickers hardness, if the thickness is 100 μm or more, there is no problem. .

FIG. 9 shows the relationship between the thickness of the coating layer and the Vickers hardness.
FIG. 3 is a diagram showing the relationship between the coating pair of the present invention (composition: Ni
₈₂B₁₈) Indicates the measured value, and the x mark indicates the conventional value (plating,
Composition: Ni₈₂B₁₈) Indicates the measured value, and the symbol Δ indicates the object of the present invention.
Overcoat (Composition: Fe₇₀Co₁₅B ₁₅) Indicates the measured value. ○ mark
Compare (invention) and x (conventional)
And, Vickers hardness is large at any thickness. One
It can be said that the present invention is harder than the conventional one.

FIG. 10 is a diagram showing the relationship between the thickness of the coating layer and the load when peeled. In this method, a drive shaft having a coating layer is rotatably installed in an air atmosphere at 120 ° C., and a load is applied on the surface of the coating layer through a plate material having a friction coefficient of 0.3 to 0.4. This is a plot of the minimum load among the peeled coating layers after rotating for 30 minutes in this state. ○ indicates the present invention (composition: N
i ₈₂ B ₁₈ ) x mark is conventional (plating, composition: Fe ₇₀ C
The measured value of o ₁₅ B ₁₅ ) is shown. For example, the thickness of the coating layer is 1
At 00 μm, the coating of the present invention did not peel off after rotating for 30 minutes under a load of 21 kg / mm ² , whereas the coating of the conventional one had 3.7 kg / mm ^2.
When the above-mentioned load was applied and rotated, the coating layers (plating layers) of all things peeled off. That is, in the case of the present invention, the coating layer is firmly fixed as compared with the conventional case (plating).

Further, according to the present invention (composition: Ni₈₂B₁₈)
Is the conventional one (plating, composition: Ni ₈₂B₁₈) Compared to
Scientific corrosion resistance improved by 5/10%. This is one rule (I
After soaking them in the hydrochloric acid solution of N) for 48 hours,
Weigh the oxides generated in each solution and compare
did. Then, the amount of oxide in the dipping solution of the present invention is 5
It can be seen from the fact that it was 10% less.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a torque sensor using an amorphous coating body of the present invention as a drive shaft.

FIG. 2 is a partial external view showing an arrangement state of exciting coils.

FIG. 3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is a partially enlarged view of FIG.

5 (a), (b), and (c) are diagrams showing distribution ratios of particle diameters of amorphous metal powders.

FIG. 6 is a diagram showing the composition of the amorphous metal powder and the magnetostrictive properties after the coating is formed.

FIG. 7 is a characteristic diagram showing the characteristics of the amorphous coating resistance of the present invention.

FIG. 8 is a diagram showing a composition of an amorphous coating body of the present invention.

FIG. 9 is a characteristic diagram showing characteristics of the amorphous coating body of the present invention.

FIG. 10 is a characteristic diagram showing characteristics of the amorphous coating body of the present invention.

[Explanation of symbols]

 1 Amorphous metal coating layer 4 Base material (torque sensor drive shaft)

Claims (4)

[Claims] 1. A coating layer of an amorphous metal is formed on the surface of a base material by subjecting an amorphous metal powder having a particle diameter of 0.01 to 200 μm to high energy velocity processing at a molding pressure of 0.7 to 80 GPa. A method for molding an amorphous coating, which comprises molding. 2. The amorphous metal is silicon,
A metal mainly containing at least one of iron, cobalt, nickel, chromium and boron.
A method for forming an amorphous coated body as described above. 3. The method for forming an amorphous coating body according to claim 1, wherein the high energy speed processing is performed in a reducing atmosphere. 4. An amorphous coating body comprising a base body and an amorphous metal coating layer formed by subjecting a surface of the base body to high energy velocity processing with a molding pressure of 0.7 to 80 GPa. .