JP2507716B2 - Process for producing flaky amorphous alloy powder - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing flaky amorphous alloy powder.

[Prior Art] Amorphous alloys are known to have excellent soft magnetism due to the absence of crystalline magnetic anisotropy, and to have unique mechanical and chemical properties due to the uniformly disordered atomic structure. .
Conventionally, it was provided in the form of a ribbon, but in recent years, amorphous alloys such as fine wires and powders have been obtained, and its application range is expanding.

In particular, the amorphous powder is attracting attention because it has the possibility of being developed into a bulk amorphous alloy by powder molding, a composite material, and the like.

In particular, when used as a filler used in a composite material such as a composite material with rubber or plastics or a pigment such as a paint, a flake shape is preferable as a powder shape.

Alternatively, as disclosed in JP-A-55-133507, an example of using flaky powder to improve the magnetism of a powder compact is also disclosed.

Conventional methods for producing flaky amorphous alloy powder are classified into two types. One is a method of injecting a molten alloy from a slit-shaped nozzle, solidifying it on a high-speed rotating body to form a ribbon, and mechanically crushing this (for example, the above-mentioned JP-A-55-1335).
No. 07, JP-A-58-197205), one of which is to inject a molten alloy from an orifice-shaped nozzle. (Kaisho 58-6907) or controlling the shape of a rotating solid (Japanese Patent Laid-Open Nos. 59-170208 and 59-212150)
By doing so, flaky powder is directly obtained from the molten metal.

However, although the former method for crushing thin strips is relatively mass-producible for producing thin strips, the number of man-hours for cutting the thin strips before crushing is large, and the material before crushing is on the order of several mm square. Therefore, the number of crushing steps is large, and the average particle size after crushing is also
It was only 10 μm. The latter method of directly obtaining flaky powder from the molten metal has a small nozzle diameter of a few tenths of mmφ,
Since the life of the nozzle was short, it was impossible to increase the capacity.

[Problems to be solved by the invention]

An object of the present invention is to provide a method for producing a flake amorphous alloy powder having a small particle size, which is easy to increase in capacity and has good pulverization efficiency.

[Means for solving problems]

The present inventor has conducted extensive studies to solve the problems of the method for producing flaky amorphous alloy powder by the above-mentioned conventional method, and mechanically pulverizes the irregularly shaped amorphous alloy powder obtained by the water atomizing method. As a result, they have found that a flake-shaped amorphous alloy powder having a large capacity, excellent pulverization efficiency, and small particle size can be obtained, and the present invention has been completed.

As a first step of the present invention, a method for obtaining irregularly shaped powder of an amorphous alloy by a water atomizing method is disclosed in JP-B-54.
It is publicly known such as in -76469. Especially the flow rate of water /
Various amorphous alloy powders can be obtained in a wide particle size range by increasing the flow rate ratio of the molten metal and increasing the water flow velocity and water pressure.

The alloy raw material used in the present invention can be in a wide range such as an alloy which is a combination of a metal and a semimetal, a metal and a metal such as a transition metal, a transition metal and a rare earth metal, and the like. In particular, a transition metal or a noble metal containing 15 to 30 atom% of a non-metal element of Group IV or Group V is typical, for example, (F
Examples include alloys of (e, Co, Ni) and (P, B, C, Si, Ge), and alloys in which various transition elements are added.

The melt of these amorphous alloys is deformed by the shearing force of the water of the atomizing medium, solidifies in an irregular shape with a significantly disturbed interface, has a high specific surface area, and has a substantially thin wall thickness. Therefore, it is easily mechanically ground. In order to obtain a flake-like powder, strong crushing conditions are used, or more preferably, crushing is performed in the presence of a grinding aid. As the crushing equipment, for example, a stamp mill method, a vibration mill method, and an attritor method can be applied. Among them, crushing with an attritor, which has the highest input energy, is the most efficient and has the smallest particle size.

The grinding aid used in the present invention has the effect of adsorbing on the surface of powder particles activated with the progress of grinding, suppressing the aggregation of the particles, and promoting the production of flaky powder. Effective solid auxiliaries include higher fatty acids such as stearic acid, oleic acid, lauric acid and palmitic acid, metallic soaps such as zinc stearate, calcium stearate, zinc laurate and aluminum laurate, stearic alcohol and higher fatty acids. Higher fatty acid amines such as group alcohols, ethanolamine, stearylamine,
Polyethylene wax and the like may be added alone or in combination of two or more. The addition amount is usually 0.1 to 5
It is 0% by weight. Further, as the liquid auxiliary agent, an organic solvent such as alcohol, glycol or ester can be used.

As described above, the present invention has found that it is possible to efficiently produce a flaky amorphous alloy powder having a small particle size by mechanically pulverizing the irregularly shaped amorphous alloy powder obtained by the water atomizing method. It is a thing. The obtained flaky powder is classified using a sieve, but it is preferably passed through 350 mesh.

Such fine flakes are optimal for pigments such as paints, especially for electromagnetic wave shielding paste, and because of their excellent dispersibility and orientation, they are composite materials with plastics and rubber, such as magnetic materials. Suitable for fillers such as plastics and magnetic rubber. It can also be used in a wide range of applications as a material for composite materials and a material for powder metallurgy.

〔Example〕

 The invention is further illustrated by the examples.

Example 1 Average particle size 100 μm obtained by water atomizing method,
Irregularly shaped Fe ₇₅ Si ₁₀ B ₁₅ amorphous alloy powder having an apparent density of 1.6 g / cm ³ was crushed by an attritor. The crushing condition is that the weight ratio of SUJ2 balls and water atomized powder is 10
As a crushing agent, ethyl alcohol and stearic acid were added as grinding aids in an amount of 1% of the powder weight. When pulverized at 300 rpm for 3 hours, a flake amorphous alloy powder according to the present invention having 350 mesh and 93% pass was obtained.

For comparison, the thickness obtained by the single roll method is about 22.
Amorphous alloy ribbon of the same component of μm is cut by a cutting machine.
When cut into 2.5 mm square and crushed for 3 hours under the above conditions,
Although crushing progressed into flakes, only 10% passed through 350 mesh. Grinding was continued, but the powder that passed through 350 mesh after 24 hours in total was 16
%Met.

Example 2 (Co ₉₄ Fe ₆ ) _77.5 Si ₁₀ B with an irregular shape having an average particle size of 80 μm and an apparent density of 2.0 g / cm ³ obtained by a water atomizing method.
_12.5 Amorphous alloy powder was ground with an attritor. The grinding conditions were such that the weight ratio of the SUJ2 balls and the water atomized powder was 10: 1, and oleic acid was added as a grinding aid at 2% of the powder weight. When pulverized at 300 revolutions per minute for 6 hours, a flake amorphous alloy powder according to the present invention having 350 mesh and 90% pass was obtained.

For comparison, the thickness obtained by the single roll method is about 18
Amorphous alloy ribbon of the same component of μm is cut by a cutting machine.
When cut into 2.5 mm square and crushed under the above conditions for 6 hours,
Although crushing progressed into flakes, only 7% passed through 350 mesh. Grinding was continued, but 15% of powder passed through 350 mesh after 48 hours in total.
Met.

Example 3 Average particle size of 115 μm obtained by water atomization method,
Irregularly shaped Fe ₈₀ P ₁₄ C ₆ amorphous alloy powder with an apparent density of 1.4 / cm ³ was pulverized by a vibration mill.

The crushing conditions were as follows: the weight ratio of carbon steel rod and water atomized powder was 25: 1, and the amplitude was 8 mm at 1200 rpm,
It was eccentrically rotated. This alloy easily oxidizes, so Ar
Only gas filled, no grinding aid was used. 5
After pulverizing for a time, a flake amorphous alloy powder according to the present invention having 350 mesh and 71% pass was obtained.

Thickness of about 20μ obtained by single roll method for comparison
Approximately 2.
When cut into 5 mm square and crushed under the above conditions for 5 hours, 350
Only 6% passed through the mesh. The powder was subsequently pulverized, but the powder passing through 350 mesh after 40 hours in total was 8%.

〔The invention's effect〕

As described above, according to the method for producing the flaky amorphous alloy powder of the present invention, it is possible to efficiently produce the flaky powder having a small particle size, and the method for increasing the capacity easily. Has great value.

Claims (3)

(57) [Claims] 1. A method for producing flaky amorphous alloy powder, which comprises mechanically pulverizing irregularly shaped amorphous alloy powder obtained by a water atomizing method. 2. The method for producing flaky amorphous alloy powder according to claim 1, wherein the mechanical pulverization is carried out in the coexistence of a pulverization aid. 3. The method for producing flaky amorphous alloy powder according to claim 2, wherein the powder is pulverized using an attritor.