JP2005256074A - Method for manufacturing metallic glass particulate and metallic glass pulverizing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulverizing technique capable of preventing the inclusion of metallic impurities and pulverizing metallic glass while maintaining a metallic glass structure. <P>SOLUTION: The metallic glass pulverizing apparatus 10 is equipped with a vessel 1 formed of an ultra-high molecular weight polyethylene and a rotating body 3 and pulverizes the metallic glass 11 in a thin belt form or powdery form which is an object for pulverization, by putting the metallic glass 11, pulverizing balls 12 made of an oxygen-base or non-oxide-base ceramic and a cooling liquid 50, such as liquid nitrogen or liquid helium or the like into the vessel 1, and rotating the rotating body 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a finely pulverized metal glass that can be used for various industrial applications such as catalysts and electrodes.

  Conventionally, as a method of pulverizing a metal at room temperature, a method of pulverizing by absorbing hydrogen or the like into a metal and making it brittle is known. Also known is a method of embrittlement of a metal at extremely low temperatures. By the way, in the technical field using the surface function of metallic glass, such as a catalyst and an electrode, it is practiced to use a thin or powdery metallic glass prepared by a method such as a liquid quenching method. However, because metallic glass has an amorphous structure with random atomic arrangement, it has high strength and toughness, so it is difficult to pulverize by applying the conventional pulverization method at room temperature. It is. Further, when hydrogen is used, there is a risk of explosion and the like, and the metal glass is crystallized because hydrogen is occluded at a high temperature. Furthermore, at a very low temperature, the metal material itself constituting the pulverizer may become brittle and be mixed into the metal glass as an impurity.

  In addition, as a technique related to the micronization of the metallic glass, plasma arc discharge is performed on the raw metal in a reaction gas mainly containing an inert gas and containing a hydrocarbon gas, and the evaporated metal and the plasma reaction gas are mixed. There has been proposed a method for producing amorphous metal ultrafine particles that are brought into contact with each other and carbon atoms are solid-dissolved in the evaporated metal, and are rapidly cooled in a reaction gas to be amorphized (for example, Patent Document 1). This method is a method in which micronization and amorphization are performed simultaneously, and it is not a method of refining an amorphous metal by pulverization.

JP-A-7-97607

  Accordingly, an object of the present invention is to provide a pulverization technique capable of preventing metal impurities from being mixed and finely pulverizing metal glass while maintaining the metal glass structure.

  The first aspect of the present invention is that a ribbon-like or powder-like metallic glass is cooled with liquid nitrogen or liquid helium, while an ultrahigh molecular weight polyethylene pulverizer and an oxide or non-oxide ceramics are used. A method for producing metal glass fine particles, characterized by grinding using a grinding ball.

  According to this method for producing fine metal glass particles, by using an ultra-high molecular weight polyethylene pulverizer and performing pulverization at a low temperature while cooling with liquid nitrogen or liquid helium, a desired crystallization can be achieved while preventing crystallization of the metal glass. Fine particles can be made up to size. In addition, since ultra-high molecular weight polyethylene does not become brittle even at low temperatures, there is no concern of impurities being mixed.

According to a second aspect of the present invention, there is provided a method for producing fine metal glass particles according to the first aspect, characterized in that pulverization is performed in an alcohol solvent.
In this second aspect, by using an alcohol solvent, the finely pulverized metal glass can be dispersed and made into fine particles in a stable state.

According to a third aspect of the present invention, there is provided a method for producing fine metal glass particles according to the first aspect or the second aspect, characterized in that pulverization is performed in the presence of a surfactant.
According to this 3rd aspect, the heat generation of the generated metal glass fine particles can be suppressed and stabilized by pulverizing in the presence of a surfactant.

According to a fourth aspect of the present invention, there is provided a rotating body made of ultra high molecular weight polyethylene having a container made of ultra high molecular weight polyethylene and a plurality of discs formed so as to be insertable into the container and integrally formed in a shaft portion. And, in the container, in a state where a ribbon-like or powdery metal glass and a pulverized ball are put, the rotating body is rotated to finely pulverize the metal glass. It is a metal glass pulverizer.
The metal glass pulverizing apparatus according to the fourth aspect can make the metal glass fine particles reliably with a simple configuration, and manufacture of the metal glass fine particles according to any one of the first to third aspects. An apparatus suitable for carrying out the method.

  According to the present invention, fine particles can be formed to a desired size while avoiding crystallization of metal glass and mixing of impurities.

  The metal glass to be microparticulated in the present invention is an alloy in an amorphous state although being a metal, and is made amorphous by utilizing the property of glass transition before crystallization in a temperature raising process. The method for producing a thin ribbon-like or powdery metallic glass is not particularly limited, and for example, those produced by a liquid quenching method typified by a single roll method or an atomizing method can be used. Here, the liquid quenching method is a method for producing an amorphous alloy by cooling a molten alloy at a faster rate than crystal nucleus growth occurs. Specifically, for example, a roller atomizing method, a water atomizing method, and the like. A method such as a gas atomizing method is known.

  The type of the metallic glass is not limited, and for example, a metallic glass of Pt—Ni—Zr, Pt—Ni—Zr—Pd, Ni—Zr, etc. can be targeted. These metallic glasses can be used as, for example, electrode materials, catalyst materials, corrosion-resistant materials, powder solidifying jig materials, etc., and those with adjusted elemental content ratios, etc., according to their final use. Provided.

  As a thin ribbon or powdery metal glass as a raw material, in the case of a thin ribbon, for example, a width of about 5 mm obtained by a roller atomizing method and a thickness of about 0.05 to 0.1 mm, in the case of a powder, for example, by a gas atomizing method Those having a particle size of about 10 to 100 μm can be suitably used.

  As a pulverizing apparatus made of ultra high molecular weight polyethylene, for example, a sand mill type pulverizing apparatus as shown in FIG. 1 (described later) can be used. Here, ultra high molecular weight polyethylene means polyethylene having a molecular weight of about 1 million to about 10 million. Ultra high molecular weight polyethylene is not easily embrittled even at low temperatures, can maintain sufficient rigidity, and does not cause a problem of impurity contamination into the metal glass because it is non-metallic.

  The pulverization is preferably performed in the presence of an alcohol solvent. By using an alcohol-based solvent, an effect of dispersing and maintaining the metal glass stably can be obtained. Examples of the alcohol solvent include isopropanol, 1-butanol, ethanol, methanol and the like.

  Further, it is preferable to add a surfactant during pulverization. The surfactant has an action to prevent heat generation of the metal glass fine particles. In particular, when an alcohol solvent such as isopropanol is used, the metal glass fine particles have an action of oxidizing the alcohol solvent, so that the metal glass fine particles themselves may generate heat and become coarse. By using a surfactant, it is possible to prevent the metal fine particles from becoming coarse.

  As the surfactant, a fluorine-based surfactant can be suitably used. Examples of the fluorosurfactant include FT 251, FTX-212M, FT 250, FTX-245M, FTX-290M (above, trade names; manufactured by Neos Co., Ltd.), and the like. For example, it is preferable to use aftergent 250, FTX-212M, FTX-245M, or the like.

  The surfactant is preferably added so as to be about 0.01 to 1% by weight, preferably about 0.2 to 0.5% by weight, based on the alcohol solvent. Further, the surfactant can be used in the form of an aqueous solution during slurrying after the pulverization step is completed. In this case as well, 0.01 to 1% by weight, preferably 0, as described above. Can be used as a 1-0.5 wt% solution.

  The pulverization step is performed while cooling with liquid nitrogen or liquid helium. Since heat is generated during pulverization, the temperature around the metal glass is considered to reach about −80 ° C. to −70 ° C., but this temperature range may be maintained during pulverization.

  After the pulverization step is completed, a cooling liquid such as liquid nitrogen is evaporated. When an alcohol solvent is added, it can be taken out as it is in a slurry state. When no alcohol solvent is added, it is preferable to evaporate the cooling liquid and then add an aqueous solution containing a surfactant to form a slurry. In these slurries, metal glass fine particles and pulverized balls are mixed, and thus the metal glass slurry can be obtained by separating the pulverized balls by means such as sieving.

  The finely pulverized metal glass obtained as described above has a particle size of about 10 to 100 nm and can be suitably used for applications such as electrode raw materials and catalyst raw materials.

  Next, the pulverizing apparatus of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a schematic configuration of a metal glass pulverizing apparatus 10 according to an embodiment of the present invention, and FIG. 2 is a drawing schematically showing a state during pulverization.

  The metal glass pulverizing apparatus 10 includes a container 1 and a rotating body 3. The container 1 has a cylindrical shape with an open top, and the material thereof is made of ultra high molecular weight polyethylene. The rotating body 3 has a shaft 5 and three disks 7a, 7b, 7c formed integrally with the shaft 5. The rotator 3 is made of ultra high molecular weight polyethylene as in the case of the container 1. When the metal glass pulverizing apparatus 10 is used, the rotating body 3 is inserted into the container 1 until the uppermost disk 7 a is hidden in the cylinder of the container 1. The arrow in FIG. 1 indicates the insertion / removal direction of the rotating body 3 with respect to the container 1. The shaft 5 is connected to a motor (not shown) and is configured to be able to rotate at a predetermined rotational speed.

  At the time of pulverization, pulverization is performed using a pulverization ball 12 made of an oxide or non-oxide ceramic. Here, examples of the oxide-based ceramics include zirconia, alumina, mullite, and silica. Examples of non-oxide ceramics include silicon carbide, aluminum nitride, and silicon nitride. As the pulverized balls 12 made of these materials, those having a diameter of about 0.05 to 0.2 mm can be used. By using a material made of oxide or non-oxide ceramics as the material of the pulverized ball 12, the pulverized ball 12 does not become brittle even at low temperatures, and impurities can be prevented from being mixed into the metal glass fine particles.

  In the metal glass pulverizing apparatus 10 having the above configuration, the metal glass 11 to be pulverized, the pulverized ball 12 and the cooling liquid 50 such as liquid nitrogen or liquid helium are placed in the container 1 and the rotating body 3 is rotated. The metal glass 11 is crushed. The rotational speed of the rotator 3 can be adjusted according to the type of the metal glass 11 and the target fine particle size. At the time of pulverization, since the cooling liquid 50 in the container 1 is reduced by evaporation, it is preferable to continue the pulverization while appropriately supplying the liquid.

  FIG. 3 is a drawing schematically showing a state during pulverization by the metal glass pulverizing apparatus 10 of the present invention. In this embodiment, the metal glass pulverizing apparatus 10 shown in FIG. At the time of pulverization, the metallic glass 11 to be pulverized, the pulverized ball 12 and the alcohol solvent 60 containing a surfactant are placed in the container 1, and the metal glass 11 is pulverized by rotating the rotating body 3. In addition, a cooling system 50 such as liquid nitrogen is filled in the gap between the heat insulating container 20 and the metal glass pulverizer 10 and cooling is performed from the outside of the metal glass pulverizer 10. Thus, by adopting an external cooling method and injecting the alcohol solvent 60 into the container 1, the metal glass 11 to be finely divided can be pulverized while being stabilized.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in more detail, this invention is not restrict | limited at all by this.
Example 1
Preparation of metal glass fine particles for electrodes:
1 is filled with zirconia beads (diameter 0.2 mm) in the container 1 until the uppermost disk 7a is hidden, and the metal glass electrode raw material [3Pt-40Ni-Zr (element % Ratio); shape 1 mm square, 0.1 mm thick piece] 1 g was added, and liquid nitrogen was further injected until the uppermost disk 7a was hidden.

  The rotating body 3 is rotated while adjusting the number of rotations so that the linear velocity is 4.7 m / sec. Since liquid nitrogen decreased by evaporation, it was replenished in a timely manner. After stirring for about 15 minutes, liquid nitrogen was evaporated, and a 1 wt% aqueous solution of a fluorosurfactant (Factent 250; manufactured by Neos Co., Ltd.) was added to obtain a slurry.

  The obtained slurry was sieved to separate the zirconia beads and the metal glass slurry. When this metal glass slurry was measured with a particle size distribution meter, it was confirmed to be a metal glass fine powder having a central particle diameter of 70 nm. This fine powder was heated in an oven at 70 ° C. for 24 hours to evaporate water, and the crystal structure was examined by an X-ray diffractometer. As a result, only a broad peak was observed and no crystal phase was confirmed.

Example 2
Preparation of metal glass fine particles for electrodes:
Similarly to FIG. 3, the heat insulating container 20 was filled with liquid nitrogen, and the pulverizing apparatus 10 was cooled from the outside. The container 1 is filled with zirconia beads (diameter 0.2 mm) until the uppermost disk 7a is hidden, and a metal glass electrode raw material [3Pt-40Ni-Zr (element% ratio); shape 1 mm square, thickness 0.1 mm About 1 g of debris was added, and isopropanol containing 1% by weight of a fluorosurfactant (Furgent 251; manufactured by Neos Co., Ltd.) was further injected until the uppermost disk 7a was hidden.

  The rotating body 3 was rotated while adjusting the rotational speed so that the linear velocity was 2.5 m / sec. Since liquid nitrogen decreased by evaporation, it was replenished in a timely manner. After stirring for about 15 minutes, the entire pulverizer was taken out and returned to room temperature, followed by sieving to separate the zirconia beads and the metal glass slurry. When this metal glass slurry was measured with a particle size distribution meter, it was confirmed to be a metal glass fine powder having a central particle diameter of 100 nm. This fine powder was heated in an oven at 40 ° C. for 24 hours to evaporate water, and the crystal structure was examined by an X-ray diffractometer. As a result, only a broad peak was observed and no crystal phase was confirmed.

  The present invention has been described above with reference to various embodiments. However, the present invention is not limited to the above embodiments, and can be applied to other embodiments within the scope of the invention described in the claims. It is.

  The present invention can be used for various applications using metallic glass, such as electrodes and catalysts.

The perspective view which shows the outline | summary of a metal glass pulverization apparatus. The schematic diagram explaining the state at the time of the grinding | pulverization of metal glass. The schematic diagram explaining the state at the time of the grinding | pulverization of the metal glass in another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Container 3 Rotating body 5 Axis 7a, 7b, 7c Disk 10 Metal glass fine grinding apparatus 11 Metal glass 12 Grinding ball 20 Thermal insulation container 50 Cooling liquid 60 Alcohol solvent

Claims (4)

  While thin ribbon or powdered metallic glass is cooled with liquid nitrogen or liquid helium, it is pulverized using a crusher made of ultrahigh molecular weight polyethylene and a pulverizing ball made of oxide or non-oxide ceramics. A method for producing metallic glass fine particles.   The method for producing fine metal glass particles according to claim 1, wherein pulverization is performed in an alcohol solvent.   The method for producing fine metal glass particles according to claim 1 or 2, wherein pulverization is performed in the presence of a surfactant. A container made of ultra high molecular weight polyethylene;
A rotating body made of ultrahigh molecular weight polyethylene that is formed so as to be insertable into the container and has a plurality of disks integrally formed on the shaft portion,
The metal glass is finely pulverized by rotating the rotating body in a state where a ribbon-like or powdery metal glass and a pulverized ball made of an oxide or non-oxide ceramic are put in the container. A metal glass pulverizing apparatus configured as described above.

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