JPH05455B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a pressed porous amorphous alloy body.

[Prior art and its problems]

Compared to conventional crystalline metals, amorphous alloys are
It exhibits excellent properties such as high strength, high wear resistance, high corrosion resistance, and high magnetic permeability, and is attracting attention as an industrial material, and many of them are already in practical use. However, the shapes that can be obtained from amorphous amorphous alloys are currently limited to ribbons, thin lines, powders, etc., and in order for this amorphous amorphous alloy to be used more widely, it is necessary to overcome the shape constraints. This is very important. For this reason, in order to obtain bulk amorphous amorphous alloys of arbitrary shapes, powder compaction conditions have been investigated using the impact gun method, explosives method, pressure sintering method, etc. However, the impact gun method and the explosives method have special Because of the problems of requiring specialized equipment, complicated processes, and low productivity, the pressure sintering method is attracting attention because it can incorporate conventional powder metallurgy technology and has high mass productivity.

However, since it is necessary to pressurize and sinter the powder while maintaining the amorphous state, the temperature cannot be raised above the crystallization initiation temperature during pressurization. For this reason, unlike conventional pressure sintering of crystalline alloy powder, attempts have been made to utilize the remarkable viscous deformation peculiar to amorphous alloys that occurs below the crystallization initiation temperature. However, it has been found that the viscosity of the amorphous alloy increases during pressurization, making it difficult to perform sufficient pressure sintering. As a result, it was necessary to thoroughly examine the pressurizing conditions under which the amorphous alloy compact could be formed.

By the way, if a porous compressed body using amorphous alloy powder can be obtained, it is possible to obtain a new material that is lightweight and has excellent properties such as high wear resistance, high corrosion resistance, and high magnetic permeability. Possible applications include materials, catalyst materials, aggregates for composite materials, and magnetic core materials. However, it is difficult to produce this porous crimped body using conventional techniques, and only those with very low strength can be obtained.

[Purpose of the invention]

Therefore, the purpose of the present invention is to develop a method for manufacturing a high-strength porous amorphous amorphous alloy compressed body by pressure sintering, and to establish a method for manufacturing a new industrial material that utilizes the physical properties unique to amorphous amorphous. .

[Structure of the invention and its operation]

The present inventors have completed the present invention as a result of intensive investigation and research into various conditions for obtaining a porous amorphous alloy crimped body with high strength. From 100℃ below the crystallization start temperature of particles to 100℃
It is characterized by being heated to a temperature of up to ℃ and pressurized at a pressure of 100 MPa or more.

The amorphous alloy particles used can be produced by various rapid solidification apparatuses. For example, amorphous spherical alloy particles having a particle size of about 100 μm or more can be obtained by granulation using a stirring water cooling method. Such amorphous spherical alloy particles are filled into a pressurizing die, heated to a predetermined temperature, and sintered under pressure for a predetermined time. The feature of the present invention is the use of large amorphous alloy particles classified to 450 μm or more, and when these are pressurized, a larger contact load is generated at the contact surface between the particles than with fine particles, causing viscous transformation. , the oxide film on the surface is destroyed and the adhesion is increased. Therefore, the pressurizing temperature is
For example, it is now possible to perform pressure sintering even at an extremely low temperature of around 100°C, which makes it very easy to manufacture sintered bodies because of the wide allowable temperature range, and because the adhesion is high, It is possible to produce a porous amorphous alloy compressed body with high strength despite having a large porosity. Note that if the pressing temperature is higher than 100° C. or less from the crystallization start temperature, the porosity will be small and the desired porous sintered body will not be obtained. When the particle size is less than 450 μm, the contact load at the contact surface between the alloy particles is small, the oxide film on the surface is difficult to break, and viscosity changes do not occur easily, so the temperature at which pressure sintering is possible is low enough for crystallization. It is limited to an extremely narrow range close to the starting temperature, and the strength of the sintered body is low and the porosity is also small. As for the shape of the alloy particles, it is preferable to have a flat flake shape or an irregular shape than a perfect spherical shape because the adhesion strength will be stronger.
Next, the pressing force must be at least 100 MPa or more, and if it is less than 100 MPa, a good crimped body cannot be obtained. Preferably, the pressure is 400 MPa or more, but
Even if this pressing force is increased too much, there is little improvement in the adhesion of the particles. On the other hand, the higher the temperature, the shorter the pressurization time, but it is generally 3 seconds or more, preferably 60~60 seconds.
1800 seconds is good; if you make it longer than that, not only will it be less effective, but there is a risk of crystallization during pressurization.

Although a good sintered body can be obtained under the above pressure conditions,
Due to the unique properties of amorphous alloys, a phenomenon has been found in which the viscosity of the alloy increases during the pressurization process and sufficient deformation does not occur, and therefore densification tends to stagnate. Therefore, after the pressure treatment has been performed, it is preferable to release only the pressure once and hold the heating temperature for an additional 60 to 1800 seconds to perform no-load annealing. This annealing alleviates the increase in viscosity, and when pressure is applied again, the pressure is sufficiently transmitted and the adhesion strength increases. If necessary, this pressing and annealing operation is repeated to perform multi-step pressure sintering, thereby producing a porous amorphous alloy compressed body having a predetermined porosity and strength.

By the manufacturing method described above, for example, Pd-
Ni-Si, Pd-Ni-Si-B, Pd-Cu-Si, Pd-
Cu-Si-B, Pd-Ni-P, Pd-Ni-P-B,
Including noble metal alloys such as Pt-Ni-P, Pt-Ni-P-B, Fe-P-C, Fe-Si-B, Co-Si-
B, Co-Fe-Si-B, Co-Fe-P-C, Fe-
Iron group magnetic alloys such as Zr, Co-Zr, Fe-Co-Zr,
A porous amorphous alloy crimped body such as Ni-Zr or Pt-Zr alloy can be obtained.

〔Example〕

The present invention will be specifically explained below using Examples.

Example 1 Alloy composition is Ni ₆₄ Pd ₁₆ P ₂₀ (Ni is 64 atomic%, Pd is
16 atomic % and P is 20 atomic % are expressed like this.
same as below. ) was granulated by cooling in stirring water. FIG. 1 shows a schematic diagram of a stirred water cooling device. A molten metal 2 of an alloy is filled into a furnace body 1 such as a melting furnace or a heat retention furnace. The bottom of the furnace body 1 has an inner diameter of 300 μm.
Attach the nozzle 3 and pressurize the top surface of the molten metal 2 with argon gas of 0.4 MPa. A stirrer 5 is installed at the center of the bottom of the cooling tank 6, and cooling water 4 is contained inside. When the stirrer 5 is operated, the cooling water 4 rotates at a predetermined flow rate. Then, the stirrer 5 is operated to rotate the cooling water 4 at a flow rate of 1.7 m/s, and the molten metal 2 is continuously rotated through the cooling water 4 at a flow rate of 11 m/s.
Amorphous spherical alloy particles were obtained.
This was classified into 450 to 1000 μm, and those of other sizes were excluded.

FIG. 2 is a schematic diagram of the hot press apparatus, in which a large number of molybdenum heaters 8 are arranged in the furnace body 7, and a maraging steel die 9 is arranged in the center. The temperature of the die 9 is measured by a thermocouple 10. This die 9 is filled with classified alloy particles 11 and heated to a predetermined temperature,
Pressure was applied from above and below at a pressure of 600 MPa for 1800 seconds using a ram 12 also made of maraging steel. and,
After performing no-load annealing for 1800 seconds with only pressure removed, pressure was applied again under the same conditions.

This pressurizing temperature Tp was varied to various temperatures below the crystallization start temperature Tx, and temperature conditions under which a porous amorphous alloy compact could be obtained were determined. the result,
A porous amorphous alloy crimped body could be obtained even at Tp=100°C. Its characteristics were a porosity of 48%, a compressive strength of 2.3GPa, and a Vickers hardness of 700DPN. In this way, the pressurizing temperature Tp
can be produced at extremely low temperatures, and the resulting porous amorphous amorphous alloy compacts have high porosity and compressive strength, and can be used in a wide range of applications such as filter media, catalyst materials, and electrode materials.

Example 2 A porous amorphous alloy pressed body was produced in the same manner as in Example 1 under the following conditions, and its properties were as follows.

Alloy type Pd ₇₇ Cu ₆ Si ₁₆ B ₁ Cooling method Stirred water cooling method Classification 1000 to 1600μm Pressure pressure 600MPa Pressure time 600 seconds annealing After 600 seconds annealing, repressing under the same conditions Pressing temperature Tp = 150℃ Porosity 53% Compressive strength 2.0GPa Bitkers hardness 452DPN Can be manufactured at a low pressurizing temperature Tp as in Example 1,
A porous amorphous alloy compact with high porosity and strength could be obtained.

Example 3 A porous amorphous amorphous alloy pressed body was produced under the following conditions, and the amorphous amorphous alloy particles used were granulated by a cavitation method. FIG. 3 shows a schematic diagram of a cavitation granulation device. After the alloy 15 is melted in the quartz tube crucible 14, it is ejected from the small hole 16 at the tip of the crucible 14 into the gap (approximately 200 μm) between a pair of silicon nitride rolls 14, and the molten metal is divided into particles. The separated particles are rapidly cooled by the liquid in the tank 17.

Alloy type Co ₇₅ Si ₁₀ B ₁₅ minutes Class 450μm or less Pressure pressure 950MPa Pressure time 600 seconds Pressure temperature Tp = 400℃ (Tx = 500℃) Porosity 77% Compressive strength 2.5GPa Vickers hardness 850DPN Same as Example 1 We were able to obtain a porous amorphous alloy crimped body with high porosity and strength.

Comparative Example 1 A porous amorphous alloy pressed body was produced under the following conditions, and its properties were as follows.

Alloy type Ni ₆₄ Pd ₁₆ P ₂₀ Cooling method Stirred water cooling method Classification 100 to 300 μm Pressure pressure 600 MPa Pressure time 1800 seconds annealing After 1800 seconds annealing, repressing under the same conditions Pressing temperature Tp = 220 to 370℃ Porosity 20% Compressive strength 1.3~1.6GPa Bitkers hardness 650~670DPN In this comparative example, since the alloy particles are small, the pressing temperature Tp required to obtain good results is high and narrow, and the porosity and strength are also low and Ta.

Comparative Example 2 A porous amorphous alloy pressed body was produced under the following conditions, and its properties were as follows.

Alloy type Pd ₇ Cu ₆ Si ₁₆ B ₁ Cooling method Stirred water cooling method Classification 200 to 400 μm Pressure pressure 600 MPa Pressure time 1800 seconds Annealing No pressurization temperature Tp = 260 to 420℃ Porosity 24% Compressive strength 1.2 to 1.4GPa Vickers hardness 400-450DPN Also in this comparative example, since the alloy particles were small, the pressing temperature Tp required to obtain good results was high and narrow, and the porosity and strength were also low.

〔Effect of the invention〕

As explained above, the present invention uses amorphous alloy particles classified to 450 μm or more.
Since it is pressurized at a pressure of 100 MPa or more, it is possible to press the alloy particles at an extremely low temperature of about 100°C, making it a porous amorphous amorphous material that is easy to manufacture and has high porosity and strength, making it extremely useful industrially. A method for producing an alloy crimped body can be established.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a stirring water cooling device, FIG. 2 is a schematic diagram of a hot press device, and FIG. 3 is a schematic diagram of a cavitation granulation device. 1... Melting furnace, 2... Molten metal, 3... Nozzle, 4
...Cooling water, 5...Agitator, 6...Cooling water tank, 7
... Furnace body, 8 ... Heater, 9 ... Dice, 10 ...
... Thermocouple, 11 ... Alloy particles, 12 ... Ram, 1
3... Crucible, 14... Roll, 15... Alloy,
16...small hole, 17...tank.

Claims (1)

[Claims] 1. A method for producing a porous amorphous alloy crimped body, which comprises heating amorphous amorphous alloy particles classified to 450 μm or more from a crystallization initiation temperature of 100°C to 100°C and pressurizing them at a pressure of 100 MPa or more. .