JPS63227731A - Manufacture of porous amorphous-alloy compact - Google Patents

Abstract

PURPOSE:To easily manufacture a porous amorphous-alloy compact having high strength, by subjecting an amorphous alloy with a specific grain size to pressure sintering by specifying temp. and pressure, respectively. CONSTITUTION:The amorphous-alloy grains granulated by means of an agitation water cooling method, etc., are classified, and a pressing die is filled with the alloy grains of >=450mu grain size. At this time, as to the shape of the alloy grains, a flat flaky shape or irregular shape is preferred to a complete spherical shape. Subsequently, the alloy grains are heated to a temp. between (initial crystallization temp. -100 deg.C) and 100 deg.C, compacted at a pressure of >=100MPa, preferably >=400MPa, held for about 60-1,800sec, and pressure-sintered so as to be formed into a porous amorphous-alloy compact. Moreover, it is preferable that pressurization alone is temporarily released after pressure sintering and holding is applied at the above heating temp. for about 60-1,800sec to carry out no-load annealing. In this way, the porous amorphous-alloy compact having high porosity and strength can be easily manufactured.

Description

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

[Prior art and its problems]

Amorphous alloy compared to conventional crystalline gold JiA.

It exhibits excellent properties such as high strength, high wear resistance, high corrosion resistance, and high '11 magnetic coefficient, and is attracting attention as a coating material.
Many of them have already been put into practical use, but at present, the shape that allows amorphous alloys to be obtained is if Vf
It is limited to F-shaped, annular-shaped, powdered, etc. shapes, and in order for this amorphous alloy to be used more widely, it is important to overcome the shape limitations. Therefore, in order to obtain bulk amorphous alloys of arbitrary shapes, powder compaction conditions have been investigated using the impact gun method, explosive method, pressure sintering method, etc.; Because of the problems of requiring specialized equipment, complicated processes, and low productivity, the pressure sintering method, which can incorporate conventional powder metallurgy technology and has high mass productivity, is attracting attention.

However, since it is necessary to pressurize and sinter the powder while maintaining an amorphous state, the temperature cannot be raised above the crystallization initiation temperature during pressurization.

Therefore, unlike conventional pressure sintering of crystalline alloy powder,
Attempts have been made to utilize the significant viscous deformation characteristic of 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 green 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 manufacture this porous crimped body using conventional techniques;
Moreover, only a product with very low strength could 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 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. .

[Structure of the invention and its operation]

As a result of intensive investigation and research into various conditions for obtaining a porous amorphous alloy crimped body with high strength, the present inventors found that
The present invention has been completed, and its structure is 450 μm
The method is characterized in that the amorphous alloy particles classified as described above are heated to a temperature from below the crystallization start temperature of 100°C to 100°C 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 approximately 100 μm or more can be obtained by granulation by a stirring water cooling method. The present invention has 45 characteristics: such amorphous spherical alloy particles are filled into a press die, heated to a predetermined temperature, and sintered under pressure for a predetermined time.
The reason is that large amorphous alloy particles classified to 0 μm or more are used, and when these are pressurized, a larger contact load is generated at the contact surface between the particles than that of fine particles, causing viscous deformation, and the oxide film on one surface is Destruction increases adhesion. Therefore, pressure sintering can be performed even if the pressure temperature is extremely low, for example, about 100°C, and the permissible temperature range is widened, making it very easy to manufacture sintered bodies. Because of the high adhesion, 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.
For grain sizes less than 1 day, contact at the interface between alloy particles (1
The r weight is small and the oxidized IEJ on the surface is not destroyed.
However, since viscosity changes do not easily occur, the temperature at which pressure sintering can be performed is limited to an extremely narrow range close to the crystallization start temperature, and the sintered body has low strength and porosity, resulting in low alloy particles. It is preferable to have a flat flake or irregular shape rather than a perfect sphere because the adhesion strength will be stronger.The pressing force must be at least 100 MPa or more, and if it is less than 100 MPa, a good crimped body is obtained. It is preferable to use a pressure of 400 MPa or more, but even if this pressure is increased too much, there will be little improvement in the adhesion of the particles.On the other hand, the higher the temperature, the shorter the pressure time. However, it is generally more than 3 seconds.

Preferably, the time is 60 to 1800 seconds; if the time is unnecessarily extended beyond this, not only will the effect be less, but there is a risk of crystallization during pressurization.

A good sintered body can be obtained under the above pressure conditions.

Due to the unique properties of amorphous alloys, the viscosity of the alloy increases during the pressurization process, resulting in a phenomenon in which sufficient deformation does not occur, and densification tends to stagnate. Therefore, after performing pressure treatment, only the pressure is released,
It is preferable to perform no-load annealing by holding the heating temperature for another 60 to 1800 seconds.This annealing alleviates the increase in viscosity, and when pressurized 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, 1, for example, Pd-Ni-8
i, Pd-Ni-8i-B, Pd-Cu-8i, Pd-
Cu-8i-T3. Pd-N1-P.

Pd-N1-P-B, Pt-N1-P, Pt-Ni
Including noble metal alloys such as -P -Ij, Fe -
P-C, Fe-Si-B, Go-S
i-B, Go-Fe-8i-B, Co-Fe
-P-C, Fe-Zr, Go-Zr, Fe-Go-Zr
A compressed body of porous amorphous alloy such as iron group magnetic alloy, Ni-Zr, and pt-Zr alloy can be obtained.

〔Example〕

The present invention will be specifically explained below using Examples.

Example 1 Alloy composition is N i 114 P d ts P *a
A molten metal (hereinafter expressed as 64 at% Ni, 16 at% Pd, and 20 at% P; the same applies hereinafter) was granulated by a stirring water cooling method. FIG. 1 shows a schematic diagram of a stirred water cooling device, in which a molten metal 2 of an alloy is filled into a furnace body 1 such as a melting furnace or a heat-retaining furnace. The bottom of the furnace body 1 has an inner diameter of 300μ.
Attach the nozzle 3 of m and press the top surface of the molten metal 2 at 0°4 M P
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 is heated at a predetermined flow rate.
rotates. However.

The stirrer 5 was operated to rotate the cooling water 4 at a flow rate of 1.7 m/s, and the molten metal 2 was continuously injected into the cooling water 4 at a flow rate of 11 m/s to obtain amorphous spherical alloy particles. This was classified into 450-1000 micrometers, and the thing of size other than this was excluded.

FIG. 2 is a schematic diagram of the hot press equipment, and the furnace body 7
A large number of molybdenum heaters 8 are arranged inside, and a maraging steel die 9 is arranged in the center.

The temperature of the die 9 is measured by a thermocouple lO. This die 9 was filled with classified alloy particles 11, heated to a predetermined temperature, and pressurized from above and below at a pressure of 600 MPa for 1800 seconds using a ram 12 also made of maraging steel. Then, no-load annealing with only the pressure removed was performed at 1800
After a few seconds, pressure was applied again under the same conditions.

The 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. As a result, a porous amorphous alloy pressed body could be obtained even at Tp=100°C.

Its characteristics include a porosity of 48% and a compressive strength of 2.
30 Pa, and Vickers hardness was 700 DPN.

In this way, the porous amorphous alloy compacted body obtained can be manufactured at an extremely low pressurizing temperature Tp.

It has 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 crimped body was produced in the same manner as in Example 1 under the following conditions, and its properties were as follows.

Alloy type 117 Pd, Cu5Si1. B.

Cooling method Cooling method in stirred water Classification 1000-1600μm Pressure
600 MPa Pressure time 600 seconds annealing After 600 seconds annealing, re-pressing under the same conditions Pressing temperature Tp = 150°C Porosity 53% Compressive strength 2.0GPa Vickers hardness 450D1'N Low pressure as in Example 1 It was possible to obtain a porous amorphous alloy pressed body that could be produced at a temperature of 1 p and had a high porosity and strength.

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

Alloy type Go-BSltaBts Classification 450μm or less Pressure pressure 950 MPa Pressure time 600 seconds Pressure temperature Tp = 400℃ ('l'x = 500℃) Porosity 77% Compressive strength 2.5GPa Vickers hardness 850DPN Implementation As in Example 1, a porous amorphous alloy crimped body with a high void vK ratio and high strength could be obtained.

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

Alloy type Ni@4Pd1. P.

Cooling method Cooling method in stirred water Classification 100-300 tt m Pressure
600 MPa Pressure time 1800 seconds annealing Re-pressing under the same conditions after 1800 seconds annealing Pressing temperature Tp = 220-370℃ Porosity 20% Compressive strength 1, 3-1, 6 GPa Vickers hardness 650-670DPN In this comparative example, since the alloy particles are small, the pressing temperature '
1゛P was high and the range was narrow, and the porosity and strength were also low.

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

Alloy type 1! i P d7. c usS1x++I3
z Cooling method Stirred water cooling method Classification 200-400μm Pressure pressure 600MPa Pressure time 1800 seconds Annealing No pressurization temperature rp = 260-420℃ Porosity 24% Compressive strength 1.2-1.4GPa Vickers hardness: 400 to 450 DPN Also in this comparative example, since the 1 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 to produce 100 M P
Since it is pressurized at a pressure higher than a, it is possible to compress alloy particles at an extremely low temperature of about 100°C, and it is easy to manufacture, and has a high porosity and strength, making it an industrially extremely useful porous amorphous material. A method for manufacturing a pressed alloy 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... Stirrer 6... Cooling water tank 7... Furnace body 8... Heater 9... Dice lO ...Thermocouple 11...Alloy particle 12...
・Rum 13... Crucible 14... Roll 15
...Alloy 16...Small hole 17...Tank Applicant Masumoto Ken Sailor Fountain Pen Co., Ltd.

Claims (1)

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