JPH0346523B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing amorphous metal powder in high yield, rapidly, and in large quantities by an atomization method. It is known that an amorphous metal can be obtained by ultra-quenching molten metal, and that it has properties different from crystalline metals. For example, it has excellent mechanical strength and corrosion resistance, and It is known that alloys with a composition mainly composed of metals have excellent electromagnetic properties, and studies have been conducted to find practical applications for materials in the form of ribbons or thin wires that have the excellent properties of these amorphous metals. has been done. On the other hand, powdery amorphous metal is used when it is pressed into a molded body or dispersed in a resin. Some of these amorphous metal powders have a flake shape or a granule shape with sharp edges, about 1 to 2 mm in length and 20 to 50 μm in thickness. Flake-like amorphous metal powder is easy to manufacture, but when it is pressed into a compact, adjacent flake-like powders come into contact with each other on their surfaces, so a large amount of heat is generated during pressure bonding, and this heat generation can cause crystallization. However, since it is not possible to give a sufficient void ratio to the molded product after crimping, it is not suitable for products that require appropriate voids. Furthermore, when the powder is made into a fluidized bed or a fixed bed and used as a catalyst, since the powder is flaky, there are various problems such as control during operation and uneven pressure drop. Compared to the many problems associated with these flaky amorphous metal powders, it is difficult to manufacture granular amorphous metal powders (hereinafter referred to as amorphous metal powder), and it is difficult to produce granular amorphous metal powders (hereinafter referred to as amorphous metal powders). It is extremely difficult to obtain amorphous metal powder with a particle size of 100%, and it is only possible to obtain it by sorting out amorphous metal powder with a small particle size that occurs by chance. When amorphous metal powder is press-molded, adjacent powders come into contact with each other at points, so there is almost no heat generation during press-molding, and therefore no crystallization occurs. In addition, by appropriately blending powders and granules with different particle sizes, it is possible to obtain a compacted product with a small void ratio, and by pressure-molding powders with uniform particle sizes, it is possible to obtain a compact product with a large void ratio. A crimped molded body is obtained,
It also has good kneading properties with iron powder and the like. In this way, any application is possible depending on the purpose of the manufacturer. For example, in JP-A-54-76469, in order to produce amorphous metal powder using the atomization method, the flow rate of the cooling liquid flow is increased to 70 m/sec or more, and the cooling liquid flow rate is increased to 70 m/sec or more, and the cooling liquid flow rate is Liquid flow ratio 10
It is described that the particle size can be as small as ~40, and it is also described that amorphous powder or granules are sorted out by classification. However, with this method, the cooling capacity is very small, and it is quite difficult to turn the material into an amorphous state.Most of the parts are crystallized, and only the very fine amorphous material is sorted out by classification. However, the yield of amorphous powder is low and the cost is high. Furthermore, the diameter of the amorphous powder after classification is small, less than 30 μm, so it is inconvenient to handle, and even if it is pressed and molded, it is empty. It was not suitable as a manufacturing method because it was not suitable for products that had small cracks and required proper cracking, and required a complicated step of classification. In addition, JP-A-57-29504 and JP-A-57-29505 disclose that molten alloy flows in a layer of water formed on the inner wall surface of a rotating drum by centrifugal force generated by rotation. A method is described in which an amorphous powder is obtained by blowing out and rapidly solidifying the powder. However, since the water layer formed on the inner wall surface of the rotating drum is a laminar flow without substantial turbulence, the atomization effect of dividing the molten metal into powder particles is small.
Therefore, the cooling ability to become amorphous is also quite low.
Amorphous powder particles have only been obtained by selecting fine particles with a diameter of 100 μm or less only by classification. In view of these circumstances, the present inventors conducted a process in which all particles, including those of large size, were in an amorphous state, and the amorphous portion and the crystallized portion were separated by classification. As a result of intensive research aimed at providing a method for producing industrially useful amorphous metal powder with high yield, we have developed a method for jetting a molten metal stream from a nozzle into a cooling liquid jet stream under specific conditions. They have discovered that the above object can be achieved by cooling and solidifying the mixture, and have completed the present invention. That is, the present invention directs the molten metal flow from the nozzle in the following manner (a). This is a method for producing amorphous metal powder, which is characterized in that it is jetted into a cooling liquid jet stream and cooled and solidified under conditions that satisfy (b), (c), and (d). 800≦V≦6000 (a) Q/q≧50 (b) 0.04≦D≦0.15 (c) θ≧70 (d) (where V is the velocity of the cooling liquid jet flow (m/min),
Q is the flow rate of the cooling liquid jet flow (g/min), q is the flow rate of the molten metal flow (g/min), D is the nozzle hole diameter (mm), and θ is the cooling fluid jet flow and the molten metal flow ejected from the nozzle. Represents the angle (°) between ) According to the present invention, the diameter of the granular material is particularly about 50 μm.
All large particles up to about 400 μm in size can be obtained in an amorphous state. For this purpose, the velocity V (m/min) of the cooling liquid jet stream is set between 800 and 6000, and the ratio Q/ It is necessary that q is 50 or more, the nozzle hole diameter D (mm) is between 0.04 and 0.15, and the angle θ (°) between the cooling liquid jet flow and the molten metal flow jetted from the nozzle is 70 or more. be. If even one of the above manufacturing conditions is not satisfied, firstly, the cooling liquid jet flow velocity V (m/
If the molten metal (hereinafter referred to as molten metal) is less than 800, the molten metal (hereinafter referred to as molten metal) will be difficult to break up, the powder particle diameter will become large, and the cooling ability will decrease, so it will be difficult to become amorphous, and the powder will have a round shape. If the speed exceeds 6000, the cooling capacity of the cooling liquid jet flow reaches a ceiling, so there is no advantage to increasing the speed beyond 6000. Next, Q/q
If it is less than 50, the molten metal may jump out of the cooling liquid jet flow during cooling or crystallize, resulting in variations in quality of the produced powder or granules. In addition, if the nozzle hole diameter D (mm) is less than 0.04, the nozzle hole is likely to become clogged, shortening the life of the nozzle, and the argon blowing pressure becomes high, which may cause damage to the nozzle itself. In terms of pore size, some of the produced powder particles have a diameter exceeding 400 μm, and particles with a diameter of 400 μm or more tend to crystallize. Nozzle hole diameter D (mm) is 0.05~
A range of 0.13 is most preferred. Furthermore, as shown in Fig. 2, if the ratio L/D of the nozzle hole diameter D (mm) and its hole length L (mm) is set to 0.8 or less, the molten metal at the time of spouting becomes unstable and tends to atomize, especially 0.6
It is preferable to do the following. When L/D exceeds 0.8, the molten metal at the time of ejection is stabilized, and the molten metal is less likely to be divided by the cooling liquid jet flow, that is, atomized. Next, when θ is less than 70°, the molten metal jumps out of the cooling liquid jet liquid and is no longer cooled, resulting in crystallization. In particular, θ is preferably 80° or more. Next, the present invention will be explained using figures. FIG. 1 shows an apparatus showing one embodiment for carrying out the present invention,
1 is a quartz nozzle having a hole for ejecting a flow of molten metal; 2 is a nozzle for ejecting a flow of cooling liquid;
Reference numeral 3 designates a pipe or groove that serves as a flow path for the cooling liquid jet flow and the solidified powder, 4 a filter that separates the cooling liquid from the powder, and 5 a tank that receives the cooling liquid. The cooling liquid is pressurized to a predetermined pressure from the tank 5 by a cooling liquid pressurizing pump, cooled to a predetermined temperature, and then jetted from the cooling liquid jet jet nozzle 2 at a constant speed determined by the pressure. The molten metal jetting nozzle No. 1 is placed close to the upper surface of the cooling liquid jet stream with a certain degree of accuracy, and jets the molten metal from the nozzle into the cooling liquid jet stream under the pressure of an inert gas or the like. The ejected molten metal flow flows into the cooling liquid jet flow, is divided, rapidly solidified, and becomes an amorphous metal powder.The filter in step 4 separates the powder from the cooling liquid, and this cooling liquid is mixed with an appropriate cooling liquid. After being recooled to temperature, it is reused. The alloy used in the present invention may be any alloy as long as it has the ability to form an amorphous state. In addition, the rapid solidification process using the atomization method is different from that of the single roll method, twin roll method, and rotating liquid spinning method, in that the atomized powder is cooled over the front surface of the spherical surface. Moreover, since the cooling liquid jet flow is turbulent and extremely fast, no film boiling occurs around the molten metal, and the heat transfer conditions are extremely good, so the cooling rate is quite fast. Accordingly, the critical diameter at which amorphous material is formed also improves, and even alloys that have conventionally been difficult to form amorphous can be used. especially
Fe-Si-B alloy, Fe-P-C alloy, Fe-Ni
- Fe-based alloys such as Si-B alloys, Co-based alloys such as Co-Si-B alloys, Pd-Cu-Si alloys, etc.
A Pd-based alloy is preferable, and it is preferable to add a component such as Ni that lowers the viscosity of the molten metal or increases the surface tension. The cooling liquid used in the present invention includes, for example, water, alcohol, ethylene glycol, and liquids to which various salts are added, and are particularly inexpensive.
Moreover, water with high cooling ability is preferable. The powder or granular material obtained by the present invention preferably has a circularity in which the ratio of the major axis diameter to the minor axis diameter of the same cross section is about 3 or less. Since the amorphous powder obtained by the present invention is completely amorphous even in large particles with a diameter of about 50 μm to about 400 μm, it can be used as a useful industrial material by various molding methods. becomes. For example, by molding large-diameter powder and fine powder with a small void ratio, it is possible to obtain a material with excellent wear resistance and high hardness characteristic of amorphous materials. It is also useful as an electromagnetic shielding material and a neutron shielding material. Furthermore, when molding amorphous powder and granules with uniform diameters, the void ratio is large, so iron in oil, etc. should be used in adsorption filters for SOx and NOx gases, and in magnetic fields. Can be used in adsorption filters for removing powder. When used as a catalyst, the product distribution can be easily controlled by adjusting the filling rate, resulting in excellent selectivity. For powders and granules obtained in this way, where all the powders and granules are in an amorphous state, it is possible to create voids by combining powders and granules with various diameters of 400 μm or less, or by using powders and granules of a single diameter. And the void ratio can be adjusted arbitrarily, and it is widely used as a useful industrial material. Hereinafter, the present invention will be specifically explained using the present example. Examples 1 to 6, Comparative Examples 1 to 4 After melting an alloy having a composition of Fe ₇₅ -Si ₁₀ -B ₁₅ (atomic %) at 1400°C, the pore diameter D (mm) shown in Table 1 was obtained.
40g/using a quartz nozzle with nozzle hole length L (mm)
Argon gas blowing pressure 2.5 to 8.0 at molten metal of minutes (q)
The liquid was jetted into a cooling liquid jet stream at a pressure of (Kg/cm ² ) at an angle of Q/q, V, and θ (°) shown in Table 1, and was rapidly solidified. The cooling liquid was separated from the solidified powder using a filter, the powders obtained under various manufacturing conditions were classified, and their particle size distributions were measured, and the results shown in Table 1 were obtained. . Further, it was determined that it was amorphous because a clear halo pattern peculiar to amorphous was observed by X-ray diffraction.

[Table] From Table 1, in Examples 1 to 6, all the powder particles obtained were almost perfectly circular and amorphous, and the particle size distribution was also good, and the amorphous metal had a diameter of about 400 μm. Powder and granules have also been obtained. In particular, in Examples 5 and 6, the ratio L/D of the nozzle hole length L (mm) to the hole diameter D (mm) is small, and the molten metal is easily disturbed and easily divided. It is clear that the incident angle of the particles is also large, the state of publication of the particle size distribution has further improved, and it has become easier to obtain powder with the desired particle size. On the other hand, in Comparative Example 1, the flow rate Q of the cooling liquid jet flow was
(g/min) and molten metal particles q (g/min) is small, the cooling ability is reduced, and the molten metal is less likely to break up, so the crystallized part into powder particles with a diameter of 401 μm or more is It was seen. Comparative example 2 has nozzle hole diameter D (mm)
Since the flow rate of the molten metal was small, the nozzle hole was blocked and the molten metal could not be continuously spouted.
Since the flow rate of the cooling liquid jet stream was smaller than the flow rate, the molten metal passed through the cooling liquid jet stream and could not be cooled and solidified. In Comparative Example 4, an alloy having a composition of Fe ₆₈ -Si ₁₇ -B ₁₅ was used, and θ was set to 25° (all other conditions satisfying the present invention), so the obtained powder was Most of the particles were crystallized, and only amorphous particles with a diameter of 20 μm or less were obtained. Examples 7 to 12, Comparative Examples 5 to 8 After melting an alloy having a composition of Fe _67.5 −Ni ₁₀ −Si ₁₅ −B _7.5 (atomic %) at 1400°C, the pore size was 0.13 mm.
40g/min (q) using L/D0.6 quartz nozzle
Q/q, V and θ (°) shown in Table 2 for the molten metal of
The liquid was jetted into the cooling liquid jet stream at an angle of When the cooling liquid and the solidified powder were sorted by a filter, classified by a sieve, and their particle size distribution was measured, the results shown in Table 2 were obtained. Further, it was determined that it was amorphous because a clear halo pattern peculiar to amorphous was observed by X-ray diffraction.

[Table] From Table 2, it is clear that in Examples 7 to 12, all the powder particles were almost perfectly circular and amorphous, and the particle distribution was also good. On the other hand, in Comparative Example 5, the velocity V (m/min) of the cooling liquid jet flow was as low as 500 m/min, and the atomization effect was small. In Comparative Example 6, the ratio Q/q of the flow rate Q (g/min) of the cooling liquid jet flow to the molten metal flow rate q (g/min) is small, and although atomization has progressed somewhat, the cooling ability is low. Comparative Example 7 has a large nozzle hole and is difficult to atomize, so an amorphous product cannot be obtained. In Comparative Example 8, θ (°) was small, the atomization effect was small, linear cuts were mixed, and the shape was not constant. Example 3 Except for changing the alloy composition to Fe ₈₁ −Si ₄ −B ₁₄ −C ₁ ,
Powder was produced under the same conditions as in Example 1. As a result, the particle distribution was 1% between 200 μm and 151 μm;
150-101μm 1%, 100-51μm 40%, 50μm
The following were 58%, all of which were almost perfectly round and amorphous. Example 4 Powder was produced under the same conditions as in Example 1 except that the alloy composition was changed to Fe ₆₈ -Si ₁₀ -B ₁₅ -Cr ₈ . As a result, the particle distribution was 8% between 200 μm and 151 μm;
150-101μm 26%, 100-51μm 60%, 50μm
The percentage below was 6%, and all of them were almost perfectly round and amorphous.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an apparatus showing one embodiment of the present invention, and FIG. 2 is a partial cross-sectional view of a molten metal jetting nozzle. 1...Nozzle for spouting molten metal, 2...Nozzle for spouting cooling liquid jet, hole diameter of D...1, L...1
hole length.

Claims (1)

[Scope of Claims] 1 The following (a), (b), (c) and
A method for producing amorphous metal powder, which comprises jetting it into a cooling liquid jet flow and cooling and solidifying it under conditions that satisfy (d). 800≦V≦6000 (a) Q/q≧50 (b) 0.04≦D≦0.15 (c) θ≧70 (d) (where V is the velocity of the cooling liquid jet flow (m/min),
Q is the flow rate of the cooling liquid jet flow (g/min), q is the flow rate of the molten metal flow (g/min), D is the nozzle hole diameter (mm), and θ is the cooling fluid jet flow and the molten metal flow ejected from the nozzle. Represents the angle (°) between )