JPH03281710A - Manufacture of alloy powder - Google Patents

Abstract

PURPOSE:To safely manufacture hydrogen occlusion alloy powder at a low cost by mixing oxide powder of rare earth metal or this alloy to metal or this oxide powder of Co, Ni, etc., adding Ca, Mg, Li, etc., to this and executing heat treatment to it. CONSTITUTION:To the metal or this oxide powder of at least one kind of Co and Ni, the oxide powder of rare earth metal or this alloy of at least one kind of La and mish metal is mixed at the prescribed ratio and if necessary, further the metal or this oxide powder of at least one kind of Mn, Cu and Al is mixed. Successively, to this mixed material, the metal or the oxide powder of at least one kind of Ca, Mg and Li is added at the prescribed ratio. After that, the heating treatment is executed to this. It is desirable that this treatment is executed at about 900 - 1,450 deg.C under vacuum or inert gas atmosphere. By this method, the hydrogen occlusion alloy powder containing the rare earth metal is easily obtd. at a low cost.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing alloy powder containing rare earth metals,
In particular, oxide powder of rare earth metals or alloys and other metals or their oxide raw materials are used as starting materials, and these are heat-treated.Alloy powder is excellent in productivity, economy, and safety, and also has good product characteristics. Regarding the manufacturing method, it is used as a hydrogen storage alloy in batteries, heat vibrators, etc.

[Prior Art] Conventionally, as a method for producing hydrogen storage alloy powder containing rare earth metals, a raw material consisting of a rare earth metal oxide or the like is reduced to a rare earth metal, and then a rare earth metal is produced.
As proposed in Japanese Patent No. 4337, rare earth metals are melted in a high frequency vacuum melting furnace and Nl, Co, and Mn are alloyed therewith.

A metal such as AJ is added to alloy the two. Next, after casting, an alloy ingot is obtained, and this is crushed and powdered using a crusher, or a method is adopted in which the alloy ingot is crushed and powdered by absorbing and releasing hydrogen into the alloy. ing.

[Problems to be Solved by the Invention] However, as described above, in the conventional production of hydrogen storage alloy powder containing rare earth metals, (1) production of rare earth metals by reducing raw materials made of rare earth metal oxides, etc. A four-step process is required: (2) melting and alloying of rare earth metals and other metals in a vacuum or inert atmosphere, (3) casting process, and (4) pulverizing the alloy ingot. becomes.

For this reason, each process requires equipment and operation costs, resulting in poor productivity and economic efficiency.

In addition, since alloys containing rare earth metals are highly susceptible to oxidation, when mechanical pulverization is used as a pulverization process, oxidation may occur to some extent, which may affect the properties of the alloy. On the other hand, although hydrogen pulverization can suppress oxidation of the alloy, there are problems such as the danger of using hydrogen, which is a flammable gas, and the need for a large amount of investment to install safety equipment.

The purpose of the present invention was made in view of the problems of the prior art, and it is not only to significantly reduce manufacturing costs and improve productivity and economic efficiency, but also to reduce the risk of oxidation and danger of alloy powder during pulverization. An object of the present invention is to provide a method for producing hydrogen storage alloy powder containing rare earth metals that prevents the above.

[Means for Solving the Problems] The above object of the present invention is to reduce a rare earth metal or an alloy oxide and other metal oxides, an alloying process of a rare earth metal and other metals, and a powder. This is achieved by carrying out the oxidation step in one step.

That is, the present invention provides at least one metal selected from Co and Ni or an oxide powder thereof, and an oxide powder of at least one rare earth metal or alloy selected from La and Mitshu metal, or in addition to Mn. ,
It is characterized by mixing at least one metal or oxide powder selected from Cu and AU, adding at least one metal selected from Ca, Mg, and Ll, and heat-treating the mixture. In the method for producing alloy powder.

In the present invention, at least 1 selected from Co, Ni
A seed metal powder (B component) or its oxide powder (B+ component) is used. These become the core of the gap in the heating reaction and become the base metal of the alloy powder.

In the present invention, L is added to these metals or their oxide powders.
a, at least one rare earth metal or alloy selected from Mitsushi metal (hereinafter abbreviated as Mll);
Component A) oxide powder (A + acid component is mixed. At this time, at least one metal powder selected from Mn, Cu, Al (C component) or its oxide powder (C + acid component is mixed. Good too.

The mixing ratio of the B (B+) component, the A1 component, or the C (C+) component in addition to these components is selected as appropriate to the chemical theoretical equivalent (composition) that allows the finally obtained hydrogen storage alloy powder to exhibit hydrogen storage performance. be done. - Generally, the hydrogen storage alloy powder is blended to have the following chemical theoretical equivalents.

That is, each component of A-C is A B 5. AB,
The raw materials are mixed in such a proportion that the final result is -08.

It is preferable.

In the present invention, these B (B+) components, A, components,
Or in addition to this, Ca
, Mg, Ll (D
ingredients). Component D is used in the form of powder, granules, or square pieces, and contains the above-mentioned rare earth metal or alloy oxide powder (A+acid component, or in addition to this, other metal oxide powders (B+ component, C1 component). Reduce rare earth metal or alloy powder (component A) or other metal powder (
The amount added must be at least the chemical theoretical equivalent required to reduce rare earth metal or alloy oxide powder and other metal oxide powder, and preferably Add at least 1.3 times the chemical theoretical equivalent.

Next, in the present invention, the B (B+) component, the A1 component, the D component, or in addition to these, the C (C1) component is heat-treated.

The heating temperature needs to be higher than the melting point of each component A, C, D, and lower than the melting point of each component A, B, B, C, and the desired temperature is determined from the melting point of each component. is selected. A typical heating temperature is 900-1450°C.

If the heating temperature is less than 900°C, co, Ni, which becomes the nucleus of the reaction,
At least one kind of metal powder (B component) selected from
Diffusion of the rare earth metal or alloy powder (component A) into the reactor is difficult, and if the temperature exceeds 1450° C., the component B, which is the core of the reaction, may melt. The heating time at this time is preferably 1 to 6 hours.

Further, the heating atmosphere here is a vacuum or an inert gas atmosphere.

The alloy powder thus obtained is, for example, AB, , A
It has a chemical theoretical equivalent such as Bs-m C. Here, X preferably has a range of 0 to 5.

In addition, the particle size of the alloy powder is determined by the B (B+) component, C (C
1) A product having a desired particle size distribution can be obtained by adjusting the particle size of the components.

[Action] B (B+) component, A1 component, or in addition to this, C
The (C+) component is blended in a proportion that will finally have the chemical theoretical equivalent (composition) described above, and the D component is added to this in a chemical theoretical equivalent equivalent to reduce the oxide, preferably 1.3 times or more, By heating in an atmosphere at a predetermined temperature, A1
The components or in addition B, component, and CI acid component are reduced, and the B component and C component are melted.

Next, A+B component or A is placed around the B component in a solid state.
A +B+C sufficient component alloy layer is formed, and the A component or A+C component is successively diffused into the B component to obtain an alloy powder.

[Example] Hereinafter, the present invention will be specifically explained based on Examples and the like.

Example 1 As shown in Table 1, lanthanum oxide powder (component A) and nickel powder (component B) were mixed so that the final chemical equivalent (composition) was LaNI, and calcium Powder (component D) was added 1.5 times the chemical theoretical equivalent required to reduce lanthanum oxide, and after further mixing, pressure molding 17 and pellets were prepared.

Next, the crucible containing the pellet was inserted into a quartz reaction tube equipped with a water-cooled cap, and the inside of the reaction tube was made into a sufficiently inert atmosphere with argon gas.
Heat treatment was performed for 8 hours.

The hydrogen storage amount of the obtained alloy powder was measured by measuring the pressure change when a certain amount of hydrogen was stored and when it was released.Table 1 shows the results. In addition,
The flPI constant temperature here was 45° C., and the hydrogen introduction pressure was SO ATM.

Examples 2 to 13 In order to obtain the final chemical equivalents as shown in Table 1, component B (B+), component A, component C (C+) was added, and component D was added. Component B, component A1, and component C1 were added in an amount 1.5 times the chemical theoretical equivalent required to reduce the components, and after further mixing, the mixture was press-molded to prepare pellets.

Next, as in Example 1, the crucible containing the pellets was inserted into a quartz reaction tube equipped with a water-cooled cap (17), and the inside of the reaction tube was made into a sufficiently inert atmosphere with argon gas.
Heat treatment was performed at 000 to 1200°C for 1 to 6 hours.

The hydrogen storage capacity of the obtained alloy powder was measured in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Examples 1 to 5 Metallic lanthanum or Mitsushi metal and nickel, as well as cobalt, manganese, and aluminum were weighed to give the final chemical theoretical equivalents as shown in Table 1.
These are prepared and melted in a high frequency vacuum melting furnace, the obtained alloy ingot is crushed in a vacuum glove box substituted with argon gas, and the alloy is about 1 cm square. A predetermined hydrogen storage alloy powder was obtained.

The hydrogen storage capacity of the obtained alloy powder was measured in the same manner as in Example 1, and the results are shown in Table 1.

[Effects of the Invention] In the method for producing alloy powder of the present invention as described in -1- below, rare earth metal or alloy oxide powder (alloyed with A + acid component [B (Bl) component or in addition to this)] teC(C+
) component], add a predetermined amount of reducing agent (component D), and perform reduction and alloying in the same process to directly produce alloy powder containing rare earth metals without going through multiple steps. can be manufactured. Therefore, compared to the conventional method of manufacturing alloy powder, it not only significantly reduces the manufacturing cost and improves productivity and economy, but also reduces the oxidation of the alloy powder that occurs when grinding the alloy mechanically as in the past. The production method of the present invention has industrial value because it is possible to suppress the generation and dangers during hydrogen pulverization.

The alloy powder thus obtained is used, for example, as a hydrogen storage alloy in a wide range of applications such as batteries and heat vibrators.

Procedural amendment 0. picture, May 21, 1990 No. 81817

Claims (1)

[Claims] 1. At least one metal selected from Co and Ni or an oxide powder thereof is mixed with an oxide powder of at least one rare earth metal or alloy selected from La and misch metal. A method for producing an alloy powder, which comprises adding thereto at least one metal selected from Ca, Mg, and Li, and heat-treating the mixture. 2. In addition to rare earth metal or alloy oxide powder, Mn
2. The method for producing an alloy powder according to claim 1, wherein at least one metal selected from , Cu, and Al or an oxide powder thereof is mixed.