JPS59140301A - Manufacture of hydrogen occluding alloy of rare earth metal-nickel system - Google Patents

Abstract

PURPOSE:To manufacture a titled alloy with a single-stage process without annealing by admixing specified pts. wt. powdered metallic Ni with metallic powder contg. specified pts. wt. powdered rare earth metal, and heating the mixture under specified conditions. CONSTITUTION:1-300pts.wt. powdered metallic Ni is admixed with metallic powder contg. at least 100pts.wt. powdered rare earth metal and/or powdered alloy thereof. La etc. is used as the rare earth metal and misch metal etc. is used as the alloy. 1-300pts.wt. metals such as Al, Fe etc. can also be added as the third and the fourth elements. All the materials to be used are regulated to <=about 20 mesh. Then the mixture is heated at 800-1,200 deg.C for 1-10hr under the vacuum (about 10<-1>-10<-4>mm.Hg) or in the presence of inert gas such as Ar. In this way, the phase wherein each constituent is diffused uniformly, can be obtained and the annealing is not required.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a rare earth metal-nickel hydrogen storage alloy, and more particularly to a method for producing a rare earth metal-nickel hydrogen storage alloy that does not require an annealing treatment.

Conventionally, rare earth metals such as lanthanum, cerium, praseodymium, neodymium, and samarium and/or nickel metals such as Mitsubishi metal are melted at a temperature of 1300°C or higher, and then hydrogen storage capacity is imparted to the melting point at 1100°C so that hydrogen can be released at a plateau pressure. A method for producing rare earth metal-based hydrogen storage alloys is known in which annealing treatment is performed at a temperature of 1200 DEG C. for about 5 hours.

This known method requires an alloy manufacturing process and an annealing process that require high temperatures of 1300° C. or higher, resulting in high costs.

The present invention provides a manufacturing method that allows various alloys to be easily blended in predetermined proportions, does not require annealing treatment, and provides a method for economically manufacturing rare earth metal-nickel hydrogen storage alloys in a one-step process. That.

purpose.

The method for producing a rare earth metal-nickel hydrogen storage alloy of the present invention is to add 1 to 300 parts of nickel metal powder to a metal powder containing at least 100 parts by weight of rare earth metal powder and 1-x alloy powder thereof.
1 to 1 part by weight at 800° to 1200°C under vacuum or in the presence of an inert gas.
It is characterized by heat treatment for 0 hours.

The present invention will be explained in more detail below.

Rare earth metals used in the present invention include lanthanum, cerium, praseodymium, neodymium, and samarium, and alloys thereof include lanthanum, cerium, praseodymium, neodymium, and samarium. Among these, lanthanum and mitshu metal are particularly preferably used because they have a low hydrogen storage pressure. In the present invention, the particle size of the pulverized rare earth metal and/or metal alloy used as powder is not particularly critical, but it is preferably 20 mesh or less.

In the present invention, in addition to the above-mentioned rare earth metals and/or alloys thereof, metals such as aluminum,
Powders of iron, manganese, chromium, titanium, and zircon may be added. The powder particle size is preferably 20 mesh or less.

In the present invention, nickel metal powder is added to and mixed with metal powder containing at least powder of rare earth metal and/or its alloy.

The particle size of the nickel metal powder is not particularly critical, but is preferably 20 mesh or less. This is because if the particle size is too large, diffusion will be insufficient, and if the particle size is too small, surface oxidation will occur. The proportion of the nickel metal powder to be added is 1 to 300 parts by weight based on the weight of the powder of the rare earth metal and/or its alloy, so that the desired final hydrogen storage alloy can be obtained. Similarly, the amount of the metal and/or its alloy that can serve as the third element and the fourth element is preferably in the range of 1 to 300 parts by weight per 10 parts by weight of the powder of the rare earth metal and/or its alloy. The amount ratio is such that the final hydrogen storage alloy of

The mixture of metal powders, including nickel metal powder, is then heated to 80%
Heat treatment is carried out at 0° to 12000° C., preferably 100° C. to 1200° C., for 1 to 10 hours, preferably 3.5 to 4.5 hours under vacuum or in the presence of an inert gas. Vacuum degree F
i Normally 10-' to 10-'y + mHg, good i <
The inert gas may include argon, helium, and argon-hydrogen mixed gas. If the heating temperature is less than 80°C, the diffusion of the metal powder will be insufficient, and the desired temperature will not be achieved. On the other hand, when the temperature exceeds 1200°C, it is difficult to maintain the shape.In the above heat treatment according to the present invention, nickel metal powder, rare earth metal and/or alloy powder, and third and fourth element The metal powder is melted and diffused to form a phase in which each component is uniformly diffused.Alloys obtained by conventional melting methods contain a mixture of heterogeneous phases, so they cannot be uniformly formed by annealing. If it is not made into a phase, the desired performance as a hydrogen storage material cannot be obtained.

Examples of rare earth-nickel hydrogen storage alloys obtained by the present invention include those of the following general formula.

RNix (x=1-5) RNix-yAy (x=1-5, y=0.1-0.7,
A=At.

Mn y F e % Co % T 1, Zr) RNi
x-yAyBz (X=1-5, y=0.1-0.72=
0.01~1, A, B=Az, Mn, Fe,
Co, T1, Zr A\B) Although the rare earth metal-nickel hydrogen storage alloy obtained by the production method of the present invention is not annealed, it is a rare earth metal-nickel hydrogen storage alloy produced by a known method. The hydrogen storage capacity is the same as that of the storage alloy, and a desired alloy can be easily obtained with a desired composition.

Hereinafter, the present invention will be explained with reference to the following examples, but it is not limited only to these examples. Note that parts represent parts by weight.

Example 1 Lanthanum was used as rare earth gold and was ground into 20 meshes using a grinder. Nickel metal was similarly ground into 20 meshes. 250 parts of nickel metal powder was added to 100 parts of lanthanum metal powder and thoroughly mixed. The metal powder mixture thus obtained was placed in a steel mold, and a hydraulic press was used to form pellets with a diameter of 30 m and a thickness of 20 m.
．． Made of stainless steel and heated under argon atmosphere for 12 hours.
Heat treatment was performed at 00°C for 4 hours.

The obtained lanthanum-nickel hydrogen storage alloy (LaNi
When the hydrogen storage properties of 5) were measured by the volumetric method, it was found that 4
At 0°C, 5Qat% of hydrogen was absorbed.

Examples 2 to 11 Various rare earth-nickel alloys were produced by the method described in Example 1 using the various rare earth metals listed in the table below and under the reaction conditions listed in the table. The results of measuring the hydrogen storage φ force according to Example 1 are shown in the table.

Claims (1)

[Claims] 1 to 300 parts by weight of nickel metal powder is added and mixed to a metal powder containing at least 100 parts by weight of rare earth metal powder and/or its alloy powder, and the mixture is heated to 800° to 800° under vacuum or in the presence of an inert gas. 1-10 at 1200℃
A method for producing a rare earth metal-nickel hydrogen storage alloy, which is characterized by time-heat treatment.