JPS6048580B2 - Alloy for hydrogen storage - Google Patents

Description

【発明の詳細な説明】 本発明は水素貯蔵用合金更に詳しくは水素化物の形態
で多量の水素を吸蔵し得、しかも若干の加熱で容易に且
つ速かに水素を放出し得る新規にして且つ有用な水素貯
蔵用ミツシユメタル系多元合金に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydrogen storage alloy, more specifically, a novel hydrogen storage alloy that can store a large amount of hydrogen in the form of a hydride, and can easily and quickly release hydrogen with slight heating. This article relates to a useful Mitsushi metal multi-component alloy for hydrogen storage.

最近、水素は資源的な制約がないこと、クリーンであ
ること、輸送、貯蔵が可能であること、自然の循環を乱
さないことなど化石燃料に代る新しいエネルギーとして
注目されてきている。Recently, hydrogen has been attracting attention as a new energy alternative to fossil fuels because it has no resource constraints, is clean, can be transported and stored, and does not disturb natural cycles.

従来より該水素は、気体水素もしくは液体水素としてま
たは金属水素化物として貯蔵され、これらの中で 最近
金属水素化物として貯蔵する方法が特に関心を持たれて
いる。この金属水素化物の形態て水素を貯蔵する物質と
して要求される性質には、（１）水素貯蔵用物質が安価
であり、しかも資源的に豊富であること、（２）活性化
が容易て水素の吸蔵能が大きいこと、（３）室温付近で
解離平衡圧をもつこと、（４）水素の吸蔵、放出反応が
可逆的であり、その速度が早いことなどがあげられる。
しかるに従来から水素化物を生成することの知られてい
るＴｉ、Ｚｒ、Ｌａ、Ｍ の遷移金属は水素化物の形態
で熱的に非常に安定て、例えは３００゜Ｃ以上の高温で
はじめて水素を放出するため、水素貯蔵用物質としての
実用性は乏しい。また近年Ｔｉ−Ｎｉ、、Ｔｉ−Ｃｏ、
Ｔｉ−ＦｅＮし−Ｎｉ）Ｍｇ−Ｎｉ）Ｍｍ（ミッシュメ
タル） −Ｎｉ等の合金が開発されたが、之等はいずれ
も水素貯蔵用物質としては不利を免がれ得ないものであ
る。即ち上記合金のうちＴｉＮＬａ及びＭｇ系合金はい
ずれも上記Ｔｉ、Ｌａ、Ｍｇの金属と同様に熱的に安定
であるか又は水素の吸蔵、放Ｊ出に長時間を要し、また
活性化が容易とは言えず、しかも使用する金属原料とし
て極めて高純度のものが要求され経済面で問顕があると
同時に、水素の純度も水素吸蔵能に１０を及ぼすために
吸蔵すべき水素もまた高純度にものにホｌ限される。ま
たＭｍ−Ｎｌ系合金は活性化に際し８０〜９０ｋ９／ｃ
透という高い水素圧を必要とするか長時間を要するか或
いは活性化に多くの回数を必要とするものであると共に
水素の吸蔵、放出に長時間を要する。以上の如く従来提
案された水素貯蔵用物質には夫々欠点があり、水素貯蔵
用物質として要求される前記諸性質を具備する金属、合
金等は未だ開発されていない現状にある。本発明者は、
上記現状に鑑み、水素貯蔵用物質として要求される諸性
質を具備する合金を得るべ フく種々研究を重ねてきた
。Traditionally, hydrogen has been stored as gaseous hydrogen, liquid hydrogen, or as metal hydrides, of which storage methods as metal hydrides have recently attracted particular interest. The properties required for a material that stores hydrogen in the form of metal hydrides include (1) hydrogen storage materials that are inexpensive and abundant in terms of resources, and (2) hydrogen storage materials that can be easily activated. (3) It has a dissociation equilibrium pressure near room temperature; (4) Hydrogen storage and release reactions are reversible and the rate is fast.
However, transition metals such as Ti, Zr, La, and M, which have been known to generate hydrides, are very thermally stable in the form of hydrides, and for example, they can only generate hydrogen at high temperatures of 300°C or higher. This makes it impractical as a hydrogen storage material. In recent years, Ti-Ni, Ti-Co,
Although alloys such as Ti--FeN--Ni) Mg--Ni) Mm (misch metal)--Ni have been developed, they all have disadvantages as hydrogen storage materials. That is, among the above-mentioned alloys, TiNLa and Mg-based alloys are either thermally stable like the above-mentioned Ti, La, and Mg metals, or require a long time to absorb and desorb hydrogen, and are difficult to activate. This is not an easy task, and it is economically problematic because the metal raw materials used must be of extremely high purity.At the same time, the purity of hydrogen has a 10% effect on the hydrogen storage capacity, so the hydrogen to be stored must also be of high purity. There are limits to purity. In addition, Mm-Nl alloys require 80 to 90k9/c upon activation.
It requires a high hydrogen pressure called hydrogen permeation, takes a long time, or requires many activations, and also takes a long time to absorb and release hydrogen. As mentioned above, each of the hydrogen storage materials proposed in the past has drawbacks, and metals, alloys, etc. that have the above-mentioned properties required as hydrogen storage materials have not yet been developed. The inventor is
In view of the above-mentioned current situation, various studies have been conducted to obtain an alloy that has the various properties required as a hydrogen storage material.

その結果ＭｍＮｌ，合金のＮ１の所定量を特定の金属で
置き換えてなるミッシユメタル系多元合金は、上記諸性
質をすべて具備し、水素貯蔵用合金として従来例を見な
い極めて有用なものであることを見出し、ここに本発明
を完成するに至つた。即ち本発明は一般式 一般式ＭｍＮｉ５−ＸＡｘで表わされる水素貯蔵用合金
である。As a result, we found that the MmNl, multi-component alloy, which is made by replacing a predetermined amount of N1 in the alloy with a specific metal, possesses all of the above-mentioned properties and is extremely useful as a hydrogen storage alloy, something that has never been seen before. This led to the completion of the present invention. That is, the present invention is a hydrogen storage alloy represented by the general formula MmNi5-XAx.

ただし、式中Ｍｍは鉄０．１〜５重量％、珪素０．１・
〜１重量％、マグネシウム０．１〜２重量％、およびア
ルミエウム０．１〜１重量％を少くとも含有するミツシ
ユメタルを表わし、ＡはＢ，Ｃａ，ＶまたはＺｎてあり
、Ｘは０．０１〜２の範囲の数を示す。However, in the formula, Mm is 0.1 to 5% by weight of iron and 0.1% of silicon.
-1% by weight, 0.1-2% by weight of magnesium, and 0.1-1% by weight of aluminum, A is B, Ca, V or Zn, and X is 0.01-2% by weight. Indicates a number in the range of 2.

本発明の上記ミツシユメタル系多元合金は、本発明者が
始めて開発した新規な合金であり、上述した水素貯蔵用
物質として要求される諸性質をすべて具備する。しかも
本発明の合金は希土類金属のみからなるミツシユメタル
を用いないので安価であり、かつ鉄、珪素、マグネシウ
ム、アルミニ．ウム等を含有するミツシユメタルを用い
ることによつて容易に活性化でき且つ多量の水素を密度
高く吸蔵し得ると共に、室温もしくはこれを若干上回る
程度の温和な加熱によつて、吸蔵した水素を容易に且つ
速やかに放出できる特長を有する。更．“に本発明合金
の水素吸蔵能は、吸蔵すべき水素の純度には何ら影響さ
れず、従つて若干量の酸素、窒素、アルゴン、炭酸ガス
等を含有する水素をも効率良く吸蔵可能てある。加えて
本発明合金は、水素の吸蔵−放出操作の繰返しによつて
も合金の−， ：性能は劣化せす、長期に亘り初期の水
素吸蔵能を保持する利点を有する。上記各種の優れた特
長は、特に一般式〔Ｉ〕中ＡがＣｒ）Ｆｅ又はＺｎであ
る合金について顕著であ （り、Ｘが０．１〜１の範囲
のものが最もよい。The Mitsushi metal multi-component alloy of the present invention is a novel alloy developed by the present inventor for the first time, and has all of the properties required as a hydrogen storage material as described above. Moreover, the alloy of the present invention is inexpensive because it does not use metals consisting only of rare earth metals, and it is made of iron, silicon, magnesium, aluminum, etc. By using Mitsushimetal containing aluminum, etc., it can be easily activated and absorb a large amount of hydrogen with high density, and the occluded hydrogen can be easily absorbed by mild heating at or slightly above room temperature. It also has the advantage of being able to be released quickly. Further. The hydrogen storage capacity of the alloy of the present invention is not affected by the purity of the hydrogen to be stored, and therefore it is capable of efficiently storing hydrogen containing small amounts of oxygen, nitrogen, argon, carbon dioxide, etc. In addition, the alloy of the present invention has the advantage of retaining its initial hydrogen storage capacity over a long period of time, even though the performance of the alloy deteriorates due to repeated hydrogen storage and release operations. These characteristics are particularly remarkable for alloys in which A in the general formula [I] is Cr)Fe or Zn, and those in which X is in the range of 0.1 to 1 are best.

斯かる合金の３０℃における水素化物の解離圧は第１表
から明らかな通り極めて低く水素貯蔵合金として特に優
れている。本発明で用いられるミツシユメタルは一般に
ランタン２５〜３５％（重量、以下同じ）、セリウム４
０〜５０％、プラセオジム４〜１５％、ネオジム４〜１
５％、サマリウム＋ガドリニウム１〜７％、鉄０．１〜
５％、珪素０．１〜１％、マグネシウム０．１〜２％、
アルミニウム０．１〜１％等からなるものであり、これ
はミツシユメタルとしてΞ徳金属工業（株）、新日本金
属工業（掬、信越化学工業（掬等から市販されている。As is clear from Table 1, the dissociation pressure of hydrides in this alloy at 30° C. is extremely low, making it particularly excellent as a hydrogen storage alloy. The Mitsushi metal used in the present invention generally contains 25 to 35% lanthanum (by weight, the same hereinafter) and 4% cerium.
0-50%, praseodymium 4-15%, neodymium 4-1
5%, samarium + gadolinium 1-7%, iron 0.1-
5%, silicon 0.1-1%, magnesium 0.1-2%,
It consists of 0.1 to 1% aluminum, etc., and is commercially available as Mitsushi Metal from ΞToku Metal Industry Co., Ltd., Shin Nippon Metal Industry Co., Ltd. (Kiku), Shin-Etsu Chemical Co., Ltd. (Kiku etc.).

本発明の上記一般式〔Ｉ〕で表わされるミツシユメタル
系多元合金を製造するに当つては、公知の各種方法を採
用できる好ましくは弧光熔融法を採用できる。In producing the Mitsushi metal-based multi-component alloy represented by the above general formula [I] of the present invention, various known methods can be employed, preferably an arc melting method.

即ち一般式〔Ｉ〕で表わされる合金の組成となるように
ミツシユメタル、ニッケル及びＡ成分を夫々粉末状もし
くは適当な成形体状（通常棒状）で混合後任意の形態に
ブレス成形し次いで該成形物を公知の弧光熔融炉に装入
し、不活性雰囲気下に加熱熔融し放冷することにより容
易に収得できる。かくして得られる本発明のミツシユメ
タル系多元合金は、この表面積を増大できるため通常粉
末の形態で用いるのが有利である。また上記合金は、極
めて容易に活性化でき、活性化後は、多量の水素を容易
に且つ急速に吸蔵及び放出できる。活性化は、上記合金
に水素を吸蔵及ひ放出する操作を唯一回又は合金の種類
によつては二回行なうことにより実施される。この水素
の吸蔵操作即ち水素化物の形成操作は、上記合金粉末を
適当な容器に充填後、室温て系内に水素を封入し約５０
ｋ９／Ｃｒｌの水素圧を印加することにより行なわれる
。特に本発明金はこの吸蔵操作を室温で数分以内の極め
て短時間に行ない得る利点がある。これに対し公知のＴ
ｉ−Ｆｅ合金は、室温、５０ｋ９／ｃイの水素圧の印加
では、水素の吸蔵は実質的に起らず、従つてそれによる
活性化も不可能である。吸蔵操作には約４００〜５００
℃の高温を要し且つ活性化には、この吸蔵操作を数回繰
返す必要がある。Ｔｉ−Ｎｉ）Ｔｉ−ＣＯ、Ｌａ−Ｎｉ
及びＭｇ−Ｎｉ合金についても、上記Ｔｉ−Ｆｅ合金の
場合と同様である。またＭｍＮｌ。合金にあつても室温
、５０ｋｇ／ｃイの水素圧の条件で活性化させるために
は、やはり上記吸蔵操作を数回繰返さねばならない。上
記吸蔵操作の完了後は系内を排気するのみで容易に吸蔵
された水素の放出が起り、これにより合金の活性化が完
結する。That is, Mitsushimetal, nickel, and component A are mixed in powder form or in the form of an appropriate molded object (usually a rod shape) so as to have the composition of the alloy represented by the general formula [I], and then press-molded into an arbitrary shape, and then the molded product is mixed. It can be easily obtained by charging the compound into a known arc-light melting furnace, heating and melting it in an inert atmosphere, and allowing it to cool. The Mitsushi metal-based multi-component alloy of the present invention thus obtained can be advantageously used in the form of a powder because its surface area can be increased. Moreover, the above-mentioned alloy can be activated very easily, and after activation, it can easily and rapidly absorb and release a large amount of hydrogen. Activation is carried out by performing the operation of absorbing and desorbing hydrogen into the alloy once or twice depending on the type of alloy. This hydrogen absorption operation, that is, the hydride formation operation, is carried out by filling the above alloy powder into a suitable container, and then sealing hydrogen into the system at room temperature for about 50 minutes.
This is done by applying a hydrogen pressure of k9/Crl. In particular, the present invention gold has the advantage that this occlusion operation can be carried out within a very short time, within several minutes, at room temperature. In contrast, the known T
The i-Fe alloy does not substantially absorb hydrogen when a hydrogen pressure of 50 k9/c is applied at room temperature, and therefore cannot be activated. Approximately 400-500 for storage operation
It requires a high temperature of 0.degree. C., and it is necessary to repeat this occlusion operation several times for activation. Ti-Ni) Ti-CO, La-Ni
The same applies to the Ti--Fe alloy and the Mg--Ni alloy. Also MmNl. Even in the case of an alloy, in order to activate it at room temperature and under a hydrogen pressure of 50 kg/cm, the above-mentioned occlusion operation must be repeated several times. After the above storage operation is completed, the stored hydrogen is easily released by simply exhausting the system, thereby completing the activation of the alloy.

かくして活性化された合金への水素の貯蔵は、．上記合
金を密封し得る容器例えば通常のボンベ等に充填し、之
に−３０’Ｃから室温までの温度で所定の水素圧（使用
する合金の水素化物の解離圧より僅かに高い水素圧）を
印加することにより実施され、これにより合金は水素化
物の形態で多量の水素を短時間に合金内に吸蔵すること
ができる。The storage of hydrogen in the thus activated alloy is... The above alloy is filled in a hermetically sealed container, such as a normal cylinder, and then heated to a predetermined hydrogen pressure (hydrogen pressure slightly higher than the dissociation pressure of the hydride of the alloy used) at a temperature from -30'C to room temperature. This is carried out by applying an electric current to the alloy, which allows the alloy to store large amounts of hydrogen in the form of hydrides within the alloy in a short period of time.

またこの水素化物からの水素の放出は、室温で上記容器
を開放するだけでも行ない得るが、より短時間に且つ効
率よく水素を放出するには、通常室温以上の温度に加熱
するか、減圧にするか又は両者を組み合せるのが望まし
い。この活性化された本発明合金への水素の吸蔵及び放
出操作は、従来公知のＴｉ−ＦｅＮＴｉ−Ｎｉ）Ｌａ−
Ｎｊ．．Ｍｍ−Ｎｉ系合金等の合金と対比して非常に容
易に実施てき、しかもこれらの合金に比し３倍以上も高
速度下に効率良く実施できる利点がある。更に本発明の
合金は、上記水素の吸蔵及び放出が完全に可逆的に行な
オ）れ、水素化物の形成及びその分解反応を繰返し行な
つても合金自体の劣化は実質的に認められず、従つて長
期に亘る使用が可能である。また酸素、窒素、アルゴン
、炭酸ガス等吸蔵ガス中の不純物による影口はほとんど
認められない。以上の通り本発明台金は、容易な操作に
より多量の水素を貯蔵し得るものであり、またその放出
も容易に且つ速やかに実施でき水素貯蔵用合金として極
めて有用なものである。以下本発明を更に詳しく説明す
るため実施例を挙げる。Hydrogen can be released from the hydride by simply opening the container at room temperature, but in order to release hydrogen more quickly and efficiently, it is usually heated to a temperature higher than room temperature or reduced pressure. It is preferable to do so or a combination of both. This operation of absorbing and desorbing hydrogen into the activated alloy of the present invention is performed using the conventionally known Ti-FeNTi-Ni)La-
Nj. ．． Compared to alloys such as Mm--Ni alloys, this method has the advantage of being extremely easy to implement, and moreover, can be performed more efficiently at speeds three times or more higher than those of these alloys. Furthermore, in the alloy of the present invention, the hydrogen absorption and release described above is completely reversible, and even if the hydride formation and its decomposition reactions are repeated, there is virtually no deterioration of the alloy itself. Therefore, it can be used for a long period of time. In addition, almost no shadows due to impurities in storage gases such as oxygen, nitrogen, argon, and carbon dioxide are observed. As described above, the base metal of the present invention can store a large amount of hydrogen through easy operation, and can also release hydrogen easily and quickly, making it extremely useful as an alloy for hydrogen storage. Examples will be given below to explain the present invention in more detail.

実施例１一般式ＭｍＮｉ。Example 1 General formula MmNi.

一、Ａｘ（式中Ｍｍはミツシユメタル、ＡはＢ，Ｃａ，
Ｃｒ，Ｆｅ，ＶまたはＺｎ，ｘは０．０１〜２の数を示
す）の組成となるようにＭｍ，Ｎｌ及びＡ成分を棒状（
径５Ｔｗｔ、長さ５ｍ１ｒｔ）もしくは粉末の形態で混
合し、次いで混合物をブレス成形して円筒形の錠剤とし
た。これを高真空弧光熔融炉の銅製るつぼ内に装入し、
炉内を高純度アルゴンふん囲気とした後、約２０００℃
に加熱熔融し、放冷して第１表に示される組成の合金を
得た。得られた合金を１２０メッシュに粉砕後その５．
０ｇをステンレス製水素吸蔵、放出反応器に採取し、以
下の通り合金の活性化を行つた。即ち反応器を排気装置
に接続して、減圧下、２００゜Ｃて加熱して脱ガス操作
を行つた。次いで室温で純度９９．９９９９％の水素を
導入し、器内の水素圧を５０ｋ９／ｃイに保持すると直
ちに合金に対する水素の吸゜蔵が認められ、水素の吸蔵
操作を完了後再び排気を行つて上記水素の放出操作を完
了させた。上記吸蔵−放出サ．イクルを１回又は２回行
つて活性化された合金に、室温（３０℃）の温度でそれ
ぞれの合金の水素化物の解肉佳圧よりも僅かに高い水素
圧・で純度９９．９９９９％の水素を吸蔵せしめ水素の
封入貯蔵を行つた。この時の本発明合金の水素吸蔵量、
水素化物の解雌圧、活性化エネルギー及び水素吸蔵速度
などの水素貯蔵特性を第１表に示す。また第１表には比
較のため、上記と同様に製造しフた公知の合金、ＭｍＮ
ｉ５についての同様の水素貯蔵特性を併記する。上記第
１表より本発明のミツシユメタル系多元合金はＭｍＮｊ
，（試料ＮＯ．．ｌ）に比し、室温においてほぼ同等も
しくはそれ以上の水素を吸蔵し得、しかも活性化エネル
ギーは小さくその活性化回数も１１３〜１１６に減少し
、水素吸蔵速度は実に３〜４倍も早いことがわかる。1. Ax (in the formula, Mm is Mitsushi Metal, A is B, Ca,
Cr, Fe, V or Zn, x represents a number from 0.01 to 2).
(diameter: 5 Twt, length: 5 ml rt) or powder form, and then the mixture was press-molded into cylindrical tablets. This is charged into a copper crucible of a high vacuum arc light melting furnace,
After surrounding the furnace with high-purity argon, the temperature was raised to approximately 2000°C.
The alloy was melted by heating and allowed to cool to obtain an alloy having the composition shown in Table 1. After pulverizing the obtained alloy to 120 mesh, 5.
0 g was collected in a stainless steel hydrogen storage and release reactor, and the alloy was activated as follows. That is, the reactor was connected to an exhaust system and heated to 200°C under reduced pressure to perform a degassing operation. Next, hydrogen with a purity of 99.9999% was introduced at room temperature and the hydrogen pressure inside the vessel was maintained at 50k9/c. Hydrogen absorption into the alloy was immediately observed, and after the hydrogen absorption operation was completed, the vessel was evacuated again. Then, the above hydrogen release operation was completed. The above storage-release service. The alloys activated by one or two cycles were heated to a purity of 99.9999% at room temperature (30°C) and hydrogen pressure slightly higher than the decomposition pressure of the respective alloy hydride. Hydrogen was absorbed and hydrogen was sealed and stored. At this time, the hydrogen storage capacity of the alloy of the present invention,
Hydrogen storage properties such as decomposition pressure, activation energy, and hydrogen storage rate of the hydride are shown in Table 1. For comparison, Table 1 also lists known alloys produced in the same manner as above, MmN
Similar hydrogen storage characteristics for i5 are also listed. From Table 1 above, the Mitsushi metal multi-component alloy of the present invention is MmNj
, (Sample No. 1), it can store almost the same or more hydrogen at room temperature, and the activation energy is small and the number of activations is reduced to 113-116, and the hydrogen storage rate is actually 3. It turns out that it is ~4 times faster.

また本発明の合金と、鉄、珪素、マグネシウム、および
アルミニウム等を含有しない従来のミツシユメタルを用
いた同一組成式て表オ）される合金の水素吸蔵速度を図
に示す。この図から明らかなように、本発明の合金Ａは
従来のミツシユメタルを用いた合金Ｂに比して水素吸蔵
速度が２倍を速い。また上記本発明合金の水素化物から
の水素の放出は、反応器を室温もしくはそれ以上の温度
に加熱するか、減圧にする−か又は之等両者を組合せる
ことにより容易に行い得、その放出速度も亦上記吸蔵速
度と同様に極めて早いものであつた。実施例２ 実施例１の操作にならつて、ＭｍＮｉ。The figure also shows the hydrogen absorption rates of the alloy of the present invention and an alloy with the same compositional formula using conventional Mitsushi metal that does not contain iron, silicon, magnesium, aluminum, etc. As is clear from this figure, the hydrogen absorption rate of alloy A of the present invention is twice as fast as that of alloy B using conventional Mitsushi metal. Furthermore, hydrogen can be easily released from the hydride of the alloy of the present invention by heating the reactor to room temperature or higher temperature, by reducing the pressure, or by a combination of both. The absorption rate was also extremely fast, similar to the absorption rate mentioned above. Example 2 Following the procedure of Example 1, MmNi.

−ＸＡｘ（Ｍｍはミツシユメタル、ＡはＢ，Ｃａ，Ｖま
たはＺｎ）ｘは０．０１〜２の数を示す）て表わされる
合金ノを製造後約９９．５％の水素を用いて活性化を行
つた。即ち水素の吸蔵、放出サイクルを１回又は２回繰
り返し、合金の活性化を完了した。次いで活性化された
合金は室温（３０゜Ｃ）でそれぞれの合金の水素化物の
解離圧よりも僅かに高い水素圧で純度９９．５％の水素
を封入し、貯蔵した。この時の本発明合金（試料ＮＯ．
．２〜１０）の水素吸蔵量、水素化物の解離圧、活性化
エネルギー及び水素吸蔵速度などの水素吸蔵特性は、実
施例１とほぼ同様であり、またかくして得られた水素化
物からの水素の放出操作及び放出速度も実施例１と同様
に容易てあり且速やかであつた。-XAx (Mm is Mitsushimetal, A is B, Ca, V, or Zn) I went. That is, the hydrogen absorption and release cycle was repeated once or twice to complete the activation of the alloy. The activated alloys were then encapsulated with 99.5% pure hydrogen and stored at room temperature (30° C.) at a hydrogen pressure slightly higher than the dissociation pressure of the respective alloy's hydride. At this time, the present invention alloy (sample No.
．． The hydrogen storage properties of items 2 to 10), such as the amount of hydrogen storage, the dissociation pressure of the hydride, the activation energy, and the hydrogen storage rate, are almost the same as in Example 1, and the release of hydrogen from the hydride thus obtained is similar to that of Example 1. The operation and release rate were also easy and rapid as in Example 1.

【図面の簡単な説明】[Brief explanation of the drawing]

図は本発明の合金と従来の合金の、水素吸蔵反応率と時
間との関係を示す図である。The figure is a diagram showing the relationship between the hydrogen storage reaction rate and time for the alloy of the present invention and a conventional alloy.

Claims (1)

【特許請求の範囲】 １ 一般式ＭｍＮｉ＿５−ｘＡｘで表わされる水素貯蔵
用合金。 ただし、式中Ｍｍは鉄０．１〜５重量％、珪素０．１〜
１重量％、マグネシウム０．１〜２重量％、およびアル
ミニウム０．１〜１重量％を少くとも含有するミツシユ
メタルを表わし、ＡはＢ，Ｃａ，ＶまたはＺｎであり、
ｘは０．０１〜２の範囲の数を示す。 ２ ＡがＺｎである特許請求の範囲第１項記載の水素貯
蔵用合金。 ３ ｘが０．１〜１の範囲の数である特許請求の範囲第
１項または第２項記載の水素貯蔵用合金。[Claims] 1. A hydrogen storage alloy represented by the general formula MmNi_5-xAx. However, in the formula, Mm is 0.1 to 5% by weight of iron and 0.1 to 5% by weight of silicon.
1% by weight, 0.1-2% by weight of magnesium, and 0.1-1% by weight of aluminum, A is B, Ca, V or Zn,
x represents a number in the range of 0.01 to 2. 2. The hydrogen storage alloy according to claim 1, wherein A is Zn. 3. The hydrogen storage alloy according to claim 1 or 2, wherein x is a number in the range of 0.1 to 1.