JPH07188809A - Silver-tin oxide contact material and its production - Google Patents

Abstract

PURPOSE:To obtain the silver-tin oxide contact material excellent in contact property and cold workability by minutely/uniformly dispersing a tin oxide grain of the specific content in Ag matrix through chemical coprecipitation method and powder sintering method. CONSTITUTION:An silver nitrate solution (acid solution) and tin oxide sodium solution (alkaline solution) are simultaneously mixed or simultaneously dripped in the water matrix prepared for pH so as to be added/mixed. Thus, after the precipitate generated/precipitated in the mixed solution is recovered and cleaning/dehydrorating treatment are repeated, it is processed by drying at about 600 deg.C. By this method, the mixed powder which consists of 5-40wt.% tin oxide and the balance silver and the tin oxide having a grain size of <=0.5mum preferably <=0.3mum is minutely/uniformly dispersed in Ag matrix, is obtained. Subsequently, this mixed powder is compacted to be sintered in atmosphere at about 800-900 deg.C. Further, the sintered body is subjected to hot extrusion and then the silver-tin oxide contact material is obtained through drawing or rolling.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】開示技術は、主として、中電流領
域で使用される電気計装にあって、銀を主成分とし、そ
の銀マトリックス中に酸化錫を微細、且つ、均一に分散
させた銀−酸化錫接点の材料とその製造の技術分野に属
する。BACKGROUND OF THE INVENTION The disclosed technology is mainly for electrical instrumentation used in a medium current region, in which tin is a main component and tin oxide is finely and uniformly dispersed in the silver matrix. It belongs to the technical field of silver-tin oxide contact material and its manufacture.

【０００２】[0002]

【従来の技術】周知の如く、各種産業の諸設備にあって
は電気計装が不可欠であり、種々の電気機器具，装置が
多々使用されているが、これらの電気計装にあっては少
からず接点が配設されており、このうち、中電流領域で
使用される接点のうち、銀−酸化錫接点が用いられてい
る。2. Description of the Related Art As is well known, electric instruments are indispensable in various industrial facilities, and various electric instruments and devices are used in many cases. At least some of the contacts are provided, and among them, of the contacts used in the medium current region, a silver-tin oxide contact is used.

【０００３】而して、該種銀−酸化錫接点材料の製造方
法には、当業者にとりこれまで内部酸化法と粉末焼結法
が知られている。As a method for producing the seed silver-tin oxide contact material, those skilled in the art have hitherto known the internal oxidation method and the powder sintering method.

【０００４】このうち、前者の内部酸化法は、銀と所定
の溶質金属とで合金を作り、該合金を大気雰囲気中、又
は、酸素ガス中にて所定の圧力下で加熱することによ
り、溶質金属のみを選択的に酸化させる手法である。Of these, the former internal oxidation method is one in which an alloy is formed from silver and a predetermined solute metal, and the alloy is heated in an air atmosphere or in an oxygen gas under a predetermined pressure to form a solute. This is a method of selectively oxidizing only the metal.

【０００５】[0005]

【発明が解決しようとする課題】かかる内部酸化法によ
る銀−酸化錫接点材料では金属酸化物の凝集層や溶質金
属の内部酸化稀薄層が出来るため、その後の加工工程に
おいて加工性が大きく阻害される欠点があり、更に、得
られた接点にあっては接点特性が著しく低下するという
難点がある。In the silver-tin oxide contact material formed by the internal oxidation method, an aggregated layer of metal oxides and a dilute internal oxide layer of solute metal are formed, so that the workability is greatly impaired in the subsequent processing steps. In addition, there is a drawback that the contact characteristics of the obtained contact are significantly deteriorated.

【０００６】又、後者の粉末焼結法には、乾式粉混合法
と化学的共沈法により原料粉末を作製する方法とがある
が、前者の該乾式粉混合法は、接点材料の製造方法とし
ては比較的に簡単な方法ではあるものの、銀粉末と酸化
錫粉末とを機械的な手段で混合させるために、両者の比
重差により酸化錫の均一分散が図れない不都合さがある
ばかりでなく、酸化錫の見掛密度が小さいために、混合
粉の焼結性が悪く、その後の加工性を大きく阻害すると
いう不具合がある。The latter powder sintering method includes a dry powder mixing method and a method of producing a raw material powder by a chemical coprecipitation method. The former dry powder mixing method is a method for manufacturing a contact material. Although it is a relatively simple method, since the silver powder and the tin oxide powder are mixed by mechanical means, there is a disadvantage that the tin oxide cannot be uniformly dispersed due to the difference in specific gravity between the two. However, since tin oxide has a low apparent density, the sinterability of the mixed powder is poor, and there is a drawback that the subsequent workability is greatly impaired.

【０００７】これらに対処するに、当業者に知られてい
る如く、後者の化学的共沈法が開発されている。To address these, the latter chemical co-precipitation method has been developed, as is known to those skilled in the art.

【０００８】該化学的共沈法は、銀を溶解した酸性溶液
に対し錫を酸で溶解した酸性溶液を添加して銀と錫の混
合酸性溶液を作り、該混合酸性溶液を水酸化ナトリウム
溶液で中和し、更に、酸化材と水酸化ナトリウム溶液を
加えてアルカリ性にした後、新たに硝酸を加えて中和す
るというプロセスをたどる手法である。In the chemical coprecipitation method, an acidic solution in which tin is dissolved in an acid is added to an acidic solution in which silver is dissolved to prepare a mixed acidic solution of silver and tin, and the mixed acidic solution is added to a sodium hydroxide solution. This is a method of tracing the process of neutralizing with, further adding an oxidizing material and a sodium hydroxide solution to make it alkaline, and then adding new nitric acid to neutralize.

【０００９】該種手法では、銀マトリックス中の金属酸
化物の粒径は５μｍ以下で平均的には２μｍ程度であ
り、酸化物の分散性については満足し得る程度のもので
あるが、粒径についてはこの段階では未だ酸化物の粒子
が大きいため、製造工程中の加工性、及び、製品接点の
接点特性で改善すべき点を有する不充分さがある。According to the above-mentioned method, the particle size of the metal oxide in the silver matrix is 5 μm or less and is about 2 μm on average, and the dispersibility of the oxide is satisfactory. However, since the oxide particles are still large at this stage, there is a deficiency in that there is a point to be improved in the processability during the manufacturing process and the contact characteristics of the product contact.

【００１０】加えて、かかる製法では銀と錫の混合溶液
のｐＨを適性に調整する作業を必要とし、したがって、
作業工程が非常に煩瑣となるデメリットがあり、且つ、
作業に際して高度の技術的熟練を要し、製造作業がし難
いという品質の安定性に係るマイナス点もあった。In addition, such a manufacturing method requires the work of properly adjusting the pH of the mixed solution of silver and tin, and therefore,
There is a demerit that the work process becomes very complicated, and
There was also a negative point regarding the stability of quality, which required a high degree of technical skill in the work and made the manufacturing work difficult.

【００１１】[0011]

【発明の目的】この出願の発明の目的は従来の製造技術
である内部酸化法や粉末焼結法の乾式粉混合法が持って
いる酸化物の稀薄層や凝集部の存在やそれらに起因する
加工性の悪さ、そして、かかる製法による接点材料性能
や特性の低さ等の問題点を解決すべき技術的課題とし、
従来から在る製造技術の化学共沈法が持つ利点を有効裡
に利用し、接点材料として確実に所望通りの接点特性を
有することが出来るようにして各種産業における電気計
装技術利用分野に益する優れた銀−酸化錫接点材料及び
その製造方法を提供せんとするものである。The object of the invention of this application is due to the existence of a dilute layer or agglomeration of oxides which are possessed by the dry powder mixing method such as the internal oxidation method and the powder sintering method, which are conventional manufacturing techniques, and the causes thereof. Technical problems to be solved such as poor workability and low contact material performance and characteristics due to such manufacturing method,
By making effective use of the advantages of the existing chemical coprecipitation method of manufacturing technology, it is possible to ensure that the contact characteristics as desired as the contact material can be obtained, which will be beneficial to the field of electric instrumentation technology application in various industries. The present invention provides an excellent silver-tin oxide contact material and a method for producing the same.

【００１２】[0012]

【課題を解決するための手段・作用】上述目的に沿い先
述特許請求の範囲を要旨とするこの出願の発明の構成
は、前述課題を解決するために、酸化錫を微細、且つ、
均一に分散して酸化錫の粒子を出来るだけ小さく（可及
的に粒子の大きさを０．５μｍ以下）することにより、
接点特性が優れ、製造に際し冷間加工性にも優れた銀−
酸化錫接点材料を得られるようにし、該銀−酸化錫接点
材料の製造にあっては、酸性溶液の硝酸銀溶液とアルカ
リ溶液の錫酸化ナトリウム溶液を同時に混合、もしく
は、水マトリックス中に同時に滴下させる（この時水溶
液の水素イオン濃度を水酸化ナトリウム溶液で適宜調整
してておいて滴下する）ことにより、沈殿物を回収して
洗浄・脱水を繰返し行った後、所定の乾燥・熱処理工程
を経て銀と錫酸化物との混合粉末を作製するようにし、
かかるプロセスにより得られた酸化錫の粒径は０．５μ
ｍ以下、望ましくは０．３μｍ以下の微粒子であって平
均０．１μｍ前後の微粒子とされ、酸化錫の粒子を小さ
く生成させることについては、錫−酸化錫接点材料とし
ての加工態様の例として上述製法によって得られた混合
粉末を、例えば、ラバープレス法によって圧粉して所定
の大きさの圧粉体を成形した後、大気中にて８００℃〜
９００℃の温度で２〜５時間焼結することで健全な焼結
体が得られるようにし、得られた焼結体を熱間押出し機
でφ６×Ｌに押出し、素材としての素線を得、かくして
得られた銀−酸化錫接点材料は酸化錫粒径が上述の如く
０．５μｍ以下、望ましくは０．３μｍ以下の微粒子で
平均０．１μｍ前後と微粒子であるため、酸化錫の凝集
部が無く、酸化錫が均一に分散されることが出来、又、
塑性加工にあっても、上述同様に酸化物が微細、且つ、
均一分散の材料のため、均一な加工性特性を有し、冷間
加工においても、酸化錫量が１３ｗｔ％の材料で、伸び
率２５％という良好な値が得られ、充分に加工可能なも
のになり（従来、金属酸化物量で１０ｗｔ％を超える組
成の加工は極めて困難なものであったが、酸化錫粒径を
大幅に下げることにより、上述のように冷間加工が可能
となった。）、この手法を用いると、酸化錫量をいかよ
うにも調整することが出来るが、酸化錫量を４０ｗｔ％
以上とした場合、加工靭性が著しく低下し加工出来なく
なるため、酸化錫の含有量の範囲を５〜４０ｗｔ％と
し、上述プロセスで作製した銀−酸化錫接点材料の接点
試験特性は酸化錫粒径の微細化と均一分散性により、耐
溶着性、及び、耐消耗性が大幅に向上するようにした技
術的手段を講じたものである。SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the structure of the invention of the present application, which is based on the above-mentioned object and has the above-mentioned claims as its gist, is fine, and
By uniformly dispersing and making tin oxide particles as small as possible (particle size of 0.5 μm or less),
Silver with excellent contact characteristics and cold workability during manufacturing-
A tin oxide contact material is obtained, and in the production of the silver-tin oxide contact material, a silver nitrate solution of an acidic solution and a sodium tin oxide solution of an alkaline solution are mixed at the same time, or simultaneously dropped into a water matrix. (At this time, the hydrogen ion concentration of the aqueous solution is appropriately adjusted with a sodium hydroxide solution and then added dropwise) to recover the precipitate, and after repeated washing and dehydration, a predetermined drying and heat treatment step is performed. Try to make a mixed powder of silver and tin oxide,
The particle size of tin oxide obtained by this process is 0.5μ.
The fine particles of m or less, preferably 0.3 μm or less and having an average of about 0.1 μm are used, and the generation of tin oxide particles is described above as an example of a processing mode as a tin-tin oxide contact material. The mixed powder obtained by the manufacturing method is compacted by, for example, a rubber press method to form a compact having a predetermined size, and then 800 ° C. in the atmosphere.
A healthy sintered body was obtained by sintering at a temperature of 900 ° C. for 2 to 5 hours, and the obtained sintered body was extruded into φ6 × L with a hot extruder to obtain a strand as a raw material. The silver-tin oxide contact material thus obtained has a tin oxide particle size of 0.5 μm or less, preferably 0.3 μm or less, and has an average particle size of about 0.1 μm. Without tin oxide, tin oxide can be uniformly dispersed, and
Even in plastic working, the oxide is fine as described above, and
Material that has uniform workability because it is a uniformly dispersed material. Even in cold working, a material with a tin oxide content of 13 wt% and a good elongation rate of 25% can be obtained, and it can be processed sufficiently. (In the past, it was extremely difficult to process a composition having a metal oxide content of more than 10 wt%, but by significantly reducing the tin oxide particle size, cold working became possible as described above. ), Using this method, the tin oxide amount can be adjusted in any way, but the tin oxide amount is 40 wt%.
If the above is set, the processing toughness is remarkably reduced and the processing becomes impossible. Therefore, the range of the tin oxide content is set to 5 to 40 wt%, and the contact test characteristics of the silver-tin oxide contact material produced by the above-mentioned process are the tin oxide particle size. The technical measures have been taken so that the welding resistance and the wear resistance are significantly improved by the miniaturization and uniform dispersibility.

【００１３】[0013]

【発明の背景】この出願の発明は、基本的に粉末冶金法
に属する製法により銀−酸化錫接点材料を作製するもの
であり、更に、技術的に細かく分類すると、化学的共沈
法による粉末作製技術に属するものであって原料粉末は
Ag と SnO₂ からなる混合粉末である。BACKGROUND OF THE INVENTION The invention of this application is to manufacture a silver-tin oxide contact material by a manufacturing method basically belonging to the powder metallurgy method. The raw material powder belongs to the manufacturing technology.
It is a mixed powder consisting of Ag and SnO ₂ .

【００１４】而して、先記特許請求の範囲に於て酸化錫
の含有量を酸化物量で５〜４０ｗｔ％と限定する理由
は、酸化錫量が５ｗｔ％未満では接点材料として必要な
耐溶着性について充分な性能が発揮出来ないからであ
り、又、４０ｗｔ％以上では材料自体の加工靭性が著し
く低下し、接点材料とて成形出来ないからである。Therefore, the reason why the content of tin oxide is limited to 5 to 40 wt% in terms of oxide in the above-mentioned claims is that when the tin oxide content is less than 5 wt%, the welding resistance required as a contact material is reduced. This is because sufficient performance of the material cannot be exhibited, and when it is 40 wt% or more, the processing toughness of the material itself is remarkably reduced and it cannot be formed as a contact material.

【００１５】[0015]

【実施例】次に、この出願の発明の実施例を説明すれば
以下の通りである。EXAMPLES Examples of the invention of this application will be described below.

【００１６】予め硝酸銀粉末に純水を加えて溶解した酸
性溶液（Ａ液）と錫酸化ナトリウム粉末を同じく純水で
溶解したアルカリ溶液に理論的に酸性溶液と中和出来る
量の水酸化ナトリウム溶液を加え、混合アルカリ溶液
（Ｂ液）を用意するが、この時、錫酸化ナトリウム粉末
は純水で充分溶解する必要がある。An acidic solution (Liquid A) prepared by adding pure water to silver nitrate powder in advance and an alkaline solution prepared by dissolving sodium tin oxide powder in the same pure water, and a sodium hydroxide solution in an amount that can theoretically be neutralized with the acidic solution. Then, a mixed alkaline solution (solution B) is prepared. At this time, the sodium tin oxide powder needs to be sufficiently dissolved in pure water.

【００１７】蓋し、この工程をおろそかにした場合は、
最終的に酸化錫の凝集部を作ってしまう虞が生じること
になるからである。If the lid is closed and this step is neglected,
This is because there is a risk that a tin oxide agglomerate will eventually be formed.

【００１８】次に、このように作製したＡ液とＢ液を純
水を張り該純水を攪拌状態にした溶解タンク中に同時に
滴下させる。Next, the thus-prepared solutions A and B are simultaneously dropped into a dissolution tank in which pure water is filled with pure water and the stirring state is maintained.

【００１９】尚、この場合、純水を攪拌しておかない
と、Ａ液とＢ液の中和反応が激しく進行して微細な粒径
の沈殿物が得られなくなる虞がある。In this case, if the pure water is not stirred, the neutralization reaction of the liquid A and the liquid B may proceed violently and a precipitate having a fine particle size may not be obtained.

【００２０】又、該中和反応を満遍なく進行させるため
に、Ａ液とＢ液の両溶液の滴下後も該溶液タンク内での
攪拌は実験によれば１時間以上続けることが望ましい。Further, in order to allow the neutralization reaction to proceed uniformly, it is desirable, according to experiments, to continue stirring in the solution tank for 1 hour or more after the addition of both solutions A and B.

【００２１】そして、この時のpH値は１０前後が好まし
いものであって、該pH値が１０を大きく外れると、Ag品
位の不良や沈殿物の回収率に大きな影響を与えてしまう
ことが実験から分った。Experiments have shown that the pH value at this time is preferably around 10, and if the pH value deviates significantly from 10, the Ag quality will be poor and the recovery rate of the precipitate will be greatly affected. I understood from

【００２２】而して、かかる中和反応により得られた沈
殿物は酸化銀粉末と水酸化錫粉末であって、該沈殿物に
は接点材料として必要のないNaが含まれているため、次
のデカント工程を経ることで該Naの除去を行う。The precipitate obtained by the neutralization reaction is a silver oxide powder and a tin hydroxide powder. Since the precipitate contains Na which is not necessary as a contact material, The Na is removed by performing the decanting step.

【００２３】ここで言うデカント工程に於ける処理は湿
式粉末の洗浄手法で上記溶解タンク内で形成した生成物
を１時間〜２時間以上攪拌した後、沈静化した上澄み分
を抜取り、沈殿物を好ましくは３回以上純水により洗浄
脱水するものである。The treatment in the decanting step referred to here is that the product formed in the dissolution tank is agitated for 1 to 2 hours or more by a wet powder washing method, and then the settled supernatant is removed to remove the precipitate. Preferably, it is washed and dehydrated three times or more with pure water.

【００２４】かくの如く、Naの除去を終了した後沈殿物
の回収を行い、濾過乾燥処理した後酸化銀の還元温度以
上の温度で生成物を金属に還元するために大気中で４５
０℃〜８００℃にて１時間以上加熱処理を行うことによ
り、微細な酸化錫粒子を有する銀−酸化錫粉末を得るこ
とが出来る。As described above, after the removal of Na is completed, the precipitate is recovered, filtered and dried, and then the product is reduced to a metal at a temperature not lower than the reduction temperature of silver oxide.
By performing a heat treatment at 0 ° C. to 800 ° C. for 1 hour or more, a silver-tin oxide powder having fine tin oxide particles can be obtained.

【００２５】尚、該加熱分解処理温度を４５０℃からと
したのは生成物の酸化銀の分解温度が４２０℃付近であ
るためであり、８００℃までとしたのは８００℃以上で
熱処理すると、該生成物が硬く凝集してしまい粉砕が出
来なくなるためである。The heat decomposition treatment temperature is set to 450 ° C. because the decomposition temperature of the product silver oxide is about 420 ° C., and the heat treatment temperature is set to 800 ° C. when heat treatment is performed at 800 ° C. or higher. This is because the product is hard and aggregates and cannot be pulverized.

【００２６】次に、加熱処理を終了した粉末を圧粉体作
製時に用いる容器に容易に充填するために、機械的粉砕
を行い、所定の大きさを有する二次凝集体の銀と酸化錫
の混合粉末を得るようにする。Next, in order to easily fill the heat-treated powder into a container used for producing a green compact, mechanical pulverization is carried out to form a secondary aggregate of silver and tin oxide having a predetermined size. Try to get a mixed powder.

【００２７】上述プロセスを経て得られた粉末は粒径が
０．５μｍ以下で平均粒径が０．１μｍ前後という微細
な酸化錫粒子を持つ銀−酸化錫粉末にされる。The powder obtained through the above process is made into a silver-tin oxide powder having fine tin oxide particles having a particle size of 0.5 μm or less and an average particle size of about 0.1 μm.

【００２８】又、銀−酸化錫接点材料の酸化錫の粉末の
サイズについてその平均粒径を０．５μｍ以下にするこ
とで従来加工性が著しく乏しかった酸化錫含有量につい
て１０ｗｔ％を超える銀−酸化錫材料の冷間加工性が飛
躍的に向上することになり、加えて接点性能試験にも多
大な影響を与えることになる。Further, the size of the tin oxide powder of the silver-tin oxide contact material has an average particle size of 0.5 μm or less, and the tin oxide content, which has been extremely poor in the conventional processability, exceeds 10 wt% of the silver oxide. The cold workability of the tin oxide material will be dramatically improved, and in addition, the contact performance test will be greatly affected.

【００２９】このことは酸化物粒子を微細にすればする
ほど接点材料の加工面では銀相互の結び付きが強固にな
ることと、接点性能面では接点開閉時のアークによる酸
化物の飛散を防止することが出来ることと相俟って接点
接触面上に露出する酸化物量が低減するため、接触抵抗
値を低く抑えることに有利に働くものである。This means that the finer the oxide particles are, the stronger the mutual connection of silver is in the processed surface of the contact material, and the scattering of the oxide due to the arc when the contact is opened and closed is prevented in the contact performance. In addition to this, the amount of oxide exposed on the contact surface of the contact is reduced, which is advantageous in suppressing the contact resistance value to be low.

【００３０】次いで、粉砕によって得られた銀−酸化錫
粉末をラバープレス（例えば、CIP＝冷間静水圧加圧装
置）を用いて加圧力２〜５ton ／cm² を加え、圧粉体を
作製し、８００℃〜９００℃で２〜５時間焼結処理した
後、押出式で線状に押出ししてこの出願の発明の１つの
要旨を成す銀−酸化錫接点材料を得ることが出来る。Then, the silver-tin oxide powder obtained by pulverization is applied with a pressing force of ² to 5 ton / cm ² using a rubber press (for example, CIP = cold hydrostatic pressure press) to prepare a green compact. Then, it is sintered at 800 ° C. to 900 ° C. for 2 to 5 hours and then extruded in a linear shape to obtain a silver-tin oxide contact material which constitutes one of the gist of the invention of this application.

【００３１】尚、ここで加圧力を２〜５ton ／cm² とす
るのは２ton ／cm² 未満では圧粉体密度が上がらず、焼
結時に焼結がうまく進まないからであり、又、５ton ／
cm²までとするのは該５ton ／cm² 以上の圧力を加えて
も、圧粉体密度が上がらないからである。The reason why the applied pressure is ² to 5 ton / cm ² is that the density of the green compact does not increase below ² ton / cm ² and the sintering does not proceed well at the time of sintering. /
The reason why the pressure is up to cm ² is that the green compact density does not increase even if a pressure of 5 ton / cm ² or more is applied.

【００３２】そして、焼結温度を８００℃〜９００℃の
範囲としたのは８００℃未満では処理プロセスで満足し
得る焼結が進まず、９００℃以上では銀融点に近づき過
ぎるきらいがあるからである。The reason why the sintering temperature is set in the range of 800 ° C. to 900 ° C. is that if the temperature is lower than 800 ° C., the sintering process does not proceed satisfactorily, and if the temperature is 900 ° C. or higher, the melting point tends to approach the silver melting point. is there.

【００３３】次に、上述実施例に則す実験例、及び、比
較例を表、及び、図（写真）を参照して示せば次の通り
である。Next, the experimental examples according to the above-mentioned examples and the comparative examples will be described below with reference to the table and the drawings (photographs).

【００３４】まず、硝酸銀13500g、錫酸化ナトリウム25
00g をそれぞれ純水で溶解した。First, silver nitrate 13500 g and sodium tin oxide 25
00 g was dissolved in pure water.

【００３５】ここで、前者の溶液をａ液、後者の溶液を
ｂ液とし、水酸化ナトリウム溶液4500 ml を該ｂ液と混
合してｃ液とする。Here, the former solution is liquid a and the latter solution is liquid b. 4500 ml of sodium hydroxide solution is mixed with liquid b to prepare liquid c.

【００３６】そこで、予め純水を張った溶解タンク内に
該ａ液とｃ液を同時に滴下し、１時間攪拌して中和反応
を促進させ、沈殿物上の上澄み液を抜取り純水を補給
し、更に１時間攪拌してデカント処理を行い、該デカン
ト処理を４回繰り返した後、沈殿物を濾過乾燥させて酸
化銀と水酸化錫の混合生成物を得た。Therefore, the a liquid and the c liquid are simultaneously dropped into a dissolution tank filled with pure water, and the mixture is stirred for 1 hour to promote the neutralization reaction, and the supernatant liquid on the precipitate is removed and replenished with pure water. Then, the mixture was further stirred for 1 hour for decanting treatment, and the decanting treatment was repeated 4 times, and then the precipitate was filtered and dried to obtain a mixed product of silver oxide and tin hydroxide.

【００３７】ここで得られた混合生成物を金属に還元す
るべく６００℃×３時間の加熱分解処理を行った後、機
械的粉砕を付与して銀−酸化錫の混合粉末を得た。The mixed product obtained here was subjected to a thermal decomposition treatment at 600 ° C. for 3 hours to reduce it to a metal, and then mechanically pulverized to obtain a silver-tin oxide mixed powder.

【００３８】そして、該混合粉末をラバープレス（CIP
＝冷間静水圧加圧装置）で加圧力４ton ／cm² を印加
し、圧粉体を得て８６０℃で５時間焼結した後、押出機
でφ６×Ｌの線状に押出した。Then, the mixed powder is subjected to rubber press (CIP
(= Cold hydrostatic pressure device), a pressing force of 4 ton / cm ² was applied to obtain a green compact, which was sintered at 860 ° C. for 5 hours and then extruded into a φ6 × L linear shape by an extruder.

【００３９】その後、押出し素線を伸線加工、焼鈍を繰
り返して所定の線径のφ１．９×Ｌまで加工した。Thereafter, the extruded wire was repeatedly drawn and annealed to a predetermined wire diameter of φ1.9 × L.

【００４０】ここで、図１に市販の島津式遠心沈降式粒
度分布測定装置SA-CP3で測定したこの出願の発明の接点
材料中の酸化錫の粒度分布（横軸に粒子量相対分布
((％))，縦軸に粒径((μｍ))）を示す。Here, the particle size distribution of tin oxide in the contact material of the invention of this application measured by a commercially available Shimadzu centrifugal sedimentation type particle size distribution measuring apparatus SA-CP3 in FIG.
((%)), And the vertical axis represents the particle size ((μm))).

【００４１】尚、当該実験例で使用した酸化錫の採取方
法は銀−酸化錫の焼結体の一部を採り、銀だけを溶解し
て採取したものである。The method of collecting tin oxide used in the experimental example is a method in which a part of a silver-tin oxide sintered body was taken and only silver was dissolved.

【００４２】上述実験態様と比較するために以下の如く
作製した比較材料について示す。A comparative material prepared as follows is shown for comparison with the above-described experimental mode.

【００４３】銀1200g に硝酸（１＋１）２．５ lを加え
て加熱して溶解した溶液に対し錫１８０g に硝酸２ lと
弗化水素酸９０ml，水８００mlの混酸で溶解した溶液を
加え、充分に攪拌して銀と錫が混合されて溶解した溶液
ｄを作製し、該溶液ｄに水酸化ナトリウム溶液を加え、
pHが８になった時点で過硫酸カリウム粉末3000g を添加
して充分に攪拌した後、更に水酸化ナトリウム溶液をpH
値が１０になるまで加えて生成物を得た。To a solution prepared by adding 2.5 l of nitric acid (1 + 1) to 1200 g of silver and heating it, a solution of 180 g of tin dissolved in 2 l of nitric acid, 90 ml of hydrofluoric acid and 800 ml of water was added, To prepare a solution d in which silver and tin are mixed and dissolved by stirring, and a sodium hydroxide solution is added to the solution d,
When the pH reaches 8, add 3000 g of potassium persulfate powder and stir well, then add sodium hydroxide solution to pH.
The product was obtained by addition until the value was 10.

【００４４】その後、該pH値が１３以上になるまで追加
的に水酸化ナトリウム溶液を加え、これに続いて硝酸を
添加してpH値を８．５に戻し沈殿物を得た。Thereafter, a sodium hydroxide solution was additionally added until the pH value became 13 or more, and then nitric acid was added thereto to return the pH value to 8.5 and obtain a precipitate.

【００４５】このようにして得られた銀と錫の混合生成
物を上述実験例と同様な手法で加工を進めて比較材を得
た。The silver-tin mixed product thus obtained was processed in the same manner as in the above-mentioned experimental example to obtain a comparative material.

【００４６】ここで、図２に前述実験例の材料の原料粉
中の SnO₂ 粒子のＳＥＭ像（20000倍の金属組織の顕微
鏡拡大写真）を示し、図３に上述比較材の87Ag−13 SnO
₂ 粒子のSEM 像（10000 倍の金属組織の顕微鏡拡大写
真）を示す。Here, FIG. 2 shows a SEM image of SnO ₂ particles in the raw material powder of the material of the above-described experimental example (a microscopic enlarged photograph of a metal structure of 20000 times), and FIG. 3 shows 87Ag-13SnO of the comparative material.
An SEM image of _two particles (a magnified micrograph of a metal structure at 10000 times) is shown.

【００４７】而して、図１の粒度分布と図２のＳＥＭ像
から先述特許請求の範囲第２項で限定したこの出願の発
明の SnO₂ 粒子の微細粒が鮮明に認識することが出来
る。Thus, from the particle size distribution of FIG. 1 and the SEM image of FIG. 2, it is possible to clearly recognize the fine particles of the SnO ₂ particles of the invention of this application, which are limited by the above-mentioned claim ₂ .

【００４８】そして、図２と図３の SnO₂ 粒子のＳＥＭ
像についてこの出願の発明の実験例の材料と比較例の材
料とを対比すると、この出願の発明による SnO₂ 粒子の
方が充分に微細化されていることが知認される。Then, the SEM of the SnO ₂ particles shown in FIGS.
By comparing the material of the experimental example of the invention of this application with the material of the comparative example with respect to the image, it is recognized that the SnO ₂ particles according to the invention of this application are sufficiently finer.

【００４９】次に、上述両材料の接点の試験例を表１に
示す。Next, Table 1 shows a test example of the contacts of the above materials.

【００５０】[0050]

【表１】 [Table 1]

【００５１】この接点試験の条件は上述実験における加
工工程を経た材料を接点頭部径φ４ｍｍ、接点頭部厚み
０．６ｍｍのリベットに成形してASTM型接点試験機（DC
14 v22.5 A）で、２０万回の開閉試験を行った。The condition of this contact test is that the material that has undergone the processing steps in the above experiment is molded into a rivet having a contact head diameter of φ4 mm and a contact head thickness of 0.6 mm, and the ASTM type contact tester (DC
14 v22.5 A), the open / close test was performed 200,000 times.

【００５２】そして、当該試験により得られた加工靭性
のデータ例を次の表２に示す。Table 2 below shows an example of data on the work toughness obtained by the test.

【００５３】[0053]

【表２】 [Table 2]

【００５４】次に、図４，図５にこの出願の発明で作製
した87Ag-13SnO₂ の金属組織拡大顕微鏡写真を示し、図
６に比較材として乾式混合法による87Ag-13SnO₂ の金属
組織の顕微鏡拡大写真を示す。Next, FIGS. 4 and 5 show enlarged microstructure photographs of the metal structure of 87Ag-13SnO ₂ produced by the invention of this application, and FIG. 6 shows the metal structure of 87Ag-13SnO ₂ by the dry mixing method as a comparative material. The microscope enlarged photograph is shown.

【００５５】該図４，図６の写真は光学顕微鏡により４
００倍に、又、図５の写真はSEM 装置により10000 倍に
それぞれ拡大撮影したものである。The photographs of FIGS. 4 and 6 are taken by an optical microscope.
The image is magnified 00 times and the photograph in FIG. 5 is magnified 10,000 times with the SEM apparatus.

【００５６】而して、 SnO₂ 粒子の均一分散性について
この出願の発明による金属組織写真の図４と比較材の金
属組織写真の図６とを比較すると、この出願の発明によ
る材料の金属組織の方が SnO₂ 粒子の均一分散性が良好
であることが充分に認められる。Thus, comparing the uniform dispersibility of SnO ₂ particles with the metallographic photograph of the invention of this application in FIG. 4 and the metallographic photograph of the comparative material in FIG. 6, the metallographic texture of the material according to the invention of this application is compared. It is fully recognized that the above results in better uniform dispersibility of SnO ₂ particles.

【００５７】[0057]

【発明の効果】以上、この出願の発明によれば、従来の
化学的共沈法が潜在的に有する利点にもかかわらず、こ
れを阻害する接点材料作製時の煩瑣性を解決すると共に
酸化錫の粒径を大幅に下げることを可能とした知見を得
たことに基づいて酸化錫含有量が１０ｗｔ％を超えて
も、冷間加工を可能とし、併せて生産性の向上とコスト
ダウンが図れるという優れた効果が奏され、又、該酸化
錫の粒子を微細、且つ、均一に分散させることの現出を
可能にしたことにより接点材に酸化錫の凝集部が無くな
り、そのため、均一な加工特性を具備することが出来る
効果があるのみならず、更に、接点特性においても、接
点開閉時のアークによる酸化物の飛散防止の実現が可能
になったことにより、接触抵抗値に有利に作用する効果
もあり、耐溶着性，耐消耗性を高め得ることによる接点
による品質の向上と接点性能の向上が共に図れるという
優れた効果が奏される。As described above, according to the invention of this application, in spite of the potential advantages of the conventional chemical co-precipitation method, it is possible to solve the inconvenience at the time of producing a contact material which inhibits this, and to prevent tin oxide. Based on the finding that it was possible to significantly reduce the particle size of tin oxide, even if the tin oxide content exceeds 10 wt%, cold working is possible, and at the same time productivity can be improved and cost can be reduced. In addition, since the tin oxide particles can be finely and uniformly dispersed, the agglomeration of tin oxide is eliminated in the contact material, which results in uniform processing. Not only is there an effect that the characteristics can be provided, but also in the contact characteristics, it is possible to prevent the scattering of oxides due to the arc when the contact is opened and closed, which has an advantageous effect on the contact resistance value. Also effective, welding resistance, Excellent effect of improving the attained both improve the contact performance of quality due contacts due to may enhance the wear resistance are obtained.

【図面の簡単な説明】[Brief description of drawings]

【図１】実施例の酸化錫の粒度分布グラフ図である。FIG. 1 is a particle size distribution graph of tin oxide of an example.

【図２】同、原料粒中の SnO₂ 粒子の20000 倍の金属組
織の顕微鏡拡大図（写真）である。FIG. 2 is a microscopic enlarged view (photograph) of the metal structure of the SnO ₂ particles in the raw material grains, which is 20,000 times as large.

【図３】比較例の SnO₂ 粒子の10000 倍の金属組織の顕
微鏡拡大図（写真）である。FIG. 3 is a microscopic enlarged view (photograph) of a metal structure of 10000 times that of SnO ₂ particles of a comparative example.

【図４】実施例の SnO₂ 粒子の400 倍の金属組織の顕微
鏡拡大図（写真）である。FIG. 4 is a microscopic enlarged view (photograph) of a metal structure of 400 times that of SnO ₂ particles of Example.

【図５】実施例の SnO₂ 粒子の10000 倍の金属組織の顕
微鏡拡大図（写真）である。FIG. 5 is a microscopic enlarged view (photograph) of a metal structure of 10000 times that of SnO ₂ particles of Example.

【図６】比較例の SnO₂ 粒子の400 倍の金属組織の顕微
鏡拡大図（写真）である。FIG. 6 is a microscopic enlarged view (photograph) of a metal structure of 400 times that of SnO ₂ particles of a comparative example.

───────────────────────────────────────────────────── フロントページの続き (72)発明者 永島 利一 埼玉県草加市青柳２丁目12番30号 石福金 属興業株式会社草加第一工場内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Riichi Nagashima 2-12-30 Aoyagi, Soka-shi, Saitama Ishifukukin Industrial Co., Ltd.

Claims (3)

【特許請求の範囲】[Claims] 【請求項１】酸化錫が５〜４０ｗｔ％の範囲内で残部が
銀から成り化学的共沈法を介しての粉末焼結法による材
料で酸化錫粒子がＡｇマトリックス中に微細、且つ均一
に分散され、更に該酸化錫粒子の粒径が０．５μｍ以下
であることを特徴とする銀−酸化錫接点材料。1. A material obtained by a powder sintering method through a chemical coprecipitation method in which tin oxide is in the range of 5 to 40 wt% and the balance is silver, and tin oxide particles are fine and uniform in an Ag matrix. A silver-tin oxide contact material which is dispersed and in which the particle size of the tin oxide particles is 0.5 μm or less. 【請求項２】硝酸銀溶液と錫酸化ナトリウム溶液を同時
に混合、もしくは水マトリックス中に同時に添加混合さ
せ、生成される沈殿物を回収し、洗浄・脱水処理を繰返
した後、乾燥・熱処理工程を経て銀と錫酸化物との混合
粉末を作製し、該混合粉末を用いて粉末焼結処理し、押
出し加工・伸線加工、又は圧延加工を経るようにするこ
とを特徴とする銀−酸化錫接点材料の製造方法。2. A silver nitrate solution and a sodium tin oxide solution are mixed at the same time or added and mixed in a water matrix at the same time to collect a precipitate formed, which is repeatedly washed and dehydrated, and then dried and heat treated. A silver-tin oxide contact characterized by producing a mixed powder of silver and tin oxide, subjecting the mixed powder to a powder sintering treatment, and performing an extrusion process, a wire drawing process, or a rolling process. Material manufacturing method. 【請求項３】上記添加混合を滴下により行うことを特徴
とする特許請求の範囲第２項記載の銀−酸化錫接点材料
の製造方法。3. The method for producing a silver-tin oxide contact material according to claim 2, wherein the addition and mixing is carried out dropwise.