【発明の詳細な説明】[Detailed description of the invention]
本発明は銅窒化物系の封入用電気接点材料に係
る。従来、封入用電気接点材料としては、銀系合
金、金系合金、パラジユウム系合金などの貴金属
系例えば銀酸化カドミウム12重量％より成る複合
電気接点材料が小電流乃至中電流域で優れた接点
特性を示すものとして各方面で広く用いられてき
た。然し乍ら、近時電気機器及び電子機器の小型
化により電気接点材料に要求される接点特性が苛
酷になつてきており、従来の銀酸化カドミウム系
の複合電気接点材料では耐溶着性に劣り、使用に
耐えなくなつてきた。この為更に耐溶着性に優れ
た封入用電気接点材料が要望されている。
一方貴金属の使用をおさえ安価な接点材料を供
給する為に電気伝導度が銀についで大きく銀より
融点の高い銅に着目し、これを母合金とする接点
材料を使用しようとする試みがなされはじめた。
銅を接点材料として使用する場合銅の耐蝕性が問
題となるが、この問題は銅を真空中あるいは中性
ガス中で使用することにより解決され貴金属を母
合金として用いた場合に比較して何ら遜色のない
特性を示すものである。特に窒化物は融点の高い
材料が多く窒化チタンあるいは窒化ジルコニユウ
ム等の高融点材料を銅の分散強化材として使用し
た場合消耗量が小さくまた、溶着力についても優
れた特性を示すものである。しかし、このような
融点が高い為に溶融、蒸発等による組成変化が少
ない材料は接点の開閉を重ねるにつれて表面層に
生成される分散強化材の凝集層が、高く不安定な
接触抵抗をもたらす傾向を有するものである。
本発明は上記諸事情に鑑みなされたものであり
従来の銅−窒化物系の複合電気接点材料よりも優
れた接点性能、とりわけ安定した低接融抵抗を有
する複合電気接点材料を提供せんとするものであ
る。
本発明の封入用電気接点材料は銅中に窒化マグ
ネシウム１〜15重量％を添加して成るものである
が銅中に窒化マグネシウムを添加した理由は窒化
マグネシウムが1300℃において熱分解し、不安定
な性質を有し接点表面の窒化物凝集バンドの生成
を防ぎ融触抵抗を安定させる働きを有するからで
ある。
本発明の電気接点材料に於いて、銅中に添加す
る窒化マグネシウムを１〜15重量％としたのは、
１重量％未満では銅の地が充分に強化されない為
に耐消耗特性、あるいは耐溶着特性に関しては良
好な結果は得られない。また15重量％を越えた組
成では加工が困難となり、材料の導電率も低くな
るので良好な結果は得られない。以上の理由によ
り特許請求の範囲に記載した組成を限定したもの
である。
なおこれらの銅−窒化物材料を窒素雰囲気中で
使用した場合さらにすぐれた耐溶着特性を示すも
のである。
実施例
平均粒径4μの銅紛と窒化マグネシウムをＶ型
混合器により３時間混合した後紛末をルツボに充
てんし所定の密度に達するまで焼結圧縮を繰り返
した材料を熱間で押出した。これを伸線機により
線材とした後、ヘツダー機により加工し下表の組
成を有する頭部径4φmm、頭高1.1mm、脚部径2.8φ
mm、脚長1.6mmのリベツト型接点を得た。
従来例 １
平均粒径4μの銅紛と窒化チタンをＶ型混合器
により３時間混合した後紛末をルツボに充てんし
所定の密度に達するまで焼結圧縮を繰り返した後
ヘツダー機により加工し下表の組成を有する頭部
径4φmm、頭高1.1mm、脚部径2.8φmm、脚長1.6mmの
リベツト型接点を得た。
従来例 ２
銀カドミウム合金を鋳造後引ぬき伸線加工を行
ないこれをヘツダー機により頭部径4φmm、頭高
1.1mm、脚部径2.8φmm、脚長1.6mmのリベツト形状
に成形した後５気圧800℃で内部酸化を行ない銀
酸化カドミウム12重量％とした。
然して上記実施例、従来例１，２の電気接点を
下記の試験条件にて開閉試験を行い、溶着発生ま
での開閉回数を測定し且つ接触抵抗、消耗を測定
したところ、下記の表の右欄に示すような結果を
得た。
試験条件
電 圧 A.C.100V 50Hz
電 流 投入電流 40A、定常電流 10A
開閉頻度 20回／分
負 荷 抵抗
開閉回数 溶着発生まで
雰囲気 窒素雰囲気
The present invention relates to a copper nitride-based encapsulating electrical contact material. Conventionally, as electrical contact materials for encapsulation, composite electrical contact materials made of precious metals such as silver-based alloys, gold-based alloys, and palladium-based alloys, such as 12% by weight of silver cadmium oxide, have excellent contact characteristics in the small to medium current range. It has been widely used in various fields to indicate. However, with the recent miniaturization of electrical and electronic devices, the contact characteristics required of electrical contact materials have become more severe, and conventional silver-cadmium oxide-based composite electrical contact materials have poor welding resistance and cannot be used. It was becoming unbearable. For this reason, there is a need for an electrical contact material for encapsulation that has even better welding resistance. On the other hand, in order to reduce the use of precious metals and provide inexpensive contact materials, attention has been paid to copper, which has the second highest electrical conductivity after silver and a higher melting point than silver, and attempts have been made to use copper as a mother alloy for contact materials. Ta.
When copper is used as a contact material, corrosion resistance of copper becomes a problem, but this problem is solved by using copper in a vacuum or neutral gas, and it is no more expensive than using precious metals as the mother alloy. It shows comparable characteristics. In particular, many nitrides have a high melting point, and when a high melting point material such as titanium nitride or zirconium nitride is used as a dispersion reinforcing material for copper, it has a small amount of wear and exhibits excellent welding strength. However, since such materials have a high melting point and therefore undergo little compositional change due to melting, evaporation, etc., as the contact is repeatedly opened and closed, an agglomerated layer of dispersion reinforcement that is generated on the surface layer tends to result in high and unstable contact resistance. It has the following. The present invention was made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a composite electrical contact material that has superior contact performance than conventional copper-nitride composite electrical contact materials, and in particular, has stable and low contact resistance. It is something. The electrical contact material for encapsulation of the present invention is made by adding 1 to 15% by weight of magnesium nitride to copper.The reason for adding magnesium nitride to copper is that magnesium nitride thermally decomposes at 1300℃ and becomes unstable. This is because it has the property of preventing the formation of nitride agglomerated bands on the contact surface and stabilizing the fusion resistance. In the electrical contact material of the present invention, the magnesium nitride added to the copper is 1 to 15% by weight.
If it is less than 1% by weight, the copper base will not be sufficiently strengthened, and good results will not be obtained in terms of wear resistance or welding resistance. Furthermore, if the composition exceeds 15% by weight, processing becomes difficult and the conductivity of the material becomes low, making it difficult to obtain good results. For the above reasons, the compositions described in the claims are limited. Furthermore, when these copper-nitride materials are used in a nitrogen atmosphere, they exhibit even better anti-welding properties. Example After mixing copper powder with an average particle size of 4 μm and magnesium nitride in a V-type mixer for 3 hours, the powder was filled in a crucible and sintered and compressed repeatedly until it reached a predetermined density, and the material was hot extruded. This is made into a wire with a wire drawing machine, and then processed with a header machine to have the composition shown in the table below: head diameter 4φmm, head height 1.1mm, leg diameter 2.8φ
A rivet-type contact with a leg length of 1.6 mm was obtained. Conventional example 1 Copper powder with an average particle size of 4μ and titanium nitride are mixed in a V-type mixer for 3 hours, then the powder is filled into a crucible, sintered and compressed repeatedly until a predetermined density is reached, and then processed using a header machine. A rivet type contact with a head diameter of 4φmm, a head height of 1.1mm, a leg diameter of 2.8φmm, and a leg length of 1.6mm having the composition shown in the table was obtained. Conventional example 2 After casting a silver cadmium alloy, it is drawn and wire-drawn, and then the head diameter is 4φmm and the head height is
After molding into a rivet shape with a diameter of 1.1 mm, a leg diameter of 2.8 φmm, and a leg length of 1.6 mm, internal oxidation was performed at 5 atm and 800°C to obtain 12% by weight of silver cadmium oxide. However, the electrical contacts of the above embodiment and conventional examples 1 and 2 were subjected to opening and closing tests under the following test conditions, and the number of openings and closings until welding occurred was measured, as well as the contact resistance and wear and tear. The results shown are obtained. Test conditions Voltage AC100V 50Hz Current Supply current 40A, steady current 10A Switching frequency 20 times/min Load Resistance switching number of times Atmosphere until welding occurs Nitrogen atmosphere
【表】
上記の表の右欄の数値で明らかなように実施例
の電気接点材料にて作つた電気接点は、従来例
１，２の電気接点材料に比し耐消耗性、耐溶着性
が優るとも劣らずかつ安定した低接触抵抗を示す
ことがわかる。
以上詳記した通り本発明による複合電気接点材
料は、従来の銀−酸化カドミウムおよび銅窒化チ
タン系の電気接点材料に較べ耐溶着性、耐消耗性
が優るとも劣らずかつすぐれた接触抵抗特性を性
すので最近の電気及び電子機器の小型化に伴なう
苛酷な使用条件にも対応できる接点特性を備えた
画期的な封入用電気接点材料と言える。[Table] As is clear from the values in the right column of the table above, the electrical contacts made with the electrical contact materials of Examples have better wear resistance and welding resistance than the electrical contact materials of Conventional Examples 1 and 2. It can be seen that it exhibits a stable low contact resistance that is as good as it is superior. As detailed above, the composite electrical contact material according to the present invention has superior welding resistance and abrasion resistance as well as superior contact resistance characteristics compared to conventional electrical contact materials based on silver-cadmium oxide and copper titanium nitride. Therefore, it can be said to be an innovative electrical contact material for encapsulation that has contact characteristics that can withstand the harsh operating conditions associated with the recent miniaturization of electrical and electronic equipment.