【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触抵抗を有
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リン
１〜15重量％を添加して成るものであるが銅中に
窒化リンを添加した理由は窒化リンが750℃で解
離する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接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
る窒化リンを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の銅粉と窒化リン粉をＶ型混合器
により３時間混合した後粉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2.8φmm、脚
長1.6mmのリベツト型接点を得た。
従来例 １
平均粒径4μの銅粉と窒化チタンをＶ型混合器
により３時間混合した後粉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, noble metals such as silver alloys, gold alloys, and palladium alloys, for example, composite electrical contact materials made of 12% by weight of silver and cadmium oxide, have been used as contacts that are excellent in the small to medium current range. It has been widely used in various fields to indicate characteristics. 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 composite electrical contact materials have poor welding resistance and are no longer used. I've become unable to bear it. 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 circumstances, and it is an object of the present invention to provide a composite electrical contact material that has superior contact performance, especially stable and low contact resistance, than conventional copper-nitride composite electrical contact materials. It is. The electrical contact material for encapsulation of the present invention is made by adding 1 to 15% by weight of phosphorus nitride to copper.The reason for adding phosphorus nitride to copper is the unstable property of phosphorus nitride, which dissociates at 750°C. This is because it has the function of preventing the formation of nitride agglomeration bands on the contact surface and stabilizing the contact resistance. In the electrical contact material of the present invention, the phosphorus nitride added to the copper is 1 to 15% by weight.
If it is less than that, 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 Copper powder with an average particle size of 4 μm and phosphorus nitride powder were mixed in a V-type mixer for 3 hours, and then the powders were filled into a crucible and sintered and compressed repeatedly until a predetermined density was reached, and the material was hot extruded. This was made into a wire with a wire drawing machine, and then processed with a header machine to obtain 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 below. Conventional example 1 Copper powder with an average particle size of 4μ and titanium nitride were mixed in a V-type mixer for 3 hours, then the powder was filled into a crucible, sintered and compressed repeatedly until the specified density was reached, and then processed using a header machine as shown in the table below. A rivet-type contact with a head diameter of 4 φ mm, a head height of 1.1 mm, a leg diameter of 2.8 φ mm, and a leg length of 1.6 mm was obtained. Conventional example 2 After casting, a silver-cadmium alloy was drawn and wire-drawn, and then formed into a rivet shape with a head diameter of 4φmm, head height of 1.1mm, leg diameter of 2.8φmm, and leg length of 1.6mm using a header machine, and then heated to 5 atm. Internal oxidation was carried out at 800°C to give 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 frequency Until welding occurs Atmosphere 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
示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性能を備え
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 excellent contact resistance properties compared to conventional silver-cadmium oxide and copper-titanium nitride electrical contact materials. Therefore, it can be said to be an innovative electrical contact material for encapsulation that has contact performance that can withstand the harsh operating conditions associated with the recent miniaturization of electrical and electronic devices.