Electrical contact material and process

Abstract

A material for use in making electrical contacts is produced in a powder form suitable for later processing into electrical contacts by standard metallurgical techniques. The material consists of a first metal, such as silver, and the oxide of a second metal, such as cadmium, added to the first metal in a proportion up to the limits of solubility of the second metal in the first metal. An oxide of a third metal having a low electronic work function level, such as lithium oxide, is added and uniformly distributed on the surfaces of the powder particles by precipitation. A fourth metal, such as tellurium, that is insoluble in the first metal is also added to provide selected characteristics.

I claim: 
     
       1. A material for use in making electrical contacts for power level applications consisting essentially of a first metal selected from a group consisting of silver and copper, an oxide of a second metal selected from a group consisting of cadmium, tin, and zinc added in an amount from a minimum effective amount up to a maximum equal to the limit of solubility of the second metal in the first metal, and an oxide of a third metal selected from a group consisting of metals in group IA and IIA of a periodic table .Iadd.with the oxides of the second and the third metals uniformly distributed throughout the material.Iaddend.. 
     
     
       2. A material according to claim 1 wherein the third metal is selected from a group consisting of lithium and barium. 
     
     
       3. A material according to claim 1 wherein the third metal is selected from a group consisting of lithium, sodium, potassium, rubidium, cesium and francium. 
     
     
       4. A material according to claim 1 wherein the third metal is selected from a group consisting of magnesium, calcium, strontium, and barium. 
     
     
       5. A material according to claim 1 wherein the first metal is silver and the second metal is cadmium.  .[.6. A material according to claim 1 wherein the third metal is selected from a group consisting of lithium and 
     
     
        barium..]. 7. A material according to claim 1 wherein the first metal is 
     
     
        silver. 8. A material according to claim 7 wherein the second metal is 
     
     
        cadmium. 9. A material according to claim 8 wherein the third metal is a 
     
     
        metal selected from the group consisting of lithium and barium. 10. A 
     
     
        material according to claim 1 wherein the third metal is lithium. 11. A material according to claim 1 wherein the amount of the oxide of the third metal is added from a minimum effective amount up to a maximum of about three weight percent of the third metal relative to the total weight of 
     
     
        the material. 12. A material according to claim 11 wherein the first metal is silver, the second metal is cadmium and the third metal is a metal 
     
     
        selected from the group consisting of lithium and barium. 13. A material 
     
     
        according to claim 11 wherein the third metal is lithium. 14. A material according to claim 1 additionally having an oxide of a fourth metal selected to be insoluble in the first metal and provide embrittlement 
     
     
        characteristics. 15. A material according to claim 14 wherein the first metal is silver, the second metal is cadmium, and the third metal is 
     
     
        lithium. 16. A material according to claim 15 wherein the fourth metal is tellurium.  .[.17. A method according to claim 14 wherein the fourth metal 
     
     
        is tellurium..]. 18. A material according to claim 14 wherein the third metal is a metal selected from the group consisting of lithium and barium. 
     
     
        9. A material according to claim 14 wherein the first metal is silver. 
     
     
            A material according to claim 14 wherein the third metal oxide is added in an amount from a minimum effective amount up to a maximum of approximately three weight percent of the third metal in relation to the 
     
     
        total amount of material present. 21. A material according to claim 20 wherein the first metal is silver, the second metal is cadmium, the third 
     
     
        metal is lithium, and the fourth metal is tellurium. 22. A material 
     
     
        according to claim 20 wherein the fourth metal is tellurium. 23. A 
     
     
        material according to claim 22 wherein the third metal is lithium. 24. A material according to claim 20 wherein the third metal is a metal selected 
     
     
        from a group consisting of lithium and barium. 25. A material according to claim 24 wherein the first metal is silver and the fourth metal is 
     
     
        tellurium. 26. A material according to claim 20 wherein the fourth metal is added from a minimum effective amount up to a maximum of about three 
     
     
        weight percent of the total of the material. 27. A material according to claim 26 wherein the first metal is silver, the second metal is cadmium, 
     
     
        the third metal is lithium, and the fourth metal is tellurium. 28. A 
     
     
        material according to claim 26 wherein the fourth metal is tellurium. 29. A material according to claim 26 wherein the third metal is a metal 
     
     
        selected from a group consisting of lithium and barium. 30. A material 
     
     
        according to claim 26 wherein the second metal is cadmium. 31. A material according to claim 26 wherein the third metal is lithium and the fourth 
     
     
        metal is tellurium. 32. A material according to claim 26 wherein the first 
     
     
        metal is silver and the second metal is cadmium. 33. An electrical contact for electrical power applications comprising a first metal selected from a group consisting of silver and copper, an oxide of a second metal selected from a group consisting of cadmium, tin and zinc added in an amount from a miniumum effective amount up to a maximum equal to the limit of solubility of the second metal in the first metal, and an oxide of a third metal selected from a group consisting of the metals in groups IA and IIA of a periodic table .Iadd.with the oxides of the second and the third metals uniformly distributed throughout the material.Iaddend..  .[.34. An electrical contact according to claim 33 wherein the third metal is selected from a group consisting of lithium, sodium, potassium, rubidium, 
     
     
        cesium, francium, magnesium, calcium, strontium, and barium..]. 35. An electrical contact according to claim 33 wherein the third metal is selected from a group consisting of lithium and barium.  .[.36. An electrical contact according to claim 33 wherein the third metal is 
     
     
        selected from a group consisting of lithium and barium..]. 37. An electrical contact according to claim 33 wherein the third metal is selected from a group consisting of lithium, sodium, potassium, rubidium, 
     
     
        cesium and francium. 38. An electrical contact according to claim 33 wherein the third metal is selected from a group consisting of magnesium, 
     
     
        calcium, strontium, and barium. 39. An electrical contact according to claim 33 wherein the first metal is silver and the second metal is cadmium.  .[.40. An electrical contact according to claim 33 wherein the third metal is selected from a group consisting of lithium and barium..]. 
     
     
         1. An electrical contact according to claim 33 wherein the first metal is 
     
     
        silver. 42. An electrical contact according to claim 33 wherein the second 
     
     
        metal is cadmium. 43. An electrical contact according to claim 33 wherein the third metal is a metal selected from the group consisting of calcium, 
     
     
        potassium, cesium and lithium. 44. An electrical contact according to 
     
     
        claim 33 wherein the third metal is lithium. 45. An electrical contact according to claim 33 wherein the oxide of the third metal is added in an amount from a minimum effective amount up to a maximum of about three weight percent of the third metal relative to the total weight of the first metal, the oxide of the second metal, and the oxide of the third 
     
     
        metal. 46. An electrical contact according to claim 45 wherein the first metal is silver, the second metal is cadmium and the third metal is 
     
     
        lithium. 47. An electrical contact according to claim 45 wherein the third 
     
     
        metal is lithium. 48. An electrical contact according to claim 33 also comprising an oxide of a fourth metal selected to have a high ionization 
     
     
        energy. 49. An electrical contact according to claim 48 wherein the first metal is silver, the second metal is cadmium, and the third metal is 
     
     
        lithium. 50. An electrical contact according to claim 49 wherein the 
     
     
        fourth metal is tellurium. 51. An electrical contact according to claim 48 
     
     
        wherein the fourth metal is tellurium. 52. An electrical contact according to claim 48 wherein the third metal is a metal selected from the group 
     
     
        consisting of lithium and barium. 53. An electrical contact according to 
     
     
        claim 48 wherein the first metal is silver. 54. An electrical contact according to claim 48 wherein the third metal oxide is added in an amount from a minimum effective amount up to a maximum of approximately three weight percent of the third metal in relation to the total weight of the first metal, the oxide of the second metal, the oxide of the third metal, 
     
     
        and the oxide of the fourth metal. 55. An electrical contact according to claim 54 wherein the first metal is silver, the second metal is cadmium, 
     
     
        the third metal is lithium, and the fourth metal is tellurium. 56. An electrical contact according to claim 54 wherein the fourth metal is 
     
     
        tellurium. 57. An electrical contact according to claim 56 wherein the 
     
     
        third metal is lithium. 58. An electrical contact according to claim 54 wherein the third metal is a metal selected from a group consisting of 
     
     
        lithium and barium. 59. An electrical contact according to claim 58 
     
     
        wherein the first metal is silver and the fourth metal is tellurium. 60. An electrical contact according to claim 54 wherein the fourth metal is added in the proportion from a minimum effective amount up to a maximum of about three weight percent of the total weight of the first metal, the oxide of the second metal, the oxide of the third metal, and the oxide of 
     
     
        the fourth metal. 61. An electrical contact according to claim 60 wherein the first metal is silver, the second metal is cadmium, the third metal is 
     
     
        lithium, and the fourth metal is tellurium. 62. An electrical contact 
     
     
        according to claim 60 wherein the fourth metal is tellurium. 63. An electrical contact according to claim 60 wherein the third metal is a 
     
     
        metal selected from a group consisting of lithium and barium. 64. An electrical contact according to claim 60 wherein the second metal is 
     
     
        cadmium. 65. An electrical contact according to claim 60 wherein the third 
     
     
        metal is lithium and the fourth metal is tellurium. 66. An electrical contact according to claim 60 wherein the first metal is silver and the second metal is cadmium.