Electrical contact and electrical equipment including the same

Abstract

An electric contact of high performance that is constituted of a Cd-free Ag alloy posing no toxic problem, excels in insulating capability and can ensure stability of brazing and consumption characteristics and that can be used in a breaker or high-load electromagnetic switch; and electrical equipment including the electric contact. In particular, an electric contact comprised of an Ag alloy containing 1 to 9 mass % of Sn in which the amount of Cd as impurity is 0 or less than 0.01 mass %, the electric contact having a double layer structure composed of a surface-side first layer and an interior second layer wherein the first layer has a thickness of 10 μm or greater and has an average hardness of 150 or higher on the microvickers scale stipulated in JIS while the second layer has an average hardness of higher than 130 on the same scale.

1 . An electrical contact comprising an Ag alloy containing Sn in an amount of from 1 to 9% by weight and Cd in an amount of 0% by weight, inclusive, to less than 0.01% by weight and having a two-layer structure composed of a first layer on a surface side thereof and a second layer on an inner side thereof, wherein the first layer has an average hardness of 150 or more on the microvickers scale defined by JIS and a thickness of 10 μm or more and the second layer has an average hardness of more than 130 on the microvickers scale.  
   
   
       2 . The electrical contact as described in  claim 1 , wherein the average hardness of the aforesaid first layer is 190 or more on the aforesaid scale.  
   
   
       3 . The electrical contact as described in  claim 1 , wherein In is incorporated therein in an amount of from 1% to 9% by weight in addition to Sn.  
   
   
       4 . The electrical contact as described in  claim 1 , wherein as additive components other than Sn and In there are incorporated at least one selected from the group of elements consisting of Sb, Ca, Bi, Ni, Co, Zn, Cu, Mo, W, Ge, Te, Cr and Pb.  
   
   
       5 . An electrical apparatus using an electrical contact as described in  claim 1 .  
   
   
       6 . An electrical apparatus using an electrical contact as described in  claim 2 .  
   
   
       7 . An electrical apparatus using an electrical contact as described in  claim 3 .  
   
   
       8 . An electrical apparatus using an electrical contact as described in  claim 4.