Electric contact and socket for electrical part

Abstract

A contact pin includes a base material composed of a material having a conductive property and an outermost surface layer made of a material into which Sn is dissolved and diffused by applying heat.

1 . A socket for an electrical part, that is used for burn-in test, comprising:
 a socket body, comprising an accommodation portion in which an electric terminal of the electrical part is accommodated, the electric terminal comprising a film on a surface thereof, the film comprising Sn, the accommodation portion comprising an electric contact which contacts the electric terminal, the electric contact comprising:   an intermediate layer comprising Ni, and   an outermost surface layer which is formed directly on the intermediate layer, the outermost surface layer comprising Ag and Sn.   
     
     
         2 . The socket for an electrical part according to  claim 1 , wherein a weight ratio of the Ag to the Sn is 80 or more weight percent of the Ag to the remaining weight percent of the Sn. 
     
     
         3 . The socket for an electrical part according to  claim 1 , wherein the outermost surface layer of the electric contact is a Ag—Sn plating layer. 
     
     
         4 . The socket for an electrical part according to  claim 1 , wherein
 Sn included in a solder is diffused into the outermost surface layer, and   the outermost surface layer has a tensile strength higher than a tensile strength of the solder, and an alloy containing both the outermost surface layer and the diffused Sn has a tensile strength higher than the tensile strength of the solder.   
     
     
         5 . The socket for an electrical part according to  claim 4 , wherein the outermost surface layer is made of an Ag—Sn alloy plating layer. 
     
     
         6 . The socket for an electrical part according to  claim 1 , wherein the electric contact comprises a pin.