Abstract: A contact surface structure including furring layers made of non-magnetic nickel formed by an electroless plating of nickel and gold plating layers applied on the furring layers is provided on contact surfaces of male and female metal members constituting a central conductor of coaxial connector. A coaxial connector having an intermodulation distortion suppressed effectively, a high mechanical strength, a high ruggedness, and can be manufactured at a low cost is realized by providing an intermetallic contact surface structure.

Abstract: A low cost electroconductive spring material excellent in electroconductivity and spring performance, has from 1.8 to 3.0% by weight of Ni, from 0.15 to 0.35% by weight of Be, from 0.2 to 1.2% by weight of Si and the balance being copper. This low cost electroconductive spring material can be used in electric devices. As preferred embodiments, the electroconductive spring material may further contain from 0.05 to 3.0% by weight in a total amount of at least one component selected from Sn, Al and Zn provided that each of Sn, Al and Zn does not exceed 1.5% by weight, or from 0.01 to 1.5% by weight in a total amount of at least one component selected from Co, Fe, Zr, Ti and Mg, provided that each of Co, Fe, Zr, Ti and Mg does not exceed 1.0% by weight. Moreover, the electroconductive spring material is subjected to a final solidification heat treatment at a temperature of 880.degree.-950.degree. C., a cold processing of not greater than 80%, and an aging treatment at a temperature of 380.degree.-530.degree. C.