Patent ID: 6432157
Filing Date: 2002-08-13
Classification: B22F,C22C,H01H

Abstract:
A method of producing an Agâ€”ZnO electrical contact material comprising casting Ag and Zn in predetermined proportions and subjecting the resultant Agâ€”ZnO alloy to internal oxidation so as to obtain a Ag matrix containing finely and uniformity disperse ZnO, the method comprising the steps of:a) melting and casting an Agâ€”Zn alloy to obtain a cast alloy comprising 5-10 wt. % Zn, the balance being Ag; b) forming the cast alloy into chips; c) internally oxidizing the chips to form billets in which ZnO is deposited in the Ag matrix in a streak-like dispersion state; d) collecting and introducing the chips of step c) into a mold and pressing the mold to produce billets; e) sintering and pressing the billets several times; f) extruding the billets to form a wire rod at an extrusion ratio of 51:1 or higher, wherein the ratio is based on the surface area of the billet to the surface area of the wire rod being formed during the extruding; and g) converting the streak-like dispersion state of ZnO into a particulate state by a shearing force generated during the extruding step to finely and uniformity disperse the ZnO in the Ag matrix.