The Processing of High-Purity Copper Powder into Mill Shapes

Abstract

Two commercial copper powders, a fine electrolytic grade and a coarse chemically precipitated grade, are chemically and physically analyzed and compared to a unique powder produced by a recently developed process. These three powders are processed into dense rods and strips by four different procedures, with only the first one depending on a melting operation: (1) reworked melted and cast bars; (2) hot extrusion of powder billets—canned and uncanned; (3) powder-rolling followed by hot-rerolling or sintering-cold-rerolling; (4) hydrostatic pressing followed by hot-swaging. In procedures (1) and (4), additional samples are prepared wherein specific amounts of oxygen are added to simulate tough-pitch copper. The end-products of these consolidation procedures are evaluated through the use of electrical conductivity measurements, tensile properties, and microstructure. Some information is also included on the effect of compacting pressure and sintering temperature on density and electrical conductivity.