Making copper chromium alloy vacuum contact material with improved, anisotropically-directed properties, employs sintering, impregnation and directed deformation

摘要

Chromium powder, alone or as a mixture, and with the required final weight of chromium, is mixed with copper powder, its weight being 5-15 wt% deficient in comparison with the copper content of the final contact material. Pressing takes place at 200-1000 MPa, forming a porus blank having 75%-90% of the theoretical density. This is coated with sufficient copper to make up the deficit. In high vacuum, heating takes place to or above the melting point of copper, sintering to a chromium- or copper-chromium matrix, impregnated with copper from the coating. At this stage the copper content is increased beyond that of the pressing and the density is 96%-98% of theoretical. Deformation by at least 30%, during extrusion with directed extension follows, drawing the chrome to filaments in the direction of extension, to form a directed structure. The unfinished contact blank material then has at least 99%, especially 99.5%-99.9 %, of the theoretical density. An INDEPENDENT CLAIM is included for the corresponding contact component. Its tensile strength and electrical conductivity parallel to extension are each at least 10% greater than in the transverse direction.