Wire electrode and process for producing a wire electrode, particular for a spark erosion process

Abstract

In order to produce a wire electrode having a core consisting of a copper/zinc alloy and to produce a specific sheath layer, the sheath layer is coated onto the core at a temperature at which no diffusion occurs. The wire electrode is subsequently heated at a heating speed higher than 10° C. per second, briefly annealed at temperatures above 500° C. and subsequently cooled again very rapidly at cooling speeds higher than 10° C. per second.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
       1. A wire electrode comprising a core and a sheath formed directly on said core, said core consisting of copper, a copper/zinc alloy having an alpha fraction or having an outer layer consisting of copper or a copper/zinc alloy phase and said sheath having an outermost layer consisting of a copper/zinc alloy consisting of a gamma phase. 
     
     
       2. The wire electrode as claimed in  claim 1 , wherein graphite is added to the sheath. 
     
     
       3. A wire electrode comprising a core and a sheath formed directly on said core, said core consisting of copper, a copper/zinc alloy having an alpha fraction or having an outer layer consisting of copper or a copper/zinc alloy phase and said sheath having an outermost layer consisting of a copper/zinc alloy predominantly containing a gamma phase, with diamond or a conductive ceramic intercalated in the sheath. 
     
     
       4. The wire electrode as claimed in  claim 3 , wherein the conductive ceramic is a boronitride. 
     
     
       5. The wire electrode as claimed in  claim 3 , wherein graphite is added to the sheath. 
     
     
       6. The wire electrode as claimed in  claim 4 , wherein graphite is added to the sheath. 
     
     
       7. A wire electrode comprising a core and a sheath formed directly on said core, said core consisting of copper, a copper/zinc alloy having an alpha fraction or having an outer layer consisting of copper or a copper/zinc alloy phase and said sheath having an outermost layer consisting of a copper/zinc alloy consisting of a gamma phase, with diamond or a conductive ceramic intercalated in the sheath. 
     
     
       8. The wire electrode as claimed in  claim 7 , wherein the conductive ceramic is a boronitride. 
     
     
       9. The wire electrode as claimed in  claim 7 , wherein graphite is added to the sheath. 
     
     
       10. A wire electrode comprising a core and a sheath formed directly on said core, said core consisting of copper, a copper/zinc alloy having an alpha fraction or having an outer layer consisting of copper or a copper/zinc alloy phase and said sheath having an outermost layer consisting of a copper/zinc alloy comprising gamma and epsilon phases and predominantly containing a gamma phase. 
     
     
       11. A wire electrode comprising a core and a sheath formed directly on said core, said core consisting of copper, a copper/zinc alloy having at least an alpha phase fraction or having an outer layer consisting of copper or a copper/zinc alloy and said sheath having an outermost layer consisting of a copper/zinc alloy consisting of gamma and epsilon phases and predominantly containing a gamma phase. 
     
     
       12. A wire electrode comprising a core and a sheath formed directly on said core, said core consisting of copper, a copper/zinc alloy having at least an alpha phase fraction or having an outer layer consisting of copper or a copper/zinc alloy and said sheath having an outermost layer consisting of a copper/zinc alloy predominantly containing a gamma phase, wherein the outermost layer consisting of a copper/zinc alloy has a substantial absence of beta phase. 
     
     
       13. A wire electrode comprising a core and a sheath formed directly on said core, said core consisting of copper, a copper/zinc alloy having at least an alpha phase fraction or having an outer layer consisting of copper or a copper/zinc alloy and said sheath having an outermost layer consisting of a copper/zinc alloy comprising of gamma and epsilon phases and predominantly containing a gamma phase. 
     
     
       14. A wire electrode comprising a core and a sheath formed directly on said core, said core consisting of copper, a copper/zinc alloy having at least an alpha phase fraction or having an outer layer consisting of copper or a copper/zinc alloy and said sheath having an outermost layer consisting of a copper/zinc alloy comprising gamma and epsilon phases and predominantly containing a gamma phase, wherein the outermost layer consisting of a copper/zinc alloy has a substantial absence of beta phase.