COMPOSITE PRODUCED FROM INTERMETALLIC PHASES AND METAL
A method is provided for producing a wire or tape, especially for use as an electrode or electrode tip in spark plugs. The method includes the following steps: (a) producing an intermetallic compound having a melting point above 1700° C.; (b) grinding the intermetallic compound; (c) mixing the intermetallic compound with metal powder; (d) introducing the mixture obtained in step (c) in a tube produced from ductile material; and (e) shaping the tube filled in step (d) to give a wire or tape. Also provided are a wrapped wire or wrapped tape, especially a semifinished product for producing electrodes or electrode tips of spark plugs.
1 .- 23 . (canceled)
24 . A method for production of a wire or tape, the method comprising performing the following steps:
a) generating an intermetallic compound having a melting point greater than 1700° C., the compound containing at least one element from the group Ru, Ir, Pt, Rh, and Pd;
b) grinding the intermetallic compound;
c) mixing the intermetallic compound with metal powder;
d) introducing the mixture obtained in step (c) into a tube made of ductile material; and
e) transforming the tube filled according to step (d) to a wire or tape.
25 . The method according to claim 24 , wherein the tube made of ductile material is closed after filling of the mixture of the intermetallic compound and the metal powder.
26 . The method according to claim 25 , wherein the filled and closed tube is pre-compressed.
27 . The method according to claim 25 , wherein the filled and closed tube is pre-compressed.
28 . The method according to claim 24 , wherein the wire or the tape is sintered.
29 . The method according to claim 24 , wherein the wire or the tape is wound up.
30 . The method according to claim 24 , wherein the intermetallic compound is generated in an electric arc.
31 . The method according to claim 24 , wherein the ground intermetallic compound is mixed with platinum powder.
32 . The method according to claim 24 , wherein the intermetallic compound is RuAl.
33 . The method according to claim 24 , wherein the tube made of ductile material comprises platinum, stainless steel, or nickel
34 . The method according to claim 24 , wherein any tube material remaining on the wire is removed.
35 . A sheathed wire or sheathed tape, comprising a sheath containing a compressed mixture of an intermetallic compound with a noble metal powder, wherein a volume proportion of the intermetallic compound in the mixture equals between 5 and 50 vol.-%.
36 . The sheathed wire or sheathed tape according to claim 35 , wherein the intermetallic compound corresponds to formula A x B y , wherein A is selected from the group Ru, Ir, Pt, Rh, and Pd, and B is selected from the group Zr, Al, Y, Hf, Th, Ti, Ta, Sc, V, Nb, Ce, W, and the lanthanides, and the ratio x:y lies between 0.8 and 5.
37 . The sheathed wire or sheathed tape according to claim 35 , wherein the mixture in the sheath contains platinum.
38 . The sheathed wire or sheathed tape according to claim 35 , wherein the sheath comprises platinum.
39 . A sheathing-free wire or sheathing-free tape comprising a compressed mixture of an intermetallic compound with a noble metal powder.
40 . The sheathed wire or sheathed tape according to claim 35 , wherein the wire or tape is a component of a spark plug.
41 . The sheathed wire or sheathed tape according to claim 40 , wherein the component is an electrode, electrode tip, support, or inlay in a spark plug.
42 . The sheathed wire or sheathed tape according to claim 35 , wherein the wire or tape is a switch contact, slide contact, or current feedthrough.
43 . The sheathed wire or sheathed tape according to claim 42 , wherein high currents lead to discharge or erosion processes in a contact region.
44 . The sheathed wire or sheathed tape according to claim 42 , wherein high thermal and corrosive loadings are present for simultaneous current transmission.
45 . An electrode tip of a spark plug, wherein the tip comprises a sheathed or stripped, compressed mixture of an intermetallic compound with a noble metal powder.
46 . The electrode tip according to claim 45 , wherein the tip includes impurities originating from a stripped sheath.