Welding apparatus coated with spatter-resistant and electrically conductive film

Claim 2

A welding contact tip comprising: (a) an elongated hollow metal body having an external surface, said body defining a longitudinal passageway extending between an electrode receiving end and an electrode discharge end spaced longitudinally from said receiving end, a portion of said body adjacent said passageway comprising an internal surface for guiding a wire electrode along the length thereof; and (b) a coating on at least a portion of said external surface or said internal surface, said coating comprising a film of a spatter-resistant substance selected from the group consisting of sulfides, selenides, and carbides of tungsten, titanium, zirconium, tantalum, vandium, chromium, and hafnium; and a metal selected from the group consisting of tungsten, molybdenum, nickel, osmium, platinum, palladium, and ruthenium.

Claim 3

A welding contact tip as claimed in claim 1 wherein said coating covers a portion of said external surface adjacent said discharge end.

Claim 4

A welding contact tip as claimed in claim 1 wherein said coating covers at least a portion of said internal surface.

Claim 5

A welding contact tip as claimed in claim 3 wherein said film has an electrical resistivity of less than 15 microohm-cm at ambient temperature.

Claim 6

A welding contact tip as claimed in claim 1 wherein said film has a thermal conductivity of greater than about 0.05 cal/cm-sec° C at ambient temperature.

Claim 7

A welding contact tip as claimed in claim 1 wherein said film has a thickness of about 5000 angstroms or less.

Claim 8

A welding contact tip as claimed in claim 1 wherein said film is applied to the body by chemical vapor deposition.

Claim 9

A welding contact tip as claimed in claim 1 wherein said film comprises tungsten disulfide.

Claim 10

A welding contact tip as claimed in claim 1 wherein said film comprises tungsten.

Claim 11

A welding contact tip as claimed in claim 1 wherein said metal body comprises copper or a copper alloy.

Claim 12

A welding apparatus comprising the contact tip of claim 1 and: (c) a metal nozzle extending around said contact tip radially outward thereof, said nozzle having a generally concave interior surface opposed to said contact tip and an exterior surface extending away from said contact tip; and (d) a coating on at least a portion of said interior surface or said exterior surface, said coating comprising a film of a spatter-resistant substance selected from the group consisting of sulfides, selenides, silicides, borides, nitrides, and carbides of tungsten, titanium, zirconium, tantalum, vanadium, chromium, and hafnium and metals having a melting point above 1100° C and electrical resistivity of less than about 30 microohm-cm at ambient temperature.

Claim 13

The welding apparatus as claimed in claim 11 wherein said film comprises tungsten disulfide.

Claim 14

A nozzle for welding comprising: (a) a shield having a generally concave interior surface and an exterior surface; and (b) a coating on said interior surface comprising a film of a spatter-resistant substance selected from the group consisting of sulfides, selenides, and carbides of tungsten, titanium, zirconium, tantalum, vanadium, chromium, and hafnium; and a metal selected from the group consisting of tungsten, molybdenum, nickel, osmium, platinum, palladium, and ruthenium.

Claim 15

A nozzle for welding comprising: (a) a shield having a generally concave interior surface and an exterior surface; and (b) a coating on said interior surface comprising a film of a spatter-resistant substance selected from the group consisting of sulfides, selenides, and carbides of tungsten, titanium, zirconium, tantalum, vanadium, chromium, and hafnium; and a metal selected from the group consisting of tungsten, molybdenum, nickel, osmium, platinum, palladium, and ruthenium.

Claim 16

The nozzle as claimed in claim 13 wherein said film comprises tungsten disulfide.

Claim 19

The method of welding as claimed in claim 15 wherein said wire electrode is in electrical contact with said internal surface, said method further comprising: (d) passing an electric current through said wire electrode.

Claim 20

The method of welding as claimed in claim 15 wherein said contact tip further comprises an external surface, said method further comprising: (e) coating said external surface with a film of a substance selected from the group consisting of sulfides, selenides, silicides, borides, nitrides, and carbides of tungsten, titanium, zirconium, tantalum, vanadium, chromium, and hafnium and metals having a melting point above 1100° C and electrical resistivity of less than about 30 microohm-cm at ambient temperature.

Claim 21

The method of welding as claimed in claim 15 wherein said wire electrode comprises an aluminum alloy or steel.

Claim 22

The method of welding as claimed in claim 15 wherein said film comprises tungsten disulfide.

Claim 23

A welding contact tip comprising: (a) an elongated hollow metal body defining a longitudinal passageway extending between an electrode receiving end and an electrode discharge end spaced longitudinally from said receiving end, a portion of said body adjacent said passageway comprising an internal surface for guiding a wire electrode along the length thereof; and (b) a coating on at least a portion of said internal surface, said coating comprising a film of a spatter-resistant substance having an electrical resistivity of less than about 30 microohm-cm at ambient temperature, said substance being selected from the group consisting of sulfides, selenides, silicides, borides, nitrides, and carbides of tungsten, titanium, zirconium, tantalum, vanadium, chromium, and hafnium; and metals having a melting point above 1100° C.

Claim 24

A welding contact tip comprising: (a) an elongated hollow metal body defining a longitudinal passageway extending between an electrode receiving end and an electrode discharge end spaced longitudinally from said receiving end, a portion of said body adjacent said passageway comprising an internal surface for guiding a wire electrode along the length thereof; and (b) a coating on at least a portion of said internal surface, said coating comprising a film of a spatter-resistant substance having an electrical resistivity of less than about 30 microohm-cm at ambient temperature, said substance being selected from the group consisting of sulfides, selenides, silicides, borides, nitrides, and carbides of tungsten, titanium, zirconium, tantalum, vanadium, chromium, and hafnium; and metals having a melting point above 1100° C.

Claim 25

A welding contact tip as claimed in claim 20 wherein said film has an electrical resistivity of less than about 15 microohm-cm at ambient temperature.

Claim 26

A welding contact tip as claimed in claim 20 wherein said film is applied to the internal surface by chemical vapor deposition.

Claim 27

A welding contact tip as claimed in claim 20 wherein said film has a thickness of about 5000 angstroms or less.

Claim 28

A welding contact tip as claimed in claim 20 wherein said metal body comprises copper or a copper alloy.