Composite substrate for rotating x-ray anode tube

Abstract

A composite substrate for use in a rotating x-ray anode tube consists of a graphite member joined to another member to which a target anode is affixed.

I claim as my invention: 
     
       1. A composite substrate .Iadd.for an anode target .Iaddend.for use in a rotating x-ray anode tube comprising 
     
     
       a first member .Iadd.having a saucer-like configuration and being adapted to receive an anode target on the protruding surface thereof, the material of said first member being selected from the group consisting of tungsten, an alloy of tungsten, molybdenum and an alloy of molybdenum, .Iaddend. a second member .[.comprising.]. .Iadd.having surface configuration contoured to match the recessed surface of said first member, the material of said second member being .Iaddend.graphite, and   .[.a layer of metal consisting essentially of a non-carbide forming material joining the first member to the second member,.].   .[.the metal is a material in which the solubility of carbon therein is practically zero up to a temperature of about 1300° C. but in which from 1 to 4 atomic weight percent of carbon is soluble therein at the temperature of joining the first member to the second member, and.].   .[.the metal is soluble in the material of the first member..].   a metallic layer extending between and joining said first and second members; said metallic layer consisting of a barrier metal lamina flanked on opposite sides by first and second brazed regions; the metal constituting said barrier metal lamina providing an effective barrier against carbon diffusion and being selected from the group consisting of rhodium, osmium, ruthenium, palladium, platinum and an alloy of platinum and chromium; said first and second brazed regions consisting of alloys formed with the metal selected for said barrier metal lamina; said first brazed region, in which the metal selected for said barrier metal lamina has reacted with carbon, extending between one side of said barrier metal lamina and said second member, and   said metallic layer having a thickness of at least 1/4 mil.  .[.   
     
     
       2.  The composite substrate of claim 1 wherein the non-carbide forming material is one selected from the group consisting of platinum, palladium, rhodium, osmium and ruthenium..]. .[.3. The composite substrate of claim 1 wherein the material of the first member is one selected from the group consisting of tungsten, an alloy of tungsten, molybdenum and an alloy of molybdenum..]. .[.4. The composite substrate of claim 3 wherein the non-carbide forming material is one selected from the group consisting of 
     
     
        platinum, palladium, rhodium, osmium and ruthenium..]. 5. The composite substrate of claim .[.4.]. .Iadd.1 .Iaddend.wherein the material of the first member is tungsten, and the .[.non-carbide forming material.]. 
     
     
        .Iadd.metal of the barrier metal lamina .Iaddend.is platinum. 6. The composite substrate of claim .[.2 wherein the non-carbide forming material is platinum to which up to 1 percent by weight of chromium has been added.]. .Iadd.1 wherein the metal of the barrier metal lamina is an alloy of platinum and chromium in which the maximum chromium content is 1 
     
     
        percent by weight. .Iaddend. 7. An anode assembly for rotating x-ray anode tubes including .[.a disc including.]. a composite substrate.[., the composite substrate.].comprising a first member having .[.two opposed major surface.]. .Iadd.a saucer-like configuration .Iaddend.and a second member .[.consisting of.]. .Iadd.having surface configuration contoured to match the recessed surface of said first member, the material of said second member being .Iaddend.graphite,   a wall defining a centrally disposed aperture extending entirely through .[.the.]. .Iadd.said .Iaddend.second member,   an anode target affixed to a selected surface area of .[.one of the two opposed major surfaces.]. .Iadd.the protruding surface .Iaddend.of .[.the.]. .Iadd.said .Iaddend.first member, .Iadd.said first member being of a material selected from the group consisting of tungsten, an alloy of tungsten, molybdenum and an alloy of molybdenum, .Iaddend.   .[.a layer of metal consisting essentially of a non-carbide forming material joining the second member to the second opposed major surface of the first member, the metal is a material in which the solubility of carbon therein is practically zero up to a temperature of about 1300° C. but in which from 1 to 4 atomic weight percent of carbon is soluble therein at the temperature of joining the first member to the second member, and the metal is soluble in the material of the first member, and.].   .Iadd.a metallic layer extending between and joining said first and second members; said metallic layer consisting of a barrier metal lamina flanked on opposite sides by first and second brazed regions; the metal constituting said barrier metal lamina providing an effective barrier against carbon diffusion and being selected from the group consisting of rhodium, osmium, ruthenium, palladium, platinum and an alloy of platinum and chromium; said first and second brazed regions consising of alloys formed with the metal selected for said barrier metal lamina; said first brazed region, in which the metal selected for said barrier metal lamina has reacted with carbon, extending between one side of said barrier metal lamina and said second member, and .Iaddend.   .Iadd.said metallic layer having a thickness of at least 1/4 mil, and .Iaddend.   a stem .[.affixed to a centrally located surface area of the second major surface of the first member and extending entirely through the aperture of the second member.]. .Iadd.extending through said aperture, affixed to centrally located surface area of said first member .Iaddend.and .[.being.]. spaced .[.apart.]. from .[.the.]. .Iadd.said .Iaddend.wall   
     
     
        defining .[.the.]. .Iadd.said .Iaddend.aperture.  .[.8.  The composite substrate of claim 7 wherein the non-carbide forming material is one selected from the group consisting of platinum, palladium, rhodium, osmium and ruthenium..]. .[.9. The composite substrate of claim 7 wherein the material of the first member is one selected from the group consisting of tungsten, an alloy of tungsten, molybdenum and an alloy of molybdenum..]. .[.10. The composite substrate of claim 9 wherein the non-carbide forming material is one selected from the group consisting of platinum, palladium, 
     
     
        rhodium, osmium and ruthenium..]. 11. The .[.composite substrate of claim 10.]. .Iadd.anode assembly of claim 1 .Iaddend.wherein the material of the first member is tungsten, and the .[.non-carbide forming material.]. 
     
     
        .Iadd.metal of the barrier metal lamina .Iaddend.is platinum. 12. The .[.composite substrate of claim 8 wherein the non-carbide forming material is platinum to.]. .Iadd.anode assembly of claim 7 wherein the metal of the barrier metal lamina is an alloy of platinum and chromium in .Iaddend.which up to 1 percent by weight of chromium has been added .Iadd.to platinum. .Iaddend.