Graphite disc assembly for a rotating x-ray anode tube

Claim 1

A disc for an anode assembly for a rotating x-ray anode tube comprising a graphite substrate having two opposed major surfaces which are, respectively, the inner and outer surface of .[.the.]. .Iadd.said .Iaddend.substrate .[.and.]. .Iadd.with each major surface having .Iaddend.an inner portion and an integral outer portion; an anode target affixed to a predetermined surface area of .[.the.]. .Iadd.said .Iaddend.integral outer portion of .[.the.]. .Iadd.said .Iaddend.substrate wherein the material of .[.the.]. .Iadd.said .Iaddend.anode target is one selected from the group consisting of tungsten and a tungsten-rhenium alloy; .[.a layer of metal joining the anode target to the predetermined surface area of the outer surface of the integral outer portion of the substrate wherein the material of the layer of metal is one within which carbon is not soluble in the temperature range of from about 1000° C. to about 1300° C. but may have a solubility therein of from 1 to 4 atomic percent at the temperature of joining the anode target to the substrate;.]. .[.the material of the layer of metal has some solubility in the material of the anode target;.]. .[.the material of the layer of metal is one selected from the group consisting of rhodium, osmium, ruthenium, platinum, palladium and an alloy of platinum and chromium; and the.]. .Iadd.a metallic layer extending between and joining said anode target and said predetermined surface area; 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 was reacted with carbon, extending between one side of said barrier metal lamina and said predetermined surface area adjacent thereto; and said metallic .Iaddend.layer has a thickness of at least 3/4 mil.