A rotary anode for an X-ray tube comprising an anode body formed of graphite, a target layer formed of tungsten or alloy thereof, and an intermediate layer containing rhenium and molybdenum, the intermediate layer being interposed between and bonded with the anode body and target layer. This rotary anode may be obtained by forming over a target area of the graphite anode body a paste layer containing rhenium powder and molybdenum powder, laminating over the paste layer a layer formed of tungsten or alloy thereof, and then hot-pressing the resultant laminated body under vacuum or in an inert gas by means of a pressure transmitting powder.

An X-ray tube including a tubular envelope having rotatably mounted therein an anode target disc provided with an annular focal track made of X-ray emissive material having an atomic number greater than forty and coated with a heat absorbent layer having a thickness in the range of 2 to 50 micrometers and made of an elemental or a compound material, comprising one or more elements having respective atomic numbers no greater than thirty.

An intermediate layer comprising several sub-layers is sandwiched between the support and a target layer of a rotary X-ray anode. The sub-layer of the intermediate layer which contacts the support and the sub-layer of the intermediate layer which contacts the target layer both consist of pure rhenium. Interposed between these two sub-layers is a further sub-layer consisting of a rhenium alloy containing at least one carbide-forming metal, for example tungsten, tantalum or hafnium. This construction of the intermediate layer provides a barrier against carbon diffusion, which barrier has substantially the heat conduction properties of metals and which offers a sufficient protection against the penetration of carbon into the target layer, even at temperaturers above 1500 K.

A method of bonding a metallic target layer and a graphite disk to provide a composite rotating X-ray tube target wherein a layer of vanadium, titanium, or their alloys is placed between the target layer and the graphite disk. The assembly is heated in a rapid manner through a temperature range as provided by a carbon-braze metal eutectic temperature and a braze metal melt temperature with continued heating to a temperature of 75.degree. C. above the melt temperature. The elevated temperature is maintained for about 5 minutes and then the assembly is cooled in a rapid manner through the temperature range. A composite X-ray tube target is produced having a high remelt temperature and bond strength.

A brazed X-ray target includes a metallic cap and a graphite back including a nonlinear record groove attached thereto along a stepped surface. An upper corner joint of the stepped surface is distanced from a cap outer edge and a focal track where the maximum heat is generated during use of the target. The graphite back is extended outward toward the cap outer edge to increase a thermal storage of the graphite, and a recess is formed into the cap to maintain a selected moment of inertia of the target and thereby maintain the rotordynamics of a given X-ray tube.