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AssigneeKoninklijke Philips N.V.
InventorMichael David Drory
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The present invention refers to hybrid anode disk structures for use in X-ray tubes of the rotary anode type and is concerned more particularly with a novel light weight anode disk structure (RA) which comprises an adhesion promoting protective silicon carbide (SiC) interlayer (SCI) deposited onto a rotary X-ray tube's anode target (AT), wherein the latter may e.g. be made of a carbon-carbon composite substrate (SUB′). Moreover, a manufacturing method for robustly attaching a coating layer (CL) consisting of a high-Z material (e.g. a layer made of a tungsten-rhenium alloy) on the surface of said anode target is provided, whereupon according to said method it may be foreseen to apply a refractory metal overcoating layer (RML), such as given e.g. by a tantalum (Ta), hafnium (Hf), vanadium (V) or rhenium (Re) layer, to the silicon carbide interlayer (SCI) prior to the deposition of the tungsten-rhenium alloy. The invention thus leverages the tendency for cracking of the silicon carbide coated carbon composite substrate (SUB′) during thermal cycling and enhances adhesion of the silicon carbide/refractory metal interlayers to the carbon-carbon composite substrate (SUB′) and focal track coating layer (CL) by an interlocking mechanism. Key aspects of the proposed invention are: a) controlled formation of coating cracks (SC) in the silicon carbide layer (SCI) and b) conformal filling of SiC crack openings with a refractory metal.
A light-weight hybrid anode disk structure for an X-ray tube of the rotary-anode type, said anode disk structure having an anode target which comprises a carbon composite substrate disk, an adhesion promoting protective interlayer vapor-deposited to an annular range on an inclined surface of said anode target, followed by a refractory metal overcoating layer attached on top of said interlayer, and a high-Z coating layer deposited onto top of said refractory metal overcoating layer, said coating layer forming an X-ray emissive focal track when being exposed to an incident X-ray beam with sufficient kinetic energy, wherein said carbon composite substrate disk is fabricated of a carbon composite having a thermal expansion coefficient lower than that of silicon carbide (SiC).
A light-weight hybrid anode disk structure for an X-ray tube of the rotary-anode type, said anode disk structure having an anode target which comprises a carbon composite substrate disk, an adhesion promoting protective interlayer realized as a silicon carbide (SiC) layer vapor-deposited to an annular range on an inclined surface of said anode target, followed by a refractory metal overcoating layer attached on top of said silicon carbide interlayer, and a high-Z coating layer deposited onto top of said refractory metal overcoating layer, said coating layer forming an X-ray emissive focal track when being exposed to an incident X-ray beam with sufficient kinetic energy, comprising a controlled formation of silicon carbide coating cracks in the adhesion promoting protective interlayer with the openings in-between said cracks being conformally filled with the refractory metal of said refractory metal overcoating layer.
A method for manufacturing a light-weight hybrid anode disk structure for an X-ray tube of the rotary-anode type, said anode disk structure having an anode target which comprises a carbon composite substrate disk, an adhesion promoting protective interlayer vapor-deposited to an annular range on an inclined surface of said anode target, followed by a refractory metal overcoating layer attached on top of said interlayer, and a high-Z coating layer deposited onto top of said refractory metal overcoating layer, said coating layer forming an X-ray emissive focal track when being exposed to an incident X-ray beam with sufficient kinetic energy, said method comprising the steps of exposing a carbon-carbon composite substrate realized by a carbon fiber reinforced carbon matrix substrate to a temperature which is high enough to remove binder constituents and increase the density of the carbon matrix by removal of the majority of void volume, depositing a thin adhesion promoting protective layer onto the inclined section of the carbon-carbon composite substrate by applying a vacuum coating processing method, heating the substrate in high vacuum to a temperature in excess of the expected focal track temperature and then cooling it down for a given number of cycles, vapor-depositing a refractory metal overcoating layer onto the adhesion promoting protective layer on top of the carbon-carbon composite substrate, and attaching a coating layer made of a high-Z material forming a focal track on top of the refractory metal overcoating layer by vapor deposition.
Dependencies are inferred from the claim text.