Diamond composite material reinforced heat dissipation anode target disc and x-ray tube

Abstract

The application provides a diamond composite material reinforced heat dissipation anode target disc and an X-ray tube. The anode target disc comprises a target disc base, a target surface layer and a reinforced heat dissipation layer. The material of the target disc base is TZM alloy or MHC alloy. The material of the target surface layer is W-Re alloy, and the content of Re is 5%-12%. The reinforced heat dissipation layer comprises a diamond composite core and a metal bonding layer fixedly wrapped outside the periphery of the diamond composite core. The reinforced heat dissipation layer is fixed to the target disc base through the metal bonding layer. The material of the diamond composite core is high-thermal-conductivity diamond composite material formed by doping and densifying diamond powder and auxiliary materials, and the volume ratio of the diamond powder is 5%-70%. The application builds a heat conduction channel for heat transfer to the liquid metal bearing by additionally arranging the reinforced heat dissipation layer in the anode target disc, improves the heat conduction capacity of the anode target disc, and avoids the risk of over-temperature or shortened service life of the target surface layer material caused by the accumulation of heat and the increase of the temperature of the target surface layer.

Description

Technical Field

[0001] This invention relates to the field of X-ray generating device technology, and in particular to an anode target disk with enhanced heat dissipation made of diamond composite material, and an X-ray tube equipped with the anode target disk. Background Technology

[0002] The X-ray tube used in CT or DSA X-ray tubes is a key component of all medical X-ray instruments, and its performance directly affects the imaging quality and lifespan of the medical equipment. Typically, an X-ray tube consists of a vacuum tube shell and anode and cathode assemblies encapsulated at both ends of the vacuum tube shell. The anode assembly includes a high-speed rotating anode target disk and an anode bearing supporting the rotation of the anode target disk. As the core component of the X-ray tube, the performance of the anode target disk largely determines the lifespan of the X-ray tube. During CT or DSA X-ray tube exposure, electrons generated by the cathode assembly of the X-ray tube form an electron beam under the influence of a high-voltage electric field and are accelerated to bombard the anode target disk. 99% of the electron energy is converted into heat energy, and only 1% of the electron energy is used to generate X-rays through bremsstrahlung radiation. As the object subjected to electron beam bombardment, the anode target rapidly converts most of the kinetic energy of the incident electrons into heat energy, which is deposited on the anode target, quickly pushing up its temperature. If the heat of the anode target cannot be quickly conducted away or stored, under continuous electron beam input, the accumulated heat will cause overheating, leading to coarsening of the anode target material, cracking of the target surface, melting and evaporation of the target material at the electron beam focal point. In severe cases, this can drastically reduce the lifespan of the anode target or X-ray tube, or even directly cause the failure of the CT tube or DSA tube. Therefore, for anode target materials, it is required that the target material can withstand the rapid increase in transient temperature (potentially exceeding 3000℃) under electron beam bombardment and can stably generate X-rays, while also requiring the target to quickly conduct away or store heat.

[0003] Traditional anode target disks employ a W-Re / TZM / graphite composite design. W-(5%~10%)Re alloy is used as the target surface material due to its high X-ray yield, good high-temperature resistance, high melting point, and low vapor pressure. Below the target surface, TZM (titanium-zirconium-molybdenum alloy) with excellent high-temperature strength and reliable thermal conductivity serves as the structural support substrate. High-specific-heat graphite is used as a heat storage material on the back of the TZM support substrate. The high-speed rotation of the anode target disk causes the electron beam focal spot to rapidly change position on the target surface, carrying away and quickly conducting heat for cooling. This achieves uniform distribution of the heat generated by continuous electron beam bombardment within the annular trajectory of the focal spot on the target surface, increasing the target disk's heat storage capacity and preventing heat concentration that could lead to target failure. This, in turn, improves the target disk's instantaneous power and thermal load capacity. Nevertheless, with the improvement of imaging resolution and imaging duration in medical X-ray imaging, high-end X-ray tubes have higher power and smaller focal points. At the focal spot of the target disk bombarded by the electron beam, traditional metal-graphite composite target disks still have the risk of overheating caused by excessively high instantaneous power density.

[0004] To improve the heat dissipation capacity and high-temperature performance of the anode target, the following anode target is disclosed in the prior art.

[0005] Prior Art 1: Chinese invention patent application CN201810737910.6 discloses an anode target disk for CT X-ray tubes and its preparation method. The anode target disk consists of two parts: a target surface and a target substrate. The target surface is sintered from 41-46% tungsten powder, 50-55% hafnium carbide powder + tantalum carbide powder, 2.5-3.0% rhenium powder, and 1.0-1.2% rare earth oxide Y2O3 powder by mass fraction. The target substrate is sintered from graphite powder and molybdenum powder. Between the graphite and molybdenum, a nickel-titanium-rhenium alloy powder with a mass fraction of 45% Ni + 51% Ti + 4% Re is added as an intermediate layer with a thickness of 1.0-2.5 mm. This prior art anode target disk has excellent high-temperature resistance, with a high temperature resistance exceeding 4000℃. However, the existing anode target disk only improves the temperature resistance of the anode target disk, but does not improve its heat dissipation capability. Under continuous exposure conditions in CT or DSA tubes, the heat generated on the anode target disk continues to accumulate, continuously pushing up the temperature of the target disk surface, the target disk substrate, and the substrate / graphite weld, leading to high-temperature grain coarsening and a decrease in mechanical strength. This results in a decrease in the reliability of the anode target disk, and consequently, a risk of failure. In addition, the unit price of hafnium carbide powder used in the target disk surface is about 13 to 17 times that of tungsten powder, and tantalum carbide powder is about 5 to 7 times that of tungsten powder. A target disk surface with a content of 50-55% hafnium carbide powder + tantalum carbide powder will significantly increase the cost of the anode target disk, becoming a major obstacle to the commercialization of CT or DSA tubes.

[0006] Prior art 2: Chinese invention patent application CN202411100896.0 discloses an X-ray anode target and its processing method, as well as an X-ray tube, a target disk, and a heat storage layer disposed on the target disk; the heat storage layer is made of a heat storage capsule, which includes a core layer and a shell layer. The core layer is made of beryllium oxide, and the shell layer is formed by constructing a three-dimensional network structure of graphene and coating the surface of the core layer; the heat capacity of the heat storage layer is M, which satisfies: 20MWs≥M≥6MWs. Thus, since the heat storage layer is formed by beryllium oxide-graphene composite phase change microspheres, the beryllium oxide-graphene composite phase change microspheres have a high thermal conductivity and heat storage performance. The graphene coating of beryllium oxide can prevent leakage during the solid-liquid phase change of beryllium oxide, ensuring that the anode target has both high heat storage and high heat dissipation capabilities. However, beryllium resources are scarce, beryllium oxide dust is highly toxic and carcinogenic, processing and grinding require fully enclosed negative pressure dust removal, and the waste is classified as hazardous waste. Production, packaging, transportation, and solid waste disposal all require specialized protective measures, resulting in high disposal costs and substantial environmental protection investments, directly increasing the commercial application cost of target disks. Furthermore, when the temperature exceeds 1500℃, the vapor pressure of beryllium oxide increases rapidly, from 4.27 x 10⁻⁶ at 1500℃. -5 When Pa changes rapidly to 1800℃, 2x10 -3 When the temperature further increases to 2000℃, the vapor pressure further increases to 304 Pa. The stable operating vacuum of the X-ray tube is 10 Pa. -6 -10 -7 Pa. Therefore, if beryllium oxide rapidly sublimates into vapor at high temperatures, causing the vacuum in the X-ray tube to drop, it will bring an irreversible risk of high-pressure arcing to the X-ray tube, which will lead to the failure of the X-ray tube and a shortened lifespan. The highly toxic beryllium oxide that evaporates also brings difficulties to the subsequent environmental treatment. Summary of the Invention

[0007] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide an anode target disk with enhanced heat dissipation made of diamond composite material, which can significantly improve the heat dissipation capacity of the target disk while taking into account cost.

[0008] To achieve the above objectives, the present invention provides an anode target disk with enhanced heat dissipation using diamond composite material. The anode target disk includes a target disk substrate and a target surface layer fixed to the end of the target disk substrate. The inner circumference of the target disk substrate is provided with a bearing hole for fixing the target disk substrate to the outer circumference of a liquid metal bearing. The material of the target disk substrate is TZM alloy or MHC alloy, and the material of the target surface layer is W-Re alloy with a Re content of 5% to 12%.

[0009] The anode target disk also includes an enhanced heat dissipation layer embedded in the target disk substrate. The enhanced heat dissipation layer is used to build a heat conduction channel for conducting heat from the target disk substrate to the liquid metal bearing. The enhanced heat dissipation layer has an enhanced thermally conductive surface for contacting and adhering to the surface of the liquid metal bearing. The enhanced heat dissipation layer includes a diamond composite core blank and a metal bonding layer fixedly covering the outer periphery of the diamond composite core blank. The enhanced heat dissipation layer is fixed to the target disk substrate through the metal bonding layer. The material of the diamond composite core blank is a high thermal conductivity diamond composite material formed by doping and densifying diamond powder and auxiliary materials, and the volume percentage of the diamond powder is 5% to 70%.

[0010] Furthermore, the auxiliary material is copper or silicon carbide, and the high thermal conductivity diamond composite material is a diamond / copper composite material or a diamond / silicon carbide composite material, and the highest thermal conductivity of the high thermal conductivity diamond composite material is higher than 700 W / (m·K).

[0011] Furthermore, the material of the metal bonding layer is any one of copper, nickel, titanium, molybdenum, and tungsten, and the thickness of the metal bonding layer is 0.5~1mm.

[0012] Furthermore, the diamond composite material enhanced heat dissipation anode target disk also includes a heat storage layer, which is fixed on one end of the target disk substrate facing away from the target surface layer. The heat storage layer is made of graphite and is used to build a heat radiation channel.

[0013] Furthermore, the diamond composite core blank and the metal bonding layer are fixed by any one of spark plasma sintering, liquid metal infiltration, and vacuum hot pressing sintering, and the metal bonding layer and the target disk substrate are fixed by any one of vacuum brazing, vacuum diffusion welding, and spark plasma sintering.

[0014] Furthermore, the enhanced heat dissipation layer is disposed on one end of the target disk substrate facing away from the target surface layer, and the inner periphery of the enhanced heat dissipation layer is provided with a heat dissipation layer extension section extending axially in a direction away from the target surface layer. The end face of the enhanced heat dissipation layer and / or the inner periphery of the heat dissipation layer extension section constitute the enhanced heat conduction surface.

[0015] Furthermore, the enhanced heat dissipation layer has a hub-type structure, including a disk body and a plurality of embedded through slots formed in the disk body. The plurality of embedded through slots are circumferentially spaced, and the target disk substrate is provided with a plurality of embedded protrusions. The plurality of embedded protrusions correspond one-to-one with the plurality of embedded through slots and fit tightly together.

[0016] Furthermore, the target disk substrate is provided with an annular groove for accommodating the enhanced heat dissipation layer, the target disk substrate is provided with a first mating surface on the outer periphery of the annular groove, and the enhanced heat dissipation layer is provided with a second mating surface on the outer periphery. The first mating surface and the second mating surface match and are in surface contact. Both the first mating surface and the second mating surface are stepped surfaces or toothed surfaces.

[0017] Furthermore, the manufacturing process of the enhanced heat dissipation layer includes the following steps in sequence:

[0018] A1. A Ti or Ni metal film layer is deposited on the surface of the diamond powder by magnetron sputtering to complete the surface metallization pretreatment of the diamond powder;

[0019] A2. The diamond powder and the copper powder constituting the auxiliary material are mixed in a preset ratio and isostatically pressed into a preform.

[0020] A3. The target disk substrate is provided with an annular groove for accommodating the enhanced heat dissipation layer. A thin layer of pure copper powder is laid on the groove wall surface of the annular groove and the outer surface of the preformed blank. Then, the preformed blank is placed in the annular groove and the reserved gap between them is filled with pure copper powder.

[0021] A4. The preformed green blank and the target disk substrate are subjected to discharge plasma sintering under vacuum conditions. A pressure of 50-70 MPa is applied to the pure copper powder, and the sintering temperature is 920-960℃. After sintering, the pure copper powder diffuses, making the diamond composite core blank dense and allowing the diamond composite core blank to diffusely bond with the target disk substrate.

[0022] Furthermore, the manufacturing process of the enhanced heat dissipation layer includes the following steps in sequence:

[0023] B1. A W metal film and a Ti metal film are deposited sequentially on the surface of the diamond powder by magnetron sputtering to complete the surface metallization pretreatment of the diamond powder.

[0024] B2. The diamond powder and copper billet are placed in a sealed vacuum melting chamber. The sealed vacuum melting chamber is heated to 1100~1200℃ in a vacuum environment to melt the copper billet into a liquid state. High-pressure argon gas is introduced into the sealed vacuum melting chamber to press the molten copper into the pores of the diamond skeleton to obtain the diamond composite core blank.

[0025] B3. Place the diamond composite core blank into a hot press mold and fill the reserved gap between the two with pure copper powder;

[0026] B4. In a vacuum environment, a pressure of 50-70 MPa is applied to the hot pressing mold and the temperature is raised to 920-950°C, so that the pure copper powder forms a metal bonding layer that is fixedly coated on the outer periphery of the diamond composite core blank by diffusion bonding.

[0027] Furthermore, the manufacturing process of the enhanced heat dissipation layer includes the following steps in sequence:

[0028] C1. A W metal film and a Ti metal film are deposited sequentially on the surface of the diamond powder and the surface of the silicon carbide powder constituting the auxiliary material by magnetron sputtering, thereby completing the surface metallization pretreatment of the diamond powder and the silicon carbide powder.

[0029] C2. The diamond powder, the silicon carbide powder, and the sintering aid are mixed in a preset ratio and then cold-pressed into a preform.

[0030] C3. Place the preformed green body into the sintering mold and fill the gap between them with titanium powder;

[0031] C4. The preformed green blank is subjected to discharge plasma sintering under vacuum conditions, with a pressure of 50-70 MPa applied to the titanium powder and a sintering temperature of 920-960℃. After sintering, the diamond composite core blank with a titanium metal layer on its outer periphery is obtained, and the titanium metal layer constitutes the metal bonding layer.

[0032] Furthermore, the target surface layer is inclined, and the end face of the target disk substrate with the target surface layer is a radially extending horizontal end face, forming a fixed target angle between the target surface layer and the horizontal end face of the target disk substrate.

[0033] The present invention also provides an X-ray tube, comprising a vacuum tube shell, and an anode assembly and a cathode assembly, both sealed and fixed within the vacuum tube shell. The cathode assembly has a cathode filament for emitting an electron beam. The anode assembly includes a liquid metal bearing and an anode target disk with enhanced heat dissipation using a diamond composite material as described above. The liquid metal bearing includes a bearing mandrel fixed to the vacuum tube shell, a bearing sleeve and a bearing end cap rotatably mounted on the outer periphery of the bearing mandrel, and liquid metal filling the space between the bearing mandrel and the bearing sleeve. The inner cavity of the bearing sleeve is sealed by the bearing end cap, and the two are sealed and fixedly connected. The bearing sleeve is tightly fitted into a bearing hole in the target disk substrate. The bearing mandrel has a cooling medium channel extending axially to the anode target disk, and the cooling medium channel is used to establish a heat convection channel.

[0034] Furthermore, the X-ray tube also includes fastening bolts, the outer periphery of the bearing sleeve is provided with a radially protruding positioning flange, the fastening bolts are threaded onto the outer periphery of the bearing sleeve, and the two ends of the anode target disk abut against the fastening bolts and the positioning flange respectively;

[0035] The enhanced heat dissipation layer is in contact with at least one of the outer periphery of the bearing bush, the outer peripheral surface of the positioning flange, and the end face of the positioning flange.

[0036] As described above, the diamond composite material-enhanced heat dissipation anode target disk and X-ray tube of the present invention have the following beneficial effects:

[0037] 1. This application constructs a heat conduction channel for heat transfer to the liquid metal bearing by adding an enhanced heat dissipation layer in the anode target disk. The heat generated by the electron beam bombardment of the target surface layer is quickly conducted to the liquid metal bearing in the center of the anode target disk through the diamond composite core blank, thereby rapidly dissipating the heat of the anode target disk, achieving efficient heat dissipation of the anode target disk, effectively improving the heat conduction capacity of the anode target disk, and avoiding the risk of overheating or shortened lifespan of the target surface layer material due to heat accumulation pushing up the temperature of the target surface layer.

[0038] 2. Compared to prior art 1, this application balances the temperature resistance and heat dissipation performance of the anode target disk, ensuring its high-temperature reliability under continuous exposure conditions in CT or DSA tubes. Compared to prior art 2, the diamond composite core blank in this application has a maximum thermal conductivity exceeding 700 W / (m·K), while the thermal conductivity of beryllium oxide in prior art 2 is 25~250 W / (m·K). The thermal conductivity of the anode target disk in this application is significantly greater than that in prior art 2. The heat conduction channels built by the enhanced heat dissipation layer have better efficiency in transferring heat from the anode target disk, effectively improving its thermal conductivity. Furthermore, the diamond composite core blank used to enhance the heat dissipation layer is a high thermal conductivity diamond composite material formed by doping and densifying diamond powder and auxiliary materials. Compared to prior art 1 and prior art 2, this application balances the cost of the anode target disk and eliminates environmental risks at high temperatures.

[0039] 3. The target surface layer material of the anode target disk in this application adopts a tungsten-rhenium alloy with a high atomic coefficient. This alloy can withstand the transient high temperature generated by high-power-density electron beam bombardment while ensuring the quality of X-rays generated by bremsstrahlung. It also possesses stronger high-temperature toughness, tensile strength, and creep resistance, ensuring the structural stability of the target surface layer material at high temperatures. Meanwhile, the target disk substrate material adopts a TZM alloy or MHC alloy with a melting point as high as 2600℃, possessing excellent high-temperature strength. This ensures the structural strength of the target disk substrate and, with a consistent BCC lattice structure with the tungsten-rhenium alloy material of the target surface layer, ensures that the thermal expansion coefficients of the target surface layer and the target disk substrate are consistent, forming an infinitely miscible solid solution. This results in an atomic-level metallurgical bond with extremely strong resistance to thermal shock and high-temperature delamination, constructing an ideal X-ray tube rotating target disk composite structure system. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the structure of an X-ray tube according to Embodiment 1 of this application.

[0041] Figure 2 This is a schematic diagram of the structure of the X-ray tube in Embodiment 2 of this application.

[0042] Figure 3 for Figure 2 Comparison of radial temperature distribution simulation calculations between the anode target disk and existing anode target disks.

[0043] Figure 4 This is a schematic diagram of the structure of the X-ray tube in Embodiment 3 of this application.

[0044] Figure 5 This is a schematic diagram of the anode target disk in Embodiment 4 of the X-ray tube of this application.

[0045] Figure 6 for Figure 5 A schematic diagram of the structure of the enhanced heat dissipation layer.

[0046] Figure 7 for Figure 6 A sectional view.

[0047] Component designation: 10, Anode target disk; 20, Target disk substrate; 21, Bearing bore; 22, Embedded protrusion; 23, First mating surface; 30, Target surface layer; 40, Reinforced heat dissipation layer; 41, Reinforced heat conduction surface; 42, Diamond composite core blank; 43, Metal bonding layer; 44, Heat dissipation layer extension; 45, Disk body; 46, Embedded through slot; 47, Second mating surface; 50, Heat storage layer; 60, Liquid metal bearing; 61, Bearing mandrel; 62, Bearing bushing; 63, Bearing end cap; 64, Cooling medium flow channel; 65, Fastening bolt; 66, Positioning flange; 67, Fastening screw. Detailed Implementation

[0048] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0049] It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and objectives of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0050] It should also be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on the other component or may be connected to an intermediary component. When a component is referred to as being "connected to" another component, it can be directly connected to the other component or indirectly connected to the other component through an intermediary component.

[0051] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed in this application.

[0052] This application relates to an anode target disk 10 with enhanced heat dissipation made of diamond composite material, and an X-ray tube equipped with the anode target disk 10. The X-ray tube is used in the field of medical devices as a CT tube or DSA tube.

[0053] The X-ray tube involved in this application includes a vacuum tube shell, and an anode assembly and a cathode assembly, both sealed and fixed within the vacuum tube shell. The cathode assembly has a cathode filament for emitting an electron beam; such as Figure 1 ,or Figure 2 ,or Figure 4As shown, the anode assembly includes a liquid metal bearing 60 and an anode target disk 10. The anode target disk 10 is rotatably supported within a vacuum tube shell by the liquid metal bearing 60. A target surface layer 30 is fixedly provided at the end of the anode target disk 10 facing the cathode assembly. The liquid metal bearing 60 includes a bearing mandrel 61, a bearing sleeve 62 and a bearing end cap 63 rotatably mounted on the outer periphery of the bearing mandrel 61, and liquid metal filling the space between the bearing mandrel 61 and the bearing sleeve 62. The end of the bearing mandrel 61 is sealed and fixedly connected to the vacuum tube shell. The inner cavity of the bearing sleeve 62 is sealed by the bearing end cap 63. The bearing sleeve 62 and the bearing end cap 63 are sealed and fixedly connected. The anode target disk 10 is fixed to the outer periphery of the bearing sleeve 62.

[0054] In particular, such as Figure 1 ,or Figure 2 ,or Figure 4 As shown, the anode target disk 10 involved in this application is a diamond composite material enhanced heat dissipation anode target disk 10, which includes a target disk substrate 20, a target surface layer 30, and an enhanced heat dissipation layer 40. The target surface layer 30 is fixed on the end face of the target disk substrate 20 facing the cathode assembly. The material of the target surface layer 30 is W-Re alloy (i.e., tungsten-rhenium alloy), and the Re content in the W-Re alloy is 5%~12%. The inner circumference of the target disk substrate 20 is provided with a bearing hole 21, and the bearing sleeve 62 is tightly fitted in the bearing hole 21 of the target disk substrate 20, so that the target disk substrate 20 is fixed on the outer circumference of the liquid metal bearing 60. The material of the target disk substrate 20 is TZM alloy (i.e., molybdenum-titanium-zirconium alloy) or MHC alloy (i.e., hafnium carbide-doped molybdenum alloy). The enhanced heat dissipation layer 40 is embedded in the target disk substrate 20. The enhanced heat dissipation layer 40 establishes a heat conduction channel that transfers heat from the target disk substrate 20 to the liquid metal bearing 60. The enhanced heat dissipation layer 40 has an enhanced thermally conductive surface 41 that is in contact with and adheres to the surface of the liquid metal bearing 60. The enhanced heat dissipation layer 40 includes a diamond composite core blank 42 and a metal bonding layer 43 fixedly covering the outer periphery of the diamond composite core blank 42. The enhanced heat dissipation layer 40 is fixed to the target disk substrate 20 via the metal bonding layer 43. The diamond composite core blank 42 is made of a high thermal conductivity diamond composite material formed by doping and densifying diamond powder and auxiliary materials, with the volume percentage of diamond powder being 5% to 70%. The metal bonding layer 43 serves two purposes: firstly, it provides machining allowance for finishing to ensure the dimensional accuracy of the final anode target disk 10; secondly, it improves the wetting fluidity of the interface connection to increase the welding rate and bonding strength. In addition, the bearing mandrel 61 is provided with a cooling medium channel 64 extending axially to the anode target disk 10, and the cooling medium channel 64 forms a heat convection channel.

[0055] During CT or DSA X-ray tube exposure, the electron beam generated by the cathode assembly of the X-ray tube is accelerated and bombards the target layer 30 of the anode target disk 10 under the action of a high-voltage electric field, generating X-rays. The target layer 30 is made of W-Re alloy, where W and Re are elements with high atomic coefficients. Under electron beam bombardment, they can efficiently generate X-rays through bremsstrahlung. Both W and Re are high-melting-point materials (above 3100℃), capable of withstanding the transient high temperature under high-power-density electron beam bombardment. The Re-doped W alloy has stronger high-temperature toughness, tensile strength, and creep resistance, and increases the recrystallization temperature of W at high temperatures, suppressing grain coarsening at high temperatures and maintaining the structural stability of the target layer 30 material at high temperatures. Meanwhile, the target disk substrate 20 is made of TZM alloy or MHC alloy, with a melting point as high as 2600℃ and good high-temperature strength. This ensures the structural strength of the target disk substrate 20 and has the same BCC lattice structure as the tungsten-rhenium alloy material of the target surface layer 30. This makes the thermal expansion coefficients of the target surface layer 30 and the target disk substrate 20 the same, which can form an infinitely miscible solid solution and an atomic-level metallurgical bond. This results in extremely strong resistance to thermal shock and high-temperature peeling, thus constructing an ideal X-ray tube rotating target disk composite structure system.

[0056] During X-ray tube exposure, a large amount of heat is generated at the electron focal spot position on the anode target disk 10. During the exposure interval, there is no input power. At this time, the heat accumulated on the anode target disk 10 is conducted to the liquid metal bearing 60 through the enhanced heat dissipation layer 40 added to the anode target disk 10. The heat generated by the electron beam bombarding the target surface layer 30 is quickly conducted to the liquid metal bearing 60 in the center of the anode target disk 10 through the diamond composite core blank 42, thereby quickly conducting away the heat of the anode target disk 10. The heat is then exchanged through the liquid cooling medium flowing in the cooling medium channel 64 inside the liquid metal bearing 60, achieving forced liquid cooling and quickly carrying the heat away from the inside of the X-ray tube, reliably ensuring that the anode target disk 10 operates within a safe temperature range. Therefore, this application constructs a heat-enhancing "thermal bridge" between the electron focal spot position of the anode target disk 10 and the centrally fitted liquid metal bearing 60 through the enhanced heat dissipation layer 40 on the anode target disk 10, effectively improving the heat conduction capacity of the anode target disk 10, enhancing the heat dissipation speed of the anode target disk 10, achieving efficient heat dissipation of the anode target disk 10, reducing the temperature of the anode target disk 10 under the same input power conditions, improving the high-temperature reliability of the anode target disk 10, and avoiding the risk of overheating or shortened lifespan of the target surface layer 30 material due to heat accumulation pushing up the temperature of the target surface layer 30.

[0057] Furthermore, the main body of the enhanced heat dissipation layer 40 in this application is a diamond composite core blank 42, which is made of a high thermal conductivity diamond composite material formed by doping and densifying diamond powder and auxiliary materials. Compared with prior art 1, this application takes into account both the temperature resistance and heat dissipation performance of the anode target disk 10, ensuring the high-temperature reliability of the anode target disk 10 under continuous exposure conditions in CT or DSA tubes. Compared with prior art 2, the highest thermal conductivity of the diamond composite core blank 42 in this application is higher than 700 W / (m·K), while the thermal conductivity of beryllium oxide in prior art 2 is 25~250 W / (m·K). The thermal conductivity of the anode target disk 10 in this application is much greater than that in prior art 2. The heat conduction channel built by the enhanced heat dissipation layer 40 has better efficiency for the heat conduction of the anode target disk 10, effectively improving the thermal conductivity of the anode target disk 10. In addition, the diamond composite core blank 42 of the heat dissipation layer 40 is made of a high thermal conductivity diamond composite material formed by doping and densifying diamond powder and auxiliary materials. Compared with the prior art 1 and prior art 2, it takes into account the cost of the anode target disk 10 and does not pose an environmental risk at high temperatures.

[0058] Furthermore, the auxiliary material in the diamond composite core blank 42 is copper or silicon carbide. The material of the metal bonding layer 43 is any one of copper, nickel, titanium, molybdenum, and tungsten. The diamond composite core blank 42 and the metal bonding layer 43 are fixed by any one of spark plasma sintering, liquid metal infiltration, and vacuum hot pressing sintering. The metal bonding layer 43 and the target disk substrate 20 are fixed by any one of vacuum brazing, vacuum diffusion welding, and spark plasma sintering. There are various structures for the anode target disk 10, the liquid metal bearing 60, and the mating structure between the liquid metal bearing 60 and the anode target disk 10. Thus, the X-ray tube in this application has multiple embodiments. Several preferred embodiments of the X-ray tube are provided below.

[0059] For ease of description, in the following embodiments, the side of the anode target disk 10 facing the cathode assembly is defined as the upper side, and the side of the anode target disk 10 facing away from the cathode assembly is defined as the lower side.

[0060] X-ray tube example 1

[0061] like Figure 1As shown, in the first embodiment of the X-ray tube, the enhanced heat dissipation layer 40 is embedded in the lower end of the target disk substrate 20 facing away from the target surface layer 30, and the lower surface of the enhanced heat dissipation layer 40 is flush with the lower surface of the target disk substrate 20. Therefore, the lower end of the target disk substrate 20 is provided with an upwardly recessed annular groove, and the enhanced heat dissipation layer 40 is embedded in the annular groove. The enhanced heat dissipation layer 40 is a radially extending disk structure. The enhanced heat dissipation layer 40, the target disk substrate 20, and the liquid metal bearing 60 are coaxially arranged. The structure of the enhanced heat dissipation layer 40 extending radially towards the center of the anode target disk 10 constitutes a rapid heat dissipation channel in the radial direction of the anode target disk 10, which rapidly conducts the heat generated by the electron beam bombardment of the target surface layer 30 to the liquid metal bearing 60 at the center of the anode target disk 10.

[0062] Furthermore, the target substrate 20 is an MHC alloy, and the W-Re alloy of the target surface layer 30 is integrally formed with the MHC alloy of the target substrate 20 by spark plasma sintering. Specifically, powder is layered in the sintering mold, and according to the structure of the anode target disk 10, the MHC mixed powder of the target substrate 20 and the W-Re mixed powder of the target surface layer 30 are laid separately. The MHC mixed powder has a ratio of 1.5~2wt% HfC powder, 0.01~0.03wt% nano carbon black powder, and the remainder is Mo; the W-Re mixed powder has a ratio of 8wt% Re powder and the remainder is W powder. Under vacuum conditions, segmented temperature and pressure controlled sintering, including low-temperature degassing, medium-temperature interface pre-diffusion, and high-temperature densification, is completed to prepare the target surface layer 30 and the target substrate 20.

[0063] Furthermore, if the auxiliary material doped in the diamond composite core blank 42 of the enhanced heat dissipation layer 40 is copper, then the high thermal conductivity diamond composite material is a diamond / copper composite material. The volume percentage of diamond powder in the diamond / copper composite material is approximately 65%, with the remainder being oxygen-free copper. The highest thermal conductivity of the high thermal conductivity diamond composite material is higher than 700 W / (m·K). The metal bonding layer 43 covering the outer periphery of the diamond composite core blank 42 is made of pure copper with a thickness of 0.5~1 mm. The manufacturing process of the enhanced heat dissipation layer 40 includes the following steps: A1, depositing a Ti or Ni metal film layer on the surface of the diamond powder using magnetron sputtering to complete the surface metallization pretreatment of the diamond powder; A2, mixing the diamond powder and high-purity copper powder in a preset ratio, and isostatically pressing them into a preformed green blank, the size of which matches the size of the annular groove on the lower surface of the target substrate 20; A3, applying a layer of copper powder to the groove wall of the annular groove on the lower surface of the target substrate 20 and the outer surface of the preformed green blank. A thin layer of pure copper powder is prepared. Then, the preformed green blank is placed in an annular groove, and the reserved gap between them is filled with pure copper powder. A4. The preformed green blank and the target substrate 20 are subjected to spark plasma sintering (SPS) under vacuum conditions. A pressure of 50-70 MPa is applied to the pure copper powder, and the sintering temperature is 920-960℃. After sintering, the pure copper powder diffuses fully, making the diamond composite core blank 42 dense, and simultaneously achieving diffusion bonding between the diamond composite core blank 42 and the target substrate 20, thus obtaining the target blank. Finally, the prepared target blank is subjected to external dimensional finishing. The upper end face of the target substrate 20 is a radially extending horizontal end face. The target surface layer 30 is inclined, forming a fixed target angle between the target surface layer 30 and the horizontal end face of the target substrate 20. A cylindrical bearing hole 21 is provided at the center of the target substrate 20, and the lower surface of the target substrate 20 and the lower surface of the diamond composite core blank 42 are on the same plane.

[0064] Furthermore, such as Figure 1 As shown, the target substrate 20 has a first mating surface 23 on the outer periphery of the annular groove, and the enhanced heat dissipation layer 40 has a second mating surface 47 on the outer periphery. The first mating surface 23 and the second mating surface 47 are matched and in surface contact. Both the first mating surface 23 and the second mating surface 47 are stepped surfaces to increase the mating surface between the target substrate 20 and the enhanced heat dissipation layer 40, thereby improving the reliability of their connection. Of course, in other embodiments, both the first mating surface 23 and the second mating surface 47 can be toothed surfaces.

[0065] Furthermore, such as Figure 1As shown, the X-ray tube also includes a fastening bolt 65. The outer periphery of the upper end of the bearing sleeve 62 is threaded, and the fastening bolt 65 is threaded onto the outer periphery of the upper end of the bearing sleeve 62. Simultaneously, the outer periphery of the bearing sleeve 62 has a radially protruding positioning flange 66. After the anode target disk 10 is fitted onto the bearing sleeve 62, the locking screws are tightened, causing the upper and lower ends of the anode target disk 10 to abut against the fastening bolt 65 and the positioning flange 66 respectively, thus more reliably fixing the anode target disk 10 to the outer periphery of the liquid metal bearing 60, improving the stability and reliability of the anode target disk 10 during high-speed rotation. A portion of the lower end face of the enhanced heat dissipation layer 40 is in surface contact with the upper end face of the positioning flange 66, forming an enhanced heat-conducting surface 41. Simultaneously, the lower end face of the inner ring of the target disk base 20 is in surface contact with the upper end face of the positioning flange 66, and the inner periphery of the target disk base 20 is in surface contact with the outer periphery of the bearing sleeve 62. Thus, the positioning flange 66 can achieve axial positioning of the anode target plate 10 during installation, and also increase the contact area for heat conduction from the anode target plate 10 to the liquid metal bearing 60.

[0066] Furthermore, such as Figure 1 As shown, in the liquid metal bearing 60, the upper end of the bearing sleeve 62 is a closed structure, with only the lower end open. Therefore, a bearing end cap 63 is only provided at the lower end of the bearing sleeve 62, and the bearing end cap 63 is preferably a thrust flange structure. During assembly of the liquid metal bearing 60, a micron-level gap is left between the bearing mandrel 61, the bearing sleeve 62, and the bearing end cap 63. The liquid metal filled in this micron-level gap is preferably a gallium indium tin alloy. The gallium indium tin alloy serves as the rotational lubricating medium of the liquid metal bearing 60, the conductive medium for applying the anode high pressure of the anode target disk 10, and the heat-conducting medium for conducting heat to the bearing mandrel 61. After the gallium indium tin alloy is filled, the bearing end cap 63 and the bearing sleeve 62 are sealed and fixed by laser welding.

[0067] Furthermore, such as Figure 1As shown, the depth of the bearing hole 21 at the center of the anode target disk 10 is less than or equal to the height of the cylindrical portion of the bearing sleeve 62 of the liquid metal bearing 60, ensuring that the inner surface of the anode target disk 10 can completely fit the outer surface of the bearing sleeve 62 to form the maximum heat conduction area. Furthermore, the bearing sleeve 62 forms an assembly gap through heat fitting (heating the anode target disk 10) or cold fitting (cooling the liquid metal bearing 60), completing the fit between the bearing hole 21 at the center of the anode target disk 10 and the liquid bearing sleeve 62. For example, by cooling the liquid metal bearing 60 to reduce the outer diameter of the bearing sleeve 62 and forming a fit gap, the liquid metal bearing 60 is then passed through the bearing hole 21 at the center of the anode target disk 10, and then mechanically locked using the fastening bolt 65. The anode target disk 10 is then fixed between the fastening bolt 65 and the upper surface of the positioning flange 66. After the temperature of the liquid metal bearing 60 returns to normal, the cylindrical outer surface of the bearing bush 62 fits tightly with the hole wall of the bearing hole 21, forming an interference fit. This avoids leaving gaps that could lead to excessive interfacial thermal resistance and weaken the conduction of heat from the anode target disk 10 to the liquid metal bearing 60, thus effectively reducing the interfacial thermal resistance.

[0068] Example 2 of X-ray tube

[0069] The difference between X-ray tube embodiment two and X-ray tube embodiment one is as follows: Figure 2 As shown, the heat dissipation enhancement layer 40 is provided on the upper surface of the target disk substrate 20, and the heat storage layer 50 is added at the lower end of the anode target disk 10. At the same time, the preparation method of the anode target disk 10 is different.

[0070] Specifically, in Example 2 of the X-ray tube, as follows: Figure 2 As shown, the enhanced heat dissipation layer 40 is embedded in the upper end of the target disk substrate 20 facing the target surface layer 30, and the upper surface of the enhanced heat dissipation layer 40 is flush with the upper surface of the target disk substrate 20. Therefore, the upper end of the target disk substrate 20 is provided with a downwardly recessed annular groove, and the enhanced heat dissipation layer 40 is embedded in the annular groove. The inner circumferential surface of the enhanced heat dissipation layer 40 is in surface contact with the outer circumferential surface of the bearing sleeve 62, and the inner circumferential surface of the enhanced heat dissipation layer 40 constitutes an enhanced heat conduction surface 41; at the same time, the inner circumferential surface of the target disk substrate 20 is in surface contact with the outer circumferential surface of the bearing sleeve 62. The bearing hole 21 of the anode target disk 10 axially penetrates the enhanced heat dissipation layer 40 and the target disk substrate 20.

[0071] Furthermore, the W-Re alloy of the target layer 30 contains 12% Re by mass; the target disk substrate 20 is a TZM alloy, in which the mass ratio of Ti is 0.4~0.5%, the mass ratio of Zr is 0.06~0.12%, and the remainder is Mo. The W-Re alloy of the target layer 30 and the TZM alloy of the target disk substrate 20 are integrally sintered by powder metallurgy.

[0072] Furthermore, if the auxiliary material doped in the diamond composite core blank 42 of the enhanced heat dissipation layer 40 is copper, then the high thermal conductivity diamond composite material is a diamond / copper composite material. The manufacturing process of the enhanced heat dissipation layer 40 includes the following steps: B1, using magnetron sputtering to successively deposit a W metal film layer and a Ti metal film layer on the surface of the diamond powder to complete the surface metallization pretreatment of the diamond powder; B2, placing the diamond powder and the high-purity copper blank into a sealed vacuum melting chamber, drawing a vacuum, and heating the sealed vacuum melting chamber to 1100~1200℃ in a vacuum environment to melt the copper blank into a liquid state; after the copper is completely melted into a liquid state, high-pressure argon gas is introduced into the sealed vacuum melting chamber, and the molten copper is pressed into the diamond skeleton by the uniform gas pressure. A. In the pores, a diamond composite core blank 42 is obtained; B3. The diamond composite core blank 42 is placed in a hot pressing mold, leaving a gap between the diamond composite core blank 42 and the opposite surfaces of the hot pressing mold, and pure copper powder is filled in the reserved gap; B4. Under vacuum, a pressure of 50-70 MPa is applied to the hot pressing mold and the temperature is raised to 920-950℃, so that the pure copper powder forms a metal bonding layer 43 fixedly covering the outer periphery of the diamond composite core blank 42 by diffusion bonding, thereby realizing the hot pressing diffusion bonding between the diamond composite core blank 42 and the metal bonding layer 43.

[0073] Furthermore, after the heat dissipation enhancement layer 40 is embedded in the annular groove at the upper end of the target disk substrate 20, the metal bonding layer 43 of the heat dissipation enhancement layer 40 is welded to the target disk substrate 20 using silver-based solder. Finally, the prepared target disk blank is subjected to external dimensional finishing. The diamond / copper composite material prepared in this way has a density ≥99% and a thermal conductivity of 650~700 W / m·K.

[0074] Furthermore, such as Figure 2 As shown, the anode target disk 10 also includes a heat storage layer 50, which is fixed to the lower surface of the target disk substrate 20 by brazing. The heat storage layer 50 is made of graphite and forms a thermal radiation channel. During exposure, there is power input, and the heat that the anode target disk 10 cannot radiate or conduct in time is stored by the heat storage layer 50. During the exposure interval, there is no power input, and the heat storage layer 50 dissipates the stored heat to the outside through thermal radiation. At the same time, the enhanced heat dissipation layer 40 conducts the heat of the anode target disk 10 to the liquid metal bearing 60 through thermal conduction, which effectively improves the withstand time of the anode target disk 10 and meets the heat dissipation requirements of long-term exposure of the X-ray tube. Preferably, a gap is left between the inner circumference of the heat storage layer 50 and the liquid metal bearing 60, which facilitates assembly and allows for thermal expansion of the heat storage layer 50.

[0075] Furthermore, using the existing anode target disk 10 without the enhanced heat dissipation layer 40 and heat storage layer 50 as a comparative example, under the premise of the same size, thermal simulation analysis was performed on the comparative example and the anode target disk 10 involved in the second embodiment of the X-ray tube to obtain the radial temperature distribution of the anode target disk 10, such as... Figure 3 As shown. Figure 3 In the diagram, curve S1 is the temperature distribution curve of the comparative anode target disk 10, and curve S2 is the temperature distribution curve of the anode target disk 10 in this embodiment 2. The horizontal axis represents the radial radius of the anode target disk 10, and the vertical axis represents the temperature of the anode target disk 10. According to Figure 3 It can be seen that, under the input conditions of a nominal focal spot size of 0.3x0.3mm (YY / T 0063) and a peak input power of 38kW, the heat dissipation performance of the anode target disk 10 of this application is significantly better than that of the anode target disk 10 in the prior art.

[0076] X-ray tube, Example 3

[0077] The difference between X-ray tube embodiment three and X-ray tube embodiment one is as follows: Figure 4 As shown, the liquid metal bearing 60 has a different structure, the lower end of the enhanced heat dissipation layer 40 is provided with a heat dissipation layer extension section 44, and the preparation method of the anode target disk 10 is different.

[0078] Specifically, in Example 3 of the X-ray tube, as follows: Figure 4 As shown, an enhanced heat dissipation layer 40 is also provided at the lower end of the target plate substrate 20. The inner circumference of the enhanced heat dissipation layer 40 has a heat dissipation layer extension section 44 extending axially downwards in a direction away from the target surface layer 30. The lower end face of the enhanced heat dissipation layer 40 is in surface contact with the upper end face of the positioning flange portion 66, and the inner circumferential surface of the heat dissipation layer extension section 44 is in surface contact with the outer circumferential surface of the positioning flange portion 66. Thus, the lower end face of the enhanced heat dissipation layer 40 and the inner circumferential surface of the heat dissipation layer extension section 44 constitute an enhanced heat conduction surface 41. This increases the contact area between the enhanced heat dissipation layer 40 and the liquid metal bearing 60, more reliably improving the enhanced heat conduction performance and achieving rapid heat dissipation of the anode target plate 10.

[0079] Furthermore, such as Figure 4 As shown, the enhanced heat dissipation layer 40 has a three-layer cylindrical stepped structure from top to bottom. The size of the upper cylindrical layer matches the annular groove at the lower end of the target disk substrate 20. The height of the middle cylindrical layer is 30-50mm, which is used to increase the rigidity of the enhanced heat dissipation layer 40 and to increase the cross-sectional area of ​​the enhanced heat dissipation layer 40, thereby improving the heat flux. The lower surface of the lower cylindrical layer is flush with the lower surface of the bearing bushing 62. The middle cylindrical layer and the lower cylindrical layer constitute the heat dissipation extension 44 of the enhanced heat dissipation layer 40.

[0080] Furthermore, such as Figure 4As shown, the bearing sleeve 62 has a through-hole structure. Bearing end caps 63 are sealed and fixed at both the upper and lower ends of the bearing sleeve 62. The upper bearing end cap 63 is locked to the upper end of the bearing sleeve 62 by fastening screws 67, and the lower bearing end cap 63 is sealed to the lower end of the bearing sleeve 62 by laser welding. The bearing spindle 61 passes vertically through the bearing sleeve 62 and both bearing end caps 63.

[0081] Furthermore, the W-Re alloy of the target layer 30 contains 12% Re by mass; the target disk substrate 20 is a TZM alloy, in which the mass ratio of Ti is 0.4~0.5%, the mass ratio of Zr is 0.06~0.12%, and the remainder is Mo. The W-Re alloy of the target layer 30 and the TZM alloy of the target disk substrate 20 are integrally sintered by powder metallurgy.

[0082] Furthermore, if the auxiliary material doped in the diamond composite core blank 42 of the enhanced heat dissipation layer 40 is silicon carbide, then the high thermal conductivity diamond composite material is a diamond / silicon carbide composite material. The manufacturing process of the enhanced heat dissipation layer 40 includes the following steps in sequence: C1, using magnetron sputtering to deposit a W metal film layer and a Ti metal film layer on the surface of the diamond powder and the surface of the silicon carbide powder constituting the auxiliary material, respectively, to complete the surface metallization pretreatment of the diamond powder and the silicon carbide powder; C2, mixing the diamond powder, silicon carbide powder, and sintering aid in a preset ratio, with the volume ratio of diamond powder being approximately 60% and the volume ratio of silicon carbide powder being approximately 40%, and cold pressing the mixture into a pre-formed shape. C3. Preform the green blank; C4. Place the preformed green blank into the sintering mold and fill the gap between them with titanium powder; C5. Place the preformed green blank and the sintering mold into a spark plasma vacuum sintering furnace and perform spark plasma sintering under vacuum conditions. Apply a pressure of 50-70 MPa to the titanium powder and sinter at a temperature of 920-960℃. After sintering, a diamond composite core blank 42 with a titanium metal layer on its outer periphery is obtained. The titanium metal layer constitutes a metal bonding layer 43 with a thermal conductivity of 530~580 W / m·K.

[0083] Furthermore, the heat dissipation enhancement layer 40 is embedded in the annular groove at the lower end of the target disk substrate 20. Following the structure of the anode target disk 10, the heat dissipation enhancement layer 40 and the target disk substrate 20 are installed into a sintering mold. After assembly, they are lightly pressed and pre-fixed to ensure seamless adhesion of each layer. Then, a fixed connection is achieved through spark plasma diffusion welding to obtain the target disk blank. Finally, the prepared target disk blank undergoes external dimensional precision machining. The diamond / copper composite material prepared in this way has a density ≥99% and a thermal conductivity of 650~700 W / m·K.

[0084] X-ray tube Example 4

[0085] The difference between X-ray tube embodiment four and X-ray tube embodiment one is as follows: Figures 5 to 7 As shown, the structure of the enhanced heat dissipation layer 40 is different. Specifically, the enhanced heat dissipation layer 40 has a hub-type structure, including a disk body 45 and multiple embedded through slots 46 formed in the disk body 45. The multiple embedded through slots 46 are circumferentially spaced. The disk body 45 is bonded to the target disk substrate 20 through a stepped surface or a toothed surface. At the same time, the target disk substrate 20 is provided with multiple embedded protrusions 22, which correspond one-to-one with the multiple embedded through slots 46 and fit tightly together. In this way, the contact area between the enhanced heat dissipation layer 40 and the target disk substrate 20 is effectively increased, the bonding strength between the enhanced heat dissipation layer 40 and the target disk substrate 20 is improved, and the creep deformation of the enhanced heat dissipation layer 40 under high temperature conditions of the high-speed rotating anode target disk 10 is reduced, thereby improving the overall reliability and lifespan of the target disk under operating conditions.

[0086] In summary, the anode target disk 10 involved in this application establishes an efficient heat dissipation channel for heat conduction from the anode target disk 10 to the liquid metal bearing 60 through the diamond composite core blank 42 of the enhanced heat dissipation layer 40. The heat generated by the electron beam bombardment of the anode target disk 10 is quickly conducted to the liquid metal bearing 60, and the heat is carried out of the X-ray tube through the liquid cooling medium flowing in the cooling medium channel 64 inside the liquid metal bearing 60. This ensures that the anode target disk 10 operates within a safe temperature range and avoids the risk of overheating or shortened lifespan of the target surface layer 30 due to heat accumulation pushing up the temperature of the target surface layer 30.

[0087] The anode target disk 10 involved in this application uses a tungsten-rhenium alloy with a high atomic factor as the material of the target surface layer 30, which can withstand the high temperature generated by electron beam bombardment and ensure the quality of X-rays generated by bremsstrahlung. It uses a titanium-zirconium-molybdenum alloy or a hafnium carbide-reinforced molybdenum alloy as the material of the target disk matrix 20, providing sufficient structural strength and constructing an ideal X-ray tube rotating target disk composite structure system. It uses a high thermal conductivity diamond composite material as the material of the diamond composite core blank 42, which can quickly conduct the heat of the anode target disk 10 to the liquid metal bearing 60.

[0088] The anode target disk 10 involved in this application does not require expensive equipment or a large number of operators during preparation. The preparation process is simple and easy to operate. While keeping costs under control, it significantly improves the heat dissipation capacity of the anode target disk 10. In particular, for medical CT tubes or DSA tubes in high-power, small-focus working mode, it can effectively control the target surface temperature within the safe temperature range, thereby enhancing the stability and reliability of the anode target disk 10 and the X-ray tube.

[0089] In summary, this invention effectively overcomes the various shortcomings of the prior art and has high industrial application value.

[0090] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. An anode target disk with enhanced heat dissipation using diamond composite material, the anode target disk (10) comprising a target disk substrate (20) and a target surface layer (30) fixed at the end of the target disk substrate (20), wherein the inner circumference of the target disk substrate (20) is provided with a bearing hole (21), the bearing hole (21) being used to fix the target disk substrate (20) to the outer circumference of a liquid metal bearing (60), characterized in that: The target disk substrate (20) is made of TZM alloy or MHC alloy, and the target surface layer (30) is made of W-Re alloy with a Re content of 5% to 12%. The anode target disk (10) also includes an enhanced heat dissipation layer (40) embedded in the target disk substrate (20). The enhanced heat dissipation layer (40) is used to build a heat conduction channel for conducting heat from the target disk substrate (20) to the liquid metal bearing (60). The enhanced heat dissipation layer (40) has an enhanced thermally conductive surface (41) for contacting and adhering to the surface of the liquid metal bearing (60). The enhanced heat dissipation layer (40) includes a diamond composite core blank (42) and a metal bonding layer (43) fixedly covering the outer periphery of the diamond composite core blank (42). The enhanced heat dissipation layer (40) is fixed to the target disk substrate (20) through the metal bonding layer (43). The material of the diamond composite core blank (42) is a high thermal conductivity diamond composite material formed by doping and densifying diamond powder and auxiliary materials, and the volume ratio of the diamond powder is 5% to 70%.

2. The anode target disk with enhanced heat dissipation from diamond composite material according to claim 1, characterized in that: The auxiliary material is copper or silicon carbide, and the high thermal conductivity diamond composite material is a diamond / copper composite material or a diamond / silicon carbide composite material. The highest thermal conductivity of the high thermal conductivity diamond composite material is higher than 700 W / (m·K).

3. The anode target disk with enhanced heat dissipation from diamond composite material according to claim 1, characterized in that: The metal bonding layer (43) is made of any one of copper, nickel, titanium, molybdenum, and tungsten, and the thickness of the metal bonding layer (43) is 0.5~1mm.

4. The anode target disk with enhanced heat dissipation from diamond composite material according to claim 1, characterized in that: It also includes a heat storage layer (50), which is fixed on one end of the target disk substrate (20) facing away from the target surface layer (30). The material of the heat storage layer (50) is graphite, and the heat storage layer (50) is used to build a heat radiation channel.

5. The anode target disk with enhanced heat dissipation from diamond composite material according to claim 1, characterized in that: The diamond composite core blank (42) and the metal bonding layer (43) are fixed by any one of spark plasma sintering, liquid metal melting and infiltration, and vacuum hot pressing sintering. The metal bonding layer (43) and the target disk substrate (20) are fixed by any one of vacuum brazing, vacuum diffusion welding, and spark plasma sintering.

6. The anode target disk with enhanced heat dissipation from diamond composite material according to claim 1, characterized in that: The enhanced heat dissipation layer (40) is disposed on one end of the target disk substrate (20) facing away from the target surface layer (30). The inner periphery of the enhanced heat dissipation layer (40) is provided with a heat dissipation layer extension section (44) extending axially in a direction away from the target surface layer (30). The end face of the enhanced heat dissipation layer (40) and / or the inner periphery of the heat dissipation layer extension section (44) constitute the enhanced heat conduction surface (41).

7. The anode target disk with enhanced heat dissipation from diamond composite material according to claim 1, characterized in that: The enhanced heat dissipation layer (40) has a hub-type structure. The enhanced heat dissipation layer (40) includes a disk body (45) and a plurality of embedded through slots (46) formed in the disk body (45). The plurality of embedded through slots (46) are circumferentially spaced. The target disk base (20) is provided with a plurality of embedded protrusions (22). The plurality of embedded protrusions (22) correspond one-to-one with the plurality of embedded through slots (46) and fit tightly together.

8. The anode target disk with enhanced heat dissipation from diamond composite material according to claim 1 or 7, characterized in that: The target disk substrate (20) is provided with an annular groove for accommodating the enhanced heat dissipation layer (40). The target disk substrate (20) has a first mating surface (23) on the outer periphery of the annular groove, and a second mating surface (47) on the outer periphery of the enhanced heat dissipation layer (40). The first mating surface (23) and the second mating surface (47) are matched and in surface contact. Both the first mating surface (23) and the second mating surface (47) are stepped surfaces or toothed surfaces.

9. The anode target disk with enhanced heat dissipation from diamond composite material according to claim 1, characterized in that: The manufacturing process of the enhanced heat dissipation layer (40) includes the following steps in sequence: A1. A Ti or Ni metal film layer is deposited on the surface of the diamond powder by magnetron sputtering to complete the surface metallization pretreatment of the diamond powder. A2. The diamond powder and the copper powder constituting the auxiliary material are mixed in a preset ratio and isostatically pressed into a preform. A3. The target plate substrate (20) is provided with an annular groove for accommodating the enhanced heat dissipation layer (40). A thin layer of pure copper powder is laid on the groove wall surface of the annular groove and the outer surface of the preformed blank. Then, the preformed blank is placed in the annular groove and the reserved gap between them is filled with pure copper powder. A4. The preformed green blank and the target disk substrate (20) are subjected to discharge plasma sintering under vacuum conditions. A pressure of 50-70 MPa is applied to the pure copper powder, and the sintering temperature is 920-960℃. After sintering, the pure copper powder diffuses, making the diamond composite core blank (42) dense and allowing the diamond composite core blank (42) to diffusely bond with the target disk substrate (20).

10. The anode target disk with enhanced heat dissipation from diamond composite material according to claim 1, characterized in that: The manufacturing process of the enhanced heat dissipation layer (40) includes the following steps in sequence: B1. A W metal film and a Ti metal film are deposited sequentially on the surface of the diamond powder by magnetron sputtering to complete the surface metallization pretreatment of the diamond powder. B2. The diamond powder and copper billet are placed in a sealed vacuum melting chamber. The sealed vacuum melting chamber is heated to 1100~1200℃ in a vacuum environment to melt the copper billet into a liquid state. High-pressure argon gas is introduced into the sealed vacuum melting chamber to press the molten copper into the pores of the diamond skeleton to obtain the diamond composite core blank (42). B3. Place the diamond composite core blank (42) into a hot press mold and fill the gap between the two with pure copper powder; B4. In a vacuum environment, a pressure of 50-70 MPa is applied to the hot pressing mold and the temperature is raised to 920-950°C, so that the pure copper powder forms a metal bonding layer (43) that is fixedly coated on the outer periphery of the diamond composite core blank (42) by diffusion bonding.

11. The anode target disk with enhanced heat dissipation from diamond composite material according to claim 1, characterized in that: The manufacturing process of the enhanced heat dissipation layer (40) includes the following steps in sequence: C1. A W metal film and a Ti metal film are deposited sequentially on the surface of the diamond powder and the surface of the silicon carbide powder constituting the auxiliary material by magnetron sputtering, thereby completing the surface metallization pretreatment of the diamond powder and the silicon carbide powder. C2. The diamond powder, the silicon carbide powder, and the sintering aid are mixed in a preset ratio and then cold-pressed into a preform. C3. Place the preformed green body into the sintering mold and fill the gap between them with titanium powder; C4. The preformed green blank is subjected to discharge plasma sintering under vacuum conditions, with a pressure of 50-70 MPa applied to the titanium powder and a sintering temperature of 920-960℃. After sintering, the diamond composite core blank (42) with a titanium metal layer on its outer periphery is obtained, and the titanium metal layer constitutes the metal bonding layer (43).

12. The anode target disk with enhanced heat dissipation from diamond composite material according to claim 1, characterized in that: The target surface layer (30) is inclined, and the target disk substrate (20) has a horizontal end face that extends radially at one end of the target surface layer (30). A fixed target angle is formed between the target surface layer (30) and the horizontal end face of the target disk substrate (20).

13. An X-ray tube comprising a vacuum tube housing, and an anode assembly and a cathode assembly both sealed and fixed within the vacuum tube housing, the cathode assembly having a cathode filament for emitting an electron beam, characterized in that: The anode assembly includes a liquid metal bearing (60) and a diamond composite material enhanced heat dissipation anode target disk as described in any one of claims 1-12. The liquid metal bearing (60) includes a bearing mandrel (61) fixed to the vacuum tube shell, a bearing sleeve (62) and a bearing end cap (63) rotatably mounted on the outer periphery of the bearing mandrel (61), and liquid metal filling the space between the bearing mandrel (61) and the bearing sleeve (62). The inner cavity of the bearing sleeve (62) is sealed by the bearing end cap (63), and the two are sealed and fixedly connected. The bearing sleeve (62) is tightly fitted in the bearing hole (21) of the target disk base (20). The bearing mandrel (61) is provided with a cooling medium channel (64) extending axially to the anode target disk (10). The cooling medium channel (64) is used to build a heat convection channel.

14. The X-ray tube according to claim 13, characterized in that: It also includes a fastening bolt (65), and the outer periphery of the bearing bush (62) is provided with a radially protruding positioning flange (66). The fastening bolt (65) is threaded onto the outer periphery of the bearing bush (62), and the two ends of the anode target disk (10) abut against the fastening bolt (65) and the positioning flange (66) respectively. The enhanced heat dissipation layer (40) is in surface contact with at least one of the outer periphery of the bearing bush (62), the outer peripheral surface of the positioning flange (66), and the end face of the positioning flange (66).

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