Method for preparing multi-layer composite anode matrix through diffusion bonding

Abstract

The invention provides a method for preparing a multi-layer composite anode matrix by diffusion bonding, which comprises the following steps of: designing and processing according to the shape requirement of the composite anode matrix to obtain a basic component of the composite anode matrix, and then carrying out sheath forming, hot isostatic pressure diffusion bonding treatment, machining and high-temperature exhaust treatment to obtain a finished product of the composite anode matrix. The preparation method is high in production efficiency, and the prepared composite anode matrix has the advantages of being high in high-temperature strength and high in dynamic balance precision.

Description

[0001] This application is a divisional application of the patent application with the application number 202210389621.8, the application date of April 13, 2022, and the invention title of "A Method for Preparing a Multilayer Composite Anode Substrate by Diffusion Bonding". Technical Field

[0002] The present invention belongs to the technical field of the preparation of anode targets for X-ray tubes, and particularly relates to a method for preparing a multilayer composite anode substrate by diffusion bonding. Background Art

[0003] X-ray tubes are used to generate X-rays and play an important role in various fields such as medical diagnosis, security inspection, and non-destructive testing. The working principle of an X-ray tube is to use thermoelectrons excited by heating the cathode filament and, under the action of an accelerating electric field, bombard the anode target; during the bombardment process, about 1% of the energy is converted into X-rays, while the remaining about 99% of the energy is converted into heat energy, resulting in a very rapid temperature rise at the impacted part of the anode target. During the loading process of the X-ray tube, the focal spot temperature of the anode target exceeds 2300 °C, and the working temperature of the TZM substrate exceeds 1400 °C.

[0004] Currently, the common structure of a rotating anode target for high-power X-ray tubes is to use a tungsten-rhenium alloy as the track layer and composite it with a molybdenum alloy, and then weld a graphite layer to the bottom surface of the molybdenum alloy. Since tungsten has the advantages of a high atomic number, a high melting point, and a low vapor pressure at high temperatures, it is often used as the target surface material. Adding a small amount of rhenium to tungsten can greatly improve the electron bombardment resistance of the target surface, effectively reduce the dose attenuation rate, and increase the service life of the target disc; while the specific gravity of the molybdenum alloy is about 1 / 2 of that of the tungsten-rhenium alloy, and the specific heat is more than 2 times that of the tungsten-rhenium alloy. Therefore, for an anode target with the same weight of the molybdenum alloy substrate, the output power of the target disc can be significantly increased, and the heat capacity can be increased by more than 2 times. In addition, graphite has the characteristics of a large specific heat, a small specific gravity, a large radiation coefficient, and fast heat dissipation. Therefore, graphite is often compounded with the substrate material of the anode target to obtain a multilayer anode composite target, which has the advantages of light weight, large specific heat, and a cooling time that can be shortened by more than 50%.

[0005] The invention patent CN105039902B discloses a method for connecting graphite and molybdenum using thermal diffusion technology. First, the surfaces of the graphite block and the molybdenum sheet are pretreated, and a Ti / Zr solder thin sheet is prepared. Then, the graphite block, the Ti / Zr solder thin sheet, and the molybdenum sheet are stacked in sequence and placed in a vacuum melting furnace, and argon is introduced for thermal diffusion bonding. Practice has proved that the content of impurity gases at the weld of this preparation process is relatively high, and only one piece can be produced per furnace, resulting in low production efficiency.

[0006] The invention patent CN105397264A discloses a method for vacuum hot pressing and diffusion welding of molybdenum and graphite. First, molybdenum and graphite are placed in a welding fixture to form a welding assembly. Then, the welding assembly is placed in a vacuum hot pressing furnace for vacuum heating and pressing treatment, so as to achieve pressure diffusion welding of molybdenum and graphite. Practice has proved that due to the direct formation of a solid solution brittle phase between C and Mo at the joint of this process, the joint is prone to cracking under the conditions of high and low temperature cycling use, and only one piece can be produced per furnace, resulting in low production efficiency.

[0007] The invention patent CN109048030A discloses an SPS diffusion welding method for dissimilar materials of TZM and graphite. Using a titanium foil as an intermediate transition layer, and then through spark plasma sintering technology (SPS), solid-phase diffusion welding is carried out on the dissimilar materials of TZM and graphite, so as to obtain a connecting piece of the dissimilar materials of TZM and graphite. Practice has proved that this method requires high manufacturing conditions, cannot be mass-produced, has high costs, and has a low yield. Summary of the Invention

[0008] Aiming at the deficiencies and defects existing in the prior art, the present invention aims to provide a method for preparing a multi-layer composite anode matrix by diffusion connection. First, according to the shape requirements of the composite anode matrix, a basic component of the composite anode matrix is designed and processed, and then through envelope forming, hot isostatic pressing diffusion connection treatment, machining, and high-temperature exhaust treatment, a finished product of the composite anode matrix is obtained. The preparation method of the present invention has high production efficiency, and the prepared composite anode matrix has the advantages of high high-temperature strength and high dynamic balance accuracy.

[0009] The first aspect of the present invention provides a method for preparing a multi-layer composite anode matrix by diffusion connection, adopting the following technical solution:

[0010] A method for preparing a multi-layer composite anode matrix by diffusion connection includes the following steps:

[0011] Step 1: First, according to the shape requirements of the composite anode matrix, a basic component of the composite anode matrix is designed and processed. The basic component includes a tungsten alloy target surface blank, a molybdenum alloy matrix blank, and a graphite matrix blank stacked in sequence from top to bottom. An intermediate transition layer material is added between the contact surfaces of the molybdenum alloy matrix blank and the graphite matrix blank.

[0012] Step 2: Put the basic component into an envelope, then perform vacuum degassing treatment on the envelope, and then seal the air extraction port of the envelope to obtain an envelope formed part.

[0013] Step 3: Perform hot isostatic pressing diffusion connection treatment on the envelope formed part.

[0014] Step 4: After removing the sheath from the sheath-formed part after hot isostatic pressing diffusion bonding treatment, perform machining treatment according to the shape requirements of the composite anode matrix to obtain the machined composite anode matrix;

[0015] Step 5: Clean the machined composite anode matrix first and then perform high-temperature exhaust treatment to obtain the finished composite anode matrix.

[0016] In the present invention, first, according to the shape requirements of the composite anode matrix, tungsten alloy target blank, molybdenum alloy matrix blank, and graphite matrix blank are designed and processed. Then, through sheath forming, hot isostatic pressing diffusion bonding treatment, machining, and high-temperature exhaust treatment, the finished composite anode matrix is obtained. Since the tungsten alloy target blank and molybdenum alloy matrix blank are deformed alloy parts and are further obtained by vacuum heat treatment, compared with traditional powder metallurgy, they have the advantages of high density and high strength, making the finally obtained finished composite anode matrix have the advantages of high high-temperature strength and high dynamic balance accuracy. Further, in the present invention, through hot isostatic pressing diffusion bonding treatment, the contact surface between the tungsten alloy target blank and the molybdenum alloy matrix blank is connected. After a period of mutual diffusion of the atoms in the bonding layer, a diffusion layer is formed on the interface, and finally a reliable and stable connection interface is generated between the tungsten alloy target blank and the molybdenum alloy matrix blank. At the same time, through hot isostatic pressing diffusion bonding treatment, the contact surface between the molybdenum alloy matrix blank and the graphite matrix blank is connected. After the mutual diffusion of atoms between the intermediate transition layer material, the molybdenum alloy matrix blank, and the graphite matrix blank, finally a reliable and stable connection interface is generated between the molybdenum alloy matrix blank and the graphite matrix blank. In addition, in the present invention, the loading amount per furnace is related to the size of the furnace chamber. The larger the furnace chamber, the more the loading amount. Generally, the hot isostatic pressing diffusion bonding treatment in the present invention is more than 100 pieces per furnace, one furnace per day, and the production efficiency is greatly improved compared with the high-temperature vacuum hot pressing welding process (1 piece / furnace, 1 furnace per day).

[0017] In the method for preparing a multi-layer composite anode substrate by diffusion bonding described above, as a preferred embodiment, in step one, the tungsten alloy target blank is prepared from tungsten alloy as raw material through plastic working and / or machining and vacuum heat treatment; preferably, in the tungsten alloy, the mass fraction of rhenium is 0-10% (such as 0.5%, 1%, 2%, 3%, 5%, 7%, 9%), and the balance is tungsten; preferably, in the tungsten alloy, the mass fraction of rhenium is 0-10% (such as 0.5%, 1%, 2%, 3%, 5%, 7%, 9%), the mass fraction of carbide is ≤1% (such as 0.05%, 0.1%, 0.2%, 0.3%, 0.5%, 0.7%, 0.9%), and the balance is tungsten, where the carbide is one or more of HfC, TaC, ZrC; preferably, the temperature of the vacuum heat treatment is 1500-1700 °C (such as 1550 °C, 1600 °C, 1650 °C), the holding time is 60-120 min (such as 80 min, 100 min, 110 min), and the vacuum degree is ≤5×10 -4 Pa.

[0018] The tungsten alloy target blank in the present invention is prepared from tungsten alloy as raw material through plastic working and vacuum heat treatment. Among them, plastic working (such as stamping or spinning into an umbrella shape) can further improve the density and strength of the tungsten alloy target blank, and vacuum heat treatment can remove surface contamination, oxidation and internal residual gas of the tungsten alloy target blank, avoiding low joint strength or diffusion bonding failure in subsequent hot isostatic pressing diffusion bonding treatment. The tungsten alloy in the present invention is obtained by powder metallurgy / vacuum melting combined with deformation processing technology; adding rhenium element to the tungsten alloy can effectively improve the plasticity of tungsten and enhance the impact resistance of the tungsten alloy target blank. However, too high rhenium content will result in high cost and wasted performance. The shape, thickness, etc. of the tungsten alloy target blank in the present invention depend on the design requirements of the finished multi-layer composite anode substrate. In existing finished multi-layer composite anode substrates, the shape of the tungsten alloy target blank is generally umbrella-shaped and the thickness is 1-1.5 mm. Therefore, usually, in order to leave machining allowance, the thickness of the tungsten alloy target blank is controlled at about 3 mm. The method for preparing a multi-layer composite anode substrate by diffusion bonding in the present invention is also applicable to treating tungsten alloy target blanks with thicker or thinner thickness.

[0019] In the above method for preparing a multi-layer composite anode substrate by diffusion bonding, as a preferred embodiment, in step one, the molybdenum alloy substrate blank is prepared from a molybdenum alloy as a raw material through plastic processing and / or machining, and vacuum heat treatment; preferably, the molybdenum alloy is one of Mo-Ti-Zr alloy (TZM), Mo-Hf-C alloy (MHC), and Mo-La alloy (MoLa); preferably, in the Mo-Ti-Zr alloy, by mass fraction, Ti: 0.40 - 0.55% (such as 0.45%, 0.50%, 0.52%), Zr: 0.06 - 0.12% (such as 0.07%, 0.09%, 0.11%), C: 0.01 - 0.04% (such as 0.02%, 0.025%, 0.03%), and the balance is Mo; preferably, in the Mo-Hf-C alloy, by mass fraction, Hf: 0.8 - 1.2% (such as 0.9%, 1.0%, 1.1%), C: 0.05 - 0.12% (such as 0.08%, 0.1%, 0.11%), and the balance is Mo; preferably, in the Mo-La alloy, by mass fraction, La2O3: 0.3 - 0.8% (such as 0.4%, 0.5%, 0.7%), and the balance is Mo; preferably, the temperature of the vacuum heat treatment is 1500 - 1700 °C (such as 1550 °C, 1600 °C, 1650 °C), the holding time is 60 - 120 min (such as 80 min, 100 min, 110 min), and the vacuum degree ≤ 5×10 -4 Pa.

[0020] In the present invention, the molybdenum alloy substrate blank is prepared from a molybdenum alloy as a raw material through plastic processing and / or machining, and vacuum heat treatment. Among them, plastic processing (such as upset forging into the shape of a blank cone) can further improve the density and strength of the molybdenum alloy substrate blank. Vacuum heat treatment can remove surface contamination, oxidation, and residual gas inside the molybdenum alloy substrate blank, avoiding low joint strength or diffusion bonding failure in subsequent hot isostatic pressing diffusion bonding treatment. The molybdenum alloy in the present invention is obtained through a powder metallurgy / vacuum melting combined with deformation processing technology. In addition, the shape, thickness, etc. of the molybdenum alloy substrate blank in the present invention depend on the design requirements of the finished composite anode substrate. In existing finished composite anode substrates, the thickness of the molybdenum alloy substrate blank is generally within 15 mm. The method for preparing a multi-layer composite anode substrate by diffusion bonding in the present invention is also applicable to treating molybdenum alloy substrate blanks with a thicker or thinner thickness.

[0021] In the above method for preparing a multi-layer composite anode substrate by diffusion bonding, as a preferred embodiment, in step one, the surface roughness Ra of the contact surface between the tungsten alloy target surface blank and the molybdenum alloy substrate blank is ≤ 0.8.

[0022] In the above method for preparing a multi-layer composite anode substrate by diffusion bonding, as a preferred embodiment, in step one, the intermediate transition layer material is a titanium sheet or a zirconium sheet; preferably, the thickness of the titanium sheet is 100-400 μm (such as 120 μm, 200 μm, 300 μm, 350 μm); preferably, the thickness of the zirconium sheet is 100-400 μm (such as 120 μm, 200 μm, 300 μm, 350 μm).

[0023] The reason for choosing a titanium sheet as the intermediate transition layer material in the present invention is that titanium can form a Ti-Mo solid solution with molybdenum and can also form TiC with graphite. The reason for choosing a zirconium sheet is that zirconium can form a Mo-Zr solid solution with molybdenum and can also form ZrC with graphite; the intermediate transition layer material added in the present invention can achieve a reliable and stable connection interface between the molybdenum alloy substrate blank and the graphite substrate blank after hot isostatic pressing diffusion bonding treatment. The shape, thickness, etc. of the graphite substrate blank in the present invention depend on the design requirements of the finished multi-layer composite anode substrate. In existing finished multi-layer composite anode substrates, the thickness of the graphite substrate blank is generally within 50 mm. The method for preparing a multi-layer composite anode substrate by diffusion bonding in the present invention is also applicable to treating graphite substrate blanks with thicker or thinner thicknesses.

[0024] In the above method for preparing a multi-layer composite anode substrate by diffusion bonding, as a preferred embodiment, in step two, the material of the jacket is a tantalum alloy, and a ceramic layer is coated inside the jacket; preferably, the thickness of the ceramic layer is 50-200 μm (such as 80 μm, 100 μm, 150 μm); preferably, the material of the ceramic layer is one or more of ZrO2, Al2O3, BN; preferably, the vacuum degree of vacuum degassing ≤ 5×10 -3 Pa.

[0025] The purpose of coating a ceramic layer inside the jacket in the present invention is to prevent the jacket material and the material of the basic component from being connected together during the hot isostatic pressing connection diffusion treatment to form a diffusion layer.

[0026] In the above method for preparing a multi-layer composite anode substrate by diffusion bonding, as a preferred embodiment, in step three, the hot isostatic pressing diffusion bonding treatment is carried out in a hot isostatic pressing furnace. The temperature of the hot isostatic pressing diffusion bonding treatment is 1500-1800 °C (such as 1550 °C, 1600 °C, 1650 °C, 1700 °C, 1750 °C), the pressure is 150-200 MPa (such as 160 MPa, 170 MPa, 180 MPa, 190 MPa), and the heat preservation and pressure holding time is 60-240 min (such as 80 min, 100 min, 150 min, 180 min, 200 min).

[0027] In the present invention, if the temperature of the hot isostatic pressing diffusion bonding treatment is lower than 1500 °C, a reliable stable bonding interface cannot be formed between the tungsten alloy target blank and the molybdenum alloy matrix blank, and a reliable stable bonding interface can be formed between the molybdenum alloy matrix blank and the graphite matrix blank; if the temperature of the hot isostatic pressing diffusion bonding treatment is higher than 1800 °C, the grains in the tungsten alloy target blank and the molybdenum alloy matrix blank will grow due to the too high temperature, thus affecting the performance of the final composite anode matrix. At the same time, the temperature is too high, and the equipment is severely limited, that is, there are few industrial high-temperature and high-pressure hot isostatic pressing equipment, making it difficult to realize industrial production.

[0028] In the above method for preparing a multi-layer composite anode matrix by diffusion bonding, as a preferred embodiment, in step five, the temperature of the high-temperature exhaust treatment is 1300 - 1400 °C (such as 1310 °C, 1340 °C, 1360 °C, 1380 °C), the heat preservation time is 120 - 300 min (such as 150 min, 180 min, 200 min, 250 min), and the exhaust vacuum degree ≤ 5×10 -4 Pa.

[0029] The high-temperature exhaust treatment in the present invention is carried out in a vacuum heating furnace, maintaining the vacuum degree in the furnace ≤ 5×10 -4 Pa. The main purpose of the high-temperature exhaust treatment is to remove the residual gas in the composite anode matrix, thereby avoiding the failure of the composite anode matrix due to excessive gas evolution when used in a high-temperature and high-vacuum environment. Due to the addition of the graphite matrix blank in the composite anode matrix of the present invention, therefore, in order to ensure the bonding strength between the molybdenum alloy matrix blank and the graphite matrix blank, the temperature during the high-temperature exhaust treatment should not be too high. Practice has proved that performing the high-temperature exhaust treatment at a temperature of 1300 - 1400 °C can meet the use requirements.

[0030] The second aspect of the present invention provides a composite anode matrix, which is prepared by the above preparation method.

[0031] In the above composite anode matrix, as a preferred implementation, the unbalance amount before weight removal of the composite anode matrix ≤ 1 g·cm.

[0032] Compared with the prior art, the present invention has the following positive effects:

[0033] (1) First, according to the shape requirements of the composite anode substrate, tungsten alloy target blank, molybdenum alloy substrate blank, and graphite substrate blank are designed and processed. Since the tungsten alloy target blank and molybdenum alloy substrate blank are made of deformed tungsten rhenium alloy and molybdenum alloy respectively through vacuum heat treatment, they have the advantages of high density and high strength. Compared with the composite anode substrate prepared by the traditional powder metallurgy method, it avoids the problems of poor dynamic balance accuracy caused by uneven powder laying and poor strength caused by small forging deformation. It has the advantages of high strength and high dynamic balance accuracy;

[0034] (2) The preparation method of the present invention introduces the hot isostatic pressing diffusion bonding process. Compared with the high-temperature vacuum hot pressing welding process, SPS diffusion welding and other processes, it greatly improves the production efficiency, can realize batch production, and has a high yield. The hot isostatic pressing diffusion bonding process of the present invention generally has more than 100 pieces per furnace, one furnace per day. The production efficiency is compared with the high-temperature vacuum hot pressing welding process (because the heating and cooling time of this process is long, the holding time is also long, and only one single piece can be produced per furnace, and the production efficiency of this process is 1 piece / furnace, per day / furnace). On the premise of ensuring the welding quality of the bonding surface between the tungsten alloy target blank and the molybdenum alloy substrate blank and the interface welding quality between the molybdenum alloy substrate blank and the graphite substrate blank, the production cost of the present invention is greatly reduced.

[0035] (3) The hot isostatic pressing diffusion bonding process of the present invention can ensure the bonding strength between the tungsten alloy target blank and the molybdenum alloy substrate blank and between the molybdenum alloy substrate blank and the graphite substrate blank. During the use process, no cracks appear on the bonding surface of each blank, and no delamination occurs on the bonding surface of each blank. Through non-destructive ultrasonic testing, the interface bonding rate between the tungsten alloy target blank and the molybdenum alloy substrate blank is ≥99%, and the interface bonding rate between the molybdenum alloy substrate blank and the graphite substrate blank is ≥95%; the unbalance amount of the composite anode substrate before weight removal is ≤1 g·cm; the life exposure times of the obtained composite anode substrate finished product is ≥1 million scanning seconds. Description of the Drawings

[0036] Figure 1 It is a schematic cross-sectional structure diagram of the sheathed forming part obtained by using the preparation method of the present invention.

[0037] Description of the reference numerals: 1. Tungsten alloy target blank; 2. Molybdenum alloy substrate blank; 3. Graphite substrate blank; 4. Intermediate transition layer material; 5. Sheath. Detailed Embodiments

[0038] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described so that those skilled in the art can practice and reproduce. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art belong to the scope protected by the present invention.

[0039] In the test methods of the following embodiments, unless otherwise specified, they are all conventional methods and can be carried out according to the techniques or conditions described in the literature in this field or according to the product specifications. The raw materials described in the following embodiments can all be obtained from public commercial channels.

[0040] The composite anode substrate prepared by the method for preparing a multi-layer composite anode substrate by diffusion bonding of the present invention can be used as an anode target of an X-ray tube.

[0041] Example 1 A method for preparing a multi-layer composite anode substrate by diffusion bonding, comprising the following steps:

[0042] (1) First, according to Figure 1 the shape requirements shown, a basic component of the composite anode substrate is designed and processed (the overall shape is a frustum of a cone, the diameter of its upper surface is denoted as d, the diameter of the lower surface is denoted as D, and the angle between the upper surface and its adjacent side surface, i.e., the track layer angle, is denoted as α). The basic component includes a tungsten alloy target surface blank (its thickness is denoted as h1), a molybdenum alloy matrix blank (its thickness is denoted as h2), and a graphite matrix blank (its height is denoted as h3) stacked in sequence from top to bottom. Among them, the tungsten alloy target surface blank is made of W5Re-0.27HfC alloy (by mass fraction, Re: 5%, HfC: 0.27%, the balance is W) as raw material through sheet stamping + machining or machining, and then vacuum heat-treated at a vacuum degree ≤ 5×10 -4 Pa at 1600 °C for 60 min, and its thickness h1 is 3 mm; the molybdenum alloy matrix blank is made of TZM molybdenum alloy as raw material through upset forging + machining or machining, and then vacuum heat-treated at a vacuum degree ≤ 5×10 -4 Pa at 1600 °C for 60 min, and its thickness h2 is 9 mm; the thickness h3 of the graphite matrix blank (high-purity graphite) is 30 mm, and a titanium sheet with a thickness of 150 μm is added between the contact surfaces of the molybdenum alloy matrix blank and the graphite matrix blank; the diameter d of the upper surface of the basic component is 105 mm, the diameter D of the lower surface is 143 mm, the track layer angle α is 8°, and the surface roughness Ra of the contact surface between the tungsten alloy target surface blank and the molybdenum alloy matrix blank ≤ 0.8.

[0043] (2) Put the basic component into a jacket (the material of the jacket is tantalum alloy, and a ceramic layer with a thickness of 100 μm is coated inside the jacket, and the material of the ceramic layer is BN), then perform vacuum degassing treatment on the jacket, and then seal and weld the air extraction port of the jacket to obtain a jacket forming part, where the vacuum degree of vacuum degassing ≤ 5×10 -3 Pa.

[0044] (3) Place the sheathed formed part in a hot isostatic pressing furnace for hot isostatic pressing diffusion bonding treatment. Among them, the temperature of the hot isostatic pressing diffusion bonding treatment is 1700 °C, the pressure is 150 MPa, and the heat preservation and pressure holding time is 240 min.

[0045] (4) After removing the sheath from the sheathed formed part after hot isostatic pressing diffusion bonding treatment, according to the shape requirements of the composite anode substrate, perform machining treatment to obtain a machined composite anode substrate with a lower surface diameter D of 140 mm;

[0046] (5) First clean the machined composite anode substrate and then perform high-temperature exhaust treatment to obtain the finished composite anode substrate; the temperature of the high-temperature exhaust treatment is 1350 °C, the heat preservation time is 300 min, and the exhaust vacuum degree ≤ 5×10 -4 Pa.

[0047] Test the unbalance amount of the composite anode substrate before removing the weight using a Schenck HM10BK dynamic balancing machine, and the unbalance amount result is 0.5 g·cm; through non-destructive ultrasonic testing, the interface bonding rate between the tungsten alloy target surface blank and the molybdenum alloy matrix blank ≥ 99%, and the interface bonding rate between the molybdenum alloy matrix blank and the graphite matrix blank ≥ 95%; the life exposure times of the obtained composite anode substrate ≥ 1 million scan seconds.

[0048] Example 2 A method for preparing a multi-layer composite anode substrate by diffusion bonding, including the following steps:

[0049] (1) First, according to Figure 1 As shown in the shape requirements, design and machine to obtain the basic component of the composite anode substrate (the overall shape is a frustum of a cone, the diameter of its upper surface is denoted as d, the diameter of its lower surface is denoted as D, and the angle between its upper surface and the adjacent side surface, that is, the track layer angle, is denoted as α). The basic component includes a tungsten alloy target surface blank (its thickness is denoted as h1), a molybdenum alloy matrix blank (its thickness is denoted as h2), and a graphite matrix blank (its height is denoted as h3) stacked in sequence from top to bottom; among them, the tungsten alloy target surface blank uses W10Re alloy (by mass fraction, Re: 10%, the balance is W) as raw material and is formed by sheet stamping + machining or machining, and then is subjected to vacuum heat treatment at a vacuum degree ≤ 5×10 -4 Pa at 1700 °C for 60 min of heat preservation to obtain, and its thickness h1 is 3 mm; the molybdenum alloy matrix blank uses MHC molybdenum alloy as raw material and is formed by upsetting + machining or machining, and then is at a vacuum degree ≤ 5×10 -4The Pa is obtained by vacuum heat treatment at 1700 °C for 60 min, and its thickness h2 is 9 mm; the thickness h3 of the graphite matrix blank (high-purity graphite) is 30 mm, and a zirconium sheet with a thickness of 300 μm is added between the contact surfaces of the molybdenum alloy matrix blank and the graphite matrix blank; the upper surface diameter d of the basic component is 90 mm, the lower surface diameter D is 143 mm, the track layer angle α is 7°, and the surface roughness Ra of the contact surface between the tungsten alloy target blank and the molybdenum alloy matrix blank is ≤ 0.8.

[0050] (2) Place the basic component into a cladding (the material of the cladding is tantalum alloy, and a ceramic layer with a thickness of 150 μm is coated inside the cladding, and the material of the ceramic layer is Al2O3), then perform vacuum degassing treatment on the cladding, and then perform welding treatment on the air extraction port of the cladding to obtain a formed cladding part, where the vacuum degree of vacuum degassing is ≤ 5×10 -3 Pa.

[0051] (3) Place the formed cladding part in a hot isostatic pressing furnace for hot isostatic pressing diffusion bonding treatment. Among them, the temperature of the hot isostatic pressing diffusion bonding treatment is 1550 °C, the pressure is 180 MPa, and the heat preservation and pressure holding time is 180 min.

[0052] (4) After removing the cladding from the formed cladding part obtained by hot isostatic pressing diffusion bonding treatment, perform machining treatment according to the shape requirements of the composite anode matrix to obtain a machined composite anode matrix with a lower surface diameter D of 140 mm;

[0053] (5) First clean the machined composite anode matrix and then perform high-temperature exhaust treatment to obtain the finished composite anode matrix; the temperature of the high-temperature exhaust treatment is 1350 °C, the heat preservation time is 240 min, and the exhaust vacuum degree is ≤ 4×10 -4 Pa.

[0054] The unbalanced amount of the composite anode matrix before weight removal is measured by a Schenck HM10BK dynamic balancing machine, and the unbalanced amount result is 0.35 g·cm; through non-destructive ultrasonic testing, the interface bonding rate between the tungsten alloy target blank and the molybdenum alloy matrix blank is ≥ 99%, and the interface bonding rate between the molybdenum alloy matrix blank and the graphite matrix blank is ≥ 95%; the life exposure times of the obtained composite anode matrix are ≥ 1 million scan seconds.

[0055] Example 3 A method for preparing a multi-layer composite anode matrix by diffusion bonding, comprising the following steps:

[0056] (1) First, according to Figure 1According to the shape requirements shown, design and process the basic components of the composite anode substrate (the overall shape is a frustum of a cone, the diameter of its upper surface is denoted as d, the diameter of the lower surface is denoted as D, and the angle between the upper surface and its adjacent side surface, i.e., the track layer angle, is denoted as α). The basic components include a tungsten alloy target blank (its thickness is denoted as h1), a molybdenum alloy matrix blank (its thickness is denoted as h2), and a graphite matrix blank (its height is denoted as h3) stacked from top to bottom in sequence. Among them, the tungsten alloy target blank is made of W10Re alloy (by mass fraction, Re: 10%, the balance is W) as raw material through sheet stamping + machining or machining, and then vacuum heat-treated at a vacuum degree ≤ 5×10 -4 Pa at 1600 °C for 90 min, and its thickness h1 is 3 mm; the molybdenum alloy matrix blank is made of MoLa molybdenum alloy (by mass fraction, La2O3: 0.5%, the balance is Mo) as raw material through upset forging + machining or machining, and then vacuum heat-treated at a vacuum degree ≤ 5×10 -4 Pa at 1600 °C for 90 min, and its thickness h2 is 12 mm; the thickness h3 of the graphite matrix blank (high-purity graphite) is 30 mm, and a titanium sheet with a thickness of 200 μm is added between the contact surfaces of the molybdenum alloy matrix blank and the graphite matrix blank; the diameter d of the upper surface of the basic components is 143 mm, the diameter D of the lower surface is 193 mm, the track layer angle α is 7°, and the surface roughness Ra of the contact surface between the tungsten alloy target blank and the molybdenum alloy matrix blank is ≤ 0.8.

[0057] (2) Put the basic components into a cladding (the material of the cladding is tantalum alloy, and a ceramic layer with a thickness of 200 μm is coated inside the cladding, and the material of the ceramic layer is ZrO2), then perform vacuum degassing treatment on the cladding, and then seal-weld the air extraction port of the cladding to obtain a formed cladding part, where the vacuum degree of vacuum degassing is ≤ 5×10 -3 Pa.

[0058] (3) Place the formed cladding part in a hot isostatic pressing furnace for hot isostatic pressing diffusion bonding treatment. Among them, the temperature of the hot isostatic pressing diffusion bonding treatment is 1800 °C, the pressure is 150 MPa, and the heat preservation and pressure holding time is 180 min.

[0059] (4) After removing the cladding from the formed cladding part subjected to hot isostatic pressing diffusion bonding treatment, perform machining treatment according to the shape requirements of the composite anode substrate to obtain a machined composite anode substrate with a lower surface diameter D of 190 mm.

[0060] (5) First clean the machined composite anode substrate and then perform high-temperature exhaust treatment to obtain the finished composite anode substrate; the temperature of the high-temperature exhaust treatment is 1380 °C, the heat preservation time is 300 min, and the exhaust vacuum degree is ≤ 5×10 -4 Pa.

[0061] The unbalanced amount of the composite anode substrate before duplicate removal was tested using a Schenck HM10BK dynamic balancing machine, and the unbalanced amount result was 0.65 g·cm; through non-destructive ultrasonic testing, the interface bonding rate between the tungsten alloy target blank and the molybdenum alloy substrate blank was ≥99%, and the interface bonding rate between the molybdenum alloy substrate blank and the graphite substrate blank was ≥95%; the life exposure times of the obtained composite anode substrate were ≥1 million scan seconds.

[0062] Comparative Example 1

[0063] In Comparative Example 1, except that step (3) was different from that in Example 2, the rest were the same as in Example 2. Specifically: (3) The cladding formed part was placed in a hot isostatic pressing furnace for hot isostatic pressing diffusion bonding treatment. Among them, the temperature of the hot isostatic pressing diffusion bonding treatment was 1400 °C, the pressure was 180 MPa, and the heat preservation and pressure holding time was 180 min.

[0064] After removing the cladding, machining was carried out according to the shape of the composite anode. Through non-destructive ultrasonic testing, the interface bonding rate between the tungsten alloy target blank and the molybdenum alloy substrate blank was about 80%; the interface bonding rate between the molybdenum alloy substrate blank and the graphite substrate blank was ≤50%, and a large area of non-welded area appeared, which could not meet the use requirements.

[0065] Comparative Example 2

[0066] In Comparative Example 2, except that step (3) was different from that in Example 2, the rest were the same as in Example 2. Specifically: (3) The cladding formed part was placed in a hot isostatic pressing furnace for hot isostatic pressing diffusion bonding treatment. Among them, the temperature of the hot isostatic pressing diffusion bonding treatment was 1900 °C, the pressure was 180 MPa, and the heat preservation and pressure holding time was 180 min. After removing the cladding, analysis showed that due to the too high temperature, first, the molybdenum alloy grains grew abnormally, and second, more zirconium solder overflowed, resulting in a large number of holes at the joint between the molybdenum alloy substrate blank and the graphite substrate blank, seriously affecting the use performance.

[0067] Comparative Example 3

[0068] In Comparative Example 3, except that step (1) was different from that in Example 2, the rest were the same as in Example 2. Specifically:

[0069] (1) First, according to Figure 1According to the shape requirements shown, the basic components of the composite anode substrate are designed and processed (the overall shape is a frustum of a cone, the diameter of its upper surface is denoted as d, the diameter of the lower surface is denoted as D, and the angle between the upper surface and its adjacent side surface, i.e., the track layer angle, is denoted as α). The basic components include a tungsten alloy target blank (its thickness is denoted as h1), a molybdenum alloy matrix blank (its thickness is denoted as h2), and a graphite matrix blank (its height is denoted as h3) stacked in sequence from top to bottom. Among them, the tungsten alloy target blank is made of W10Re alloy (by mass fraction, Re: 10%, the balance is W) as raw material through sheet stamping + machining, and its thickness h1 is 3 mm; the molybdenum alloy matrix blank is made of MHC molybdenum alloy as raw material through upset forging + machining or machining, and its thickness h2 is 9 mm; the thickness h3 of the graphite matrix blank (high-purity graphite) is 30 mm, and a zirconium sheet with a thickness of 300 μm is added between the contact surfaces of the molybdenum alloy matrix blank and the graphite matrix blank; the diameter d of the upper surface of the basic components is 90 mm, the diameter D of the lower surface is 143 mm, the track layer angle α is 7°, and the surface roughness Ra of the contact surface between the tungsten alloy target blank and the molybdenum alloy matrix blank is ≤ 0.8.

[0070] The unbalance of the anode substrate before removing duplicates is tested by Schenck HM10BK dynamic balancing machine, and the unbalance result is 0.75 g·cm. Through non-destructive ultrasonic testing, the interface bonding rate between the tungsten alloy target blank and the molybdenum alloy matrix blank is about 80%, and the interface bonding rate between the molybdenum alloy matrix blank and the graphite matrix blank is about 75%, which cannot meet the requirement that the interface bonding rate ≥ 90%.

[0071] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are within the scope of protection of the pending claims of the present invention.

Claims

1. A method for preparing a multi-layer composite anode substrate by diffusion bonding, characterized in that, It includes the following steps: Step 1: First, according to the shape requirements of the composite anode substrate, design and process the basic components of the composite anode substrate. The basic components include a tungsten alloy target blank, a molybdenum alloy matrix blank, and a graphite matrix blank stacked in sequence from top to bottom. An intermediate transition layer material is added between the contact surfaces of the molybdenum alloy matrix blank and the graphite matrix blank; Step 2: Place the basic components into a sheath, then perform vacuum degassing treatment on the sheath, and then seal and weld the air extraction port of the sheath to obtain a formed sheath part; Step 3: Perform hot isostatic pressing diffusion bonding treatment on the formed sheath part; The hot isostatic pressing diffusion bonding treatment is carried out in a hot isostatic pressing furnace. The temperature of the hot isostatic pressing diffusion bonding treatment is 1500 - 1800 °C, the pressure is 150 - 200 MPa, and the heat preservation and pressure holding time is 60 - 240 min; Step 4: After removing the sheath from the formed sheath part treated by hot isostatic pressing diffusion bonding, perform machining treatment according to the shape requirements of the composite anode substrate to obtain a machined composite anode substrate; Step Five: First, clean the machined composite anode substrate and then perform high-temperature exhaust treatment to obtain the finished composite anode substrate. Among them, the temperature of the high-temperature exhaust treatment is 1300 - 1400 °C, the heat preservation time is 120 - 300 min, and the exhaust vacuum degree ≤ 5×10 -4 Pa.

2. The method for preparing a multi-layer composite anode substrate by diffusion bonding according to claim 1, characterized in that, In step one, the tungsten alloy target blank is made of tungsten alloy as raw material through plastic processing and / or machining, and vacuum heat treatment. The temperature of the vacuum heat treatment of the tungsten alloy is 1500 - 1700 °C, the holding time is 60 - 120 min, and the vacuum degree ≤ 5×10 - 4 Pa; In Step 1, the molybdenum alloy matrix blank is prepared from molybdenum alloy as raw material through plastic processing and / or machining and vacuum heat treatment. The temperature of the vacuum heat treatment of the molybdenum alloy is 1500 - 1700 °C, the holding time is 60 - 120 min, and the vacuum degree ≤ 5×10 -4 Pa.

3. The method for preparing a multi-layer composite anode substrate by diffusion bonding according to claim 2, characterized in that In the tungsten alloy, the mass fraction of rhenium is 0 - 10%, and the balance is tungsten; The molybdenum alloy is one of Mo-Ti-Zr alloy, Mo-Hf-C alloy, and Mo-La alloy.

4. The method for preparing a multi-layer composite anode substrate by diffusion bonding according to claim 3, characterized in that, In the tungsten alloy, the mass fraction of rhenium is 0 - 10%, the mass fraction of carbide ≤ 1%, and the balance is tungsten, where the carbide is one or more of HfC, TaC, and ZrC; In the Mo-Ti-Zr alloy, by mass fraction, Ti: 0.40 - 0.55%, Zr: 0.06 - 0.12%, C: 0.01 - 0.04%, and the balance is Mo; In the Mo-Hf-C alloy, by mass fraction, Hf: 0.8 - 1.2%, C: 0.05 - 0.12%, and the balance is Mo; In the Mo-La alloy, by mass fraction, La2O3: 0.3 - 0.8%, and the balance is Mo.

5. The method for preparing a multi-layer composite anode substrate by diffusion bonding according to any one of claims 1-4, characterized in that, In Step 1, the surface roughness Ra of the contact surface between the tungsten alloy target blank and the molybdenum alloy matrix blank ≤ 0.

8.

6. The method for preparing a multi-layer composite anode substrate by diffusion bonding according to any one of claims 1-5, characterized in that, In Step 1, the intermediate transition layer material is a titanium sheet or a zirconium sheet.

7. The method for preparing a multi-layer composite anode substrate by diffusion bonding according to claim 6, characterized in that, The thickness of the titanium sheet is 100 - 400 μm; the thickness of the zirconium sheet is 100 - 400 μm.

8. The method for preparing a multi-layer composite anode substrate by diffusion bonding according to any one of claims 1-7, characterized in that, In step two, the material of the cladding is tantalum alloy, and a ceramic layer is coated inside the cladding; preferably, the thickness of the ceramic layer is 50 - 200 μm; preferably, the material of the ceramic layer is one or more of ZrO2, Al2O3, BN; preferably, the degree of vacuum for vacuum degassing ≤ 5×10 -3 Pa.

9. A composite anode substrate, characterized in that, The composite anode substrate is obtained by the preparation method described in any one of claims 1 - 8.

10. The composite anode substrate according to claim 9, characterized in that, The unbalance amount of the composite anode substrate before weight removal ≤ 1 g·cm.

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