Welding structure and welding method of anode target disc and anode target disc

Abstract

The invention relates to the technical field of heterogeneous material connection, and provides a welding structure and a welding method of an anode target disc and the anode target disc, the welding structure of the anode target disc comprises graphite, metal and a welding flux block placed between the graphite and the metal, and the graphite and the metal are annular; on two opposite surfaces of the graphite and the metal, one surface is provided with an annular convex block, and the other surface is provided with an annular groove matched with the annular convex block; a flow storage groove is formed in the joint of the groove bottom face of the annular groove and the side wall of the annular groove, and the flow storage groove is used for capillary spreading of molten solder at the joint between the side wall of the annular groove and the side wall of the annular protruding block. The metal and graphite composite part connector is high in remelting temperature, few in welding face defect and full in appearance welding flux filling, the welding strength of the connector can reach 17-25 MPa, the full welding rate of the welding face is 98% or above, and the performance of the welded connector is stable.

Description

Technical Field

[0001] This application belongs to the technical field of joining of heterogeneous materials, and particularly relates to a welding structure, a welding method and an anode target disc of an anode target disc. Background Art

[0002] As one of the most important refractory metals, molybdenum alloys are ideal for many high-temperature applications (such as nuclear energy and aerospace systems) due to their excellent mechanical properties, good thermal and electrical conductivities at high temperatures. However, due to the high density of molybdenum alloys and the difficulty in processing and welding, the wide application of molybdenum alloys has been restricted. As a non-metallic material, graphite has a layered structure, a high melting point, and good electrical and thermal conductivities, but its strength and oxidation resistance are relatively low, especially at high temperatures, which limits the application of graphite. In order to utilize the superior properties of graphite and molybdenum alloys, it is usually necessary to join graphite and molybdenum alloys to obtain a structural material. The graphite / molybdenum alloy composite structure is often used as a heat transfer component in the nuclear fusion industry due to its good heat dissipation structure, and the low-density graphite and molybdenum alloy have excellent mechanical properties at high temperatures. It can also be used in the civilian industry, such as the anode target material for CT machines in medical diagnostic equipment.

[0003] Many scholars at home and abroad have done a lot of research on the joining of graphite and molybdenum-based alloys, such as friction welding, diffusion welding and brazing. For example: by pre-treating the molybdenum and graphite areas to be welded to increase the specific surface area, then placing a foil filler metal, and then performing vacuum pressure welding. This method is relatively complex in actual production operation for the pre-treatment process of increasing the specific surface area of molybdenum and graphite, and is not suitable for mass production. There is also a method of using hot pressing technology to perform diffusion at high temperatures to form a carbide layer of Mo as a welding transition layer, and finally form an effective connection between molybdenum and graphite. The welding methods of molybdenum and its alloys with graphite involved in these methods are all brazing methods with different added elements, different numbers of filler metal layers, different added forms, including powders, foils, coatings, etc., and the purpose is to change the welding surface structure to increase the contact area between the filler metal and the base metal, and increase the wettability and adhesiveness. And all of them require external pressure welding. The disadvantage of this process is that only a few products can be welded per furnace, with low production efficiency and high cost, and it is not suitable for mass production. In addition, the welding strength of the molybdenum alloy and graphite composite parts obtained by these methods is generally between 10 - 16 MPa. For the rotating anode target disc in an X-ray tube, when the working conditions are 1400 °C and the rotation frequency is 180 Hz, this welding strength cannot meet the use requirements of the rotating anode target disc.

[0004] Some other studies use a CNC electric discharge lathe to roughen the molybdenum surface to be welded and use sandpaper to polish the graphite surface to be welded. Its disadvantage is that it will introduce new pollution and impurities, and it is necessary to perform additional alkali washing and deoxidation treatment on molybdenum. Moreover, its processing thickness of molybdenum is greater than 1 mm, which will instead increase the welding pores and is not conducive to improving the welding strength of the joint. Summary of the Invention

[0005] The purpose of the present application is to provide a welding structure, a welding method and an anode target disc of an anode target disc, aiming to solve the problems of many defects in the brazing joint surface between metal and graphite and the insufficient filling of the solder in the mating gap between metal and graphite.

[0006] To achieve the above application purpose, the technical solution adopted by the present application is as follows:

[0007] In the first aspect, the present application provides a welding structure of an anode target disc, including graphite, metal and a solder block placed between the graphite and the metal, and the graphite and the metal are annular;

[0008] On two surfaces of the graphite and the metal facing each other, one surface is constructed with an annular convex block, and the other surface is constructed with an annular groove that matches the annular convex block;

[0009] A flow storage groove is arranged at the junction of the bottom surface of the annular groove and the side wall of the annular groove, and the flow storage groove is used to make the molten solder at the junction capillary spread between the side wall of the annular groove and the side wall of the annular convex block.

[0010] In the second aspect, the present application provides a welding method of an anode target disc, including the following steps:

[0011] An annular groove and a flow storage groove are processed on the surface to be welded of the metal or graphite, and the flow storage groove is arranged at the junction of the bottom surface of the annular groove and the side wall of the annular groove;

[0012] The solder block is placed between the surface to be welded of the graphite and the surface to be welded of the metal, and welding treatment is carried out.

[0013] In the third aspect, the present application provides an anode target disc, which is welded and made by the anode target disc welding structure described in the first aspect, or welded and made by the welding method of the anode target disc described in the second aspect.

[0014] An anode target disk provided in the first aspect of the present application. Since a current storage groove structure is added to the metal surface to be welded or the graphite surface to be welded in the present application, when the solder is liquefied at high temperature, the current storage groove structure helps the liquid-phase solder to spread more evenly in the circumferential direction of the welding surface, and there will be no situation where the thickness of the local solder layer on the welding surface is too thick or too thin, making the thickness of the solder layer on the entire welding surface uniform, thereby reducing the porosity. When the solder is in the liquid phase, the current storage groove will be first filled with the liquid-phase solder, and under the capillary tension of the mating gap between the metal and the graphite, the solder in the current storage groove climbs along the mating gap, and the solder at other places on the welding surface continues to supplement the current storage groove, so as to fill the mating gap between the metal and the graphite.

[0015] A welding method for an anode target disk provided in the second aspect of the present application. An annular groove and a current storage groove are processed on the metal surface to be welded or the graphite surface to be welded, and the current storage groove is located at the junction of the bottom surface of the annular groove and the side wall of the annular groove. The design of adding a current storage groove to the metal surface to be welded or the graphite surface to be welded in the present application is beneficial to the capillary spreading of the molten solder between the side walls of the annular groove and the side walls of the annular convex block during the welding process after the solder block melts, making the solder layer more uniform and reducing the welding porosity at the same time. The design of the current storage groove is beneficial to the solder filling the mating gaps on the outer side and the inner side of the metal and the graphite. Moreover, the current storage groove structure of the present application is simple and easy to process in batches.

[0016] The welding method of the present application has high feasibility for the surface treatment methods of molybdenum alloy and graphite, high production efficiency, and does not require additional cleaning treatment after treatment, and is applicable to the batch treatment of the metal and graphite surfaces to be welded before high-temperature brazing. The surface treatment method of the graphite in the welding method of the present application is simple, low-cost, can be processed in batches, and can increase the welding strength between the metal and the graphite by 20 - 50%.

[0017] The anode target disk provided in the third aspect of the present application has a high remelting temperature at the joint of the metal and graphite composite, few defects on the welding surface, full filling of the appearance solder, the joint welding strength can reach 17 - 25 MPa, the full-welding rate of the welding surface is above 98%, the performance of the welded joint is stable, and the service life cycle is long. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a top view of the structure diagram of the metal or graphite provided by the embodiment of the present application;

[0020] Figure 2It is a sectional view of the structure diagram of metal or graphite provided by an embodiment of the present application.

[0021] Figure 3 It is a partial structure diagram of the surface-treated graphite provided by an embodiment of the present application;

[0022] Figure 4 It is a partial structure diagram of the surface-treated metal provided by an embodiment of the present application;

[0023] Figure 5 It is a partial structure diagram of the welding treatment provided by Embodiment 3 of the present application;

[0024] Figure 6 It is a partial structure diagram of the welding treatment provided by Embodiment 8 of the present application.

[0025] Among them, each reference numeral in the figure:

[0026] 10 - graphite, 20 - metal, 30 - solder block, 40 - current storage tank, 41 - first current storage tank, 42 - second current storage tank, 3 - annular groove, 4 - through hole, 5 - annular protrusion;

[0027] a1 represents the interval width between every two adjacent first pits; a2 represents the interval width between every two adjacent second pits; b1 represents the diameter of the first pit; b2 represents the diameter of the second pit; c1 represents the width of the first current storage tank; c2 represents the width of the second current storage tank; d1 represents the depth of the first current storage tank, and d2 represents the depth of the second current storage tank. Detailed implementation manners

[0028] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer, the present application will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0029] In the present application, the term "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. Among them, A and B may be singular or plural. The character " / " generally represents an "or" relationship between the front and rear associated objects.

[0030] In this application, "at least one" means one or more, and "a plurality" means two or more. "At least one of the following" or a similar expression means any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can both represent: a, b, c, a - b (i.e., a and b), a - c, b - c, or a - b - c, where a, b, and c can each be single or multiple.

[0031] It should be understood that in various embodiments of this application, the magnitudes of the serial numbers of the above - mentioned processes do not imply the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of this application.

[0032] The terms used in the embodiments of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The singular forms "a", "the", and "said" used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0033] The weights of the relevant components mentioned in the specification of the embodiments of this application can not only refer to the specific contents of each component, but also represent the proportional relationship of the weights between the components. Therefore, as long as the contents of the relevant components in the specification of the embodiments of this application are scaled up or down proportionally, they are within the scope disclosed in the specification of the embodiments of this application. Specifically, the mass described in the specification of the embodiments of this application can be mass units well - known in the chemical industry such as μg, mg, g, kg, etc.

[0034] The terms "first" and "second" are only used for descriptive purposes to distinguish objects such as substances from each other, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. For example, without departing from the scope of the embodiments of this application, the first XX can also be called the second XX, and similarly, the second XX can also be called the first XX. Thus, the features defined with "first" and "second" can explicitly or implicitly include one or more of such features.

[0035] The first aspect of the embodiments of this application provides a welding structure of an anode target disc, including graphite 10, metal 20, and a solder block 30 placed between graphite 10 and metal 20, and graphite 10 and metal 20 are annular;

[0036] On two surfaces of graphite 10 and metal 20 facing each other, one surface is configured with an annular convex block 5, and the other surface is configured with an annular groove 3 that cooperates with the annular convex block 5;

[0037] A flow storage groove 40 is provided at the junction of the groove bottom surface of the annular groove 3 and the side wall of the annular groove 3. The flow storage groove 40 is used to enable the molten solder at the junction to capillary spread between the side wall of the annular groove 3 and the side wall of the annular bump 5.

[0038] As an example, Figure 5 There is shown a welding structure of an anode target disc, including graphite 10, metal 20, and a solder block 30 placed between the graphite 10 and the metal 20. The graphite 10 and the metal 20 are annular, and there is a through hole 4 at the center of the circle. An annular groove 3 and a flow storage groove 40 are provided on the metal 20 and arranged around the central axis. The graphite 10 is configured as an annular bump 5 that cooperates with the annular groove 3. Specifically, the flow storage groove 40 is opened at the junction of the groove bottom surface of the annular groove 3 and the side wall of the annular groove 3. This junction can be the junction with the outer ring side wall or the junction with the inner ring side wall. This junction can include the groove bottom surface of the annular groove 3 and / or the groove side surface of the annular groove 3, that is, the flow storage groove can be provided on the groove bottom surface of the annular groove 3 and / or the side wall surface of the annular groove 3 at the junction.

[0039] As an example, Figure 6 There is shown a welding structure of an anode target disc, in which an annular groove 3 and a flow storage groove 40 are provided on the graphite 10 and arranged around the central axis. The metal 20 is configured as an annular bump 5 that cooperates with the annular groove 3. Specifically, the flow storage groove 40 is opened at the junction of the groove bottom surface of the annular groove 3 and the side wall of the annular groove 3. This junction can be the junction with the outer ring side wall or the junction with the inner ring side wall. This junction can include the groove bottom surface of the annular groove 3 or the groove side surface of the annular groove 3, that is, the flow storage groove can be provided on the groove bottom surface of the annular groove 3 and / or the side wall surface of the annular groove 3 at the junction.

[0040] A welding structure of an anode target disc provided in the first aspect of the present application. Due to the addition of a flow storage groove structure on the metal welding surface or the graphite welding surface in the present application, when the solder is liquefied at high temperature, the flow storage groove structure helps the liquid-phase solder to spread more evenly in the circumferential direction of the welding surface, and there will be no situation where the local solder layer thickness of the welding surface is too thick or too thin, making the solder layer thickness of the entire welding surface uniform, thereby reducing the porosity. When the solder is in the liquid phase, the flow storage groove will be first filled with the liquid-phase solder. Under the capillary tension of the mating gap between the metal and the graphite, the solder in the flow storage groove climbs along the mating gap, and the solder at other parts of the welding surface continues to supplement the flow storage groove, so as to fill the mating gap between the metal and the graphite.

[0041] In some embodiments, the flow storage groove 40 includes a first flow storage groove 41 and / or a second flow storage groove 42. The first flow storage groove 41 is located at the junction of the groove bottom surface of the annular groove 3 and the outer ring side wall of the annular groove 3, and the second flow storage groove 42 is provided at the junction of the groove bottom surface of the annular groove 3 and the inner ring side wall of the annular groove 3.

[0042] As Figure 1 and Figure 2 shown, the first solder storage groove 41 is formed on the bottom surface of the annular groove 3, specifically at the junction of the bottom surface of the annular groove 3 and the outer ring side surface of the annular groove 3; the second solder storage groove 42 is formed on the bottom surface of the annular groove 3, specifically at the junction of the bottom surface of the annular groove 3 and the outer ring side surface of the annular groove 3.

[0043] In some embodiments, the width range of the solder storage groove 40 is 0.05 - 0.2 mm. For example, the width range of the solder storage groove 40 includes but is not limited to 0.05 - 0.1 mm, 0.07 - 0.14 mm, 0.10 - 0.15 mm, 0.13 - 0.18 mm, 0.15 - 0.20 mm, etc. The depth range of the solder storage groove 40 is 0.2 - 2.0 mm. For example, the depth range of the solder storage groove 40 includes but is not limited to 0.2 - 1.0 mm, 0.6 - 1.4 mm, 0.9 - 1.6 mm, 1.2 - 1.9 mm, 1.5 - 2.0 mm, etc. It is found that the solder storage groove within this size range is more conducive to the solder climbing along the mating gap, thereby effectively filling the mating gap. At the same time, the size range of the solder storage groove set in this application is reasonable and will not cause the solder to need to fill the voids of the solder storage groove, resulting in loose welding or solder shortage.

[0044] In some embodiments, as Figure 3 shown, a number of first pits 6 arranged at intervals are provided on the welding surface to be welded of the graphite 10. The diameter b1 range of the first pits 6 is 10 - 400 μm. For example, the diameter b1 range includes but is not limited to 10 - 100 μm, 50 - 150 μm, 100 - 200 μm, 150 - 300 μm, 250 - 400 μm, etc. The interval width a1 between every two adjacent first pits 6 ranges from 10 to 400 μm. For example, the interval width a1 range includes but is not limited to 10 - 100 μm, 50 - 150 μm, 100 - 200 μm, 150 - 300 μm, 250 - 400 μm, etc. By providing a micro - pit morphology structure on the welding surface to be welded of the graphite in this application, the wettability between the solder and the graphite can be provided, the specific surface area of the welding surface to be welded of the graphite can be increased, thereby reducing the porosity of the welding layer and improving the bonding strength of the welding surface.

[0045] In some embodiments, as Figure 4As shown, a number of second pits 7 arranged at intervals are provided on the surface of the metal 20 to be welded. The diameter b2 of the second pits 7 ranges from 20 to 200 μm. For example, the diameter b2 range includes but is not limited to 20 to 100 μm, 50 to 130 μm, 80 to 160 μm, 110 to 190 μm, 140 to 200 μm, etc. The interval width a2 between every two adjacent second pits 7 ranges from 10 to 50 μm. For example, the interval width a2 range includes but is not limited to 10 to 30 μm, 15 to 35 μm, 20 to 40 μm, 25 to 45 μm, 30 to 50 μm, etc. In the present application, by forming a micro-pit morphology structure on the surface of the metal to be welded, the wettability between the solder and the metal surface is improved, which is beneficial to the capillary action spreading of the liquid solder at high temperature, making the solder layer more evenly distributed, helping to remove air holes, and reducing the porosity of the welding surface. The micro-pit structure can also improve the wettability between the solder and the metal, and can increase the bonding surface area between the solder layer and the metal by about 20%-50%, increasing the bonding strength.

[0046] In some embodiments, the solder includes a zirconium-based solder or a titanium-based solder. The zirconium-based solder includes a zirconium alloy foil, such as pure zirconium, and also includes a molybdenum-zirconium alloy foil in any mass ratio. The titanium-based solder is, for example, a Ti metal foil.

[0047] In some embodiments, the metal includes one of a molybdenum alloy and a tungsten alloy, where the molybdenum alloy can be pure molybdenum or a molybdenum alloy doped with other metals, such as a TZM alloy (titanium-zirconium-molybdenum alloy), an MHC alloy (molybdenum-hafnium-carbon alloy), an ML alloy (molybdenum-lanthanum alloy), an MRe alloy (molybdenum-rhenium alloy), etc. In some embodiments, in the molybdenum alloy, the mass percentage content of molybdenum element is 80 to 100%.

[0048] In a second aspect of the embodiments of the present application, a welding method for an anode target disc is provided, including the following steps:

[0049] Step S01: Process an annular groove 3 and a flow storage groove 40 on the surface of the metal 20 or the graphite 10 to be welded. The flow storage groove 40 is arranged at the intersection of the bottom surface of the annular groove 3 and the side wall of the annular groove 3;

[0050] Step S02: Place the solder block 30 between the surface of the graphite 10 to be welded and the surface of the metal 20 to be welded, and perform welding treatment.

[0051] A welding method for an anode target disc provided in the second aspect of the present application. First, an annular groove is machined on the metal surface to be welded or the graphite surface to be welded, and then a flow storage groove is machined at the junction of the bottom surface of the annular groove and the outer ring side wall and / or at the junction of the bottom surface and the inner ring side wall. The present application adds a flow storage groove design to the molybdenum alloy surface to be welded, which is beneficial to the capillary spreading of the solder, makes the solder layer more uniform, and reduces the welding porosity. The design of the flow storage groove is beneficial to the solder to fill the mating gaps on the outer and inner sides of the metal and graphite. Moreover, the flow storage groove structure of the present application is simple and easy to be processed in batches.

[0052] In the present application, a metal foil solder with a thickness of 0.1 - 0.3 mm is selected as the solder block. During the welding process, the upper surface of the metal foil solder contacts the graphite surface to be welded or the metal surface to be welded, and the lower surface of the metal foil solder contacts the metal surface to be welded or the graphite surface to be welded.

[0053] Step S01:

[0054] Provide a metal part, such as a molybdenum alloy part, or provide a graphite part, and use a CNC machine tool or laser processing method to machine an annular groove 3 and a first flow storage groove 41 and / or a second flow storage groove 42 on the molybdenum alloy surface to be welded or the graphite surface to be welded. As an example, as Figure 5 shown, in some embodiments, a CNC machine tool is used to machine an annular groove on the metal part, and the graphite part is placed in the annular groove of the metal part for welding. Therefore, there is a mating gap between the side of the graphite part and the side of the annular groove. The width of the first flow storage groove and / or the second flow storage groove in the present application is consistent with the initial mating gap between the molybdenum alloy and the graphite.

[0055] In some embodiments, before the welding treatment, the surfaces of the graphite and the metal are first treated. The steps of the surface treatment include: using metallographic sandpaper to polish the surfaces to be welded of the graphite and the molybdenum alloy to obtain roughness, and then ultrasonically cleaning in a solvent for 10 - 60 min to remove impurities and contaminants on the surfaces of the samples to be welded.

[0056] In some embodiments, the steps of the surface treatment include: using a plasma cleaner to clean and polish the surfaces to be welded of the graphite and the metal to obtain roughness.

[0057] In some embodiments, before the welding treatment, the surface of the graphite to be welded is first subjected to a first plasma surface treatment, and a plurality of first pits arranged at intervals are machined on the surface to be welded of the graphite through the first plasma surface treatment. As Figure 3 shown, the diameter b1 of the first pit is 10 - 400 μm, and the interval width a1 between every two adjacent first pits is 10 - 400 μm.

[0058] The process conditions for the first plasma surface treatment of the graphite welding surface include: placing the graphite welding surface face up in a plasma cleaner and using plasma etching to process a micro-pitted morphology structure. The plasma output power of the vacuum plasma equipment is 600W - 1200W, the vacuum degree ≤ 1×10 -1 Pa, the temperature is 5 - 40°C, the treatment time is 5 - 20min, controlling the thickness of the graphite corrosion layer to be 10 - 200μm, and the surface roughness ranges from Ra1.6μm to Ra6.3μm. The process conditions of the plasma etching treatment in this application can process the size of the micro-pitted morphology structure required by this application, thereby increasing the specific surface area of the graphite welding surface, providing the wettability between the brazing filler metal and the graphite, and improving the welding strength of the welded joint.

[0059] In some embodiments, before the welding treatment, a second plasma surface treatment is also performed on the metal welding surface. Through the second plasma surface treatment, a number of second pits arranged at intervals are processed on the metal welding surface, such as Figure 4 shown. The diameter b2 of the second pit is 20 - 200μm, and the interval width a2 between every two adjacent second pits is 10 - 50μm. Because a large number of active particles such as ions, excited state molecules, and free radicals in the plasma act on the metal surface, the original pollutants, impurities, and oxides on the surface can be removed, thereby improving the wettability between the solder and the metal surface, facilitating the capillary action spreading of the liquid solder at high temperatures, making the solder layer more evenly distributed, helping to remove pores, and reducing the porosity of the welded joint.

[0060] The process conditions for the second plasma surface treatment of the metal welding surface include: placing the metal welding surface face up in a plasma cleaner and using plasma etching to process a micro-pitted morphology structure. The output power of the vacuum plasma equipment is 600w - 1200w, the vacuum degree is ≤ 1×10 -1 Pa, the temperature is 5 - 40°C, the treatment time is 5 - 20min, controlling the depth of the metal corrosion layer to be 20 - 200μm, and the surface roughness ranges from Ra1.6μm to Ra6.3μm.

[0061] By performing plasma etching treatment on the metal welding surface in this application, not only the original pollutants and impurities on the metal surface are removed, achieving the effect of further cleaning the welding surface. Moreover, through the etching effect, the metal surface becomes rough, forming many fine pits and depressions, increasing the specific surface area of the metal welding surface, and at the same time increasing the capillary tension of the liquid solder on the metal surface, effectively improving the wettability between the solder and the metal, thereby being able to reduce the porosity of the welding layer and improve the bonding strength of the welding surface.

[0062] In some embodiments, the surfaces to be welded of the metal and the graphite can be placed face up simultaneously in a plasma cleaner, and the plasma cleaner is turned on. The plasma output power of the vacuum plasma equipment is 600 W to 1200 W, the vacuum degree is ≤ 1×10 -1 Pa, the temperature is 5 to 40 °C, and the treatment time is 10 to 30 min.

[0063] The method for surface treatment of the metal and the graphite in this application has high feasibility and high production efficiency. After treatment, no additional cleaning is required, and it is suitable for batch treatment of the surfaces to be welded of the metal and the graphite before high-temperature brazing. At the same time, the method for surface treatment of the graphite in this application is simple, low in cost, can be batch-treated, and can increase the welding strength between the metal and the graphite by 20 - 50%.

[0064] In some embodiments, before the welding treatment, the solder, the graphite, and the metal are respectively subjected to vacuum degassing treatment and then welded. The specific steps for vacuum degassing the solder include: putting the solder into a high-temperature vacuum furnace, heating it at a heating rate of 5 - 10 °C / min to 900 - 1000 °C, keeping it warm for 30 - 60 min, with a vacuum degree ≤ 5×10 -4 Pa, and then cooling it in the furnace. After cooling to below 70 °C, it is taken out of the furnace.

[0065] The specific steps for vacuum degassing the surface-treated metal and graphite include: putting the surface-treated metal and graphite into a high-temperature vacuum furnace, heating it at a heating rate of 5 - 10 °C / min to 1300 - 1400 °C, keeping it warm for 60 - 120 min, with the high-temperature vacuum degree of the vacuum equipment ≤ 5×10 -4 Pa, and then cooling it in the furnace. After cooling to below 70 °C, it is taken out of the furnace.

[0066] In some embodiments, before the welding treatment, after the plasma surface treatment, it further includes graphite metallization treatment. The treatment method is to spray the transition metal hydride powder on the surface to be welded of the graphite by means of plasma spraying.

[0067] S02:

[0068] Place the solder block between the surface to be welded of the metal and the surface to be welded of the graphite, that is, place a metal foil solder with a thickness of e between the surface to be welded of the metal and the surface to be welded of the graphite. The size range of e is 0.1 mm to 0.3 mm, and the upper surface of the metal foil solder is in contact with the surface to be welded of the graphite or the metal, and the lower surface of the metal foil solder is in contact with the surface to be welded of the metal or the graphite. Then place them together in a vacuum brazing furnace. The brazing temperature is 1550 - 1700 °C, the holding time is 10 - 30 min, and the vacuum degree is 2×10 -3 ~1×10 -4 Pa, and cool it in the furnace to below 70 °C and then take it out of the furnace. The placement method is asFigure 5 or Figure 6 as shown

[0069] In a third aspect, the present application provides an anode target disc, which is welded and formed by the anode target disc welding structure of the first aspect, or is welded and formed by the welding method of the anode target disc of the second aspect.

[0070] For the anode target disc provided in the third aspect of the present application, the remelting temperature of the metal and graphite composite joint is high, the defects on the welding surface are few, the appearance solder filling is full, the welding strength of the joint can reach 17 - 25 MPa, the full welding rate of the welding surface is above 98%, the performance of the welded joint is stable, and the life cycle is long.

[0071] The following is an illustration with specific embodiments.

[0072] Embodiment 1

[0073] In this embodiment, the metal used is taken as an example of molybdenum alloy. The molybdenum alloy is selected from TZM molybdenum alloy (titanium zirconium molybdenum alloy). Calculated based on the total weight of the TZM molybdenum alloy being 100%, the TZM molybdenum alloy includes Ti: 0.4 - 0.55%, Zr: 0.66 - 0.12%, C: 0.01 - 0.04%, and the balance is Mo. The density of the graphite used is 1.85 g / cm 3 , and the ash content of the graphite ≤ 20 ppm. The solder used is zirconium alloy foil, and the zirconium alloy foil is pure zirconium, with the mass percentage content of Zr ≥ 98.5%. This embodiment provides a welding method for this kind of anode target disc, including the following steps:

[0074] S1: Provide the molybdenum alloy. By using the CNC machine tool processing method, an annular groove, a first flow storage groove, and a second flow storage groove are processed on the surface to be welded of the molybdenum alloy. The first flow storage groove is arranged at the intersection of the bottom surface of the annular groove and the outer ring side wall of the annular groove, and the second flow storage groove is arranged at the intersection of the bottom surface of the annular groove and the inner ring side wall of the annular groove. The depth of the first flow storage groove is 0.5 mm, and the width is 0.05 mm. The depth of the second flow storage groove is 0.5 mm, and the width is 0.05 mm;

[0075] S2: Use metallographic sandpaper to polish the surfaces to be welded of the graphite and the molybdenum alloy to obtain roughness, and then ultrasonically clean in acetone for 30 min to remove impurities and contaminants on the surfaces of the samples to be welded;

[0076] S3: Put the surface-treated molybdenum alloy and graphite into a high-temperature vacuum furnace for high-temperature vacuum degassing treatment. The degassing process conditions are as follows: Heat up to 1300 °C at a heating rate of 7 °C / min, keep the temperature for 60 min, the high-temperature vacuum degree of the vacuum equipment ≤ 5 × 10 -4 Pa, and then cool with the furnace. After cooling to below 70 °C, take out the furnace;

[0077] S4: Place a pure zirconium metal foil solder with a thickness of 0.2 mm between the surface to be welded of the molybdenum alloy and the surface to be welded of the graphite. The upper surface of the metal foil solder is in contact with the surface to be welded of the graphite, and the lower surface of the metal foil solder is in contact with the surface to be welded of the molybdenum alloy. Then place them together in a vacuum brazing furnace. The brazing temperature is 1550 °C, the holding time is 20 min, and the vacuum degree is 2×10 -3 ~1×10 -4 Pa, and cool it in the furnace to below 70 °C before taking it out of the furnace.

[0078] Example 2

[0079] The molybdenum alloy, graphite and solder used in this example are the same as those in Example 1. This example provides a welding method for this anode target disc, including the following steps:

[0080] S1: Provide a molybdenum alloy. By using the CNC machine tool processing method, a circular groove, a first flow storage groove and a second flow storage groove are processed on the surface to be welded of the molybdenum alloy. The first flow storage groove is arranged at the junction of the bottom surface of the circular groove and the outer ring side wall of the circular groove, and the second flow storage groove is arranged at the junction of the bottom surface of the circular groove and the inner ring side wall of the circular groove. The depth d1 of the first flow storage groove is 1 mm, and the width c1 is 0.1 mm. The depth d2 of the second flow storage groove is 1 mm, and the width c2 is 0.1 mm;

[0081] S2: Place the surface to be welded of the graphite upward in a plasma cleaner. Turn on the plasma cleaner. The plasma output power of the vacuum plasma equipment is 800 W, the vacuum degree is ≤1×10 -1 Pa, the temperature is 25 °C, the treatment time is 20 min, control the thickness of the graphite corrosion layer to be 10 - 200 μm, and the range of the surface roughness is Ra1.6 μm ∽ Ra6.3 μm. After the treatment, a first pit structure morphology arranged at intervals is processed on the surface to be welded of the graphite, as Figure 3 shown, where the interval width a1 between every two adjacent first pits is 10 - 50 μm, and the diameter b1 of the first pit is 10 - 100 μm.

[0082] S3: Step S3 is the same as step S3 in Example 1;

[0083] S4: Step S4 is the same as step S4 in Example 1.

[0084] Example 3

[0085] The molybdenum alloy, graphite and solder used in this example are the same as those in Example 1. This example provides a welding method for this anode target disc, including the following steps:

[0086] S1: Step S1 is the same as step S1 in Example 2;

[0087] S2: Place the surfaces to be welded of the molybdenum alloy and graphite facing upwards together in a plasma cleaner. Turn on the plasma cleaner. The plasma output power of the vacuum plasma equipment is 800 W, the vacuum degree is ≤1×10 -1 Pa, the temperature is 25 °C, and the treatment time is 20 min. After the treatment, a first pit structure morphology arranged at intervals is machined on the surface to be welded of the graphite, and a second pit structure morphology arranged at intervals is machined on the surface to be welded of the molybdenum alloy. As shown in Figure 3 and Figure 4 , among which, the interval width a1 between every two adjacent first pits is 10 - 50 μm, and the diameter b1 of the first pit is 10 - 100 μm; the interval width a2 between every two adjacent second pits is 10 - 50 μm, and the diameter b2 of the second pit is 20 - 100 μm.

[0088] S3: Step S3 is the same as step S3 of Example 1;

[0089] S4: Step S4 is the same as step S4 of Example 1.

[0090] Example 4

[0091] This Example 4 is basically the same as Example 3, the difference is that this example further includes the metallization treatment of graphite between steps S2 and S3. The specific steps are: Use ZrH powder with a purity of not less than 99% and a particle size of 400 mesh to conduct metallization treatment on the surface-treated graphite surface to be welded to obtain a metal layer with a thickness of 50 μm.

[0092] Example 5

[0093] This example is basically the same as Example 3, the difference is that the molybdenum alloy used in this example is pure molybdenum and the solder is a Ti metal foil with a thickness of 0.3 mm.

[0094] Example 6

[0095] This example is basically the same as Example 3, the difference is that the size of the flow storage tank in step S1 is different. Specifically:

[0096] S1: Provide a molybdenum alloy. By using laser processing, an annular groove, a first flow storage tank and a second flow storage tank are machined on the surface to be welded of the molybdenum alloy. The first flow storage tank is arranged at the junction of the bottom surface of the annular groove and the outer ring side wall of the annular groove, and the second flow storage tank is arranged at the junction of the bottom surface of the annular groove and the inner ring side wall of the annular groove. The depth d1 of the first flow storage tank is 2 mm, the width c1 is 0.2 mm, the depth d2 of the second flow storage tank is 2 mm, and the width c2 is 0.2 mm.

[0097] Example 7

[0098] This embodiment is basically the same as Embodiment 1, except that the flow storage tank in this embodiment only includes the first flow storage tank.

[0099] Embodiment 8

[0100] This embodiment is basically the same as Embodiment 1, except that in this embodiment, an annular groove, a first flow storage tank and a second flow storage tank are machined on the graphite surface to be welded.

[0101] Embodiment 9

[0102] This embodiment is basically the same as Embodiment 1, except that in this embodiment, the metal used is tungsten alloy. Among them, based on the total weight of the tungsten alloy being 100%, the tungsten alloy includes: tungsten content of 85 - 99%, nickel content of 0.5 - 10.5%, and iron content of 0.3 - 7.5%.

[0103] Comparative Example 1

[0104] This comparative example is basically the same as Embodiment 1, except that in step S1 of this comparative example, the first flow storage tank and the second flow storage tank are not machined in the annular groove.

[0105] Comparative Example 2

[0106] This comparative example is basically the same as Embodiment 2, except that in step S1 of this comparative example, the first flow storage tank and the second flow storage tank are not machined in the annular groove.

[0107] Performance Test

[0108] The molybdenum alloy and graphite composite target disks obtained by brazing Embodiments 1 - 6, Comparative Example 1 and Comparative Example 2 are subjected to ultrasonic non - destructive testing to detect the bonding rate of the brazing interface between the molybdenum alloy and the graphite. At the same time, samples are taken for mechanical property testing, and the testing is carried out on a universal material testing machine to measure the room - temperature shear strength. The results are shown in Table 1.

[0109] Table 1 Performance Data

[0110] Room temperature shear strength / MPa Interface bonding rate / % Example 1 20 ≥98 Example 2 21 ≥98 Example 3 26 ≥98 Example 4 26 ≥98 Example 5 24 ≥98 Example 6 24 ≥98 Example 7 20 ≥98 Example 8 21 ≥98 Example 9 19 ≥98 Comparative Example 1 14 ≥95 Comparative Example 2 18 ≥95

[0111] As can be seen from Table 1, for the metal and graphite composite obtained by brazing using the welding method of the present application, the bonding rate of the brazing interface between the metal and the graphite is above 98%. At the same time, samples were taken for mechanical property testing. The testing was carried out on a universal material testing machine, and the measured room temperature shear strength range was within 20 - 25 MPa, which is close to the shear strength of the graphite body, and the welding effect is excellent. Compared with the molybdenum alloy and graphite composites obtained in Comparative Examples 1 and 2, by adding a flow storage groove design on the surface of the molybdenum alloy to be welded, the obtained molybdenum alloy and graphite composite joint has a high remelting temperature, few defects on the welding surface, full filling of the appearance solder, the joint welding strength can reach 20 - 25 MPa, and the full welding rate of the welding surface is above 98%. The method of plasma etching treatment on the surfaces of the molybdenum alloy and graphite can increase the welding strength between the molybdenum alloy and graphite by 20 - 50%.

Claims

1. A welding structure of an anode target disc, characterized in that, It includes graphite (10), metal (20) and a solder block (30) placed between the graphite (10) and the metal (20), and the graphite (10) and the metal (20) are annular; On two opposite surfaces of the graphite (10) and the metal (20), one surface is configured with an annular bump (5), and the other surface is configured with an annular groove (3) that mates with the annular bump (5); A flow storage groove (40) is provided at the junction of the bottom surface of the annular groove (3) and the side wall of the annular groove (3), and the flow storage groove (40) is used to cause the molten solder at the junction to capillary spread between the side wall of the annular groove (3) and the side wall of the annular bump (5).

2. The welding structure of the anode target disc according to claim 1, characterized in that, The flow storage groove (40) includes a first flow storage groove (41) and / or a second flow storage groove (42). The first flow storage groove (41) is located at the junction of the bottom surface of the annular groove (3) and the outer ring side wall of the annular groove (3), and the second flow storage groove (42) is provided at the junction of the bottom surface of the annular groove (3) and the inner ring side wall of the annular groove (3).

3. The welding structure of the anode target disc according to claim 1, characterized in that, The width range of the flow storage groove (40) is 0.05 - 0.2 mm, and the depth range of the flow storage groove (40) is 0.2 - 2.0 mm.

4. The welding structure of the anode target disc according to any one of claims 1 to 3, characterized in that, A number of first pits (6) arranged at intervals are provided on the welding surface of the graphite (10). The diameter range of the first pits (6) is 10 - 400 μm, and the interval width range between every two adjacent first pits (6) is 10 - 400 μm.

5. The welding structure of the anode target disc according to any one of claims 1 to 3, characterized in that, A number of second pits (7) arranged at intervals are provided on the welding surface of the metal (20). The diameter range of the second pits (7) is 20 - 200 μm, and the interval width range between every two adjacent second pits (7) is 10 - 50 μm.

6. The welding structure of the anode target disc according to claim 1, characterized in that, The solder includes at least one of a zirconium-based solder and a titanium-based solder; and / or, The metal (10) includes one of a molybdenum alloy and a tungsten alloy, and the mass percentage content range of molybdenum element in the molybdenum alloy is 80 - 100%.

7. A welding method for an anode target disc, characterized in that, It includes the following steps: An annular groove (3) and a flow storage groove (40) are machined on the welding surface of the metal (20) or the graphite (10), and the flow storage groove (40) is provided at the junction of the bottom surface of the annular groove (3) and the side wall of the annular groove (3); The solder block (30) is placed between the welding surface of the graphite (10) and the welding surface of the metal (20), and welding treatment is carried out.

8. The welding method of the anode target disc according to claim 7, characterized in that, Before welding treatment, first perform a first plasma surface treatment on the welding surface to be welded of the graphite, and process a number of first pits arranged at intervals on the welding surface to be welded of the graphite. The process conditions of the first plasma surface treatment are: the output power is 600W to 1200W, the vacuum degree is ≤1×10 -1 Pa, the temperature is 5 to 40°C, and the treatment time is 5 to 20 minutes.

9. The welding method of the anode target disc according to claim 8, characterized in that, Before the welding treatment, the surface to be welded of the metal is also subjected to a second plasma surface treatment, and a plurality of second pits arranged at intervals are machined on the surface to be welded of the metal. The process conditions of the second plasma surface treatment are as follows: the output power is 600 w to 1200 w, the vacuum degree is ≤ 1×10 -1 Pa, the temperature is 5 to 40 °C, and the treatment time is 5 to 20 min.

10. The welding method of the anode target disc according to claim 9, wherein, Before carrying out the welding treatment, the solder, graphite and metal are respectively subjected to vacuum degassing treatment and then the welding treatment is carried out; and / or, Before carrying out the welding treatment, the transition metal hydride powder is sprayed on the welding surface of the graphite by means of plasma spraying.

11. The welding method of the anode target disc according to any one of claims 7-10, characterized in that, The welding process includes: placing the solder block between the welding surface of the metal and the welding surface of the graphite, and then performing welding; wherein, the welding temperature is 1550-1700 °C, the heat preservation time is 10-30 min, and the vacuum degree is 2×10 -3 -1×10 -4 Pa.

12. An anodic target disc, characterized in that, It is welded and made by the anode target disc welding structure according to claims 1 - 6, or welded and made by the welding method of the anode target disc according to any one of claims 7 - 11.

Images