Diffusion welding method for cobalt target material

Abstract

The invention provides a diffusion welding method of a cobalt target material, which comprises the following steps of: (1) carrying out coating treatment on a welding surface of a cobalt target blank, and then carrying out second ultrasonic cleaning to obtain a coated cobalt target blank; (2) a welding groove matched with the cobalt target blank is formed in the welding face of the back plate through first turning, then second turning is conducted on the surface of the welding groove, third ultrasonic cleaning is conducted, and the machined back plate is obtained; (3) the cobalt target blank coated with the film in the step (1) and the back plate machined in the step (2) are assembled and then placed in a sheath, and hot isostatic pressing welding is conducted after the sheath is degassed; the step (1) and the step (2) are not divided into a sequence. According to the method, the welding groove is formed in the back plate through first turning, then second turning is conducted, the good contact area between the cobalt target blank and the back plate is ensured, meanwhile, the cleanliness of the welding face of the back plate is effectively controlled, and therefore the welding strength of the cobalt target blank and the back plate can be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of target material preparation and relates to a diffusion welding method of a cobalt target material. Background Art

[0002] With the rapid development of semiconductor technology, target materials, as important raw materials for sputtering coating, are increasingly widely used. Due to strength and other reasons, target materials usually need to be welded with backing plates to form target material components, which can only be used when they have a certain bonding strength. Therefore, the quality of welding will directly affect the bonding performance between the target material and the backing plate, thereby affecting the effect of sputtering coating.

[0003] At present, the welding methods of semiconductor sputtering targets usually include diffusion welding and brazing welding. Diffusion welding usually makes the welding surface of the target and the back plate fully contact under high temperature and high pressure conditions, causing atomic diffusion to form chemical bonding to achieve welding. It is mainly suitable for welding targets that require high-power sputtering, such as cobalt targets. During high-power sputtering, high-speed particles bombard the target surface, and the target surface temperature will rise sharply. Metals or alloys with good thermal conductivity are required as back plate materials, such as copper or copper alloys. However, diffusion welding between cobalt targets and back plates is difficult, so the welding surface needs to be pre-treated to meet welding requirements.

[0004] At present, there are two pre-treatment methods for diffusion welding of cobalt target materials: the welding surface of the target blank is ground and cleaned, and then a titanium metal layer is plated after cleaning, and then the target blank is welded with a copper back plate, and finally diffusion welded by hot isostatic pressing equipment; or the welding surface of the target blank is sandblasted, cleaned, and then a titanium metal layer is plated, and then the target blank is welded with a copper back plate, and finally diffusion welded by hot isostatic pressing equipment. Although both methods can be used for welding, their welding strength is not high, which affects the welding quality of the product.

[0005] In summary, for the welding process of cobalt targets, it is also necessary to provide a suitable pre-treatment process according to the characteristics of the target material to simplify the operation, reduce costs and improve welding strength. Summary of the invention

[0006] The object of the present invention is to provide a diffusion welding method for a cobalt target material. By first turning a welding groove on a back plate and then performing a second turning process, a good contact area between the cobalt target blank and the back plate is ensured, while the cleanliness of the back plate welding surface is effectively controlled, thereby reducing the difficulty of combining the cobalt target blank and the back plate and improving the welding strength between the two.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] The present invention provides a diffusion welding method for a cobalt target material, the diffusion welding method comprising the following steps:

[0009] (1) performing a coating treatment on the welding surface of the cobalt target blank, and then performing a second ultrasonic cleaning to obtain a coated cobalt target blank;

[0010] (2) a first turning process is performed on the welding surface of the back plate to form a welding groove matching the cobalt target blank, and then a second turning process is performed on the surface of the welding groove, and then a third ultrasonic cleaning process is performed to obtain a processed back plate;

[0011] (3) assembling the cobalt target blank after coating in step (1) and the back plate processed in step (2) and placing them in a sheath, degassing the sheath and performing hot isostatic pressing welding;

[0012] There is no particular order in which steps (1) and (2) are performed.

[0013] In the present invention, due to the material characteristics of the cobalt target, diffusion welding between the target and the back plate is difficult, so the cobalt target blank or the back plate needs to be pre-treated. The cobalt target blank in step (1) is a cobalt target blank that has been subjected to frustum grinding.

[0014] The diffusion welding method provided by the present invention, through the first turning processing welding groove on the back plate welding surface, as a positioning feature in the welding process, helps to control welding deformation, and can ensure that there is a good contact area between the cobalt target blank and the back plate, which helps to achieve more uniform heat distribution and pressure transfer during the welding process, thereby improving the welding quality; and then the second turning processing is performed on the surface of the welding groove, which can not only remove the oil stains such as cutting fluid generated during the first turning process, thereby effectively controlling the cleanliness of the back plate welding surface, but also effectively control the flatness and roughness of the back plate welding surface; at the same time, by coating the cobalt target blank welding surface and controlling the cleanliness of the cobalt target blank welding surface, the difficulty of combining the cobalt target blank and the back plate can be reduced, thereby improving the welding strength between the two, and then improving the welding quality and efficiency of the product. The diffusion welding method is simple to operate, has high welding strength and welding efficiency, and good stability.

[0015] As a preferred technical solution of the present invention, before the coating treatment in step (1), a first ultrasonic cleaning and a first vacuum drying are sequentially performed.

[0016] Preferably, the medium used for the first ultrasonic cleaning is IPA liquid.

[0017] In the present invention, the cobalt target blank is placed with its welding surface facing downward during the first ultrasonic cleaning.

[0018] Preferably, the first ultrasonic cleaning time is 3-7 min, for example, 3.5 min, 4 min, 5 min, 5.5 min, 6 min or 6.5 min, etc., but is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0019] Preferably, the first vacuum drying time is ≥ 60 min, for example, it can be 62 min, 65 min, 68 min, 70 min, 75 min or 80 min, but is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0020] As a preferred technical solution of the present invention, the material of the coating in step (1) includes titanium.

[0021] Preferably, the thickness of the film layer formed after the coating treatment in step (1) is 3-5 μm, for example, it can be 3.2 μm, 3.5 μm, 3.8 μm, 4 μm, 4.2 μm, 4.5 μm or 4.8 μm, but is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0022] As a preferred technical solution of the present invention, the medium used for the second ultrasonic cleaning in step (1) is IPA liquid.

[0023] In the present invention, the cobalt target blank is placed with its welding surface facing downward during the second ultrasonic cleaning.

[0024] Preferably, the time for the second ultrasonic cleaning in step (1) is 3-7 min, for example, 3.5 min, 4 min, 5 min, 5.5 min, 6 min or 6.5 min, etc., but is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0025] Preferably, in step (1), a second vacuum drying is also performed after the second ultrasonic cleaning.

[0026] Preferably, the second vacuum drying time is ≥60 min, for example, it can be 62 min, 65 min, 68 min, 70 min, 75 min or 80 min, but is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0027] As a preferred technical solution of the present invention, the backplane in step (2) comprises a copper backplane or a copper alloy backplane.

[0028] Preferably, the depth of the welding groove in step (2) is less than the thickness of the cobalt target blank, and the difference is 0.3-0.5 mm, for example, it can be 0.32 mm, 0.35 mm, 0.38 mm, 0.4 mm, 0.42 mm, 0.45 mm or 0.48 mm, etc., but is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0029] In the present invention, the thickness of the cobalt target blank refers to the thickness of the cobalt target blank before coating. By controlling the depth of the back plate welding groove to be smaller than the thickness of the cobalt target blank, the back plate and the target blank can be better combined during welding.

[0030] As a preferred technical solution of the present invention, in step (2), no cutting fluid is used during the second turning process.

[0031] It is worth noting that the present invention does not use cutting fluid in the second turning process to avoid the cooling of the cutting fluid causing the welding surface to be contaminated with oil or rust, affecting the subsequent diffusion welding. The oil stains generated by the cutting fluid need to be removed using a series of cleaning agents such as degreasing liquid, which makes the operation complicated.

[0032] Preferably, the feed rate of the second turning process in step (2) is 0.04-0.06 mm, for example, it can be 0.042 mm, 0.045 mm, 0.048 mm, 0.05 mm, 0.052 mm, 0.055 mm or 0.058 mm, but is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0033] Preferably, the rotation speed of the second turning process in step (2) is 450-550r / min, for example, it can be 460r / min, 470r / min, 480r / min, 490r / min, 500r / min, 510r / min, 520r / min, 530r / min or 540r / min, but is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0034] In the present invention, since the second turning process does not use cutting fluid, the feed rate and rotation speed of the second turning process need to be controlled to ensure that the surface of the welding groove is bright, uniform in color, and free of rust and dirt after processing, thereby helping to improve the welding strength between the cobalt target blank and the backing plate.

[0035] As a preferred technical solution of the present invention, in step (2), the surface flatness of the welding groove after the second turning process is less than 0.1 mm, for example, it can be 0.09 mm, 0.08 mm, 0.07 mm, 0.06 mm, 0.05 mm, 0.04 mm or 0.02 mm, etc., but is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0036] Preferably, the roughness of the welding groove surface after the second turning process in step (2) is 0.12-0.2 μm, for example, it can be 0.13 μm, 0.14 μm, 0.15 μm, 0.16 μm, 0.17 μm, 0.18 μm or 0.19 μm, etc., but is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0037] As a preferred technical solution of the present invention, the medium used in the third ultrasonic cleaning in step (2) is IPA liquid.

[0038] In the present invention, during the third ultrasonic cleaning, the back plate is placed with its welding surface facing downward.

[0039] Preferably, the time for the third ultrasonic cleaning in step (2) is 3-7 min, for example, 3.5 min, 4 min, 5 min, 5.5 min, 6 min or 6.5 min, etc., but is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0040] Preferably, the third ultrasonic cleaning in step (2) is followed by a third vacuum drying.

[0041] Preferably, the third vacuum drying time is ≥ 60 min, for example, it can be 62 min, 65 min, 68 min, 70 min, 75 min or 80 min, but is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0042] As a preferred technical solution of the present invention, vacuum is drawn during the degassing in step (3), and the degassing is completed and then sealed.

[0043] Preferably, the degassing temperature in step (3) is 200-400°C, for example, it can be 220°C, 250°C, 280°C, 300°C, 320°C, 350°C or 380°C, but is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0044] Preferably, the degassing insulation time in step (3) is 2-4 h, for example, it can be 2.2 h, 2.5 h, 2.6 h, 2.8 h, 3 h, 3.2 h, 3.5 h, 3.6 h or 3.8 h, but is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0045] Preferably, the temperature of the hot isostatic pressing welding in step (3) is 300-500°C, for example, it can be 320°C, 350°C, 380°C, 400°C, 420°C, 450°C or 480°C, but is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0046] Preferably, the pressure of the hot isostatic pressing welding in step (3) is 100-120 MPa, for example, it can be 102 MPa, 105 MPa, 106 MPa, 108 MPa, 110 MPa, 112 MPa, 115 MPa, 116 MPa or 118 MPa, but is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0047] Preferably, the hot isostatic pressing welding time in step (3) is 2-4 hours, for example, it can be 2.2 hours, 2.5 hours, 2.6 hours, 2.8 hours, 3 hours, 3.2 hours, 3.5 hours, 3.6 hours or 3.8 hours, but is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0048] Preferably, after the hot isostatic pressing welding in step (3), the welding bonding rate of the welding interface between the cobalt target blank and the back plate is ≥99%, and the welding strength is ≥70 MPa.

[0049] As a preferred technical solution of the present invention, the diffusion welding method comprises the following steps:

[0050] (1) subjecting the cobalt target blank to a first ultrasonic cleaning for 3-7 minutes and a first vacuum drying for ≥60 minutes, and then subjecting the welding surface of the cobalt target blank to a coating treatment, wherein the coating material includes titanium, and the thickness of the formed film layer is 3-5 μm, and then subjecting the cobalt target blank to a second ultrasonic cleaning for 3-7 minutes and a second vacuum drying for ≥60 minutes, to obtain a coated cobalt target blank;

[0051] (2) a first turning process is performed on the welding surface of the back plate to form a welding groove matching the cobalt target blank, and then a second turning process is performed on the surface of the welding groove without using a cutting fluid, at a feed rate of 0.04-0.06 mm and a rotation speed of 450-550 r / min, and then a third ultrasonic cleaning process is performed for 3-7 minutes and a third vacuum drying process is performed for ≥60 minutes to obtain a processed back plate;

[0052] The back plate includes a copper back plate or a copper alloy back plate; the depth of the welding groove is less than the thickness of the cobalt target blank, and the difference is 0.3-0.5 mm;

[0053] After the second turning process, the flatness of the welding groove surface is less than 0.1 mm and the roughness is 0.12-0.2 μm;

[0054] The medium used in the first ultrasonic cleaning, the second ultrasonic cleaning and the third ultrasonic cleaning is IPA liquid;

[0055] (3) Assembling the cobalt target blank after the coating in step (1) and the back plate processed in step (2) and placing them in a sheath, and degassing the sheath at a temperature of 200-400° C. for 2-4 hours, vacuumizing the sheath during degassing, and sealing the sheath after the degassing is completed; then hot isostatic pressing welding is performed at a temperature of 300-500° C. and a pressure of 100-120 MPa for 2-4 hours;

[0056] After the hot isostatic pressing welding, the welding bonding rate of the cobalt target blank and the back plate welding interface is ≥99%, and the welding strength is ≥70MPa;

[0057] There is no particular order in which steps (1) and (2) are performed.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] The diffusion welding method provided by the present invention, by first turning the welding groove on the back plate welding surface, as a positioning feature in the welding process, helps to control welding deformation, and can ensure that there is a good contact area between the cobalt target blank and the back plate, which helps to achieve more uniform heat distribution and pressure transfer during the welding process, thereby improving the welding quality; and then the second turning process without using cutting fluid on the surface of the welding groove can not only remove the oil stains such as cutting fluid generated during the first turning process, thereby effectively controlling the cleanliness of the back plate welding surface, but also effectively controlling the flatness and roughness of the back plate welding surface; at the same time, by coating the cobalt target blank welding surface and controlling the cleanliness of the cobalt target blank welding surface, the difficulty of combining the cobalt target blank with the back plate can be reduced, thereby improving the welding strength between the two, and then improving the welding quality and efficiency of the product, and the welding strength reaches more than 70MPa. The diffusion welding method is simple to operate, has high welding strength and welding efficiency, good stability, and low cost. DETAILED DESCRIPTION

[0060] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only used to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0061] In the following embodiments and comparative examples, the thickness of the cobalt target blank refers to the thickness of the cobalt target blank that has not been plated with a titanium film.

[0062] Example 1

[0063] This embodiment provides a diffusion welding method for a cobalt target material, and the diffusion welding method comprises the following steps:

[0064] (1) The cobalt target blank is subjected to a first ultrasonic cleaning for 5 minutes and a first vacuum drying for 60 minutes, and then the welding surface of the cobalt target blank is subjected to a titanium film coating treatment to form a titanium film layer with a thickness of 4 μm, and then a second ultrasonic cleaning for 5 minutes and a second vacuum drying for 60 minutes are sequentially performed to obtain a cobalt target blank after the titanium film is coated;

[0065] (2) a first turning process is performed on the welding surface of the copper back plate to form a welding groove matching the cobalt target blank, and then a second turning process is performed on the surface of the welding groove without using a cutting fluid, at a feed rate of 0.05 mm and a rotation speed of 500 r / min, and then a third ultrasonic cleaning process is performed for 5 minutes and a third vacuum drying process is performed for 60 minutes in sequence to obtain a processed copper back plate;

[0066] The depth of the welding groove is less than the thickness of the cobalt target blank, and the difference is 0.4 mm;

[0067] The medium used in the first ultrasonic cleaning, the second ultrasonic cleaning and the third ultrasonic cleaning is IPA liquid;

[0068] (3) Assembling the cobalt target blank after the titanium film is plated in step (1) and the copper back plate processed in step (2) and placing them in a sheath, and degassing the sheath at a temperature of 300° C. for 3 h, vacuumizing the sheath during degassing, and sealing the sheath after the degassing is completed; then hot isostatic pressing welding is performed at a temperature of 400° C. and a pressure of 110 MPa for 3 h;

[0069] There is no particular order in which steps (1) and (2) are performed.

[0070] Example 2

[0071] This embodiment provides a diffusion welding method for a cobalt target material, and the diffusion welding method comprises the following steps:

[0072] (1) The cobalt target blank is subjected to a first ultrasonic cleaning for 5 minutes and a first vacuum drying for 60 minutes, and then the welding surface of the cobalt target blank is subjected to a titanium film coating treatment to form a titanium film layer with a thickness of 3 μm, and then a second ultrasonic cleaning for 5 minutes and a second vacuum drying for 60 minutes are sequentially performed to obtain a cobalt target blank after the titanium film is coated;

[0073] (2) a first turning process is performed on the welding surface of the copper back plate to form a welding groove matching the cobalt target blank, and then a second turning process is performed on the surface of the welding groove without using a cutting fluid, at a feed rate of 0.04 mm and a rotation speed of 550 r / min, and then a third ultrasonic cleaning process is performed for 5 min and a third vacuum drying process is performed for 60 min in sequence to obtain a processed copper back plate;

[0074] The depth of the welding groove is less than the thickness of the cobalt target blank, and the difference is 0.5 mm;

[0075] The medium used in the first ultrasonic cleaning, the second ultrasonic cleaning and the third ultrasonic cleaning is IPA liquid;

[0076] (3) Assembling the cobalt target blank after the titanium film is plated in step (1) and the copper back plate processed in step (2) and placing them in a sheath, and degassing the sheath at a temperature of 300° C. for 3 h, vacuumizing the sheath during degassing, and sealing the sheath after the degassing is completed; then hot isostatic pressing welding is performed at a temperature of 300° C. and a pressure of 120 MPa for 4 h;

[0077] There is no particular order in which steps (1) and (2) are performed.

[0078] Example 3

[0079] This embodiment provides a diffusion welding method for a cobalt target material, and the diffusion welding method comprises the following steps:

[0080] (1) The cobalt target blank is subjected to a first ultrasonic cleaning for 5 minutes and a first vacuum drying for 60 minutes, and then the welding surface of the cobalt target blank is subjected to a titanium film coating treatment to form a titanium film layer with a thickness of 5 μm, and then a second ultrasonic cleaning for 5 minutes and a second vacuum drying for 60 minutes are sequentially performed to obtain a cobalt target blank after the titanium film is coated;

[0081] (2) a first turning process is performed on the welding surface of the copper back plate to form a welding groove matching the cobalt target blank, and then a second turning process is performed on the surface of the welding groove without using a cutting fluid, at a feed rate of 0.06 mm and a rotation speed of 450 r / min, and then a third ultrasonic cleaning process is performed for 5 min and a third vacuum drying process is performed for 60 min in sequence to obtain a processed copper back plate;

[0082] The depth of the welding groove is less than the thickness of the cobalt target blank, and the difference is 0.3 mm;

[0083] The medium used in the first ultrasonic cleaning, the second ultrasonic cleaning and the third ultrasonic cleaning is IPA liquid;

[0084] (3) Assembling the cobalt target blank after the titanium film is plated in step (1) and the copper back plate processed in step (2) and placing them in a sheath, and degassing the sheath at a temperature of 300° C. for 3 h, vacuumizing during the degassing, and sealing after the degassing is completed; then hot isostatic pressing welding is performed at a temperature of 500° C. and a pressure of 100 MPa for 2 h;

[0085] There is no particular order in which steps (1) and (2) are performed.

[0086] Example 4

[0087] This embodiment provides a diffusion welding method for a cobalt target material. Except that the depth of the welding groove in step (2) is less than the thickness of the cobalt target blank and the difference is 0.1 mm, other conditions are the same as those in Embodiment 1.

[0088] Example 5

[0089] This embodiment provides a diffusion welding method for a cobalt target material. Except that the depth of the welding groove in step (2) is less than the thickness of the cobalt target blank, and the difference is 0.8 mm, other conditions are the same as those in Embodiment 1.

[0090] Example 6

[0091] This embodiment provides a diffusion welding method for a cobalt target material. Except that the rotation speed of the second turning process in step (2) is 350 r / min, other conditions are the same as those in Embodiment 1.

[0092] Example 7

[0093] This embodiment provides a diffusion welding method for a cobalt target material. Except that the rotation speed of the second turning process in step (2) is 650 r / min, other conditions are the same as those in Embodiment 1.

[0094] Comparative Example 1

[0095] This comparative example provides a diffusion welding method for a cobalt target material. Except for using cutting fluid in the second turning process in step (2), other conditions are the same as those in Example 1.

[0096] Comparative Example 2

[0097] This comparative example provides a diffusion welding method for a cobalt target material. Except that the second turning process is not performed in step (2), other conditions are the same as those in Example 1.

[0098] The surface roughness of the welding groove after processing in step (2) in the above-mentioned embodiment and comparative example was detected by a roughness detector, and the welding bonding rate and welding strength of the welding interface between the cobalt target blank and the copper back plate after the hot isostatic pressing welding in step (3) in the above-mentioned embodiment and comparative example were detected by an ultrasonic flaw detector; the results are shown in Table 1.

[0099] Table 1

[0100]

[0101] From Table 1, we can see that:

[0102] (1) The diffusion welding method provided in Examples 1-3 of the present invention, by first turning a welding groove on the welding surface of the copper back plate, and then performing a second turning process on the surface, ensures that there is a good contact area between the cobalt target blank and the copper back plate, while effectively controlling the cleanliness of the welding surface of the copper back plate, thereby reducing the difficulty of combining the cobalt target blank and the copper back plate, and improving the welding strength between the two. The welding bonding rate of the obtained cobalt target assembly is 100%, and the welding strength is ≥70MPa;

[0103] (2) By comparing Example 1 with Examples 4-5, it can be seen that the height difference between the target blank and the back plate can make the sheath fully shrink and wrap the product during hot isostatic pressing welding, so that the welding surface contact is closer, thereby improving the welding strength; when the depth of the copper back plate welding groove is too small, the welding strength decreases, but it cannot be lower than the thickness of the sheath, and there is a risk of penetration; when the depth of the copper back plate welding groove is too large, although the effect is similar to that of Example 1, because the target blank is very thin, during the early preparation of welding, the target blank may be separated from the positioning groove due to factors such as transportation, resulting in the risk of welding failure, thereby causing the target blank to be scrapped;

[0104] (3) By comparing Example 1 with Examples 6-7, it can be seen that when the rotation speed of the second turning process is too slow, not only is the production efficiency low, but the too slow rotation speed is easy to wear the tool, affecting the surface finish of the welding surface, resulting in an increase in the roughness of the copper back plate welding surface; when the rotation speed of the second turning process is too fast, it leads to heat dissipation difficulties, and at the same time, the tool vibration is obvious during the processing, which also causes the roughness of the copper back plate welding surface to increase, thereby affecting the welding quality;

[0105] (4) By comparing Example 1 and Comparative Example 1, it can be seen that when cutting fluid is used in the second turning process, the copper back plate welding surface is contaminated with oil and is not easy to remove, resulting in poor cleanliness of the copper back plate welding surface, affecting the welding strength; By comparing Example 1 and Comparative Example 2, it can be seen that when the second turning process is not performed, not only can the cutting fluid and other oil stains generated during the first turning process not be removed, resulting in poor cleanliness of the copper back plate welding surface, but the flatness and roughness of the copper back plate welding surface cannot be effectively controlled, affecting the welding strength.

[0106] The applicant declares that the present invention illustrates the detailed structural features of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed structural features, that is, it does not mean that the present invention must rely on the above-mentioned detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the components selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A diffusion welding method for a cobalt target, characterized in that: The diffusion welding method comprises the following steps: (1) performing a coating treatment on the welding surface of the cobalt target blank, and then performing a second ultrasonic cleaning to obtain a coated cobalt target blank; (2) a first turning process is performed on the welding surface of the back plate to form a welding groove matching the cobalt target blank, and then a second turning process is performed on the surface of the welding groove, and then a third ultrasonic cleaning process is performed to obtain a processed back plate; (3) assembling the cobalt target blank after coating in step (1) and the back plate processed in step (2) and placing them in a sheath, degassing the sheath and performing hot isostatic pressing welding; There is no particular order in which steps (1) and (2) are performed.

2. The diffusion welding method according to claim 1, characterized in that: Before the coating treatment in step (1), a first ultrasonic cleaning and a first vacuum drying are sequentially performed; Preferably, the medium used in the first ultrasonic cleaning is IPA liquid; Preferably, the first ultrasonic cleaning time is 3-7 minutes; Preferably, the first vacuum drying time is ≥ 60 min.

3. The diffusion welding method according to claim 1 or 2, characterized in that: The material of the coating in step (1) includes titanium; Preferably, the thickness of the film layer formed after the coating treatment in step (1) is 3-5 μm.

4. The diffusion welding method according to any one of claims 1 to 3, characterized in that: Step (1) The medium used in the second ultrasonic cleaning is IPA liquid; Preferably, the second ultrasonic cleaning time in step (1) is 3-7 minutes; Preferably, in step (1), the second ultrasonic cleaning is followed by a second vacuum drying; Preferably, the second vacuum drying time is ≥ 60 min.

5. The diffusion welding method according to any one of claims 1 to 4, characterized in that: The back plate in step (2) comprises a copper back plate or a copper alloy back plate; Preferably, the depth of the welding groove in step (2) is less than the thickness of the cobalt target blank, and the difference is 0.3-0.5 mm.

6. The diffusion welding method according to any one of claims 1 to 5, characterized in that: Step (2) No cutting fluid is used during the second turning process; Preferably, the feed rate of the second turning process in step (2) is 0.04-0.06 mm; Preferably, the rotation speed of the second turning process in step (2) is 450-550 r / min.

7. The diffusion welding method according to any one of claims 1 to 6, characterized in that: Step (2) the flatness of the welding groove surface after the second turning process is less than 0.1 mm; Preferably, the roughness of the welding groove surface after the second turning process in step (2) is 0.12-0.2 μm.

8. The diffusion welding method according to any one of claims 1 to 7, characterized in that: The medium used in the third ultrasonic cleaning in step (2) is IPA liquid; Preferably, the time of the third ultrasonic cleaning in step (2) is 3-7 minutes; Preferably, the third ultrasonic cleaning in step (2) is followed by a third vacuum drying; Preferably, the third vacuum drying time is ≥ 60 min.

9. The diffusion welding method according to any one of claims 1 to 8, characterized in that: During the degassing in step (3), vacuum is drawn and the degassing is sealed after completion; Preferably, the degassing temperature in step (3) is 200-400°C; Preferably, the degassing holding time in step (3) is 2-4 hours; Preferably, the temperature of the hot isostatic pressing welding in step (3) is 300-500°C; Preferably, the pressure of the hot isostatic pressing welding in step (3) is 100-120 MPa; Preferably, the hot isostatic pressing welding time in step (3) is 2-4 hours; Preferably, after the hot isostatic pressing welding in step (3), the welding bonding rate of the welding interface between the cobalt target blank and the back plate is ≥99%, and the welding strength is ≥70 MPa.

10. The diffusion welding method according to any one of claims 1 to 9, characterized in that: The diffusion welding method comprises the following steps: (1) subjecting the cobalt target blank to a first ultrasonic cleaning for 3-7 minutes and a first vacuum drying for ≥60 minutes, and then subjecting the welding surface of the cobalt target blank to a coating treatment, wherein the coating material includes titanium, and the thickness of the formed film layer is 3-5 μm, and then subjecting the cobalt target blank to a second ultrasonic cleaning for 3-7 minutes and a second vacuum drying for ≥60 minutes, to obtain a coated cobalt target blank; (2) a first turning process is performed on the welding surface of the back plate to form a welding groove matching the cobalt target blank, and then a second turning process is performed on the surface of the welding groove without using a cutting fluid, at a feed rate of 0.04-0.06 mm and a rotation speed of 450-550 r / min, and then a third ultrasonic cleaning process is performed for 3-7 minutes and a third vacuum drying process is performed for ≥60 minutes to obtain a processed back plate; The back plate includes a copper back plate or a copper alloy back plate; the depth of the welding groove is less than the thickness of the cobalt target blank, and the difference is 0.3-0.5 mm; After the second turning process, the flatness of the welding groove surface is less than 0.1 mm and the roughness is 0.12-0.2 μm; The medium used in the first ultrasonic cleaning, the second ultrasonic cleaning and the third ultrasonic cleaning is IPA liquid; (3) Assembling the cobalt target blank after the coating in step (1) and the back plate processed in step (2) and placing them in a sheath, and degassing the sheath at a temperature of 200-400° C. for 2-4 hours, vacuumizing the sheath during degassing, and sealing the sheath after the degassing is completed; then hot isostatic pressing welding is performed at a temperature of 300-500° C. and a pressure of 100-120 MPa for 2-4 hours; After the hot isostatic pressing welding, the welding bonding rate of the cobalt target blank and the back plate welding interface is ≥99%, and the welding strength is ≥70MPa; There is no particular order in which steps (1) and (2) are performed.

Images