A method for manufacturing a niobium tube target

Abstract

The present application relates to a kind of preparation methods of niobium tube target material, belong to the preparation technical field of tubular target material for magnetron sputtering, the present application uses niobium powder as raw material, designs special cold isostatic pressing tooling, successively after granularity control proportioning and mechanical uniform mixing, cold isostatic pressing structure assembly, powder filling and cold isostatic pressing, cold isostatic pressing compact machining, hot isostatic pressing structure assembly, vacuum hot degassing of sheath, sheath hot isostatic pressing and machining process preparation niobium tube target material, the niobium tube target material prepared by the present application has the characteristics of high density, uniform structure, small radial thickness deviation, good straightness, controllable length-diameter ratio, and integral binding with back tube forming, etc., coating film applicability is wide, test shows that its relative density is ≥99%, oxygen content is ≤2500ppm, structure is uniform, radial thickness deviation is ≤0.3mm, straightness is ≤1mm, length-diameter ratio is controllable in the range of 8:1~20:1.

Description

Technical Field

[0001] This invention belongs to the field of preparation technology of tubular targets for magnetron sputtering, and relates to a method for preparing niobium tube targets, particularly a method for preparing niobium tube targets formed by hot isostatic pressing. Background Technology

[0002] Niobium sputtering targets, as a key raw material for the preparation of niobium and its alloy films by magnetron sputtering, are widely used in display panels, optical lenses, advanced glass, solar cells, and corrosion-resistant applications. With the continuous development of cutting-edge consumer industries such as automobiles, mobile phones, and computers, the demand for niobium sputtering targets in my country is increasing daily. However, at present, the domestic technology for preparing niobium sputtering targets still lags significantly behind that of foreign countries, and a large amount of targets are heavily reliant on imports. There is an urgent need to develop new technologies to break free from this dependence on foreign technology.

[0003] Based on their shape, sputtering targets can be divided into two categories: planar targets and tubular targets. Planar targets are unevenly etched during sputtering, and their utilization rate is only 25% to 35%. Tubular targets, on the other hand, are uniformly etched around the circumferential surface during sputtering, and their utilization rate is as high as 80% to 90%. In addition, tubular targets have advantages such as good coating continuity, strong coating uniformity, and large coating area. Tubular targets have become the high-end direction of target development and will inevitably gradually replace planar targets as the standard material for coating manufacturers.

[0004] Currently, the main method for preparing niobium tube targets in China is plasma spraying. This method suffers from drawbacks such as low density (relative density only 85%), high oxygen content (≥20000ppm), and poor microstructure uniformity. Furthermore, it is difficult to prepare thick-walled niobium tube targets, failing to meet the increasingly stringent requirements of domestic manufacturers. However, some domestic technicians have developed higher-quality niobium tube targets, and the relevant patents are shown in Table 1.

[0005] Table 1. Domestic Patents Related to Niobium Tube Targets

[0006]

[0007]

[0008] In the relevant patents on the preparation of niobium tube targets, the finished niobium tube targets do not have a back tube, which means that part of the niobium layer acts as a back tube or requires secondary bonding. The preparation technology mostly uses niobium ingots as raw materials and combines plastic deformation and machining to prepare niobium tube targets. The process is complicated and involves many steps. In addition, the use of lubricant during plastic deformation will lead to the introduction of impurities. The quality control of the finished target is poor. A lot of niobium waste is generated during machining, the material utilization rate is low, the overall cost is high, and it is not suitable for large-scale production. Summary of the Invention

[0009] The technical problem to be solved by the present invention is to provide a method for preparing a niobium tube target material with high density, uniform structure, small radial thickness deviation, good straightness, controllable aspect ratio, and integral bonding with the back tube. The prepared niobium tube target material has the following characteristics: high density (relative density ≥ 99%), low oxygen content (oxygen content ≤ 2500 ppm), uniform structure, small radial thickness deviation (deviation ≤ 0.3 mm), good straightness (straightness ≤ 1 mm), and controllable aspect ratio within the range of 8:1 to 20:1. The target material and the back tube are bonded simultaneously during hot isostatic pressing, avoiding secondary bonding.

[0010] The above-mentioned objectives of the present invention are mainly achieved through the following technical solutions:

[0011] A method for preparing a niobium tube target includes:

[0012] Niobium powder of different particle sizes is mixed evenly according to the specified ratio;

[0013] The uniformly mixed niobium powder is loaded into the powder loading area of ​​the cold isostatic pressing fixture, sealed, and then subjected to cold isostatic pressing. The cold isostatic pressing fixture includes a rubber sleeve body, a rubber sleeve upper cover, an upper positioning dish, a lower positioning dish, a mandrel, and a back tube. The mandrel is fitted inside the back tube, and the upper and lower positioning dishes are respectively set on the upper and lower end faces and are placed inside the rubber sleeve body. The uniformly mixed niobium powder is loaded into the annular cavity formed by the inner wall of the rubber sleeve body and the outer wall of the back tube. The rubber sleeve upper cover is connected to the rubber sleeve body and presses the upper positioning dish tightly.

[0014] Take out the niobium powder compact, back tube, and mandrel as a whole after cold isostatic pressing, and process the outer surface of the niobium powder compact as required.

[0015] The processed niobium powder blank-back tube-mandrel is loaded into a hot isostatic pressing (HIP) cladding. Welding rings are sealed on the upper and lower end faces of the outer cladding of the HIP cladding. After welding degassing tubes on the side walls, vacuum hot degassing is performed.

[0016] The vacuum thermally degassed hot isostatic cladding is subjected to hot isostatic pressing to obtain a niobium tube blank.

[0017] After the mandrel inside the niobium tube blank is ejected, it is machined to obtain the niobium tube target material.

[0018] In the above-mentioned method for preparing niobium tube targets, the niobium powder has two particle sizes, with laser particle sizes of D10 = 15-20 μm, D50 = 26-35 μm, D90 = 55-70 μm and D10 = 55-75 μm, D50 = 110-145 μm, D90 = 200-250 μm, respectively.

[0019] In the above-mentioned method for preparing niobium tube targets, the mass ratio of the two niobium powders is 12:1 to 1:12, and the tap density of the mixed powder is 5.1 to 5.3 g / cm³. 3Oxygen content ≤2500ppm.

[0020] In the above-mentioned method for preparing niobium tube targets, the cold isostatic pressing fixture further includes at least one of the following:

[0021] The outer wall of the back tube is coated with a transition layer. The uniformly mixed niobium powder is loaded into the powder loading area of ​​the cold isostatic pressing fixture. After cold isostatic pressing, the transition layer is bonded between the niobium powder and the back tube. The transition layer is a composite layer of any one or any two of the following materials: silver, copper, nickel, or titanium, with a thickness of 0.2 to 0.5 mm.

[0022] A lubricating layer is coated between the core rod and the back tube; the lubricating layer is made of aluminum oxide or boron nitride and has a thickness of 0.5 to 1.5 mm.

[0023] In the above-mentioned method for preparing niobium tube targets, the cold isostatic pressing fixture further includes an upper pressure plate and a lower pressure plate, and the upper cover of the rubber sleeve and the main body of the rubber sleeve are mechanically connected through the upper pressure plate and the lower pressure plate.

[0024] In the above-mentioned method for preparing niobium tube targets, the material of the main body of the rubber sleeve and the upper cover of the rubber sleeve in the cold isostatic pressing fixture is polyurethane or nitrile rubber, the material of the upper pressure plate, the lower pressure plate, the upper positioning dish and the lower positioning dish is carbon steel, the material of the mandrel is tungsten and tungsten alloy, molybdenum and molybdenum alloy or high temperature steel, and the material of the back tube is stainless steel.

[0025] In the above-mentioned method for preparing niobium tube targets, the mandrel is frustum-shaped, and the cross-section along the axial direction is an isosceles trapezoid, with the angle between the waist of the isosceles trapezoid and the axis being 1 to 3°.

[0026] In the above-mentioned method for preparing niobium tube targets, uniformly mixed niobium powder is loaded into the powder loading area of ​​a cold isostatic pressing fixture and compacted by tapping. After compaction, the powder density is ≥5.5 g / cm³. 3 .

[0027] In the above-mentioned method for preparing niobium tube targets, the cold isostatic pressing process is as follows: the first-stage holding pressure is 160-350 MPa, and the first-stage holding time is 10-50 min; the second-stage holding pressure is 90-140 MPa, and the second-stage holding time is 5-20 min.

[0028] In the above-mentioned method for preparing niobium tube targets, the outer sheath, welding ring, and degassing tube are all made of carbon steel or stainless steel.

[0029] In the above-mentioned method for preparing niobium tube targets, the vacuum thermal degassing process involves a first-stage degassing temperature of 350–500°C and a first-stage degassing vacuum degree ≤ 5 × 10⁻⁶. -3 Pa, first-stage degassing time 1–3 h; second-stage degassing temperature 750℃–1000℃, second-stage degassing vacuum degree ≤1×10 -3 Pa, secondary degassing time 5-10h.

[0030] In the above-mentioned method for preparing niobium tube targets, the hot isostatic pressing process is characterized by a holding temperature of 1000–1400℃, a holding pressure of 130–180 MPa, and a holding time of 2–5 h.

[0031] In the above-mentioned method for preparing niobium tube targets, the mandrel inside the niobium powder tube blank is pushed out from the inner surface of the back tube in the direction of small radial diameter and large diameter. Then, the inner surface of the back tube is processed, the outer sheath is removed by processing again, and finally the finished niobium tube target is obtained by precision machining.

[0032] In the above-mentioned method for preparing niobium tube targets, the prepared niobium tube targets meet the following requirements: relative density ≥ 99%, radial thickness deviation ≤ 0.3 mm, straightness ≤ 1 mm, and length-to-diameter ratio controllable within the range of 8:1 to 20:1.

[0033] A niobium tube target material is obtained using the above-described preparation method.

[0034] Compared with the prior art, the present invention has at least the following beneficial effects:

[0035] (1) This invention uses niobium powder as raw material and designs a special cold isostatic pressing tooling. The process involves particle size control and mechanical uniform mixing, assembly of cold isostatic pressing structure, powder filling and cold isostatic pressing, machining of cold isostatic pressing blank, assembly of hot isostatic pressing structure, vacuum thermal degassing of the cladding, hot isostatic pressing of the cladding and machining. The niobium tube target material prepared by this invention has the characteristics of high density, uniform structure, small radial thickness deviation, good straightness, controllable length-to-diameter ratio, and integral bonding with the back tube. It has wide applicability for coating.

[0036] (2) In the preferred embodiment of the present invention, by controlling the particle size of the raw material niobium powder, the niobium powder particles can be fully meshed during the cold isostatic pressing process, thereby improving the strength of the pressed blank and preventing cracking during the pressing process. At the same time, the oxygen content of the powder can be regulated to avoid excessive oxygen content in the finished niobium tube target material.

[0037] (3) In the preferred embodiment of the present invention, the frustum-shaped mandrel in the cold isostatic pressing fixture prevents the back tube from shrinking during the cold isostatic pressing process, and the upper and lower positioning plates ensure that the back tube and the main body of the rubber sleeve are coaxial. After cold isostatic pressing, the blank is machined to avoid wasting raw material powder, thus laying the foundation for the thickness uniformity of the niobium tube target material.

[0038] (4) In the preferred embodiment of the present invention, the vacuum thermal degassing process removes the gas in the powder gap and adsorbed on the powder surface, ensuring that the vacuum degree in the casing meets the requirements of hot isostatic pressing, which is a typical basis for the hot isostatic pressing of niobium tube targets.

[0039] (5) In the preferred embodiment of the present invention, the frustum-shaped high-temperature resistant mandrel in the hot isostatic pressing tooling simultaneously restricts the radial and axial shrinkage of the back tube, which can achieve precise control of the target material size. The lubrication layer prevents the mandrel from sticking to the back tube during the hot isostatic pressing process, and facilitates the ejection of the mandrel after hot isostatic pressing for reuse to reduce production costs. The binding transition layer enables the target material to be bound to the back tube at the same time as hot isostatic pressing, reducing subsequent binding processes.

[0040] (6) In the preferred embodiment of the present invention, the niobium tube target material prepared has the following characteristics: high density, relative density ≥99%, low oxygen content, oxygen content ≤2500ppm, uniform structure, small radial thickness deviation, deviation ≤0.3mm, good straightness, straightness ≤1mm, and the length-to-diameter ratio is controllable in the range of 8:1 to 20:1. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the cold isostatic pressing tooling mechanism for the hot isostatic pressing integral forming of niobium tube target material in an embodiment of the present invention;

[0042] Figure 2 This is a schematic diagram of the hot isostatic pressing (HIP) cladding of the integrally formed niobium tube target material in an embodiment of the present invention;

[0043] Figure 3 The following are structural diagrams of several typical finished niobium tube targets according to embodiments of the present invention. Detailed Implementation

[0044] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments:

[0045] The method for preparing the niobium tube target of the present invention includes the following steps:

[0046] 1. The raw material niobium powder is mixed with controlled particle size and mechanically until uniform.

[0047] In this embodiment of the invention, the niobium powder has two particle sizes, with laser-etched particle sizes of D10 = 15–20 μm, D50 = 26–35 μm, D90 = 55–70 μm and D10 = 55–75 μm, D50 = 110–145 μm, D90 = 200–250 μm, respectively. The two niobium powders are mechanically mixed at a mass ratio of 12:1 to 1:12, and the tap density of the mixed powder is 5.1–5.3 g / cm³. 3 Oxygen content ≤2500ppm.

[0048] The purpose of selecting a specific particle size of niobium powder for mixing in this embodiment of the invention is twofold: first, to ensure that the niobium powder particles can fully mesh during the cold isostatic pressing process, thereby improving the strength of the pressed blank and preventing cracking during the pressing process; and second, to control the oxygen content of the powder by adjusting the particle size, thereby preventing the oxygen content of the finished niobium tube target material from being too high.

[0049] II. Cold Isostatic Pressing Fixture Design

[0050] like Figure 1 As shown, the cold isostatic pressing fixture in this embodiment of the invention includes a rubber sleeve body 1, a rubber sleeve upper cover 2, an upper positioning dish 3, a lower positioning dish 4, a mandrel 5, a back tube 6, an upper pressure plate 11, a lower pressure plate 12, and bolts 13. The mandrel 5 is fitted inside the back tube 6. The upper and lower end faces are respectively provided with the upper positioning dish 3 and the lower positioning dish 4, and the whole is placed inside the rubber sleeve body 1. The uniformly mixed niobium powder is loaded into the annular cavity formed by the inner wall of the rubber sleeve body 1 and the outer wall of the back tube 6 and tapped and compacted. It is also compacted by the upper positioning dish 3. The rubber sleeve upper cover 2 and the rubber sleeve body 1 are sealed and connected by the upper pressure plate 11, the lower pressure plate 12 and the bolts 13, and the upper positioning dish 3 is pressed tightly.

[0051] In this embodiment of the invention, a lubricating layer 10 is coated between the mandrel 5 and the back tube 6 to prevent the mandrel 5 from sticking to the back tube 6, so that the mandrel 5 can be ejected and reused after hot isostatic pressing. The lubricating layer 10 is made of aluminum oxide or boron nitride, with a thickness of 0.5 to 1.5 mm, and is prepared by spraying. A bonding transition layer 9 is coated on the outer surface of the back tube 6 to achieve bonding between the target material and the back tube while the target material is hot isostatically pressed. The transition layer is made of silver, copper, nickel, titanium, or a composite layer of any two of the above materials, with a thickness of 0.2 to 0.5 mm, and is prepared by electroplating or spraying.

[0052] In this embodiment of the invention, the material of the rubber sleeve body 1 and the rubber sleeve cover 2 is polyurethane or nitrile rubber, the material of the upper pressure plate 11, the lower pressure plate 12, the upper positioning dish 3 and the lower positioning dish 4 is carbon steel, the material of the core rod 5 is tungsten and tungsten alloy, molybdenum and molybdenum alloy or high temperature steel, and the material of the back tube 6 is stainless steel.

[0053] The core rod 5 is a frustum shape, and its cross-section along the axial direction is an isosceles trapezoid. The angle between the legs of the isosceles trapezoid and the axis is 1 to 3°. That is, the inner surface of the back tube 6 and the outer surface of the core rod 5 are offset by the same angle, which is 1 to 3°.

[0054] III. Powder Filling and Cold Isostatic Pressing

[0055] In this invention, the powder loading density is a crucial factor affecting cold isostatic pressing (COP). If the niobium powder loading density is too low, the rubber sleeve will shrink significantly during COP, potentially causing the upper and lower positioning vessels to tear the sleeve. Therefore, a certain powder loading density is necessary for the COP structure to be effective. In this embodiment, mechanically mixed niobium powder is loaded into the powder loading area of ​​the COP fixture and compacted by tapping. After compaction, the powder loading density is ≥5.5 g / cm³. 3The cold isostatic pressing process is a key factor in achieving the forming of the compact and its attachment to the outer surface of the back tube for machining. In this embodiment of the invention, the cold isostatic pressing process is as follows: the first-stage holding pressure is 160-350 MPa, and the first-stage holding time is 10-50 min; the second-stage holding pressure is 90-140 MPa, and the second-stage holding time is 5-20 min.

[0056] IV. Turning of cold isostatic pressed blanks

[0057] After the cold isostatic pressing of the blank, back tube, and mandrel is completed, the outer surface of the blank is machined to a complete circle using the outer circle of the back tube as a reference. This ensures that the radial thickness of the annular blank is uniform, avoids uneven shrinkage during subsequent hot isostatic pressing, and helps to ensure the straightness and thickness uniformity of the finished niobium tube target.

[0058] V. Hot Isostatic Pressing Enclosure Design

[0059] like Figure 2 As shown, in this embodiment of the invention, the processed niobium powder blank-back tube-mandrel is loaded into a hot isostatic pressing (HIP) sleeve. Welding rings 7 are sealed on the upper and lower end faces of the outer sleeve 16 of the HIP sleeve, and degassing pipes 8 are welded on the side wall before vacuum hot degassing. The HIP sleeve is a cavity structure, including the outer sleeve 16, welding rings 7 and degassing pipes 8, all of which are made of carbon steel or stainless steel.

[0060] VI. Vacuum thermal degassing of the enclosure.

[0061] This invention performs vacuum thermal degassing on the sealed hot isostatic pressing (HIP) structure to remove gases from the powder gaps and adsorbed on the powder surface, ensuring that the target material can be densified during the HIP process. In this embodiment, the vacuum thermal degassing process involves a first-stage degassing temperature of 350–500°C and a first-stage degassing vacuum degree ≤5 × 10⁻⁵. -3 Pa, first-stage degassing time 1–3 h; second-stage degassing temperature 750℃–1000℃, second-stage degassing vacuum degree ≤1×10 -3 Pa, secondary degassing time 5-10h.

[0062] VII. Hot isostatic pressing of the sheath

[0063] In this invention, the hot isostatic pressing (HIP) process is a key factor in achieving the densification of the compact and the integral bonding of the target material and the back tube. The HIP process in this invention is carried out at 1000–1400°C, with a holding pressure of 130–180 MPa and a holding time of 2–5 hours.

[0064] VIII. Machining of Niobium Tube Targets

[0065] In this embodiment of the invention, the machining of the finished niobium tube target should follow a certain sequence: first, the mandrel 5 is pushed out from the inner surface of the back tube 6 from the small radial direction to the large diameter direction. The pushed-out mandrel 5 can be reused. Second, the inner surface of the back tube 6 is machined. Third, the outer sheath 16 is removed. Finally, the finished niobium tube target is obtained by precision machining.

[0066] The niobium tube target material prepared by this invention has high density (relative density ≥99%), uniform structure, small radial thickness deviation (≤0.3mm), good straightness (≤1mm), and controllable length-to-diameter ratio within the range of 8:1 to 20:1. The target material and the back tube are bonded simultaneously during hot isostatic pressing, avoiding secondary bonding.

[0067] Example 1

[0068] This example provides a method for preparing a niobium tube target material by hot isostatic pressing, the method comprising the following:

[0069] The main tooling required for this example and its specifications are shown in Table 1.

[0070] Table 1 shows the main tooling and specifications required for Example 1.

[0071]

[0072] Two types of niobium powder with laser particle sizes of D10 = 12 μm, D50 = 29 μm, D90 = 62 μm and D10 = 61 μm, D50 = 127 μm, D90 = 233 μm respectively were mixed uniformly at a mass ratio of 1:12. The tap density of the mixed powder was 5.24 g / cm³. 3 The oxygen content is 1735 ppm. The outer surface of the mandrel is coated with a boron nitride layer, 0.5 mm thick, and the outer surface of the back tube is coated with a copper-nickel composite layer, 0.2 mm thick, and then... Figure 1 After assembling the cold isostatic pressing structure as shown, the powder is loaded into the reserved annular powder loading area and compacted by tapping and vibrating. The final powder density is 5.59 g / cm³. 3 After the bolts are sealed, the rubber sleeve is subjected to cold isostatic pressing. The cold isostatic pressing process consists of a first-stage holding pressure of 180 MPa for 15 minutes and a second-stage holding pressure of 90 MPa for 10 minutes. After cold isostatic pressing, the entire pressed blank, back tube, and mandrel are removed from the rubber sleeve. The outer diameter of the pressed blank is then machined to the required diameter using the outer diameter of the back tube as a reference. The machined blank, back tube, and mandrel are assembled as a whole. Figure 2 After being placed into the outer casing and sealed by welding, the gas is degassed using a primary degaussing process at a temperature of 350℃ and a vacuum degree of ≤5×10⁻⁶. -3 Pa, first-stage degassing time 1.5h; second-stage degassing temperature 850℃, second-stage degassing vacuum degree ≤1×10 -3The secondary degassing time is 5 hours. The degassed casing is then subjected to hot isostatic pressing (HIP). The HIP process involves holding at 1050℃, a holding pressure of 160MPa, and a holding time of 3 hours. After HIP, the mandrel is ejected, and the finished niobium tube target is obtained through machining.

[0073] In this example, the finished niobium tube target has a relative density of 99.25%, an oxygen content of 1755 ppm, uniform microstructure, a radial thickness deviation of 0.13 mm, a straightness of 0.68 mm, an aspect ratio of 10.27:1, and a bonding rate of 99.77%. A structural diagram of the finished niobium tube target is attached. Figure 3 As shown in (a).

[0074] Example 2

[0075] This example provides a method for preparing a niobium tube target material by hot isostatic pressing, the method comprising the following:

[0076] The main tooling required for this example and its specifications are shown in Table 2.

[0077] Table 2 shows the main tooling and specifications required for Example 2.

[0078]

[0079] Two types of niobium powder with laser particle sizes of D10 = 18 μm, D50 = 33 μm, D90 = 59 μm and D10 = 55 μm, D50 = 133 μm, D90 = 241 μm, respectively, were mixed uniformly at a mass ratio of 1:7. The tap density of the mixed powder was 5.17 g / cm³. 3 The oxygen content is 1826 ppm. The outer surface of the mandrel is coated with an aluminum oxide layer, 1 mm thick, and the outer surface of the back tube is electroplated with a nickel-copper composite layer, 0.3 mm thick, and then... Figure 1 After assembling the cold isostatic pressing structure as shown, the powder is loaded into the reserved annular powder loading area and compacted by tapping and vibrating. The final powder density is 5.52 g / cm³. 3 After the bolts are sealed, the rubber sleeve is subjected to cold isostatic pressing. The cold isostatic pressing process consists of a first-stage holding pressure of 240 MPa and a first-stage holding time of 25 minutes; and a second-stage holding pressure of 100 MPa and a second-stage holding time of 5 minutes. After cold isostatic pressing, the entire pressed blank, back tube, and mandrel are removed from the rubber sleeve. The outer diameter of the pressed blank is then machined to the required diameter using the outer diameter of the back tube as a reference. The machined blank, back tube, and mandrel are assembled as a whole. Figure 2 After being placed into the outer casing and sealed by welding, the gas is degassed using a primary degaussing process at a temperature of 440℃ and a vacuum degree of ≤5×10⁻⁶. -3 Pa, first-stage degassing time 2h; second-stage degassing temperature 960℃, second-stage degassing vacuum degree ≤1×10 -3The secondary degassing time is 10 hours. The degassed casing is then subjected to hot isostatic pressing (HIP). The HIP process involves holding at 1200℃, a holding pressure of 135 MPa, and a holding time of 3.5 hours. After HIP, the mandrel is ejected, and the finished niobium tube target is obtained through machining.

[0080] In this example, the finished niobium tube target has a relative density of 99.58%, an oxygen content of 1863 ppm, uniform microstructure, a radial thickness deviation of 0.19 mm, a straightness of 0.11 mm, an aspect ratio of 13.16:1, and a bonding law of 99.67%. A structural diagram of the finished niobium tube target is attached. Figure 3 As shown in (b).

[0081] Example 3

[0082] This example provides a method for preparing a niobium tube target material by hot isostatic pressing, the method comprising the following:

[0083] The main tooling required for this example and its specifications are shown in Table 3.

[0084] Table 3 shows the main tooling and specifications required for Example 3.

[0085]

[0086] Two types of niobium powder with laser particle sizes of D10 = 17 μm, D50 = 27 μm, D90 = 55 μm and D10 = 73 μm, D50 = 139 μm, D90 = 244 μm respectively were mixed uniformly at a mass ratio of 1:6. The tap density of the mixed powder was 5.25 g / cm³. 3 The oxygen content is 1907 ppm. The outer surface of the mandrel is sprayed with a boron nitride layer, 0.5 mm thick, and the outer surface of the back tube is electroplated with a nickel layer, 0.2 mm thick, and then... Figure 1 After assembling the cold isostatic pressing structure as shown, the powder is loaded into the reserved annular powder loading area and compacted by tapping and vibrating. The final powder density is 5.60 g / cm³. 3 After the bolts are sealed, the rubber sleeve is subjected to cold isostatic pressing. The cold isostatic pressing process consists of a first-stage holding pressure of 300 MPa for 35 minutes, and a second-stage holding pressure of 120 MPa for 15 minutes. After cold isostatic pressing, the entire pressed blank, back tube, and mandrel are removed from the rubber sleeve. The outer diameter of the pressed blank is then machined to the required diameter using the outer diameter of the back tube as a reference. The machined blank, back tube, and mandrel are assembled as a whole. Figure 2 After being placed into the outer casing and sealed by welding, the gas is degassed. The degassed process consists of a first-stage degassed temperature of 480℃ and a first-stage degassed vacuum degree of ≤5×10⁻⁶. -3 Pa, first-stage degassing time 3h; second-stage degassing temperature 1000℃, second-stage degassing vacuum degree ≤1×10 -3The secondary degassing time is 5 hours. The degassed casing is then subjected to hot isostatic pressing (HIP). The HIP process involves holding at 1270℃, a holding pressure of 130MPa, and a holding time of 2.5 hours. After HIP, the mandrel is ejected, and the finished niobium tube target is obtained through machining.

[0087] In this example, the finished niobium tube target material has a relative density of 99.63%, an oxygen content of 1929 ppm, uniform microstructure, a radial thickness deviation of 0.18 mm, a straightness of 0.13 mm, an aspect ratio of 12.58:1, and a bonding law of 99.51%. A structural diagram of the finished niobium tube target material is attached. Figure 3 As shown in (c).

[0088] Example 4

[0089] This example provides a method for preparing a niobium tube target material by hot isostatic pressing, the method comprising the following:

[0090] The main tooling required for this example and its specifications are shown in Table 4.

[0091] Table 4 shows the main tooling and specifications required for Example 4.

[0092]

[0093] Two types of niobium powder with laser particle sizes of D10 = 20 μm, D50 = 34 μm, D90 = 67 μm and D10 = 67 μm, D50 = 127 μm, D90 = 232 μm respectively were mixed uniformly at a mass ratio of 12:1. The tap density of the mixed powder was 5.19 g / cm³. 3 The oxygen content is 2208 ppm. The outer surface of the mandrel is sprayed with a boron nitride layer, 1.2 mm thick, and the outer surface of the back tube is sprayed with a coating layer, 0.5 mm thick, and then... Figure 1 After assembling the cold isostatic pressing structure as shown, the powder is loaded into the reserved annular powder loading area and compacted by tapping and vibrating. The final powder density is 5.54 g / cm³. 3 After the bolts are sealed, the rubber sleeve is subjected to cold isostatic pressing. The cold isostatic pressing process consists of a first-stage holding pressure of 35 MPa and a first-stage holding time of 40 minutes; and a second-stage holding pressure of 140 MPa and a second-stage holding time of 20 minutes. After cold isostatic pressing, the entire pressed blank, back tube, and mandrel are removed from the rubber sleeve. The outer diameter of the pressed blank is then machined to the required diameter using the outer diameter of the back tube as a reference. The machined blank, back tube, and mandrel are assembled as a whole. Figure 2 After being placed into the outer casing and sealed by welding, the gas is degassed using a primary degaussing process at a temperature of 550℃ and a vacuum degree of ≤5×10⁻⁶. -3 Pa, first-stage degassing time 2h; second-stage degassing temperature 980℃, second-stage degassing vacuum degree ≤1×10 -3The secondary degassing time is 8 hours. The degassed casing is then subjected to hot isostatic pressing (HIP). The HIP process involves holding at 1360℃, a holding pressure of 130MPa, and a holding time of 2 hours. After HIP, the mandrel is ejected, and the finished niobium tube target is obtained through machining.

[0094] In this example, the finished niobium tube target has a relative density of 99.75%, an oxygen content of 2243 ppm, uniform microstructure, a radial thickness deviation of 0.23 mm, a straightness of 0.59 mm, an aspect ratio of 20:1, and a bonding law of 99.96%. A structural diagram of the finished niobium tube target is attached. Figure 3 As shown in (d).

[0095] The above description is only the best specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the protection scope of the present invention.

[0096] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A method for preparing a niobium tube target, characterized in that, include: Niobium powder of different particle sizes is mixed evenly according to the specified ratio; The uniformly mixed niobium powder is loaded into the powder loading area of ​​the cold isostatic pressing fixture, sealed, and then subjected to cold isostatic pressing. The cold isostatic pressing fixture includes a rubber sleeve body (1), a rubber sleeve upper cover (2), an upper positioning dish (3), a lower positioning dish (4), a mandrel (5), and a back tube (6). The mandrel (5) is fitted inside the back tube (6), and the upper and lower end faces are respectively provided with the upper positioning dish (3) and the lower positioning dish (4), and the whole is placed inside the rubber sleeve body (1). The uniformly mixed niobium powder is loaded into the annular cavity formed by the inner wall of the rubber sleeve body (1) and the outer wall of the back tube (6). The rubber sleeve upper cover (2) is connected to the rubber sleeve body (1) and presses the upper positioning dish (3) tightly. Take out the niobium powder compact, back tube, and mandrel as a whole after cold isostatic pressing, and process the outer surface of the niobium powder compact as required. The processed niobium powder blank-back tube-mandrel is loaded into the hot isostatic pressing sleeve. Welding rings (7) are sealed on the upper and lower end faces of the outer sleeve (16) of the hot isostatic pressing sleeve. After welding the degassing tube (8) on the side wall, vacuum hot degassing is performed. The vacuum thermally degassed hot isostatic cladding is then subjected to hot isostatic pressing to obtain a niobium tube blank. After the mandrel (5) inside the niobium tube blank is ejected, it is machined to obtain the niobium tube target material; The cold isostatic pressing fixture also includes an upper pressure plate (11) and a lower pressure plate (12). The upper cover (2) of the rubber sleeve and the main body (1) of the rubber sleeve are mechanically connected through the upper pressure plate (11) and the lower pressure plate (12). The material of the rubber sleeve body (1) and the rubber sleeve cover (2) in the cold isostatic pressing fixture is polyurethane or nitrile rubber, the material of the upper pressure plate (11), the lower pressure plate (12), the upper positioning dish (3) and the lower positioning dish (4) is carbon steel, the material of the mandrel (5) is tungsten, tungsten alloy, molybdenum, molybdenum alloy or high temperature steel, and the material of the back tube (6) is stainless steel. The outer sheath (16), welding ring (7) and degassing pipe (8) are all made of carbon steel or stainless steel; The outer wall of the back tube (6) is coated with a transition layer (9); a lubricating layer (10) is coated between the core rod (5) and the back tube (6). The niobium powder has two particle sizes, with laser particle sizes of D10=15~20μm, D50=26~35μm, D90=55~70μm and D10=55~75μm, D50=110~145μm, D90=200~250μm respectively. The mass ratio of the two niobium powders is 12:1 to 1:12, and the tap density of the mixed powder is 5.1 to 5.3 g / cm³. 3 Oxygen content ≤2500ppm; The core rod (5) is frustum-shaped, and the cross section along the axial direction is an isosceles trapezoid. The angle between the waist of the isosceles trapezoid and the axis is 1~3°.

2. The method for preparing the niobium tube target according to claim 1, characterized in that, The cold isostatic pressing fixture also includes: The uniformly mixed niobium powder is loaded into the powder loading area of ​​the cold isostatic pressing fixture. After cold isostatic pressing, a transition layer (9) is bound between the niobium powder and the back tube. The transition layer is a composite layer of any one or any two of the following materials: silver, copper, nickel or titanium, with a thickness of 0.2~0.5mm. The lubricating layer (10) is made of aluminum oxide or boron nitride and has a thickness of 0.5~1.5mm.

3. The method for preparing the niobium tube target according to claim 1, characterized in that, The uniformly mixed niobium powder is loaded into the powder loading area of ​​the cold isostatic pressing fixture and compacted by tapping. After compaction, the powder density is ≥5.5 g / cm³. 3 .

4. The method for preparing the niobium tube target according to claim 1, characterized in that, The cold isostatic pressing process has a first-stage holding pressure of 160~350MPa and a first-stage holding time of 10~50min; a second-stage holding pressure of 90~140MPa and a second-stage holding time of 5~20min.

5. The method for preparing the niobium tube target according to claim 1, characterized in that, The vacuum thermal degassing process has a primary degassing temperature of 350~500℃ and a primary degassing vacuum degree of ≤5×10⁻⁵. -3 Pa, first-stage degassing time 1~3h; second-stage degassing temperature 750℃~1000℃, second-stage degassing vacuum degree ≤1×10 -3 Pa, secondary degassing time 5~10h.

6. The method for preparing the niobium tube target according to claim 1, characterized in that, The hot isostatic pressing process involves a holding temperature of 1000~1400℃, a holding pressure of 130~180MPa, and a holding time of 2~5h.

7. The method for preparing the niobium tube target according to claim 1, characterized in that, The mandrel (5) inside the niobium powder tube blank is pushed out from the inner surface of the back tube (6) from the small radial direction to the large diameter direction. Then the inner surface of the back tube (6) is processed, the outer sleeve (16) is removed again, and finally the finished niobium tube target is obtained by finishing.

8. The method for preparing the niobium tube target according to claim 1, characterized in that, The prepared niobium tube target material meets the following requirements: relative density ≥ 99%, radial thickness deviation ≤ 0.3 mm, straightness ≤ 1 mm, and length-to-diameter ratio controllable within the range of 8:1 to 20:

1.

9. A niobium tube target material, characterized in that, It is obtained by the preparation method described in any one of claims 1 to 8.

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