A method of forming a tubular target

Abstract

The application relates to the technical field of target material preparation, and provides a forming method of a tubular target material, which comprises the following steps: providing a target material forming die, which comprises a flexible diaphragm in a cylindrical shape and a die sleeve; placing the flexible diaphragm in the die sleeve, so that the inside of the cylinder of the flexible diaphragm constitutes an inner cavity, and a die cavity is formed between the flexible diaphragm and the die sleeve; performing plugging treatment on the bottom of the inner cavity and the die cavity; filling plastic particles into the inner cavity and target material powder into the die cavity; performing plugging treatment on the top of the inner cavity and the die cavity; performing cold isostatic pressing treatment on the forming die together with the filled plastic particles and target material powder, and obtaining a target material green body through demolding. The plastic particles and the flexible diaphragm are used to construct a plastic mold core, the plastic mold core has good compressibility, can uniformly transmit pressure and realize self-adaptive compensation, and the target material powder in the die cavity is uniformly stressed in the cold isostatic pressing. Compared with a traditional rigid mold core, the method can greatly reduce defects such as uneven green body density, deformation and cracking, improve the quality of the green body, and meet the flexible production demand.

Description

Technical Field

[0001] This application belongs to the field of target preparation technology, and particularly relates to a method for forming a tubular target. Background Technology

[0002] Cold isostatic pressing (CIP) is a key powder forming process widely used in the preparation of ceramic or metal targets. This technology typically uses rigid stainless steel as the core for constructing the target forming cavity, and polymer sheaths such as polyurethane or silicone as the outer mold. By filling the cavity with powder, sealing it, and then applying isotropic high pressure using a liquid medium, the powder particles are densified, resulting in a green body with a predetermined shape and strength.

[0003] However, when cold isostatic pressing (CIP) is used for forming tubular targets, its limitations become more pronounced. First, the core versatility is poor. Because it relies on rigid stainless steel cores of specific dimensions to control the inner diameter of the target, a dedicated core is required for each size of tubular target produced. This significantly increases mold costs and inventory management complexity, and makes it difficult to adapt to the flexible production needs of multiple varieties and small batches. Second, the forming quality is easily affected. During the pressurization process, the rigid stainless steel core can easily lead to uneven powder stress distribution, causing defects such as density gradients in the green blank, deformation, and even cracking, affecting the final product performance and yield.

[0004] Therefore, there is an urgent need to develop a molding method that is versatile and can stably form high-quality tubular targets. Summary of the Invention

[0005] The purpose of this application is to provide a method for forming tubular targets, which aims to solve the problems of poor versatility and poor forming quality in existing tubular target forming methods.

[0006] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows: This application provides a method for forming a tubular target material, comprising the following steps: A target forming mold is provided, the target forming mold comprising a cylindrical flexible diaphragm and a mold sleeve; The flexible diaphragm is placed inside the mold sleeve, so that the inside of the flexible diaphragm's cylindrical body forms an inner cavity, and a mold cavity is formed between the flexible diaphragm and the mold sleeve; The bottom of the inner cavity and the mold cavity are sealed. Plastic granules are filled into the inner cavity, and target powder is filled into the mold cavity; The top of the inner cavity and the mold cavity are sealed. The molding die, along with the plastic granules and the target powder contained therein, is subjected to cold isostatic pressing, and the target blank is obtained after demolding.

[0007] Compared with the prior art, this application has the following beneficial effects: (1) Plastic cores are constructed using plastic granules and flexible diaphragms. Through simple adjustments, tubular targets with different wall thicknesses and even different inner / outer diameters can be produced. This solves the problem that traditional rigid cores can only produce one type of target with corresponding size specifications, reduces mold costs, and meets the needs of flexible production.

[0008] (2) The plastic mold core is compressible and can uniformly transmit and adaptively compensate for pressure, so that the target powder in the mold cavity is subjected to uniform force during the cold isostatic pressing process, reducing defects such as uneven density, deformation, and cracking of the blank, improving the uniformity of target density and yield, while the regularity of the blank also reduces the difficulty of machining.

[0009] (3) After molding, the plastic granules can be recycled after simple processing such as crushing and granulation, reducing material consumption and conforming to the concept of green manufacturing. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a process flow diagram of the forming method of the tubular target material provided in the embodiments of this application; Figure 2 This is a schematic diagram of the target molding die used in the embodiments of this application before the material is filled; Figure 3 This is an exploded structural diagram of the target molding die used in the embodiments of this application before filling with material; Figure 4 This is a schematic cross-sectional view of the target molding die before it is filled with material, as used in the embodiments of this application. Figure 5 This is a schematic cross-sectional view of the target molding die after it has been filled with material, as used in the embodiments of this application. Figure 6 This is a schematic cross-sectional view of the target molding die before it is filled with material, as used in another embodiment of this application. Figure 7 This is a schematic cross-sectional view of the target molding die after it has been filled with material, according to another embodiment of this application. Figure 8 This is a photograph of the target blank prepared in Example 1 of this application; Figure 9This is a photograph of the target blank prepared in Example 2 of this application; Figure 10 This is a photograph of the target blank prepared in Comparative Example 1 of this application.

[0012] The labels for the attached figures are as follows: 1—Flexible diaphragm; 2—Mold sleeve; 21—First mold sleeve; 22—Second mold sleeve; 31—Inner cavity; 32—Mold cavity; 321—First mold cavity; 322—Second mold cavity; 4—Mold core positioning component; 41—Rigid support component; 42—Cover plate; 421—First feed port; 422—Second feed port; 423—Handle; 5—Plastic granules; 6—Target powder; 71—First sealing component; 72—Second sealing component; 73—Third sealing component. Detailed Implementation

[0013] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0014] This application provides a method for forming a tubular target material, such as... Figure 1 As shown, it includes the following steps: S1: Provide a target forming mold, which includes a cylindrical flexible diaphragm 1 and a mold sleeve 2; S2: Place the flexible diaphragm 1 inside the mold sleeve 2, so that the inside of the cylinder of the flexible diaphragm 1 forms an inner cavity, and a mold cavity 32 is formed between the flexible diaphragm 1 and the mold sleeve 2. S3: Seal the bottom of the inner cavity 31 and the mold cavity 32; S4: Fill the inner cavity 31 with plastic granules 5 and fill the mold cavity 32 with target powder 6; S5: Seal the top of the inner cavity 31 and the mold cavity 32; S6: The molding die, along with the plastic granules 5 and the target powder 6, is subjected to cold isostatic pressing, and the target blank is obtained after demolding.

[0015] The tubular target molding method provided in this application utilizes plastic granules and a flexible diaphragm 1 to construct a plastic mold core. Through simple adjustments, it can produce tubular targets with various wall thicknesses and even different inner / outer diameters, solving the problem that traditional rigid mold cores can only produce targets of one corresponding size. This reduces mold costs and meets the needs of flexible production. Furthermore, the plastic mold core is compressible, enabling uniform pressure transmission and adaptive compensation. This ensures uniform stress on the target powder within the mold cavity 32 during cold isostatic pressing, reducing defects such as uneven density, deformation, and cracking in the preform, improving the density uniformity and yield of the target material. The regularity of the preform also reduces machining difficulty. In addition, the molded plastic granules can be recycled after simple processing such as crushing and granulation, reducing material consumption and conforming to the concept of green manufacturing.

[0016] In this embodiment, the flexible diaphragm 1 is made of polyurethane or silicone. Both polyurethane and silicone have excellent elasticity, fatigue resistance, and tear strength, which ensures that the flexible diaphragm 1 deforms uniformly under high pressure to transmit pressure, while being less prone to damage during repeated use, thus extending its service life and reducing costs.

[0017] In this embodiment, the thickness of the flexible diaphragm 1 is 0.5~2mm. This thickness range gives the flexible diaphragm 1 suitable flexibility and deformability, enabling it to uniformly transmit pressure during cold isostatic pressing, allowing the plastic particles and target powder to shrink synchronously and uniformly, thereby improving the quality of the green body forming.

[0018] In this embodiment, the mold sleeve 2 is made of polyurethane or silicone. Both polyurethane and silicone possess excellent elasticity, fatigue resistance, and tear strength, ensuring that the mold sleeve 2 undergoes uniform elastic deformation under high pressure, thereby stably and uniformly transmitting pressure. Furthermore, they are not easily damaged during repeated use, extending their service life and reducing costs. In addition, they exhibit good chemical stability, preventing reactions with the target powder.

[0019] In this embodiment, the thickness of the mold sleeve 2 is 1.5~6mm. This thickness range gives the flexible diaphragm 1 suitable flexibility and deformability, enabling it to uniformly transmit pressure during cold isostatic pressing, allowing the plastic particles and target powder to shrink synchronously and uniformly, thereby improving the quality of the green blank.

[0020] Specifically, both the flexible diaphragm 1 and the mold sleeve 2 are cylindrical.

[0021] The following example uses a single mold sleeve 2 to form a single mold cavity 32. Figures 2-5 As shown, the method for forming tubular targets is explained in detail.

[0022] In this embodiment, the target molding die further includes a core positioning component 4, which includes a cylindrical rigid support component 41 and a cover plate connected to one end of the rigid support component 41; the rigid support component 41 and the cover plate are an integral structure. The materials of the rigid support component 41 and the cover plate can be expanded according to the molding requirements, with high-strength, lightweight and smooth materials being preferred. The rigid support component 41 is cylindrical in shape, and the cover plate is circular in shape, with its diameter being the same as the inner diameter of the mold sleeve 2. As a basic support, the rigid support component 41 and the cover plate can ensure that the flexible diaphragm 1 and the mold sleeve 2 maintain coaxiality, avoiding deformation of the flexible diaphragm 1 and the mold sleeve 2 during the filling of plastic particles and target powder, which would cause the cavity of the inner cavity 31 and the mold cavity 32 to shift, thereby ensuring the uniform wall thickness of the tubular target.

[0023] The core positioning component 4 is assembled after the steps of sealing the bottom of the inner cavity 31 and the mold cavity 32 respectively, and before the steps of filling the plastic particles into the inner cavity 31 and filling the target powder into the mold cavity 32. Specifically, it includes: inserting the core positioning component 4 into the inner side of the flexible diaphragm 1, so that the outer wall of the rigid support component 41 is in contact with the inner wall of the flexible diaphragm 1, and the side of the cover plate 42 is in contact with the top of the inner wall of the mold sleeve 2.

[0024] In some embodiments, the cover plate 42 is provided with a first feed port 421 and at least two second feed ports 422. The first feed port 421 communicates with the inner cavity 31, and the second feed ports 422 communicate with the mold cavity 32. The first feed port 421 has a circular opening with a diameter less than or equal to the diameter of the rigid support member 41; the second feed ports 422 have a circular opening with a diameter of 5-15 cm. Preferably, there are 2-4 second feed ports 422, and they are evenly spaced. By integrating the first feed port 421 and the second feed port 422 on the cover plate 42, the plastic particles and target powder are separated and directionally fed, avoiding mixing of the two materials and ensuring the cleanliness and purity of the molding cavity. Specifically, the steps of filling the inner cavity 31 with plastic granules and the mold cavity 32 with target powder include: filling the inner cavity 31 with plastic granules through the first feed port 421; filling the mold cavity 32 with target powder through the second feed port 422, and applying mechanical vibration to the target powder during the filling process; after the target powder is filled, removing the mold core positioning part 4, and compacting the plastic granules and target powder. Applying mechanical vibration to the target powder during the filling process effectively promotes powder flow and rearrangement, making it more densely and uniformly filled in the first mold cavity 321; the subsequent compaction process further removes air between the powder particles, increasing the initial bulk density of the powder; therefore, the two work together to significantly improve the uniformity and density of the powder filling, reducing initial density differences and defects from the source, making the density increase more uniform during subsequent cold isostatic pressing, thereby obtaining a high-density green body.

[0025] In some embodiments, at least one handle 423 is also provided on the cover plate 42, and the handle 423 is provided on the side of the cover plate 42 opposite to the inner cavity 31 and the mold cavity 32. The handle 423 is provided for gripping to lift and move the entire mold core positioning member 4. The surface of the handle 423 may be provided with anti-slip texture or rubber anti-slip sleeve to further improve grip stability and prevent slippage during operation.

[0026] In some embodiments, the target molding die further includes two first sealing members 71, two second sealing members 72, and two fasteners; the two first sealing members 71 are used to seal both ends of the inner cavity 31; the two second sealing members 72 are used to seal both ends of the mold cavity 32; the two fasteners are respectively disposed on the outer periphery of both ends of the mold sleeve 2, and are used to fasten the two first sealing members 71, the flexible diaphragm 1, the two second sealing members 72, and the mold sleeve 2. By using fasteners to lock the first sealing members 71, the flexible diaphragm 1, the second sealing members 72, and the mold sleeve 2, the airtightness of the inner cavity 31 and the mold cavity 32 can be ensured, preventing the plastic particles and target powder from overflowing and the liquid medium from seeping in, ensuring that the pressure can be fully applied to the plastic particles and target powder during cold isostatic pressing, and ensuring the molding effect.

[0027] In some embodiments, the first sealing element 71 can be a soft round plug, made of polyurethane, with the same diameter as the inner diameter of the flexible diaphragm 1. The second sealing element 72 can be a soft plug ring, also made of polyurethane, with the same inner diameter as the outer diameter of the flexible diaphragm 1 and the same outer diameter as the inner diameter of the mold sleeve 2. Fasteners can be metal wire or adjustable clamp structures, adaptable to mold sleeves 2 of different diameters, allowing for adaptation to various sizes of molding dies without changing fasteners. Through dimensional control, the first sealing element 71 and the flexible diaphragm 1, and the second sealing element 72 and the flexible diaphragm 1 and mold sleeve 2 are tightly fitted without gaps or misalignment, improving sealing performance, preventing material leakage from sealing gaps, and ensuring no material mixing during the filling stage. Simultaneously, precise dimensional matching ensures consistent coaxiality of all components, preventing end sealing misalignment from causing deformation of the inner cavity 31 and mold cavity 32.

[0028] In some embodiments, the step of sealing the bottom of the inner cavity 31 and the mold cavity 32 includes: placing a first sealing member 71 at the bottom of the inner cavity 31 and a second sealing member 72 at the bottom of the mold cavity 32; then fitting a fastener around the outer periphery of the bottom end of the mold sleeve 2 and locking it in place. This operation can prevent the overflow of plastic particles and target powder and the infiltration of liquid media.

[0029] In some embodiments, the step of sealing the top of the inner cavity 31 and the mold cavity 32 includes: placing another first sealing member 71 on the top of the inner cavity 31 and another second sealing member 72 on the top of the mold cavity 32; then fitting another fastener around the outer periphery of the top of the mold sleeve 2 and locking it. This operation can prevent the overflow of plastic particles and target powder and the infiltration of liquid media.

[0030] The following is an example of using a double mold sleeve 2 to form a double mold cavity 32, such as... Figures 6-7 As shown, the method for forming tubular targets is explained in detail.

[0031] In some embodiments, the mold sleeve 2 includes a first mold sleeve 21 and a second mold sleeve 22. The step of placing the flexible diaphragm 1 inside the mold sleeve 2 includes: coaxially placing the flexible diaphragm 1 inside the second mold sleeve 22; and coaxially placing the first mold sleeve 21 between the flexible diaphragm 1 and the second mold sleeve 22, so that a first mold cavity 321 is formed between the flexible diaphragm 1 and the first mold sleeve 21, and a second mold cavity 322 is formed between the first mold sleeve 21 and the second mold sleeve 22. The first mold cavity 321 is used to fill target powder, and the second mold cavity 322 is used to fill plastic particles. By adding the second mold cavity 322 and filling it with plastic particles, not only can its radial thickness be flexibly adjusted to adapt to the production of tubular targets of different specifications, but also the process adaptability can be enhanced. More importantly, compared to the conventional single-mold structure, this structure forms a multi-layer pressure transmission system of "plastic particle core - target powder intermediate layer - plastic particle outer layer". During the cold isostatic pressing process, this system can achieve balanced pressure in both the inner and outer directions, improve the uniformity of pressure distribution, thereby effectively suppressing the deformation of the green body and compensating for the unevenness of the initial powder filling stage. This improves the density uniformity and dimensional accuracy of the green body, providing a high-quality green body for the subsequent sintering preparation of high-performance and highly consistent target materials.

[0032] In some embodiments, the target molding die includes, in addition to the flexible diaphragm 1, the core positioning member 4 (where the diameter of the cover plate 42 of the core positioning member 4 is the same as the inner diameter of the second mold sleeve 22, and the side of the cover plate 42 is in contact with the top of the inner wall of the second mold sleeve 22), the first sealing member 71, the second sealing member 72 (where the inner diameter of the second sealing member 72 is the same as the outer diameter of the flexible diaphragm 1, and the outer diameter is the same as the inner diameter of the first mold sleeve 21), and fasteners, two third sealing members 73; the two second sealing members 72 are respectively used to seal the two ends of the first mold cavity 321; the two third sealing members 73 are used to seal the two ends of the first mold cavity 321. The three sealing components 73 are used to seal both ends of the second mold cavity 322 respectively; the two fasteners are respectively located on the outer periphery of both ends of the second mold sleeve 22, and are used to fasten the two first sealing components 71, the flexible diaphragm 1, the two second sealing components 72, the first mold sleeve 21, the two third sealing components 73 and the second mold sleeve 22; thereby locking the first sealing components 71, the second sealing components 72 and the third sealing components 73, preventing the plastic particles and target powder from overflowing and the liquid medium from seeping in, while ensuring the airtightness of the inner cavity 31 and the mold cavity 32, and ensuring that the pressure can be completely applied to the plastic particles and target powder during cold isostatic pressing, thereby ensuring the pressure molding effect.

[0033] Specifically, the third sealing element 73 can be a soft plug ring, made of polyurethane. Its inner diameter is the same as the outer diameter of the first mold sleeve 21, and its outer diameter is the same as the inner diameter of the second mold sleeve 22. Through dimensional control, the third sealing element 73 fits tightly with the first mold sleeve 21 and the second mold sleeve 22 without gaps or misalignment, improving sealing performance, preventing material leakage from the sealing gaps, and ensuring that the material does not mix during the filling stage. At the same time, precise dimensional matching ensures that the coaxiality of each component is consistent, preventing end sealing misalignment from causing deformation of the first mold cavity 321 and the second mold cavity 322.

[0034] In some embodiments, the step of sealing the bottom of the inner cavity 31 and the mold cavity 32 may include: placing a first sealing member 71 at the bottom of the inner cavity 31, placing a second sealing member 72 at the bottom of the first mold cavity 321, and placing a third sealing member 73 at the bottom of the second mold cavity 322; then fitting a fastener around the outer periphery of the bottom end of the second mold sleeve 22 and locking it; this operation can prevent the overflow of plastic particles and target powder and the infiltration of liquid media.

[0035] In some embodiments, the step of sealing the top of the inner cavity 31 and the mold cavity 32 may include: placing another first sealing member 71 on top of the inner cavity 31, placing another second sealing member 72 on top of the first mold cavity 321, and placing another third sealing member 73 on top of the second mold cavity 322; then fitting another fastener around the outer periphery of the top of the second mold sleeve 22 and locking it in place. This operation can prevent the overflow of plastic particles and target powder and the infiltration of liquid media.

[0036] In this embodiment, in addition to retaining the first feed port 421 and at least two second feed ports 422 (where the second feed ports 422 are connected to the first mold cavity 321) that cooperate with the single mold sleeve 2 and single mold cavity 32, the cover plate 42 is also provided with at least two third feed ports, which are connected to the second mold cavity 322. The shape and size of the first feed port 421 and the second feed port 422 are as described above and will not be repeated here; the third feed port has a circular opening with a diameter of 5-15 cm. Preferably, there are 2-4 third feed ports, and each third feed port is equally spaced. By integrating the first feed port 421, the second feed port 422, and the third feed port on the cover plate 42, the plastic particles and the target powder are separated and directionally fed, avoiding mixing of the two materials and ensuring the cleanliness and purity of the molding cavity.

[0037] In this embodiment, the steps of filling plastic granules into the inner cavity 31 and filling target powder into the mold cavity 32 may include: filling plastic granules into the inner cavity 31 through the first feed port 421; filling plastic granules into the second mold cavity 322 through the third feed port; filling target powder into the first mold cavity 321 through the second feed port 422, and applying mechanical vibration to the target powder during the filling process; after the target powder is filled, removing the mold core positioning part 4, and compacting the plastic granules and target powder. Applying mechanical vibration to the target powder during the filling process effectively promotes powder flow and rearrangement, making it more densely and uniformly filled in the first mold cavity 321; the subsequent compaction process further removes air between the powder particles, increasing the initial bulk density of the powder; therefore, the two work together to significantly improve the uniformity and density of the powder filling, reducing initial density differences and defects from the source, making the density increase more uniform during subsequent cold isostatic pressing, thereby obtaining a high-density preform.

[0038] In this embodiment, the plastic particles are selected from thermoplastic polymer particles, and the thermoplastic polymer particles, after being held for 24 hours at a compression rate of 25% and a temperature of 23±2℃, exhibit a compression set of less than 30%. The use of thermoplastic polymer particles with low compression set in this embodiment allows for elastic deformation during cold isostatic pressing, ensuring uniform stress on the target powder and synchronous shrinkage with it, effectively improving the density uniformity and shape accuracy of the preform. After pressure release, thanks to its excellent elastic recovery capability, the mold core quickly rebounds and can be easily separated from the preform, achieving non-destructive demolding. Furthermore, it can be reused, reducing production costs.

[0039] In this embodiment, the thermoplastic polymer particles are selected from thermoplastic polyamide elastomer particles or thermoplastic vulcanized rubber particles. These thermoplastic polymer particles have low compression set and can undergo elastic deformation during cold isostatic pressing, resulting in uniform stress on the target powder and synchronous shrinkage with the target powder, effectively improving the density uniformity and shape accuracy of the preform. After pressure release, thanks to their excellent elastic recovery ability, the mold core quickly rebounds and can be easily separated from the preform, achieving non-destructive demolding. It can also be reused, reducing production costs.

[0040] In the embodiments, the particle size of the plastic particles is 0.1~1000μm, preferably 10~500μm. Plastic particles in this particle size range can serve as an effective pressure transmission medium, producing uniform deformation characteristics similar to fluids when under pressure, ensuring uniform pressure distribution and guaranteeing the surface quality of the blank.

[0041] In this embodiment, the target powder is selected from metal target powder or ceramic target powder. The metal target powder is selected from one or more metal powders from Groups IIIB, IVB, VB, VIB, VIIB, VIII, IB, IIB, IIIA, IV, and VA of the periodic table; for example, tungsten powder, niobium powder, molybdenum powder, zirconium powder, ytterbium powder, titanium powder, aluminum powder, nickel-chromium powder, tungsten-titanium powder, tungsten-carbon powder, aluminum-titanium powder, silicon-aluminum powder, molybdenum-niobium powder, etc. Ceramic target powder includes one or more compound powders formed by the combination of a metallic element and any one of the non-metallic elements selected from oxygen, nitrogen, carbon, sulfur, selenium, tellurium, and silicon. The metallic element is selected from any one of the metal elements in Groups IIIB, IVB, VB, VIB, VIIB, VIII, IB, IIB, IIIA, IV, and VA of the periodic table; for example, alumina powder, zinc oxide powder, titanium oxide powder, niobium oxide powder, titanium nitride powder, chromium carbide powder, cadmium sulfide powder, zinc telluride powder, aluminum silicon powder, indium gallium zinc oxide powder, zinc aluminum oxide powder, indium tin oxide powder, nickel oxide powder, indium zinc oxide powder, zinc tin oxide powder, silicon carbide powder, indium cerium oxide powder, etc.

[0042] In the embodiments, the particle size of the target powder is 45~150μm.

[0043] In the embodiment, the pressure of the cold isostatic pressing process is 100~300MPa.

[0044] The following description is based on specific embodiments.

[0045] Example 1 This embodiment provides a method for forming a tubular target material, including the following steps: (1) Prepare the target molding mold: it includes a polyurethane diaphragm (1 mm thick), a silicone mold sleeve (5 mm thick), a mold core positioning component, two identical polyurethane round plugs, two identical polyurethane plug rings, and two identical metal wire rings. The mold core positioning component consists of a rigid support and a cover plate connected to one end of the rigid support. The rigid support is cylindrical, with its height and outer diameter being the same as the height and inner diameter of the polyurethane diaphragm, respectively. The cover plate is circular, with its diameter being the same as the inner diameter of the silicone mold sleeve. The cover plate has one first inlet communicating with the inner cavity and three equally spaced second inlets communicating with the second mold cavity. The diameter of the first inlet is smaller than that of the rigid support, and the second inlets are circular openings with a diameter of 10 cm. The cover plate also has two handles facing away from the mold cavity for gripping, lifting, and moving the mold core positioning component. The outer diameter of the polyurethane plug is the same as the inner diameter of the polyurethane diaphragm, and the inner and outer diameters of the polyurethane plug ring are the same as the outer diameter of the polyurethane diaphragm and the inner diameter of the silicone mold sleeve, respectively; the thickness of both the polyurethane plug and the polyurethane plug ring is 10cm.

[0046] (2) Assemble the target molding mold: Place the polyurethane diaphragm inside the silicone mold sleeve, so that the inside of the polyurethane diaphragm cylinder forms an inner cavity, and a mold cavity is formed between the polyurethane diaphragm and the mold sleeve; place a polyurethane round plug at the bottom of the inner cavity and a polyurethane plug ring at the bottom of the mold cavity; then put a metal wire ring around the outer periphery of the bottom end of the silicone mold sleeve and lock it to lock the polyurethane round plug and polyurethane plug ring located at the bottom end of the polyurethane diaphragm and the silicone mold sleeve to seal the inner cavity and the mold cavity, thereby preventing material overflow and liquid medium seepage; insert the rigid support of the mold core positioning component into the inner side of the polyurethane diaphragm, so that the outer wall of the rigid support component is in contact with the inner wall of the polyurethane diaphragm, and the side of the cover plate is in contact with the top of the inner wall of the mold sleeve.

[0047] (3) Filler: Thermoplastic polyamide elastomer particles (particle size of 50~500μm) are filled into the inner cavity through the first feed port; then indium gallium zinc oxide powder is filled into the mold cavity through the three second feed ports, and mechanical vibration is applied to the indium gallium zinc oxide powder during the filling process; after the indium gallium zinc oxide powder is filled, the mold core positioning part is removed by holding the handle, and the thermoplastic polyamide elastomer particles in the inner cavity and the indium gallium zinc oxide powder in the mold cavity are compacted.

[0048] (4) Sealing the top: Place another polyurethane round plug at the top of the inner cavity and another polyurethane plug ring at the top of the mold cavity; then put another metal wire ring around the outer periphery of the top of the silicone mold sleeve and lock it to lock the polyurethane round plug and polyurethane plug ring located at the top of the polyurethane diaphragm and the silicone mold sleeve to seal the inner cavity and the mold cavity, thereby preventing material spillage and liquid medium infiltration.

[0049] (5) Molding process: The target molding mold filled with material is placed in a cold isostatic pressing medium and isostatically pressed at a pressure of 200MPa. After pressing, the target molding mold is removed from the liquid medium. Then, the metal wire rings on the top and bottom of the silicone mold sleeve are loosened and removed. The polyurethane plug ring and polyurethane round plug at the top and the polyurethane plug ring and polyurethane round plug at the bottom are removed in sequence. Then, the thermoplastic polyamide elastomer particles are sucked out from the inner cavity. Finally, the polyurethane diaphragm and silicone mold sleeve are peeled off from the side wall of the tubular blank by hand or air gun to obtain the target blank.

[0050] Example 2 This embodiment provides a method for forming a tubular target material, which differs from Embodiment 1 in that: In step (1), the target forming mold does not include a core positioning component; In step (2), the rigid support of the mold core positioning component was not inserted into the inner side of the flexible diaphragm; In step (3), it is not necessary to remove the mold core positioning component.

[0051] Example 3 This embodiment provides a method for forming a tubular target material, including the following steps: (1) Prepare the target molding mold: it includes a polyurethane diaphragm (thickness of 1mm), a first silicone mold sleeve (thickness of 2mm), a second silicone mold sleeve (thickness of 5mm), a mold core positioning component, two identical polyurethane round plugs, two identical first polyurethane plug rings, two identical second polyurethane plug rings, and two identical metal wire rings. The mold core positioning component consists of a rigid support and a cover plate connected to one end of the rigid support. The rigid support is cylindrical, with its height and outer diameter being the same as the height and inner diameter of the polyurethane diaphragm, respectively. The cover plate is circular, with its diameter being the same as the inner diameter of the second silicone mold sleeve. The cover plate has one first inlet communicating with the inner cavity, three evenly distributed second inlets communicating with the first mold cavity, and three evenly distributed third inlets communicating with the second mold cavity. The second inlets are circular openings with a diameter of 10 cm, and the third inlets are circular openings with a diameter of 10 cm. The cover plate also has two handles facing away from the mold cavity for gripping, lifting, and moving the mold core positioning component. The outer diameter of the polyurethane plug is the same as the inner diameter of the polyurethane diaphragm. The inner and outer diameters of the first polyurethane plug ring are the same as the outer diameter of the polyurethane diaphragm and the inner diameter of the first silicone mold, respectively. The inner and outer diameters of the second polyurethane plug ring are the same as the outer diameter of the first silicone mold and the inner diameter of the second silicone mold, respectively. The thickness of the polyurethane plug, the first polyurethane plug ring, and the second polyurethane plug ring is 10cm.

[0052] (2) Assemble the target molding mold: Place the polyurethane diaphragm coaxially inside the second silicone mold sleeve, and place the first silicone mold sleeve coaxially between the polyurethane diaphragm and the second silicone mold sleeve, so that the inside of the polyurethane diaphragm forms an inner cavity, the polyurethane diaphragm and the first silicone mold sleeve form a first mold cavity, and the first silicone mold sleeve and the second silicone mold sleeve form a second mold cavity; then place a polyurethane round plug at the bottom of the inner cavity, place a first polyurethane plug ring at the bottom of the second mold cavity, and place a second polyurethane plug ring at the bottom of the third mold cavity; then put a metal wire ring around the outer periphery of the bottom end of the second silicone mold sleeve and lock it, so as to lock the polyurethane round plug, the first polyurethane plug ring, and the second polyurethane plug ring located at the bottom end of the polyurethane diaphragm, the first silicone mold sleeve, and the second silicone mold sleeve to seal the inner cavity, the first mold cavity, and the second mold cavity, thereby preventing material overflow and liquid medium seepage; insert the rigid support of the mold core positioning component into the inner side of the polyurethane diaphragm, so that the outer wall of the rigid support component is in contact with the inner wall of the polyurethane diaphragm, and the side of the cover plate is in contact with the top of the inner wall of the second silicone mold sleeve.

[0053] (3) Filler: Thermoplastic polyamide elastomer particles (particle size of 50~500μm) are filled into the inner cavity through the first feed port, and thermoplastic polyamide elastomer particles (particle size of 50~500μm) are filled into the second mold cavity through the three third feed ports respectively; then indium gallium zinc oxide powder is filled into the first mold cavity through the three second feed ports respectively, and mechanical vibration is applied to the indium gallium zinc oxide powder during the powder filling process; after the indium gallium zinc oxide powder is filled, the mold core positioning part is removed by holding the handle, and the thermoplastic polyamide elastomer particles in the inner cavity, the indium gallium zinc oxide powder in the first mold cavity, and the thermoplastic polyamide elastomer particles in the second mold cavity are compacted.

[0054] (4) Sealing the top: Place another polyurethane round plug at the top of the inner cavity, place another first polyurethane plug ring at the top of the first mold cavity, and place another second polyurethane plug ring at the top of the second mold cavity; put another metal wire ring around the outer periphery of the top of the second silicone mold sleeve and lock it to lock the polyurethane round plug, first polyurethane plug ring and second polyurethane plug ring located at the top of the polyurethane diaphragm, the first silicone mold sleeve and the second silicone mold sleeve to seal the inner cavity, the first mold cavity and the second mold cavity, thereby preventing material spillage and liquid medium infiltration.

[0055] (5) Molding process: The target molding mold filled with material is placed in a cold isostatic pressing medium and isostatically pressed at a pressure of 200MPa. After pressing, the target molding mold is removed from the liquid medium. Then, the metal wire rings on the top and bottom of the silicone mold sleeve are loosened and removed. The first polyurethane plug ring, the second polyurethane plug ring and the polyurethane round plug at the top are removed in sequence, as are the first polyurethane plug ring, the second polyurethane plug ring and the polyurethane round plug at the bottom. Then, the thermoplastic polyamide elastomer particles are sucked out from the inner cavity. Finally, the first silicone mold sleeve of the polyurethane diaphragm is peeled off from the side wall of the tubular blank by hand or air gun to obtain the target blank.

[0056] Comparative Example 1 This comparative example provides a method for forming a tubular target material, including the following steps: (1) Prepare the target molding mold: it includes a stainless steel rigid mold core, a silicone mold sleeve (thickness of 5mm), two identical polyurethane plug rings, and two identical metal wire rings; The inner and outer diameters of the polyurethane plug ring are the same as the outer diameter of the stainless steel rigid mold core and the inner diameter of the silicone mold sleeve, respectively; the thickness of the polyurethane plug ring is 10cm.

[0057] (2) Assemble the target molding mold: Place the stainless steel rigid mold core inside the silicone mold sleeve to form a mold cavity between the stainless steel rigid mold core and the silicone mold sleeve; place a polyurethane round plug at the bottom of the mold cavity, and then put a metal wire ring around the outer periphery of the bottom end of the silicone mold sleeve and lock it to lock the polyurethane plug ring located at the bottom end of the silicone mold sleeve to seal the mold cavity, thereby preventing material overflow and liquid medium seepage.

[0058] (3) Filler: Indium gallium zinc oxide powder is filled into the mold cavity, and mechanical vibration is applied to the indium gallium zinc oxide powder during the filling process; after the indium gallium zinc oxide powder is filled, it is compacted.

[0059] (4) Sealing the top: Place another polyurethane plug ring on the top of the mold cavity; put another metal wire ring around the outer periphery of the top of the silicone mold sleeve and lock it to lock the polyurethane plug ring located at the top of the silicone mold sleeve to seal the mold cavity, thereby preventing material spillage and liquid medium seepage.

[0060] (5) Molding process: The target molding mold filled with material is placed in a cold isostatic pressing medium and isostatic pressing is performed under a pressure of 200MPa. After pressing, the target molding mold is removed from the liquid medium and demolded to obtain the target blank.

[0061] Relevant performance test analysis: from Figure 8 As can be seen, the target blank prepared in Example 1 has a regular geometry, a smooth surface, and is free of cracks, dents, or deformation. This indicates that the blank is subjected to uniform stress during the molding process and demolds smoothly. This is mainly due to the fact that Example 1 used a plastic mold core constructed from thermoplastic polymer particles. These thermoplastic polymer particles undergo elastic deformation during cold isostatic pressing, allowing the pressure to be uniformly transmitted to the target powder, thereby ensuring the uniformity of the blank density. After depressurization, the thermoplastic polymer particles recover rapidly due to their low compressive strength, thus achieving non-destructive separation of the blank.

[0062] from Figure 9 It can be seen that the sidewall of the target blank prepared in Example 2 has obvious depressions and wrinkles. The main reason is that Example 2 did not use a mold core positioning component, which makes it difficult for the flexible diaphragm 1 and the mold sleeve to maintain coaxiality when filling thermoplastic polymer particles and target powder. The two are prone to relative displacement or local deformation, resulting in uneven thickness of the filled target powder, which causes wrinkles and depressions on the surface of the blank.

[0063] from Figure 10 It can be seen that the target blank prepared in Comparative Example 1 has an irregular geometry, crush marks on the surface, and slight local dents or deformations on the sides. The main reason is that Comparative Example 1 uses a stainless steel rigid mold core. During the cold isostatic pressing process, the rigid mold core does not deform, which may lead to local stress concentration in the target powder, thereby causing defects such as density gradient, dents, and even deformation of the blank.

[0064] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for forming a tubular target material, characterized in that, Includes the following steps: A target forming mold is provided, the target forming mold comprising a cylindrical flexible diaphragm and a mold sleeve; The flexible diaphragm is placed inside the mold sleeve, so that the inside of the flexible diaphragm's cylindrical body forms an inner cavity, and a mold cavity is formed between the flexible diaphragm and the mold sleeve; The bottom of the inner cavity and the mold cavity are sealed. Plastic granules are filled into the inner cavity, and target powder is filled into the mold cavity; The top of the inner cavity and the mold cavity are sealed. The molding die, along with the plastic granules and the target powder contained therein, is subjected to cold isostatic pressing, and the target blank is obtained after demolding.

2. The molding method as described in claim 1, characterized in that, The target forming mold also includes a core positioning component, which includes a cylindrical rigid support and a cover plate connected to one end of the rigid support. After sealing the bottom of the inner cavity and the mold cavity respectively, and before filling the inner cavity with plastic particles and the mold cavity with target powder, the method further includes: inserting the mold core positioning member into the inner side of the flexible diaphragm, so that the outer wall of the rigid support member is in contact with the inner wall of the flexible diaphragm, and the side of the cover plate is in contact with the top of the inner wall of the mold sleeve.

3. The molding method as described in claim 2, characterized in that, The cover plate is provided with a first inlet and at least two second inlets, the first inlet being connected to the inner cavity and the second inlets being connected to the mold cavity; The steps of filling the inner cavity with plastic granules and filling the mold cavity with target powder include: filling the inner cavity with plastic granules through the first feed port; filling the mold cavity with target powder through the second feed port, and mechanically vibrating the target powder during the filling process; after the target powder is filled, removing the mold core positioning part, and compacting the plastic granules and the target powder.

4. The molding method as described in claim 3, characterized in that, The number of the second feed inlets is 2 to 4; And / or, the second feed inlet is a circular opening with a diameter of 5~15cm.

5. The molding method as described in claim 4, characterized in that, The target forming mold further includes two first sealing components, two second sealing components, and two fasteners; the two first sealing components are used to seal both ends of the inner cavity; the two second sealing components are used to seal both ends of the mold cavity; the two fasteners are respectively disposed on the outer periphery of both ends of the mold sleeve, and are used to fasten the two first sealing components, the flexible diaphragm, the two second sealing components, and the mold sleeve; The steps of sealing the bottom of the inner cavity and the mold cavity include: placing a first sealing member at the bottom of the inner cavity and a second sealing member at the bottom of the mold cavity; then fitting a fastener around the outer periphery of the bottom end of the mold sleeve and locking it. The steps of sealing the top of the inner cavity and the mold cavity include: placing another first sealing member on the top of the inner cavity and another second sealing member on the top of the mold cavity; and then fitting another fastener around the outer periphery of the top of the mold sleeve and locking it.

6. The molding method as described in claim 5, characterized in that, The mold includes a first mold and a second mold; the step of placing the flexible diaphragm inside the mold includes: placing the flexible diaphragm coaxially inside the second mold; placing the first mold coaxially between the flexible diaphragm and the second mold, so that a first mold cavity is formed between the flexible diaphragm and the first mold, and a second mold cavity is formed between the first mold and the second mold.

7. The molding method as described in claim 6, characterized in that, The target forming mold further includes two third sealing components; the two second sealing components are respectively used to seal both ends of the first mold cavity; the two third sealing components are respectively used to seal both ends of the second mold cavity; the two fasteners are respectively provided on the outer periphery of both ends of the second mold sleeve, for fastening the two first sealing components, the flexible diaphragm, the two second sealing components, the first mold sleeve, the two third sealing components and the second mold sleeve; The steps of sealing the bottom of the inner cavity and the mold cavity include: placing a first sealing member at the bottom of the inner cavity, placing a second sealing member at the bottom of the first mold cavity, and placing a third sealing member at the bottom of the second mold cavity; then, fitting a fastener onto the outer periphery of the bottom end of the second mold sleeve and locking it. The steps of sealing the top of the inner cavity and the mold cavity include: placing another first sealing member on the top of the inner cavity, placing another second sealing member on the top of the first mold cavity, and placing another third sealing member on the top of the second mold cavity; then fitting another fastener around the outer periphery of the top of the second mold sleeve and locking it.

8. The molding method as described in claim 6, characterized in that, The cover plate is also provided with at least two third feed ports, the first feed port is connected to the inner cavity, the second feed port is connected to the first mold cavity, and the third feed port is connected to the second mold cavity; The steps of filling the inner cavity with plastic granules and filling the mold cavity with target powder include: filling the inner cavity with plastic granules through the first feed port; filling the second mold cavity with plastic granules through the third feed port; filling the first mold cavity with target powder through the second feed port, and mechanically vibrating the target powder during the filling process; after the target powder is filled, removing the mold core positioning part, and compacting the plastic granules and the target powder.

9. The molding method as described in claim 1, characterized in that, The plastic granules are selected from thermoplastic polymer granules, and the thermoplastic polymer granules, after being kept for 24 hours at a compression rate of 25% and a temperature of 23±2℃, have a compression set of less than 30%. And / or, the target powder is selected from metal target powder or ceramic target powder; the metal target powder is selected from one or more metal powders of Group IIIB, IVB, VB, VIB, VIIB, VIII, IB, IIB, IIIA, IV, and VA metals of the periodic table; the ceramic target powder includes one or more compound powders formed by the combination of a metal element and any one of the non-metallic elements of oxygen, nitrogen, carbon, sulfur, selenium, tellurium, and silicon, wherein the metal element is selected from any one of the metal elements of Group IIIB, IVB, VB, VIB, VIIB, VIII, IB, IIB, IIIA, IV, and VA metals of the periodic table.

10. The molding method as described in claim 9, characterized in that, At least one of the following conditions must be met: The thermoplastic polymer particles are selected from thermoplastic polyamide elastomer particles or thermoplastic vulcanized rubber particles; The particle size of the plastic granules is 0.1~1000μm; The particle size of the target material powder is 45~150μm; The thickness of the flexible diaphragm is 0.5~2mm; The flexible diaphragm is made of polyurethane or silicone. The thickness of the mold sleeve is 1.5~6mm; The material of the mold includes polyurethane or silicone; The pressure for the cold isostatic pressing process is 100~300MPa.

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