A method for casting medical fixed anode X-ray target and its application

Abstract

This invention discloses a casting method for a medical fixed anode X-ray target, comprising the following steps: S1, pretreatment: high-temperature degassing of the graphite pad and graphite crucible, and cleaning of the tungsten sheet and copper rod; S2, installation: mounting the tungsten sheet on the graphite pad, and placing the graphite pad and copper rod into the graphite crucible; S3, casting: placing the graphite crucible into a continuous pushboat furnace for casting, and obtaining the fixed anode X-ray target after casting. This invention combines the tungsten sheet and copper rod through a casting method, and during casting, the graphite crucible gradually enters the high-temperature zone, ensuring effective wetting of copper and tungsten in the high-temperature zone. This results in a fixed anode X-ray target with excellent thermal conductivity, extended service life, and a strong, stable, and non-delaminating bonding surface between the copper and tungsten.

Description

Technical Field

[0001] This invention relates to the field of medical X-ray tube technology, specifically to a casting method for a medical fixed anode X-ray target and its application. Background Technology

[0002] X-ray tubes are used in medicine for diagnosis and treatment, and in industrial technology for non-destructive testing of materials, structural analysis, spectral analysis, and film exposure. Fixed anode X-ray tubes mainly consist of three parts: the anode, the cathode, and the glass shell. The primary function of the anode is to block the high-speed electron stream to generate X-rays, while also radiating or conducting away the heat generated during exposure. Secondly, it absorbs secondary electrons and scattered rays.

[0003] Because X-ray tubes have very low energy efficiency in producing X-rays, a relatively large power must be supplied to the anode. This results in more than 99% of the electron beam power being consumed as anode heat. Fixed anode X-ray targets are subjected to high temperatures and X-ray damage over a long period of time, and a lot of volatile substances will evaporate from the inner wall of the tube. These volatile substances will affect the overall service life of the X-ray tube. Therefore, fixed anode X-ray targets have very high requirements in terms of material selection and manufacturing process.

[0004] Currently, most fixed anode X-ray targets on the market are constructed by welding tungsten sheets and copper. However, welded fixed anode X-ray targets have poor thermal conductivity, resulting in insufficient heat dissipation during operation, leading to severe anode wear and a short service life. Therefore, this paper proposes a casting method for medical fixed anode X-ray targets and its application. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a casting method for a medical fixed anode X-ray target and its application.

[0006] The technical solution of this invention is: a casting method for a medical fixed anode X-ray target, comprising the following steps:

[0007] S1, Preprocessing

[0008] The graphite gasket and graphite crucible are degassed at high temperature, and the tungsten sheet and copper rod are cleaned.

[0009] S2, Installation

[0010] The cleaned tungsten sheet is installed on the graphite pad, and then the graphite pad with the tungsten sheet and the cleaned copper rod are placed into the graphite crucible one after the other.

[0011] S3, casting

[0012] S3-1. Place the graphite crucible at the starting point of the heating zone of the continuous pusher furnace, and then push the graphite crucible once in the heating zone every 90 to 150 minutes to gradually increase the temperature of the graphite crucible.

[0013] S3-2. After pushing 3 to 5 times, the graphite crucible enters the high-temperature zone and stays in the high-temperature zone for 90 to 150 minutes. Then, push the graphite crucible into the starting point of the cooling zone.

[0014] S3-3. Then, every 90 to 150 minutes, push the graphite crucible once in the cooling zone to gradually reduce the temperature of the graphite crucible. After pushing 2 to 4 times, the graphite crucible will move to the end point of the cooling zone.

[0015] S3-4. Remove the graphite crucible to obtain the fixed anode X-ray target.

[0016] Explanation: The above method combines tungsten sheets and copper rods through melting and casting. During melting and casting, the graphite crucible is gradually introduced into the high-temperature zone, ensuring that copper and tungsten can effectively wet each other in the high-temperature zone. This results in a fixed anode X-ray target with excellent thermal conductivity, extended service life, and a strong, stable, and non-delaminating bond between copper and tungsten.

[0017] Furthermore, the high-temperature degassing method involves keeping the graphite gasket and graphite crucible at 1300°C for 2 hours.

[0018] Note: High-temperature degassing can effectively remove excess gas inside the graphite crucible, ensuring the cleanliness of the graphite crucible and graphite gasket surfaces, and preventing defects from appearing inside the fixed anode X-ray target after casting.

[0019] Furthermore, in step S2, the inner diameter of the graphite crucible is 1 to 1.6 mm larger than the outer diameter of the copper rod.

[0020] Note: Limiting the inner diameter of the graphite crucible ensures the size of the gap between the graphite crucible and the copper rod, preventing significant displacement of the copper rod's position.

[0021] Furthermore, the tungsten sheet is made of a 4mm thick pure tungsten plate, and the copper rod is made of high-purity oxygen-free copper with a purity of 99.99%.

[0022] Note: Pure tungsten plates can withstand higher temperatures and prevent target surface deformation. Using high-purity oxygen-free copper ensures that the anode has less outgassing in a vacuum environment, thereby improving the anode's service life.

[0023] Further, in step S3, the temperature at the starting point of the heating zone is 300-480℃; the temperature at the starting point of the cooling zone is 1100-1200℃; the temperature at the ending point of the cooling zone is room temperature; and the temperature in the high-temperature zone is 1250-1350℃.

[0024] Note: Limiting the above temperature ensures that the copper rod can be completely melted into molten copper, and that the molten copper can effectively wet the tungsten sheet, thus ensuring the bonding strength between the copper and tungsten.

[0025] Further, in step S1, after cleaning the tungsten sheet, a surface treatment is performed on the tungsten sheet. The surface treatment method includes the following steps:

[0026] S1-1. Wrap a stainless steel mesh around the surface of the tungsten sheet, then spray a first coating liquid onto the surface of the tungsten sheet wrapped with the stainless steel mesh. The spray volume of the first coating liquid is 20-40 ml / cm². 2 Spraying time is 5-10 seconds, and after spraying, let it stand for 5-8 minutes, then remove the stainless steel mesh.

[0027] S1-2. Apply an electric current to the tungsten sheet. The initial voltage is 5-15V, the current is 1-8A, and the energizing time is 10-15min.

[0028] S1-3. After the energizing treatment is completed, alternately spray the second coating liquid and the first coating liquid onto the tungsten sheet surface 2-4 times. The spray volume of the second coating liquid is 40-50 ml / cm². 2 Spraying time: 5-8 seconds; First spray volume: 30-40 ml / cm² 2 The spraying time is 5-8 seconds; after each type of spray liquid is sprayed, an electrical treatment is performed, and the voltage of each electrical treatment is reduced by 0.5-2V and the current is increased by 0.5-1A compared to the previous one.

[0029] S1-4. After the final power-on process is completed, the surface-treated tungsten sheet is obtained.

[0030] Explanation: The above surface treatment method first uses a stainless steel mesh to shield the first spraying liquid, which then forms a mesh coating under the action of an electric current. Subsequently, the second spraying liquid is used alternately with the first spraying liquid, which forms an interlocking bonding layer under the action of an electric current. This bonding layer improves the bonding between tungsten and copper, making the copper-tungsten bonding surface stronger and improving the heat conduction effect of the tungsten sheet to the copper rod.

[0031] Furthermore, in steps S1-3, the amount of the second spraying liquid sprayed each time is reduced by 3-5 ml / cm compared to the previous spraying. 2 The amount of the first spray liquid applied is reduced by 2-4 ml / cm² compared to the previous application. 2 .

[0032] Explanation: Gradually reducing the amount of the second spray liquid compared to the first spray liquid ensures that the residual second and first spray liquids from the previous spraying can fully form a coating, reducing waste of the second and first spray liquids and improving the quality of the bonding layer.

[0033] Furthermore, the first spraying liquid comprises, by mass percentage: 20-30% nickel sulfate, 10-20% sodium hypophosphite, 8-12% citric acid, 8-15% diacetone acrylamide, 10-15% hexadecyltrimethylammonium bromide, with the remainder being deionized water; the second spraying liquid comprises, by mass percentage: 25-40% copper sulfate, 10-15% potassium sodium tartrate, 6-12% methanol, 8-12% diacetone acrylamide, 2-8% sodium stearate, with the remainder being deionized water.

[0034] Note: The first and second spraying liquids can generate stable coatings under the action of electric current. By using the two spraying liquids alternately, the coatings generated by the two spraying liquids interlock, which improves the strength of the bonding layer.

[0035] Furthermore, the stainless steel mesh is 60-180 mesh.

[0036] Note: Limiting the aperture of the stainless steel mesh ensures the interlocking strength of the connecting layers and prevents insufficient connection strength.

[0037] On the other hand, the present invention provides an application of the above-mentioned casting method, which is used to prepare a fixed anode X-ray target.

[0038] Note: The fixed anode X-ray target prepared by the above casting method has excellent thermal conductivity, the target surface can withstand high temperatures, and the loss is small, thus extending its service life.

[0039] The beneficial effects of this invention are:

[0040] (1) The present invention combines tungsten sheets and copper rods by melting and casting, and gradually introduces the graphite crucible into the high temperature zone during melting and casting, which ensures that copper and tungsten can be effectively wetted in the high temperature zone, resulting in the prepared fixed anode X-ray target with excellent thermal conductivity, extended service life, and the bonding surface between copper and tungsten is firm, stable and not easy to delaminate.

[0041] (2) The surface treatment method of the present invention first uses a stainless steel mesh to shield the first spray liquid to generate a mesh coating under the action of an electric current. Then, the second spray liquid is used alternately with the first spray liquid to generate a mutually interlocking connecting layer under the action of an electric current. The connecting layer improves the bonding between tungsten and copper, makes the bonding surface between copper and tungsten more solid, and improves the heat conduction effect of tungsten sheet to copper rod. Detailed Implementation

[0042] The present invention will now be described in more detail with reference to specific embodiments, so as to better demonstrate the advantages of the present invention.

[0043] Example 1

[0044] A method for casting a medical fixed anode X-ray target includes the following steps:

[0045] S1, Preprocessing

[0046] The graphite gasket and graphite crucible are degassed at high temperature, and the tungsten sheet and copper rod are cleaned. The high-temperature degassed method is to keep the graphite gasket and graphite crucible at 1300℃ for 120 minutes.

[0047] S2, Installation

[0048] The cleaned tungsten sheet is installed on a graphite pad, and then the graphite pad with the tungsten sheet and the cleaned copper rod are placed into a graphite crucible one after the other. The inner diameter of the graphite crucible is 1.2 mm larger than the outer diameter of the copper rod. The tungsten sheet is made of 4 mm thick pure tungsten plate, and the copper rod is made of high-purity oxygen-free copper with a purity of 99.99%.

[0049] S3, casting

[0050] S3-1. Place the graphite crucible at the starting point of the heating zone of the continuous pusher furnace, and then push the graphite crucible once in the heating zone every 120 minutes. After each push, the temperature of the graphite crucible increases by 235℃.

[0051] S3-2. After pushing 4 times, the graphite crucible enters the high-temperature zone and stays in the high-temperature zone for 120 minutes. Then, push the graphite crucible into the starting point of the cooling zone.

[0052] S3-3. Then, every 120 minutes, the graphite crucible is pushed once in the cooling zone. After each push, the temperature of the graphite crucible decreases by 375℃. After pushing 3 times, the graphite crucible moves to the end point of the cooling zone.

[0053] S3-4. Remove the graphite crucible to obtain the fixed anode X-ray target;

[0054] The temperature at the starting point of the heating zone is 360℃; the temperature at the starting point of the cooling zone is 1150℃, and the temperature at the ending point of the cooling zone is room temperature; the temperature in the high-temperature zone is 1300℃.

[0055] The above-mentioned casting method is applied to the preparation of fixed anode X-ray targets.

[0056] Example 2

[0057] This embodiment is basically the same as Embodiment 1, except that in step S1, after the tungsten sheet is cleaned, a surface treatment is performed on the tungsten sheet. The surface treatment method includes the following steps:

[0058] S1-1. Wrap a stainless steel mesh around the surface of the tungsten sheet, then spray a first coating liquid onto the surface of the tungsten sheet wrapped with the stainless steel mesh. The spray volume of the first coating liquid is 35 ml / cm². 2 The spraying time is 8 seconds, and after spraying, the stainless steel mesh is left to stand for 6 minutes before being removed.

[0059] S1-2. The tungsten sheet is energized. The initial energizing voltage is 12V, the current is 2A, and the energizing time is 12min.

[0060] S1-3. After the energizing process is completed, the second coating liquid and the first coating liquid are sprayed alternately three times onto the surface of the tungsten sheet. The spraying volume of the second coating liquid is 45 ml / cm³. 2 Spraying time: 6 seconds; First spray volume: 35 ml / cm³ 2 The spraying time is 6 seconds; after each type of spray liquid is sprayed, an electric current treatment is performed, and the voltage of each electric current treatment is reduced by 1V and the current is increased by 0.75A compared to the previous one.

[0061] S1-4. After the final power-on process is completed, the surface-treated tungsten sheet is obtained.

[0062] In steps S1-3, the amount of the second spraying liquid sprayed each time is reduced by 4 ml / cm compared to the previous spraying. 2 The amount of the first spray liquid applied was reduced by 3 ml / cm² compared to the previous application. 2 ;

[0063] The first spraying liquid comprises, by mass percentage: 25% nickel sulfate, 15% sodium hypophosphite, 10% citric acid, 12% diacetone acrylamide, 12% hexadecyltrimethylammonium bromide, with the remainder being deionized water; the second spraying liquid comprises, by mass percentage: 30% copper sulfate, 12% potassium sodium tartrate, 10% methanol, 10% diacetone acrylamide, 6% sodium stearate, with the remainder being deionized water; the stainless steel mesh is 100 mesh;

[0064] Example 3

[0065] This embodiment is basically the same as Embodiment 1, except that the high-temperature degassing method is as follows: the graphite gasket and the graphite crucible are kept at 1200°C for 100 minutes.

[0066] Example 4

[0067] This embodiment is basically the same as Embodiment 1, except that the high-temperature degassing method is as follows: the graphite gasket and the graphite crucible are kept at 1400°C for 140 minutes.

[0068] Example 5

[0069] This embodiment is basically the same as Embodiment 1, except that...

[0070] S3-1. Place the graphite crucible at the starting point of the heating zone of the continuous pusher furnace, and then push the graphite crucible once in the heating zone every 90 minutes. After each push, the temperature of the graphite crucible increases by 315℃.

[0071] S3-2. After pushing 3 times, the graphite crucible enters the high-temperature zone and stays in the high-temperature zone for 90 minutes. Then, push the graphite crucible into the starting point of the cooling zone.

[0072] S3-3. Then, every 90 minutes, the graphite crucible is pushed once in the cooling zone. After each push, the temperature of the graphite crucible decreases by 535℃. After pushing twice, the graphite crucible moves to the end point of the cooling zone.

[0073] The temperature at the starting point of the heating zone is 300℃; the temperature at the starting point of the cooling zone is 1100℃; and the temperature in the high-temperature zone is 1250℃.

[0074] Example 6

[0075] This embodiment is basically the same as Embodiment 1, except that...

[0076] S3-1. Place the graphite crucible at the starting point of the heating zone of the continuous pusher furnace, and then push the graphite crucible once in the heating zone every 150 minutes. After each push, the temperature of the graphite crucible increases by 174℃.

[0077] S3-2. After pushing 5 times, the graphite crucible enters the high-temperature zone and stays in the high-temperature zone for 150 minutes. Then, push the graphite crucible into the starting point of the cooling zone.

[0078] S3-3. Then, every 150 minutes, the graphite crucible is pushed once in the cooling zone. After each push, the temperature of the graphite crucible decreases by 294℃. After 4 pushes, the graphite crucible moves to the end of the cooling zone.

[0079] The temperature at the starting point of the heating zone is 480℃; the temperature at the starting point of the cooling zone is 1200℃; and the temperature in the high-temperature zone is 1350℃.

[0080] Example 7

[0081] This embodiment is basically the same as Embodiment 2, except that the spraying volume of the first spraying liquid is 20 ml / cm². 2 The spraying time is 5 seconds, and after spraying, let it stand for 5 minutes before removing the stainless steel mesh.

[0082] Example 8

[0083] This embodiment is basically the same as Embodiment 2, except that the spraying volume of the first spraying liquid is 40 ml / cm². 2 The spraying time is 5 seconds, and after spraying, let it stand for 5 minutes before removing the stainless steel mesh.

[0084] Example 9

[0085] This embodiment is basically the same as embodiment 2, except that the voltage of the first power-on process is 10V, the current is 1A, the power-on time is 10min, and the voltage of each power-on process is reduced by 0.5V and the current is increased by 0.5A compared to the previous one.

[0086] Example 10

[0087] This embodiment is basically the same as embodiment 2, except that the voltage of the first power-on process is 15V, the current is 3A, the power-on time is 15min, and the voltage of each power-on process is 2V lower and the current is 1A higher than the previous one.

[0088] Example 11

[0089] This embodiment is basically the same as Embodiment 2, except that the second spraying liquid and the first spraying liquid are sprayed alternately twice onto the tungsten sheet surface, and the spraying volume of the second spraying liquid is 40 ml / cm². 2 Spraying time: 5 seconds; First spray volume: 30 ml / cm³ 2 Spraying time: 5 seconds.

[0090] Example 12

[0091] This embodiment is basically the same as Embodiment 2, except that the second spraying liquid and the first spraying liquid are alternately sprayed four times onto the tungsten sheet surface, and the spraying volume of the second spraying liquid is 50 ml / cm². 2 Spraying time: 8 seconds; First spray volume: 40 ml / cm³ 2 Spraying time: 8 seconds.

[0092] Example 13

[0093] This embodiment is basically the same as Embodiment 2, except that the amount of the second spray liquid sprayed each time is reduced by 3 ml / cm compared to the previous time. 2 The amount of the first spray liquid applied was reduced by 2 ml / cm² compared to the previous application. 2 .

[0094] Example 14

[0095] This embodiment is basically the same as Embodiment 2, except that the amount of the second spray liquid sprayed each time is reduced by 5 ml / cm compared to the previous time. 2 The amount of the first coat of liquid sprayed each time was reduced by 4 ml / cm compared to the previous spray. 2 .

[0096] Example 15

[0097] This embodiment is basically the same as Embodiment 2, except that the components of the first spraying liquid, by mass percentage, include: 20% nickel sulfate, 10% sodium hypophosphite, 8% citric acid, 8% diacetone acrylamide, 10% hexadecyltrimethylammonium bromide, and the remainder is deionized water; the components of the second spraying liquid, by mass percentage, include: 25% copper sulfate, 10% potassium sodium tartrate, 6% methanol, 8% diacetone acrylamide, 2% sodium stearate, and the remainder is deionized water.

[0098] Example 16

[0099] This embodiment is basically the same as Embodiment 2, except that the components of the first spraying liquid, by mass percentage, include: 30% nickel sulfate, 20% sodium hypophosphite, 12% citric acid, 15% diacetone acrylamide, 15% hexadecyltrimethylammonium bromide, and the remainder is deionized water; the components of the second spraying liquid, by mass percentage, include: 40% copper sulfate, 15% potassium sodium tartrate, 12% methanol, 12% diacetone acrylamide, 8% sodium stearate, and the remainder is deionized water.

[0100] Experimental Example

[0101] To investigate the influence of various preparation parameters on the performance of fixed anode X-ray targets, the performance of fixed anode X-ray targets prepared in each example was tested, and the specific investigation is as follows:

[0102] 1. Investigating the effects of high-temperature degassing parameters on the performance of a fixed anode X-ray target.

[0103] Using Examples 1, 3, and 4 as experimental comparisons, the performance of the fixed anode X-ray target under different high-temperature degassing parameters is shown in Table 1 below:

[0104] Table 1 Performance of fixed anode X-ray targets under different high-temperature degassing parameters

[0105] Group Tensile strength (MPa) Thermal conductivity (W / m·K) Example 1 368 255 Example 3 354 248 Example 4 370 259

[0106] As shown in Table 1, compared with Example 3, Example 1 has higher tensile strength and thermal conductivity, indicating that the fixed anode X-ray target of Example 1 has better strength and thermal conductivity, and the high-temperature degassing parameters selected in Example 1 are better. Compared with Example 4, although Example 4 has higher tensile strength and thermal conductivity, the improvement is not significant. Considering the time cost, the high-temperature degassing parameters selected in Example 1 are better.

[0107] 2. Investigate the influence of casting parameters on the performance of a fixed anode X-ray target.

[0108] Using Examples 1, 5, and 6 as comparative experiments, and with Example 1 as a reference, a graphite crucible was directly placed at 1300℃ for 16 hours as Comparative Example 1. The performance of the fixed anode X-ray target under different casting parameters is shown in Table 2 below:

[0109] Table 2 Performance of fixed anode X-ray targets under different casting parameters

[0110] Group Tensile strength (MPa) Thermal conductivity (W / m·K) Example 1 368 255 Example 5 342 237 Example 6 349 241 Comparative Example 1 330 226

[0111] As shown in Table 2, compared with Examples 1, 5, and 6, Example 1 has the highest tensile strength and thermal conductivity, indicating that the fixed anode X-ray target of Example 1 has the best strength and thermal conductivity, and the casting parameters selected in Example 1 are optimal. Compared with Comparative Example 1, Example 1 has higher tensile strength and thermal conductivity, indicating that the fixed anode X-ray target of Example 1 has better strength and thermal conductivity, and the casting method selected in Example 1 is superior.

[0112] 3. Investigate the effect of surface treatment on the performance of fixed anode X-ray targets.

[0113] Using Examples 1 and 2 as experimental comparisons, the effects of surface treatment on the performance of the fixed anode X-ray target are shown in Table 3 below:

[0114] Table 3. Effects of surface treatment on the performance of fixed anode X-ray targets

[0115] Group Tensile strength (MPa) Thermal conductivity (W / m·K) Example 1 368 255 Example 2 473 311

[0116] As shown in Table 3, the tensile strength and thermal conductivity of Example 2 are higher, indicating that the fixed anode X-ray target of Example 2 has better strength and thermal conductivity. Surface treatment can effectively improve the strength and thermal conductivity of the fixed anode X-ray target.

[0117] 4. Investigate the effect of the initial spraying parameters of the first coating liquid on the performance of the fixed anode X-ray target.

[0118] Using Examples 2, 7, and 8 as experimental comparisons, the performance of the fixed anode X-ray target under different initial spraying parameters of the first spraying liquid is shown in Table 4 below:

[0119] Table 4 Performance of the fixed anode X-ray target under different initial spraying parameters of the first spraying liquid.

[0120]

[0121]

[0122] As shown in Table 4, the tensile strength and thermal conductivity of Example 2 are the highest, indicating that the fixed anode X-ray target of Example 2 has the best strength and thermal conductivity, and the initial spraying parameters of the first spraying liquid selected in Example 2 are optimal.

[0123] 5. Investigate the effects of energizing parameters on the performance of a fixed anode X-ray target.

[0124] Using Examples 2, 9, and 10 as experimental comparisons, and with Example 2 as a reference, the voltage and current of the energizing treatment remained unchanged as Comparative Example 2. The performance of the fixed anode X-ray target under different energizing treatment parameters is shown in Table 5 below:

[0125] Table 5 Performance of fixed anode X-ray targets under different energizing parameters

[0126] Group Tensile strength (MPa) Thermal conductivity (W / m·K) Example 2 473 311 Example 9 455 292 Example 10 458 296 Comparative Example 2 423 270

[0127] As shown in Table 5, compared with Examples 2, 9, and 10, Example 2 has the highest tensile strength and thermal conductivity, indicating that the fixed anode X-ray target of Example 2 has the best strength and thermal conductivity, and the selected energizing treatment parameters of Example 2 are optimal. Compared with Comparative Example 2, Example 2 has higher tensile strength and thermal conductivity, indicating that the fixed anode X-ray target of Example 2 has better strength and thermal conductivity, and the selected energizing treatment method of Example 2 is superior.

[0128] 6. Investigate the effects of alternating parameters of the second and first spraying solutions on the performance of a fixed anode X-ray target.

[0129] Using Examples 2, 11, and 12 as comparative experiments, and with Example 2 as a reference, Comparative Example 3 used only the first spraying liquid, and Comparative Example 4 used only the second spraying liquid. The performance of the fixed anode X-ray target under different alternation parameters of the second and first spraying liquids is shown in Table 6 below:

[0130] Table 6. Performance of the fixed anode X-ray target under different alternating parameters of the second and first spraying liquids.

[0131] Group Tensile strength (MPa) Thermal conductivity (W / m·K) Example 2 473 311 Example 11 466 305 Example 12 459 292 Comparative Example 3 431 279 Comparative Example 4 425 274

[0132] As shown in Table 6, compared with Examples 2, 11, and 12, Example 2 has the highest tensile strength and thermal conductivity, indicating that the fixed anode X-ray target of Example 2 has the best strength and thermal conductivity, and the alternation parameters of the second and first spraying liquids selected in Example 2 are optimal. Compared with Comparative Examples 3 and 4, the tensile strength and thermal conductivity of Comparative Examples 3 and 4 are significantly reduced, indicating that the method of alternating the use of the second and first spraying liquids is better than using only the first or second spraying liquid.

[0133] 7. Investigate the effect of the difference in the amount of the second spraying liquid compared to the first spraying liquid on the performance of the fixed anode X-ray target.

[0134] Using Examples 2, 13, and 14 as comparative experiments, and with Example 2 as a reference, Comparative Example 5 was prepared by keeping the spraying amount of the second spraying liquid the same as that of the first spraying liquid. The performance of the fixed anode X-ray target under different spraying amounts of the second and first spraying liquids is shown in Table 7 below:

[0135] Table 7 Performance of the fixed anode X-ray target under different coating variations of the second and first spraying liquids

[0136]

[0137]

[0138] As shown in Table 7, compared with Examples 2, 13, and 14, Example 2 has the highest tensile strength and thermal conductivity, indicating that the fixed anode X-ray target of Example 2 has the best strength and thermal conductivity, and the variation of the second and first spraying liquids selected in Example 2 is optimal. Compared with Comparative Example 5, Example 2 has higher tensile strength and thermal conductivity, indicating that the fixed anode X-ray target of Example 2 has better strength and thermal conductivity, and the spraying method of the second and first spraying liquids selected in Example 2 is superior.

[0139] 8. Investigate the influence of the composition of the first and second spraying solutions on the performance of the fixed anode X-ray target.

[0140] Using Examples 2, 15, and 16 as comparative experiments, the performance of the fixed anode X-ray target under different compositions of the first and second spraying liquids is shown in Table 8 below:

[0141] Table 8 Performance of fixed anode X-ray targets with different compositions of the first and second spraying solutions.

[0142] Group Tensile strength (MPa) Thermal conductivity (W / m·K) Example 2 473 311 Example 15 461 300 Example 16 456 292

[0143] As shown in Table 8, compared with Examples 2, 15, and 16, Example 2 has the highest tensile strength and thermal conductivity, indicating that the fixed anode X-ray target of Example 2 has the best strength and thermal conductivity, and the first and second spray liquids selected in Example 2 have the optimal composition.

Claims

1. A casting method for a medical fixed anode X-ray target, characterized in that, Includes the following steps: S1, Preprocessing The graphite gasket and graphite crucible are degassed at high temperature, and the tungsten sheet and copper rod are cleaned. S2, Installation The cleaned tungsten sheet is installed on the graphite pad, and then the graphite pad with the tungsten sheet and the cleaned copper rod are placed into the graphite crucible one after the other. S3, casting S3-1. Place the graphite crucible at the starting point of the heating zone of the continuous pusher furnace, and then push the graphite crucible once in the heating zone every 90 to 150 minutes to gradually increase the temperature of the graphite crucible. S3-2. After pushing 3 to 5 times, the graphite crucible enters the high-temperature zone and stays in the high-temperature zone for 90 to 150 minutes. Then, push the graphite crucible into the starting point of the cooling zone. S3-3. Then, every 90 to 150 minutes, push the graphite crucible once in the cooling zone to gradually reduce the temperature of the graphite crucible. After pushing 2 to 4 times, the graphite crucible will move to the end point of the cooling zone. S3-4. Remove the graphite crucible to obtain the fixed anode X-ray target.

2. The casting method for a medical fixed anode X-ray target according to claim 1, characterized in that, In step S1, the high-temperature degassing method is as follows: the graphite gasket and the graphite crucible are kept at 1200-1400℃ for 100-140 minutes.

3. The casting method for a medical fixed anode X-ray target according to claim 1, characterized in that, In step S2, the inner diameter of the graphite crucible is 1 to 1.6 mm larger than the outer diameter of the copper rod.

4. The casting method for a medical fixed anode X-ray target according to claim 1, characterized in that, In step S2, the tungsten sheet is made of a 4mm thick pure tungsten plate, and the copper rod is made of high-purity oxygen-free copper with a purity of 99.99%.

5. The casting method for a medical fixed anode X-ray target according to claim 1, characterized in that, In step S3, the temperature at the starting point of the heating zone is 300-480℃; the temperature at the starting point of the cooling zone is 1100-1200℃; the temperature at the ending point of the cooling zone is room temperature; and the temperature in the high-temperature zone is 1250-1350℃.

6. The casting method for a medical fixed anode X-ray target according to claim 1, characterized in that, In step S1, after cleaning the tungsten sheet, a surface treatment is performed on the tungsten sheet. The surface treatment method includes the following steps: S1-1, wrapping the surface of the tungsten sheet with a stainless steel mesh, then spraying a first spraying liquid onto the surface of the tungsten sheet wrapped with the stainless steel mesh, the spraying amount of the first spraying liquid being 20-40 ml / cm 2 , the spraying time being 5-10 s, and after the spraying is completed, standing for 5-8 min, then taking off the stainless steel mesh; S1-2. Apply an electric current to the tungsten sheet. The initial voltage is 5-15V, the current is 1-8A, and the energizing time is 10-15min. S1-3. After the energizing treatment is completed, alternately spray the second coating liquid and the first coating liquid onto the tungsten sheet surface 2-4 times. The spray volume of the second coating liquid is 40-50 ml / cm². 2 Spraying time: 5-8 seconds; First spray volume: 30-40 ml / cm² 2 The spraying time is 5-8 seconds; after each type of spray liquid is sprayed, an electrical treatment is performed, and the voltage of each electrical treatment is reduced by 0.5-2V and the current is increased by 0.5-1A compared to the previous one. S1-4. After the final power-on process is completed, the surface-treated tungsten sheet is obtained.

7. The casting method for a medical fixed anode X-ray target according to claim 6, characterized in that, In steps S1-3, the amount of the second spray liquid sprayed each time is reduced by 3-5 ml / cm compared to the previous spray. 2 The amount of the first spray liquid applied is reduced by 2-4 ml / cm² compared to the previous application. 2 .

8. The casting method for a medical fixed anode X-ray target according to claim 6, characterized in that, The first spraying liquid comprises, by mass percentage: 20-30% nickel sulfate, 10-20% sodium hypophosphite, 8-12% citric acid, 8-15% diacetone acrylamide, 10-15% hexadecyltrimethylammonium bromide, with the remainder being deionized water; the second spraying liquid comprises, by mass percentage: 25-40% copper sulfate, 10-15% potassium sodium tartrate, 6-12% methanol, 8-12% diacetone acrylamide, 2-8% sodium stearate, with the remainder being deionized water.

9. The casting method for a medical fixed anode X-ray target according to claim 6, characterized in that, The stainless steel mesh is 60-180 mesh.

10. The application of the casting method for a medical fixed anode X-ray target according to any one of claims 1 to 9, characterized in that, The casting method described above is used to prepare fixed anode X-ray targets.

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