Oxide cathode and sintering device thereof

Abstract

This invention discloses an oxide cathode and its sintering apparatus. The oxide cathode includes a cathode cylinder and a porous sponge layer. The cathode cylinder has two annular stepped surfaces, which are spaced apart from each other along the axial direction of the cathode cylinder. The cathode cylinder also has a sintering region located between the two stepped surfaces. The sponge layer is disposed within the sintering region, with its two ends respectively attached to the two stepped surfaces. Simultaneously, the sponge layer does not protrude from the stepped surfaces radially within the cathode cylinder. This invention can effectively suppress the axial scattering of electrons from the non-emission region of the oxide cathode, reduce interference with high-frequency fields, reduce the bombardment of the magnetron anode end cap by scattered electrons from the non-emission region, effectively solve the oxidation problem of the anode end cap during magnetron use, and improve the overall performance of the magnetron.

Description

[0001] This utility model relates to the field of electronic vacuum device technology, and in particular to an oxide cathode and its sintering apparatus. Background Technology

[0002] Oxide cathodes are among the most widely used thermionic cathodes in vacuum electronic devices. Currently, most columnar nickel sponge oxide cathodes for magnetrons are prepared using a mold dry-sintering method. The mold dry-sintering method typically involves machining the desired nickel sponge layer shape on the inner surface of a mold, then placing it into a cathode cylinder, filling the space between the sintering mold and the cathode cylinder with nickel powder, and then placing it in a hydrogen furnace for low-temperature sintering and shaping. After demolding, it undergoes high-temperature sintering to obtain the desired nickel sponge cathode.

[0003] During use, a brush is typically used to apply emission paste to fill the pores of the sponge layer. Inevitably, the ends of the nickel sponge layer, which serves as the non-emitting surface of the cathode, are also filled with emission material. Under the influence of an axial field, these non-emitting ends, filled with emission material, generate electrons that scatter axially from their self-interacting space, interfering with the high-frequency field and significantly impacting the tube's performance, such as spectrum, power, and efficiency. Furthermore, the electrons scattered from the non-emitting areas bombard the magnetron's anode cap, causing localized high temperatures at the cathode and leading to oxidation of the anode cap, thus shortening its lifespan. Therefore, it is necessary to improve the existing technology to overcome its shortcomings. Utility Model Content

[0004] To address the aforementioned technical problems, this invention provides an oxide cathode and its sintering apparatus, which can effectively suppress electron emission from the non-emission regions at both ends of the oxide cathode, improve product performance, and simultaneously mitigate the oxidation problem of the magnetron anode end cap.

[0005] The technical solution adopted by this utility model to solve its technical problem is: an oxide cathode, comprising: a cathode cylinder and a porous sponge layer, wherein the cathode cylinder is provided with two annular stepped surfaces, the two stepped surfaces are distributed relative to each other in the axial direction of the cathode cylinder, the cathode cylinder is also provided with a sintering region between the two stepped surfaces, the sponge layer is disposed in the sintering region, and the two ends of the sponge layer are respectively attached to the two stepped surfaces, while the sponge layer does not protrude from the stepped surfaces in the radial direction of the cathode cylinder.

[0006] As a further improvement of this utility model, two annular protrusions are provided at intervals on the outer circumferential surface of the cathode cylinder, and the two stepped surfaces are the sides of the two annular protrusions facing each other.

[0007] As a further improvement of this utility model, the cathode cylinder is provided with an annular groove around its outer circumference, and the two stepped surfaces are the two opposite sides of the annular groove along the axial direction of the cathode cylinder.

[0008] As a further improvement of this utility model, the two annular bosses have rounded corners along their outer edges on their back-to-back sides.

[0009] As a further improvement of this utility model, both ends of the cathode cylinder are further improved by the sponge layer being formed by sintering nickel powder in the sintering region.

[0010] As a further improvement of this utility model, the width of the stepped surface along the radial direction of the cathode cylinder is the same as the thickness of the sponge layer.

[0011] This utility model also provides an oxide cathode sintering apparatus, including a sintering mold, the sintering mold being used to sinter and form the oxide cathode as described above.

[0012] As a further improvement of this utility model, the sintering mold includes two symmetrical sintering molds, and a sintering hole for placing the cathode cylinder is provided between the two sintering molds. The inner diameter of the sintering hole is consistent throughout, and the outer diameter of the stepped surface is the same as the inner diameter of the sintering hole. A powder filling port leading to the sintering hole is also provided between the two sintering molds.

[0013] As a further improvement of this utility model, the oxide cathode sintering apparatus further includes a locking frame and fasteners mounted on the locking frame, the sintering mold being housed within the locking frame, and the fasteners being used to lock the sintering mold within the locking frame.

[0014] The beneficial effects of this utility model are as follows: This utility model provides an oxide cathode and its sintering device. By setting two stepped surfaces that are relatively spaced apart on the cathode cylinder, and setting a sponge layer in the sintering area between the two stepped surfaces, with both ends of the sponge layer attached to the stepped surfaces and not protruding radially from the stepped surfaces, the two stepped surfaces completely block the two ends of the non-emissive surface of the sponge layer. During use, it can effectively suppress the axial scattering of electrons from the non-emissive area of ​​the oxide cathode, reduce interference with the high-frequency field, reduce the bombardment of the anode end cap of the magnetron by the scattered electrons from the non-emissive area, effectively solve the problem of anode cover plate oxidation during the use of the magnetron, and improve the overall performance of the magnetron. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments 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.

[0016] Figure 1 This is a perspective view of the oxide cathode of this utility model, in embodiment one;

[0017] Figure 2 This is a cross-sectional view of the oxide cathode of this utility model, in embodiment one;

[0018] Figure 3 This is a cross-sectional view of the oxide cathode of this utility model, in embodiment two.

[0019] Figure 4 This is a perspective view of the oxide cathode sintering apparatus of this utility model;

[0020] Figure 5 This is a cross-sectional view of the oxide cathode sintering apparatus of this utility model.

[0021] Referring to the accompanying drawings, the following explanations are provided:

[0022] 1. Cathode cylinder; 11. Annular boss; 12. Annular groove; 13. Outer flange; 101. Stepped surface; 102. Sintering area; 103. Rounded corner; 2. Sponge layer; 3. Sintering mold; 31. Sintering mold; 311. Sintering hole; 312. Powder filling port; 4. Locking frame; 5. Fastener. Detailed Implementation

[0023] The present application will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0024] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0026] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The illustrations only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0027] Additionally, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that practice can be carried out without these specific details.

[0028] The technical solutions provided by the various embodiments of this application are described below with reference to the accompanying drawings.

[0029] Example 1

[0030] See Figure 1 and Figure 2 This utility model provides an oxide cathode, comprising: a cathode cylinder 1 and a porous sponge layer 2. The outer peripheral surface of the cathode cylinder 1 is provided with two annular stepped surfaces 101, which are distributed relative to each other in the axial direction of the cathode cylinder 1. The cathode cylinder 1 is also provided with a sintering region 102 located between the two stepped surfaces 101. The sponge layer 2 is disposed in the sintering region 102, and the two ends of the sponge layer 2 are respectively attached to the two stepped surfaces 101. At the same time, the sponge layer 2 does not protrude from the stepped surfaces 101 in the radial direction of the cathode cylinder 1.

[0031] This invention provides two stepped surfaces 101 that are spaced apart from each other on the cathode cylinder 1. The sponge layer 2 is disposed in the sintering region 102 between the two stepped surfaces 101, and the two ends of the sponge layer 2 are attached to the stepped surfaces 101 and do not protrude radially from the stepped surfaces 101. The two stepped surfaces 101 completely block the two ends of the non-emissive surface of the sponge layer 2, which can effectively suppress the axial scattering of electrons from the non-emissive region of the oxide cathode during use.

[0032] The oxide cathode provided by this invention can be used in magnetrons. By adopting this oxide cathode structure, on the one hand, interference with high-frequency fields can be reduced, significantly improving the spectral purity, power output stability and efficiency of the magnetron; on the other hand, since the axial scattering of electrons from the non-emission region of the oxide cathode is effectively suppressed, the bombardment of the anode end cap by the scattered electrons from the non-emission region is reduced, which can effectively solve the problem of anode end cap oxidation during the use of the magnetron and improve the overall performance of the magnetron.

[0033] The sponge layer 2 is formed by sintering nickel powder on the sintering region 102, and the emission region of the oxide cathode is the outer circumferential surface of the sponge layer 2.

[0034] Understandably, when using an oxide cathode, the pores of the sponge layer 2 need to be filled with an emissive material. For example, a carbonate suspension can be applied to the sponge layer 2 using a brush to fill the pores.

[0035] like Figure 2 As shown, two annular protrusions 11 are spaced apart on the outer circumferential surface of the cathode cylinder 1, and the two stepped surfaces 101 are the sides of the two annular protrusions 11 facing each other.

[0036] In this embodiment, the cathode cylinder 1 is made of pure nickel. It is a cylindrical shape with open ends and a uniform inner diameter throughout. The two annular protrusions 11 can be integrally machined on the outer circumferential surface of the cathode cylinder 1 by machining. This machining method is simple and easy to implement.

[0037] It is worth mentioning that the two annular protrusions 11 have rounded corners 103 along their outer edges on the sides facing away from each other. The rounded corners 103 can prevent the oxide cathode from sparking at the tip during use.

[0038] Furthermore, both ends of the cathode cylinder 1 are provided with radially protruding flanges 13, which facilitate the connection of the oxide cathode with other components. For example, in a magnetron, the filament of the magnetron is housed inside the cathode cylinder 1, and the magnetron is provided with a shielding cap at each end of the cathode cylinder 1. The cathode cylinder 1 is welded and fixed to the shielding caps through the outer flanges 13.

[0039] Preferably, the width of the stepped surface 101 or the annular boss 11 along the radial direction of the cathode cylinder 1 is the same as the thickness of the sponge layer 2. This precise size matching design helps to better sinter the sponge layer 2 during the production process, ensuring the consistency of the sintering thickness of the sponge layer 2 and the accuracy of its position, thereby improving the manufacturing precision of the oxide cathode.

[0040] Example 2

[0041] The difference between this embodiment and Embodiment 1 is that the form of the stepped surface 101 is different.

[0042] like Figure 3 As shown, in this embodiment, the cathode cylinder 1 no longer has an annular boss 11, but instead has an annular groove 12 directly around its outer circumference. The two stepped surfaces 101 are the two opposite sides of the annular groove 12 along the axial direction of the cathode cylinder 1, while the sintering area 102 is the entire annular groove 12.

[0043] In this embodiment, an annular groove 12 is provided on the outer peripheral surface of the cathode cylinder 1. The two opposite sides of the annular groove 12 along the axial direction of the cathode cylinder 1 serve as two stepped surfaces 101. The two stepped surfaces 101 completely block the two ends of the non-emissive surface of the sponge layer 2. During use, this can effectively suppress the axial scattering of electrons from the non-emissive region of the oxide cathode, reduce interference with the high-frequency field, reduce the bombardment of the anode end cap of the magnetron by the scattered electrons from the non-emissive region, effectively solve the problem of anode cover oxidation during the use of the magnetron, and improve the overall performance of the magnetron.

[0044] It is understood that the thickness of the main body of the cathode cylinder 1 in this embodiment is greater than that of the cathode cylinder 1 in embodiment one, and the annular groove 12 can also be machined on the outer circumferential surface of the cathode cylinder 1.

[0045] Example 3

[0046] This utility model also provides an oxide cathode sintering apparatus, including a sintering mold 3, which is used to sinter and form an oxide cathode as in Example 1 or Example 2.

[0047] The following section will provide a detailed description using the example of sintering to form an oxide cathode, as shown in Example 1.

[0048] See Figure 4 and Figure 5 The sintering mold 3 is a cuboid structure, which includes two symmetrical sintering molds 31. Each of the two sintering molds 31 has a semi-circular groove on one side facing each other. When the two sintering molds 31 are closed, the two semi-circular grooves are joined together to form a sintering hole 311 for positioning the cathode cylinder 1.

[0049] Furthermore, the inner diameter of the sintering hole 311 is uniform throughout, and the outer diameter of the stepped surface 101, or the annular boss 11, is the same as the inner diameter of the sintering hole 311. After the cathode cylinder 1 is placed inside the sintering hole 311, the outer walls of the two annular bosses 11 fit against the inner wall of the sintering hole 311 to achieve radial positioning of the cathode cylinder 1, and at the same time, a powder filling cavity can be formed between the sintering area 102 of the cathode cylinder 1 and the inner wall of the sintering hole 311. A powder filling port 312 leading to the sintering hole 311 is also provided between the two sintering molds 31, and the powder filling port 312 is distributed directly opposite the powder filling cavity.

[0050] Since the cathode cylinder 1 is provided with two annular bosses 11, the two annular bosses 11 are used to cooperate with the inner wall of the sintering hole 311 to achieve radial positioning and form a powder filling cavity. Therefore, the inner diameter of the sintering hole 311 can be set to be consistent throughout (the inner wall of the traditional sintering hole needs to be made with positioning steps), which makes the sintering mold 3 easier to process and more precise, thereby ensuring that the sponge layer 2 is sintered uniformly in the powder filling cavity, improving the sintering quality of the oxide cathode and the consistency of the product.

[0051] It is worth mentioning that after the cathode cylinder 1 is placed in the sintering hole 311, the outer flanges 13 at both ends of the cathode cylinder 1 and the two end faces of the sintering mold 3 can be used to form a stop and limit, so as to achieve axial positioning of the cathode cylinder 1, so that the cathode cylinder 1 can be accurately placed during the sintering process, and the positional stability of the cathode cylinder during the sintering process is guaranteed.

[0052] In addition, the oxide cathode sintering apparatus also includes a locking frame 4 and a fastener 5. The locking frame 4 is U-shaped, and the fastener 5 is installed on one of the side walls of the locking frame 4. The sintering mold 3 is housed in the locking frame 4, and the fastener 5 is used to lock the sintering mold 3 in the locking frame 4.

[0053] In this embodiment, the fastener 5 is specifically a screw.

[0054] The processing steps of the oxide cathode of this utility model are as follows:

[0055] S1, Cathode cylinder 1 is machined;

[0056] S2, with the mold open, the cathode cylinder 1 is placed into the sintering hole 311 of the sintering mold 3, and then the mold is closed;

[0057] S3, place the sintering mold 3 into the locking frame 4, and lock the sintering mold 3 into the locking frame 4 using fasteners 5;

[0058] S4, nickel powder is poured into the powder filling chamber through the powder filling port 312, wherein the nickel powder particle size is 50~60μm;

[0059] S5. Place the oxide cathode sintering device after powder filling into the hydrogen furnace, heat it to 850℃, hold it for 40 minutes, then turn off the power and cool it down. After cooling to room temperature with the furnace, demold it.

[0060] S6. Place the demolded semi-finished product back into the hydrogen furnace, heat it to 1210℃, hold it at that temperature for 60 minutes, and then cool it to room temperature with the furnace to obtain the desired product. Figure 1 The oxide cathode shown.

[0061] Because the sponge layer 2 of the oxide cathode has non-porous annular protrusions 11 at both ends, these protrusions can prevent carbonate from flowing during the application of carbonate suspension with a pen. Even if carbonate adheres to the surface of the annular protrusions 11 during the application, it can be easily wiped off. Therefore, the nickel sponge cathode sintered by this method can effectively suppress the axial scattering of electrons from the non-emitting region of the oxide cathode during use, reduce interference with the high-frequency field, reduce the bombardment of the magnetron anode end cap by scattered electrons from the non-emitting region, effectively solve the problem of anode cover oxidation during magnetron use, and improve the overall performance of the magnetron.

[0062] The same or similar parts between the various embodiments in this specification can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments.

[0063] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An oxide cathode, comprising a cathode cylinder (1) and a porous sponge layer (2), characterized in that: The cathode cylinder (1) is provided with two annular stepped surfaces (101), which are distributed relative to each other in the axial direction of the cathode cylinder (1). The cathode cylinder (1) is also provided with a sintering region (102) between the two stepped surfaces (101). The sponge layer (2) is disposed in the sintering region (102), and the two ends of the sponge layer (2) are respectively attached to the two stepped surfaces (101). At the same time, the sponge layer (2) does not protrude from the stepped surfaces (101) in the radial direction of the cathode cylinder (1).

2. The oxide cathode according to claim 1, characterized in that: Two annular protrusions (11) are spaced apart on the outer circumferential surface of the cathode cylinder (1), and the two stepped surfaces (101) are the sides of the two annular protrusions (11) facing each other.

3. The oxide cathode according to claim 1, characterized in that: The cathode cylinder (1) has an annular groove (12) around its outer circumference, and the two stepped surfaces (101) are the two opposite sides of the annular groove (12) along the axial direction of the cathode cylinder (1).

4. The oxide cathode according to claim 2, characterized in that: The two annular bosses (11) have rounded corners (103) along their outer edges on their opposite sides.

5. The oxide cathode according to claim 1, characterized in that: Both ends of the cathode cylinder (1) are provided with external flanges (13).

6. The oxide cathode according to claim 1, characterized in that: The sponge layer (2) is formed by sintering nickel powder on the sintering region (102).

7. The oxide cathode according to claim 1, characterized in that: The width of the stepped surface (101) along the radial direction of the cathode cylinder (1) is the same as the thickness of the sponge layer (2).

8. An oxide cathode sintering apparatus, characterized in that: Includes a sintering mold (3) for sintering to form an oxide cathode as described in any one of claims 1 to 7.

9. The oxide cathode sintering apparatus according to claim 8, characterized in that: The sintering mold (3) includes two symmetrical sintering molds (31), and a sintering hole (311) for placing the cathode cylinder (1) is provided between the two sintering molds (31). The inner diameter of the sintering hole (311) is consistent throughout, and the outer diameter of the stepped surface (101) is the same as the inner diameter of the sintering hole (311). A powder filling port (312) leading to the sintering hole (311) is also provided between the two sintering molds (31).

10. The oxide cathode sintering apparatus according to claim 9, characterized in that: It also includes a locking frame (4) and fasteners (5) mounted on the locking frame (4), the sintering mold (3) being housed within the locking frame (4), and the fasteners (5) being used to lock the sintering mold (3) within the locking frame (4).

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