Stainless steel box suitable for grain boundary diffusion of magnetic material

Abstract

The invention discloses a stainless steel box suitable for magnetic material grain boundary diffusion, which comprises a bottom plate, a frame body and a plurality of reinforcing plates, the frame body is placed on the bottom plate, the surface of the bottom plate protrudes to form a positioning part, the positioning part is inserted into the frame body, the reinforcing plates are distributed outside the frame body in an annular structure, and the reinforcing plates are arranged in the frame body. And a fixing frame for locking and fixing the reinforcing plates on the bottom plate is sleeved outside the plurality of reinforcing plates. The graphite box is simple in structure, and successfully solves the two problems that a traditional graphite box easily absorbs moisture to pollute a magnet and easily deforms at a high temperature by selecting a proper high-temperature-resistant stainless steel material, optimizing the thickness and designing a unique reinforcing structure and a modular assembly mode.

Description

Technical Field

[0001] This invention relates to the field of magnetic material production technology, and more specifically to a stainless steel box suitable for use in magnetic material grain boundary diffusion. Background Technology

[0002] The iron boron grain boundary diffusion process involves uniformly covering and bonding the diffusion source to the magnetic material through methods such as spraying, printing, and magnetron sputtering. The materials are then placed in a box and sintered in a sintering furnace.

[0003] Traditionally, graphite boxes are used to mount products. However, graphite boxes are prone to absorbing moisture. When a graphite box absorbs moisture, the moisture accelerates the oxidation and corrosion of NdFeB magnets in the grain boundary diffusion matrix. The main components of NdFeB magnets are rare earth elements such as neodymium (Nd), praseodymium (Pr), and holmium (Ho), as well as iron (Fe) and boron (B), which are very reactive and readily react with the moisture in the graphite box after absorption, leading to the oxidation of the NdFeB magnets. Similarly, the diffusion sources in grain boundary diffusion are heavy rare earth elements (dysprosium (Dy), terbium (Tb), etc.), which are more reactive and more easily contaminated by water molecules. This can cause the diffusion process to fail to achieve the target performance. Furthermore, it can also cause magnet pulverization and peeling, magnetic performance decay, and blistering and peeling of the electroplated layer. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a stainless steel box suitable for grain boundary diffusion in magnetic materials. The base plate is longer and wider than the frame, which strengthens the overall strength of the stainless steel and can also serve as a lid for the lower box, reducing the need for lids and minimizing the impact of other factors on grain boundary diffusion.

[0005] The present invention is achieved through the following technical solution: a stainless steel box suitable for the diffusion of magnetic material grain boundaries, comprising a base plate, a frame and multiple reinforcing plates, wherein the frame is placed on the base plate, the surface of the base plate protrudes to form a positioning part, the positioning part is inserted into the frame, the reinforcing plates are distributed in a ring structure on the outside of the frame, and a fixing frame is sleeved on the outside of the multiple reinforcing plates to lock and fix the reinforcing plates to the base plate.

[0006] As a preferred technical solution, the end face of the frame away from the bottom plate is provided with multiple connecting grooves, and one end of the reinforcing plate protrudes to form a connecting part. The connecting parts are all inserted into the positioning groove. The surface of the bottom plate is provided with slots opposite the reinforcing plate. The end of the reinforcing plate facing the bottom plate protrudes to form a pressure-bearing part. The pressure-bearing part is provided with a plug, and the plug is inserted into the slot.

[0007] As a preferred technical solution, the fixing frame is set in a frame structure. Multiple fixing parts are protruded on the inner side of the fixing frame. The fixing parts are all placed on the surface of the base plate. The surface of the fixing parts is provided with countersunk holes vertically. The surface of the base plate is provided with screw holes directly opposite the countersunk holes. Bolts are threaded into the countersunk holes and screw holes respectively. The bottom surface of the fixing frame is set to abut against the surface of the pressure part.

[0008] As a preferred technical solution, a groove is formed on the end face of the base plate away from the frame to form a weight reduction groove, and a positioning frame is installed on the outside of the base plate located in the building groove. The length and width of the positioning frame match the length and width of the inner cavity of the frame.

[0009] As a preferred technical solution, the frame and the positioning part are combined to form a storage cavity for placing magnets.

[0010] As a preferred technical solution, both the connecting groove and the connecting part have trapezoidal cross-sections.

[0011] As a preferred technical solution, the inner side of the fixing frame is set to abut against the outer end face of the reinforcing plate.

[0012] As a preferred technical solution, the base plate, reinforcing plate, fixing frame, and frame body are all made of stainless steel.

[0013] As a preferred technical solution, the outer side of the fixing frame is flush with the outer side of the base plate.

[0014] As a preferred technical solution, the upper surface of the connecting part is flush with the open end face of the frame.

[0015] The beneficial effects of this invention are: the base plate is larger and can be directly used as the top cover of the lower box, reducing the number of box covers and the weight of the furnace. The top layer uses a separate cover plate, and the stainless steel box has a metallic luster, no floating powder, and the diffusion source is completely absorbed. In contrast, the graphite box product has floating powder on its surface and the product is black, indicating that the diffusion source has not been completely absorbed. Furthermore, the base plate, frame, reinforcing plate, and fixing frame are all independently detachable, allowing for direct replacement in case of deformation or damage, thus reducing costs. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a bottom view of the present invention; Figure 3 This is a schematic diagram of the structure of the base plate and the fixing frame in this invention; Figure 4 This is a schematic diagram of the structure of the base plate in the invention; Figure 5 This is a schematic diagram of the structure of the fixing frame in this invention.

[0018] The components are as follows: 1. Base plate; 2. Positioning part; 3. Frame; 4. Reinforcing plate; 5. Connecting part; 6. Pressure-bearing part; 7. Fixing frame; 8. Fixing part; 9. Bolt; 10. Weight reduction groove; 11. Positioning frame; 12. Connecting groove; 13. Screw hole; 14. Slot. Detailed Implementation

[0019] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0020] Any feature disclosed in this specification (including any appended claims, abstract, and drawings) may be replaced by other equivalent or similar features, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0021] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, a stainless steel box suitable for magnetic material grain boundary diffusion includes a base plate 1, a frame 3, and multiple reinforcing plates 4. The frame 3 is placed on the base plate 1, and a positioning part 2 is formed by protrusion on the surface of the base plate 1. The positioning part 2 is inserted into the frame 3. The reinforcing plates 4 are distributed in a ring structure on the outside of the frame 3. A fixing frame 7 is provided on the outside of the multiple reinforcing plates 4 to lock and fix the reinforcing plates 4 to the base plate 1.

[0022] In this embodiment, a plurality of connecting grooves 12 are provided on the end face of the frame 3 away from the bottom plate 1. One end of the reinforcing plate 4 protrudes to form a connecting part 5, and the connecting part 5 is inserted into the positioning groove. The surface of the bottom plate 1 is provided with slots 14 opposite to the reinforcing plate 4. The end of the reinforcing plate 4 facing the bottom plate 1 protrudes to form a pressure-bearing part 6. Inserts are installed on the pressure-bearing part 6 and are inserted into the slots 14.

[0023] In this embodiment, the fixing frame 7 is set in a frame structure. Multiple fixing parts 8 are protruding on the inner side of the fixing frame 7. The fixing parts 8 are all placed on the surface of the base plate 1. The surface of the fixing parts 8 is provided with countersunk holes of the fixing parts 8 vertically. The surface of the base plate 1 is provided with screw holes 13 opposite to the countersunk holes. Bolts 9 are threaded into the countersunk holes and screw holes 13. The bottom surface of the fixing frame 7 is in contact with the surface of the pressure part 6. After the bolts are removed, the fixing bracket can be taken out from the outside of the frame. After the fixing bracket is no longer obstructed, each reinforcing plate can be taken out from the frame. After the reinforcing plate is no longer obstructed, the frame can be taken out directly, so that the frame, reinforcing plates, fixing bracket and base plate can be set up independently and can be replaced independently.

[0024] In this embodiment, a weight-reducing groove 10 is formed on the end face of the base plate 1 away from the frame 3. A positioning frame 11 is installed on the outside of the building groove of the base plate 1. The length and width of the positioning frame 11 match the length and width of the inner cavity of the frame 3.

[0025] In this embodiment, the frame 3 and the positioning part 2 are combined to form a storage cavity for placing magnets.

[0026] In this embodiment, the cross-sections of the connecting groove 12 and the connecting part 5 are both trapezoidal, which allows the connecting part and the connecting groove to be horizontally positioned, preventing one end of the reinforcing plate from detaching from the connecting groove.

[0027] In this embodiment, the inner side of the fixing bracket 7 abuts against the outer end face of the reinforcing plate 4, thereby pressing the reinforcing plate inward to ensure the stability of the reinforcing plate installation.

[0028] In this embodiment, the base plate 1, reinforcing plate 4, fixing frame and frame 3 are all made of stainless steel to ensure overall strength.

[0029] In this embodiment, the outer side of the fixing frame 7 is flush with the outer side of the base plate 1; the upper surface of the connecting part 5 is flush with the opening end face of the frame 3. The weight reduction groove 10 and positioning frame 11 on the base plate 1 reduce weight while ensuring strength and facilitate positioning during stacking. The details such as the outer side of the fixing frame 7 being flush with the outer side of the base plate 1 and the upper surface of the connecting part 5 being flush with the opening end face of the frame 3 make the structure compact, neat, and easy to operate and stack.

[0030] When the stainless steel box is in operation, its base plate 1, frame 3, reinforcing plate 4, and fixing frame 7 together form a sturdy and well-sealed support. The neodymium iron boron magnets that have been coated or bonded with diffusion source are neatly placed into the storage cavity formed by the positioning part 2 on the frame 3 and the base plate 1. Multiple stainless steel boxes containing magnets can be stacked. Taking advantage of the fact that the base plate 1 is larger than the frame 3, the base plate 1 of the lower box can also serve as the lid of the upper box, covering the opening of the upper box. The positioning frame on the upper base plate can be inserted into the lower frame, thereby horizontally positioning the stainless steel box. Stacking can reduce the number of individual lids required. The topmost box needs to be sealed with a separate lid.

[0031] The stacked box assembly is fed into a sintering furnace for grain boundary diffusion heat treatment, during which the stainless steel box exhibits its core advantages: Unlike traditional graphite boxes, stainless steel is non-hygroscopic, eliminating the risk of water molecules oxidizing and corroding the active neodymium iron boron matrix and heavy rare earth diffusion sources at high temperatures due to moisture absorption by the box. This fundamentally avoids defects such as magnet powdering, peeling, magnetic performance attenuation, and subsequent blistering and peeling of the electroplated layer.

[0032] To address the prolonged high-temperature environment of approximately 900°C in grain boundary diffusion processes, this invention effectively resists thermal deformation through a multi-layered structural design: 310S stainless steel is used, which has good high-temperature strength and strong oxidation resistance. The thickness of key components such as base plate 1 and frame 3 is optimized to be greater than or equal to 2mm. After repeated verification, this thickness can maintain sufficient structural rigidity at high temperature and basically does not undergo significant deformation.

[0033] By using reinforcing plates 4 arranged in a ring around the outside of the frame 3 and locking them with fixing brackets 7, a reinforcing rib structure similar to a cross or grid is formed. This design greatly enhances the overall resistance to torsion and collapse of the box, ensuring shape stability under long-term use at high temperatures.

[0034] The positioning part 2 on the base plate 1, the connecting part 5 on the reinforcing plate 4, the connecting groove 12 on the frame 3, and the insertion block and slot 14 together form a precise positioning system. Then, the fixing part 8 and bolts 9 on the fixing frame 7 are used to fasten each component to the base plate 1, making the whole box a solid whole.

[0035] After the above-mentioned high-temperature heat treatment, the magnet products placed in the stainless steel box of the present invention have a metallic luster on the surface, no floating powder, and complete absorption of the diffusion source. In contrast, the magnets treated with graphite boxes often have floating powder and blackening on the surface, and the diffusion source is not completely absorbed. After subsequent processing and electroplating, the products produced using stainless steel boxes have a better electroplated appearance.

[0036] In addition, the stainless steel box adopts a modular design, and the base plate 1, frame 3, reinforcing plate 4, and fixing frame 7 can all be disassembled independently. If local deformation or damage occurs after long-term use, the corresponding parts can be directly replaced without discarding the entire box, which significantly reduces the cost of use and maintenance.

[0037] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions conceived without inventive effort should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A stainless steel box suitable for use in magnetic material grain boundary diffusion, characterized in that: It includes a base plate (1), a frame (3) and multiple reinforcing plates (4). The frame (3) is placed on the base plate (1). The surface of the base plate (1) protrudes to form a positioning part (2). The positioning part (2) is inserted into the frame (3). The reinforcing plates (4) are distributed in a ring structure on the outside of the frame (3). The multiple reinforcing plates (4) are fitted with a fixing frame (7) to lock and fix the reinforcing plates (4) to the base plate (1).

2. The stainless steel box suitable for magnetic material grain boundary diffusion according to claim 1, characterized in that: Multiple connecting grooves (12) are provided on the end face of the frame (3) away from the bottom plate (1). One end of the reinforcing plate (4) protrudes to form a connecting part (5). The connecting part (5) is inserted into the positioning groove. The surface of the bottom plate (1) is provided with slots (14) directly opposite the reinforcing plate (4). The end of the reinforcing plate (4) facing the bottom plate (1) protrudes to form a pressure-bearing part (6). Inserts are installed on the pressure-bearing part (6). The inserts are inserted into the slots (14).

3. The stainless steel box suitable for magnetic material grain boundary diffusion according to claim 2, characterized in that: The fixing frame (7) is set in a frame structure. Multiple fixing parts (8) are protruding on the inner side of the fixing frame (7). The fixing parts (8) are all placed on the surface of the base plate (1). The surface of the fixing parts (8) is provided with countersunk holes of the fixing parts (8) vertically. The surface of the base plate (1) is provided with screw holes (13) opposite to the countersunk holes. Bolts (9) are threaded into the countersunk holes and screw holes (13). The bottom surface of the fixing frame (7) is in contact with the surface of the pressure part (6).

4. The stainless steel box suitable for magnetic material grain boundary diffusion according to claim 1, characterized in that: A weight-reducing groove (10) is formed on the end face of the base plate (1) away from the frame (3). A positioning frame (11) is installed on the outside of the base plate (1) located in the building groove. The length and width of the positioning frame (11) match the length and width of the inner cavity of the frame (3).

5. The stainless steel box suitable for magnetic material grain boundary diffusion according to claim 1, characterized in that: The frame (3) and the positioning part (2) are combined to form a storage cavity for placing magnets.

6. The stainless steel box suitable for magnetic material grain boundary diffusion according to claim 2, characterized in that: Both the connecting groove (12) and the connecting part (5) have trapezoidal cross sections.

7. The stainless steel box suitable for magnetic material grain boundary diffusion according to claim 1, characterized in that: The inner side of the fixing bracket (7) is set to abut against the outer end face of the reinforcing plate (4).

8. The stainless steel box suitable for magnetic material grain boundary diffusion according to claim 1, characterized in that: The base plate (1), reinforcing plate (4), fixing frame and frame (3) are all made of stainless steel.

9. The stainless steel box suitable for magnetic material grain boundary diffusion according to claim 1, characterized in that: The outer side of the fixing frame (7) is flush with the outer side of the base plate (1).

10. The stainless steel box suitable for magnetic material grain boundary diffusion according to claim 1, characterized in that: The upper surface of the connecting part (5) is flush with the opening end face of the frame (3).

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