A mold and method for making a gradient metal porous element

Abstract

The embodiment of the application provides a mold and a method for preparing a gradient metal porous element. The mold is tubular, comprising an outer mold assembly, an inner mold assembly, a metal wire mesh tube, a first rubber plug and a second rubber plug. The metal wire mesh tube has a first gap with the inner mold assembly and a second gap with the outer mold assembly. The first gap and the second gap for loading metal powder of different particle sizes are obtained by arranging the metal wire mesh tube in the mold. After loading the metal powder of different particle sizes, respectively, a blank of the gradient metal porous structure is obtained by one-time pressing, and then the blank is sintered into the gradient metal porous element. The preparation process is simplified, the metal wire mesh tube in the gradient metal porous element improves the bonding strength between the two layers of metal powder, and the use strength is ensured to be high. In addition, since the preparation process is only one-time pressing, the degree of deformation of the metal powder is small, the production efficiency is improved, and the air permeability and the filtering precision of the gradient metal porous element are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of filter elements, and particularly relates to a mold and a method for preparing a gradient metal porous element. BACKGROUND

[0002] Gradient porous materials are porous materials with gradient changes in porous properties, i.e., pore size and porosity. With the rapid development of industry, porous filtration and separation products with higher requirements such as high precision, high permeability and high strength are gradually proposed. However, there is a positive contradiction between high precision and high permeability in homogeneous porous materials, i.e., the improvement of precision often leads to a great loss of air permeability of the porous material, and the improvement of permeability also requires a certain compromise in precision requirements.

[0003] Gradient porous materials can realize the simultaneous increase of high precision and high permeability due to the gradient changes and designability of the porous structure, and have a wide application prospect in the development of gradient high-precision, high-permeability and high-strength porous materials in the fields of filtration and separation and other fields.

[0004] In the prior art, the gradient porous structure is prepared by multiple compression molding, which is a complex process and leads to low batch processing efficiency. In addition, multiple compression molding causes deformation of the powder, resulting in poor filtration precision and low bonding strength between powder layers, which is prone to cracking. SUMMARY

[0005] The embodiments of the application provide a mold and a method for preparing a gradient metal porous element to solve the problems of low processing efficiency and easy cracking in the prior art.

[0006] The embodiments of the application provide a mold for preparing a gradient metal porous element, characterized in that the mold is tubular and comprises an outer mold assembly arranged outside the mold, an inner mold assembly arranged inside the outer mold assembly, a metal wire mesh tube, a first rubber plug and a second rubber plug.

[0007] The metal wire mesh tube is located between the outer mold assembly and the inner mold assembly and has a first gap with the inner mold assembly and a second gap with the outer mold assembly; the first gap is used for loading first metal powder, and the second gap is used for loading second metal powder; the particle sizes of the first metal powder and the second metal powder are different.

[0008] The first rubber plug is located at the first end of the mold; the first end of the mold comprises the first end of the inner mold assembly, the first end of the outer mold assembly and the first end of the wire mesh tube; the inner surface of the first rubber plug is tightly fitted with the outer surface of the first end of the inner mold assembly, and the inner surface and the outer surface of the first end of the outer mold assembly and the inner surface and the outer surface of the first end of the wire mesh tube are tightly fitted with the first end of the outer mold assembly, the first end of the inner mold assembly and the first end of the wire mesh tube;

[0009] The second rubber plug is located at the second end of the mold; the second end of the mold comprises the second end of the inner mold assembly, the second end of the outer mold assembly and the second end of the wire mesh tube; the inner surface of the second rubber plug is tightly fitted with the outer surface of the second end of the inner mold assembly, and the inner surface and the outer surface of the second end of the outer mold assembly and the inner surface and the outer surface of the second end of the wire mesh tube are tightly fitted with the second end of the outer mold assembly, the first end of the inner mold assembly and the second end of the wire mesh tube.

[0010] Optionally, the outer mold assembly comprises a tightly fitted first metal pipe and a first rubber sleeve, and the first metal pipe is located outside the first rubber sleeve.

[0011] The inner mold assembly comprises a tightly fitted second metal pipe and a second rubber sleeve, and the second rubber sleeve is located outside the second metal pipe.

[0012] The end surface of the first metal pipe is flush with the end surface of the first rubber sleeve; the end surface of the second metal pipe is flush with the end surface of the second rubber sleeve.

[0013] Optionally, the first metal pipe and the second metal pipe are uniformly distributed with through holes in the radial direction.

[0014] Optionally, the first rubber plug is an outer diameter variable diameter tubular structure, comprising a small diameter end and a large diameter end.

[0015] The end surface of the small diameter end is flush with the end surface of the inner mold assembly; the end surface of the large diameter end is provided with a groove for positioning the outer mold assembly, the inner mold assembly and the wire mesh tube.

[0016] Optionally, it further comprises a first metal buckle and a second metal buckle.

[0017] The first metal buckle is used for fixing the small diameter end and the inner mold assembly.

[0018] The second metal buckle is used for fixing the large diameter end and the outer mold assembly.

[0019] The application further provides a preparation method of the gradient metal porous element, which is prepared by using the mold.

[0020] obtaining the inner mold assembly and the outer mold assembly of the mold, the metal wire mesh tube, the first rubber plug and the second rubber plug;

[0021] sleeving the first end of the inner mold assembly in the first rubber plug, and tightly fitting the outer surface of the inner mold assembly with the inner surface of the first rubber plug;

[0022] sleeving the metal wire mesh tube outside the inner mold assembly, and embedding the first end of the metal wire mesh tube in the first rubber plug, so that a first gap exists between the outer surface of the inner mold assembly and the metal wire mesh tube;

[0023] sleeving the outer mold assembly outside the metal wire mesh tube, and embedding the first end of the outer mold assembly in the first rubber plug, so that a second gap exists between the inner surface of the outer mold assembly and the metal wire mesh tube;

[0024] filling the first metal powder into the first gap, and filling the second metal powder into the second gap; the particle sizes of the first metal powder and the second metal powder are different;

[0025] sleeving the second end of the inner mold assembly in the second rubber plug, and embedding the second end of the outer mold assembly and the second end of the metal wire mesh tube in the second rubber plug, so as to seal the first gap and the second gap, and obtain a sealed mold;

[0026] placing the sealed mold into a cold isostatic pressing machine for pressing, so as to shape the first metal powder, the metal wire mesh tube and the second metal powder, and obtain a blank element;

[0027] after sequentially disassembling the second rubber plug, the outer mold assembly and the first rubber plug, taking out the blank element;

[0028] sintering the blank element, and obtaining a gradient metal porous element.

[0029] Optionally, the sintering of the blank element to obtain the gradient metal porous element specifically comprises:

[0030] placing the blank element into a high-temperature-resistant material boat, and filling high-temperature-resistant particles on the outer surface of the blank element;

[0031] sintering the blank element in a sintering atmosphere of vacuum or inert gas or hydrogen and a sintering temperature of 1100-1400 DEG C for 2-4 hours, and obtaining the gradient metal porous element after cooling.

[0032] Optionally, the filling of the second metal powder into the second gap comprises:

[0033] After fixing the first end of the mold and tilting the second end of the mold by the first angle, the second metal powder is filled into the second gap while using a vibrating platform to vibrate and compact.

[0034] Optionally, the placing of the sealed mold into a cold isostatic press for pressing comprises:

[0035] The sealed mold is placed into a cold isostatic press, and the pressure range of the cold isostatic press is set to 100-200 Mpa.

[0036] The mold is pressed in the pressure range of 100-200 Mpa.

[0037] Optionally, the mold further comprises a first metal buckle and a second metal buckle, and the structure of the first rubber plug component comprises a small-diameter end and a large-diameter end; after the second end of the outer mold assembly and the second end of the metal wire mesh tube are embedded into the second rubber plug, the method further comprises:

[0038] The first metal buckle is used to fix the small-diameter end and the inner mold assembly.

[0039] The second metal buckle is used to fix the large-diameter end and the outer mold assembly.

[0040] The embodiments of the present application have at least the following beneficial effects:

[0041] The embodiment of the present application provides a mold and a method for preparing a gradient metal porous element, the mold is tubular, comprising an outer mold component arranged outside the mold, an inner mold component arranged inside the outer mold component, a metal wire mesh tube, a first rubber plug and a second rubber plug; the metal wire mesh tube is located between the outer mold component and the inner mold component, and a first gap exists between the metal wire mesh tube and the inner mold component, and a second gap exists between the metal wire mesh tube and the outer mold component; the first gap is used for filling first metal powder, and the second gap is used for filling second metal powder; the particle sizes of the first metal powder and the second metal powder are different; the first rubber plug is located at a first end of the mold; the first end of the mold comprises a first end of the inner mold component, a first end of the outer mold component and a first end of the metal wire mesh tube; the inner surface of the first rubber plug is tightly attached to the outer surface of the first end of the inner mold component, the inner surface and the outer surface of the first end of the outer mold component and the inner surface and the outer surface of the first end of the metal wire mesh tube are tightly attached, and the first end of the outer mold component, the first end of the inner mold component and the first end of the metal wire mesh tube are fixed; the second rubber plug is located at a second end of the mold; the second end of the mold comprises a second end of the inner mold component, a second end of the outer mold component and a second end of the metal wire mesh tube; the inner surface of the second rubber plug is tightly attached to the outer surface of the second end of the inner mold component, the inner surface and the outer surface of the second end of the outer mold component and the inner surface and the outer surface of the second end of the metal wire mesh tube are tightly attached, and the second end of the outer mold component, the first end of the inner mold component and the second end of the metal wire mesh tube are fixed. According to the present application, the metal wire mesh tube is arranged in the mold, the first gap and the second gap for filling metal powder with different particle sizes are obtained, the metal porous structure with gradient is obtained by filling metal powder with different particle sizes and pressing once, and then the metal porous element with gradient is obtained by sintering the metal porous structure with gradient. The process for preparing the metal porous element with gradient is simple, the metal wire mesh tube in the metal porous element with gradient improves the bonding strength between the two layers of metal powder, and the use strength is high. In addition, since the process for preparing the metal porous element with gradient is only pressed once, the deformation degree of the metal powder is small, the actual production batch preparation efficiency is improved, and the air permeability and the filtering precision of the metal porous element with gradient are improved. BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only show some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor.

[0043] Figure 1A mold for preparing a gradient metal porous element provided by the embodiment of the present application is shown in the schematic diagram.

[0044] Figure 2 A first rubber plug profile structure schematic diagram provided by the embodiment of the present application is shown in the schematic diagram.

[0045] Figure 3 A preparation method flow chart of a gradient metal porous element provided by the embodiment of the present application is shown in the schematic diagram.

[0046] Figure 4 An axial profile structure schematic diagram of a blank element provided by the embodiment of the present application is shown in the schematic diagram.

[0047] Figure 5 A radial cross-section schematic diagram of a gradient metal porous element provided by the embodiment of the present application is shown in the schematic diagram.

[0048] Reference signs:

[0049] 1-first metal tube; 2-first rubber sleeve; 3-support layer; 4-precision control layer; 5-metal wire mesh tube; 6-second rubber sleeve; 7-second metal tube; 8-first rubber plug; 9-second rubber plug; 10-first metal buckle; 11-second metal buckle; 12-through hole; 801-large diameter end; 802-small diameter end; 803-first groove; 804-second groove. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0051] Figure 1 A mold for preparing a gradient metal porous element provided by the embodiment of the present application is shown in the schematic diagram.

[0052] As shown in the schematic diagram, the mold is tubular, comprising an outer mold component arranged outside the mold, an inner mold component arranged inside the outer mold component, a metal wire mesh tube 5, a first rubber plug 8 and a second rubber plug 9. Figure 1 The metal wire mesh tube 5 is located between the outer mold component and the inner mold component, and there is a first gap between the metal wire mesh tube 5 and the inner mold component, and a second gap between the metal wire mesh tube 5 and the outer mold component; the first gap is used for filling first metal powder, and the second gap is used for filling second metal powder; the particle sizes of the first metal powder and the second metal powder are different.

[0053]

[0054] ​Specifically, the mold is a center-through tubular structure, mainly composed of an outer mold assembly, an inner mold assembly, a wire mesh tube 5, a first rubber plug 8 and a second rubber plug 9.

[0055] The outer mold assembly is sleeve-shaped and is arranged outside the mold to support the mold from outside and keep the stability of the overall structure of the mold outside.

[0056] The wire mesh tube 5 is coaxially sleeved between the outer mold assembly and the inner mold assembly. There is a first gap between the wire mesh tube 5 and the inner mold assembly, and a second gap between the wire mesh tube 5 and the outer mold assembly. Both the first gap and the second gap are used to fill metal powder. By filling metal powder of different particle sizes in the first gap and the second gap, the preparation of the gradient metal porous element is realized. In the embodiment of the present application, the first metal powder filled in the first gap has larger particles than the second metal powder filled in the second gap. The first metal powder filled in the first gap serves as the support layer 3, and the second metal powder filled in the second gap serves as the precision control layer 4. The wire mesh tube 5 serves as a separation layer for the support layer 3 and the precision control layer 4. The wire mesh tube 5 used is a stainless steel mesh sheet which is cut, rolled, straight-seam spot welded and spot-welded smooth. Other embodiments can also use a wire mesh tube 5 of other materials as a separation layer.

[0057] The first rubber plug is located at the first end of the mold; the first end of the mold includes the first end of the inner mold assembly, the first end of the outer mold assembly and the first end of the wire mesh tube; the inner surface of the first rubber plug is tightly fitted with the outer surface of the first end of the inner mold assembly, and the inner surface and the outer surface of the first end of the outer mold assembly and the inner surface and the outer surface of the first end of the wire mesh tube are tightly fitted with the first end of the outer mold assembly, the first end of the inner mold assembly and the first end of the wire mesh tube;

[0058] The second rubber plug is located at the second end of the mold; the second end of the mold includes the second end of the inner mold assembly, the second end of the outer mold assembly and the second end of the wire mesh tube; the inner surface of the second rubber plug is tightly fitted with the outer surface of the second end of the inner mold assembly, and the inner surface and the outer surface of the second end of the outer mold assembly and the inner surface and the outer surface of the second end of the wire mesh tube are tightly fitted with the second end of the outer mold assembly, the first end of the inner mold assembly and the second end of the wire mesh tube.

[0059] Specifically, as Figure 1As shown, the two ends of the mold are respectively provided with a first rubber plug 8 and a second rubber plug 9. Mainly used for fixing the two ends of the mold, ensuring the stability of each component of the mold, preventing any component of the outer mold assembly, the inner mold assembly and the metal wire mesh tube 5 from being displaced, avoiding the deformation of the prepared blank during the pressing process after the first gap and the second gap are filled with metal powder, and affecting the filtration precision. During the fixing process, the inner surface of the first rubber plug 8 is tightly attached to the outer surface of the first end of the inner mold assembly, preventing the displacement of the inner mold assembly. The first end of the outer mold assembly and the first end of the metal wire mesh tube 5 are embedded into the solid structure of the first rubber plug 8, thereby being fixed by the first rubber plug 8. Similarly, the second rubber plug 9 is provided at the second end of the mold. During the fixing process, the inner surface of the second rubber plug 9 is tightly attached to the outer surface of the first end of the inner mold assembly, preventing the displacement of the inner mold assembly. The second end of the outer mold assembly and the second end of the metal wire mesh tube 5 are embedded into the solid structure of the second rubber plug 9, thereby being fixed by the second rubber plug 9. Under the combined limiting and fixing of the first rubber plug 8 and the second rubber plug 9, the outer mold assembly, the inner mold assembly and the metal wire mesh tube 5 are coaxial and are simultaneously fixed.

[0060] The mold filled with metal powder of different particle sizes can be directly placed in a cold isostatic pressing machine for pressing to obtain a porous blank, and then the blank is sintered to obtain a gradient metal porous element. Using this mold to prepare a gradient metal porous element only needs to be pressed once, the powder is not easy to deform, and the preparation process is simple, which improves the filtration precision and the efficiency of preparing a gradient metal porous element.

[0061] In summary, the mold and the method for preparing the gradient metal porous element provided by the embodiment of the application are tubular, and the mold comprises an outer mold assembly arranged outside the mold, an inner mold assembly arranged inside the outer mold assembly, a metal wire mesh tube, a first rubber plug and a second rubber plug. The metal wire mesh tube is located between the outer mold assembly and the inner mold assembly, and a first gap exists between the metal wire mesh tube and the inner mold assembly, and a second gap exists between the metal wire mesh tube and the outer mold assembly. The first gap is used for filling the first metal powder, and the second gap is used for filling the second metal powder. The particle sizes of the first metal powder and the second metal powder are different. The first rubber plug is located at a first end of the mold. The first end of the mold comprises a first end of the inner mold assembly, a first end of the outer mold assembly and a first end of the metal wire mesh tube. The inner surface of the first rubber plug is tightly fitted with the outer surface of the first end of the inner mold assembly, and the inner surface and the outer surface of the first end of the outer mold assembly and the inner surface and the outer surface of the first end of the metal wire mesh tube are tightly fitted with each other, so as to fix the first end of the outer mold assembly, the first end of the inner mold assembly and the first end of the metal wire mesh tube. The second rubber plug is located at a second end of the mold. The second end of the mold comprises a second end of the inner mold assembly, a second end of the outer mold assembly and a second end of the metal wire mesh tube. The inner surface of the second rubber plug is tightly fitted with the outer surface of the second end of the inner mold assembly, and the inner surface and the outer surface of the second end of the outer mold assembly and the inner surface and the outer surface of the second end of the metal wire mesh tube are tightly fitted with each other, so as to fix the second end of the outer mold assembly, the first end of the inner mold assembly and the second end of the metal wire mesh tube. In this scheme, the metal wire mesh tube is arranged in the mold, the first gap and the second gap for filling the metal powder with different particle sizes are obtained, the metal powder with different particle sizes is filled respectively, and then a blank of the gradient metal porous structure can be obtained by one-time pressing. Then, the blank is sintered into the gradient metal porous element. The process for preparing the gradient metal porous element is simplified, the bonding strength between the two layers of powder is improved, and the use strength is ensured to be high. In addition, since the metal powder is pressed only once in the preparation process, the degree of deformation of the metal powder is small, the actual production batch preparation efficiency is improved, and the air permeability and the filtration precision of the gradient metal porous element are improved.

[0062] In a possible implementation, the outer mold assembly comprises a first metal pipe and a first rubber sleeve which are tightly fitted, and the first metal pipe is located outside the first rubber sleeve.

[0063] The inner mold assembly comprises a second metal pipe and a second rubber sleeve which are tightly fitted, and the second rubber sleeve is located outside the second metal pipe.

[0064] The end surface of the first metal pipe is flush with the end surface of the first rubber sleeve, and the end surface of the second metal pipe is flush with the end surface of the second rubber sleeve.

[0065] Specifically, as shown in Figure 1 The outer mold assembly is composed of a first metal tube 1 and a first rubber sleeve 2 which are sleeved together and closely fitted. The first rubber sleeve 2 is also tubular, the first rubber sleeve 2 is sleeved on the inside of the first metal tube 1, and the outer surface of the first rubber sleeve 2 is fitted with the first metal tube 1. The inner surface of the first rubber sleeve 2 is opposite to the outer surface of the metal wire mesh tube 5, and the gap between the inner surface of the first rubber sleeve 2 and the outer surface of the metal wire mesh tube 5 is the second gap.

[0066] The inner mold assembly is composed of a second metal tube 7 and a second rubber sleeve 6 which are sleeved together and closely fitted. The second rubber sleeve 6 is also tubular, and the second rubber sleeve 6 is sleeved on the outside of the second metal tube 7, and the inner surface of the second rubber sleeve 6 is closely fitted with the outer surface of the second metal tube 7. The outer surface of the second rubber sleeve 6 is opposite to the inner surface of the metal wire mesh tube 5, and the gap between the outer surface of the second rubber sleeve 6 and the inner surface of the metal wire mesh tube 5 is the first gap.

[0067] The end faces of the first metal tube 1 and the first rubber sleeve 2 in the outer mold assembly are flush, and the end faces of the second metal tube 7 and the second rubber sleeve 6 in the inner mold assembly are flush. During the assembly of the mold, it can be prevented that the first metal tube 1 and the first rubber sleeve 2, and the second metal tube 7 and the second rubber sleeve 6 are not fitted, which may cause the surface of the blank element prepared subsequently to be uneven, affecting the filtration precision.

[0068] In a possible implementation, the first metal tube and the second metal tube are uniformly provided with through holes in the radial direction of the tube body.

[0069] Specifically, the mold filled with metal powder is to be put into a cold isostatic pressing machine for pressing. The cold isostatic pressing machine process is to place the object to be processed in a special mold, and then put the mold containing the workpiece into a sealed container filled with liquid, gradually pressurize through a pressurizing system, and transmit the pressure through the liquid, so that each surface of the object is subjected to equal pressure.

[0070] The through holes 12 provided on the first metal tube 1 and the second metal tube 7 in the radial direction of the tube body are to make the liquid pressure transmitted to the first rubber sleeve 2 and the second rubber sleeve 6 through the through holes 12 of the mold, and the pressure is transmitted to the first metal powder, the metal wire mesh tube 5 and the second metal powder through the deformation of the first rubber sleeve 2 and the second rubber sleeve 6, and the pipe-shaped gradient metal porous element blank is formed under the stress. In addition, the through holes 12 provided on the first metal tube 1 and the second metal tube 7 are to realize simultaneous pressing inside and outside the mold, so that the metal wire mesh tube 5 is uniformly stressed and not deformed during the pressing process. In the embodiment of the present application, the uniformly distributed through holes 12 on the first metal tube 1 and the second metal tube 7 are through holes 12 with a uniform diameter of 8 mm and a spacing of 50 mm. In other embodiments, other sizes of through holes 12 can also be used.

[0071] In a possible implementation, the first rubber plug is a variable-diameter tubular structure including a small-diameter end and a large-diameter end.

[0072] The end face of the small-diameter end is flush with the end face of the inner mold assembly; the end face of the large-diameter end is provided with a groove for positioning the outer mold assembly, the inner mold assembly, and the wire mesh tube.

[0073] Figure 2 A first rubber plug 8 cross-sectional view provided by an embodiment of the present application.

[0074] The variable diameter of the outer diameter refers to the diameter of the outer surface of the first rubber plug 8 is not uniform. As shown, according to the diameter of the outer surface of the first rubber plug 8, the first rubber plug 8 is divided into a large-diameter end 801 and a small-diameter end 802. The end face of the small-diameter end 802 is flush with the end face of the inner mold assembly, which is used to protect the inner mold assembly and prevent the end face of the metal pipe of the inner mold assembly from protruding and causing deformation due to bumps during use. Figure 2

[0075] The end face of the large-diameter end 801 is larger than the end face of the small-diameter end 802, and the large-diameter end 801 is designed with two annular grooves. The two annular grooves of the large-diameter end 801 of the first rubber plug 8 include a first groove 803 and a second groove 804. The first groove 803 is close to the inner surface of the first rubber plug 8 and is used to fix the first end of the wire mesh tube 5, and the second groove 804 is close to the outer surface of the large-diameter end 801 of the first rubber plug 8 and is used to fix the first end of the outer mold assembly.

[0076] The structure and function of the second rubber plug 9 are the same as those of the first rubber plug 8. The large-diameter end 801 of the second rubber plug 9 includes two annular grooves, which are used to limit the second end of the outer mold assembly and the second end of the wire mesh tube 5. The two annular grooves of the first rubber plug 8 are coaxial with the annular grooves of the second rubber plug 9, which together realize the limitation of the outer mold assembly and the wire mesh tube 5 and ensure that the outer mold assembly, the wire mesh tube 5, and the outer mold assembly are coaxial. It should be noted that in the embodiment of the present application, the end face of the small-diameter end 802 of the second rubber plug 9 is not flush with the end face of the inner mold assembly, and the axial distance is 20 mm. This is mainly to facilitate the distinction between the two ends of the mold and facilitate the distinction between the two ends of the mold. In other embodiments, the small-diameter ends 802 of the first rubber plug 8 and the second rubber plug 9 can be flush with the first end of the inner mold assembly and the second end of the inner mold assembly, respectively.

[0077] In a possible implementation, it further includes a first metal buckle and a second metal buckle;

[0078] The first metal buckle is used to fix the small-diameter end and the inner mold assembly;

[0079] The second metal buckle is used to fix the large-diameter end and the outer mold assembly.​

[0080] Specifically, as shown in Figure 1 the large diameter end 801 and the small diameter end 802 of the first rubber plug 8 and the second rubber plug 9 are also provided with buckles. The first metal buckle 10 is arranged at the small diameter end 802, tightly buckling the small diameter end 802 with the first end of the inner mold assembly, preventing displacement and misplacement. The second metal buckle 11 is arranged at the large diameter end 801, on the one hand fixing the first end of the outer mold assembly, and on the other hand fixing the large diameter end 801, ensuring that the first end of the wire mesh tube 5 cannot move.

[0081] Figure 3 is a flow chart of a preparation method of a gradient metal porous element provided by an embodiment of the present application.

[0082] As shown in Figure 3 , the preparation method of the gradient metal porous element comprises the following steps:

[0083] Step 101, obtaining the inner mold assembly and the outer mold assembly of the mold, the metal wire mesh tube, the first rubber plug and the second rubber plug.

[0084] Specifically, prepare each component of the assembled mold, including the outer mold assembly, the metal wire mesh tube 5, the first rubber plug 8 and the second rubber plug 9. Assemble the outer mold assembly, tightly fit the first rubber sleeve 2 to the inside of the first metal pipe 1, and make the end faces of the first rubber sleeve 2 and the first metal pipe 1 flush. Assemble the inner mold assembly, and tightly fit the second rubber sleeve 6 to the outer surface of the second metal pipe 7, and make the end faces of the second rubber sleeve 6 and the second metal pipe 7 flush.

[0085] Step 102, the first end of the inner mold assembly is sleeved in the first rubber plug, and the outer surface of the inner mold assembly is tightly combined with the inner surface of the first rubber plug.

[0086] Specifically, start assembling the mold, first sleeve the first end of the inner mold assembly in the first rubber plug 8, and tightly combine the inner surface of the first rubber plug 8 with the outer surface of the inner mold assembly, i.e. the outer surface of the second rubber sleeve 6.

[0087] Step 103, the metal wire mesh tube is sleeved outside the inner mold assembly, and the first end of the metal wire mesh tube is embedded in the first rubber plug, so that there is a first gap between the outer surface of the inner mold assembly and the metal wire mesh tube.

[0088] Specifically, after the first end of the inner mold assembly is sleeved on the first rubber plug 8, the first end of the wire mesh tube 5 is embedded into the groove closest to the inner mold assembly in the large-diameter end 801 of the first rubber plug 8. The groove closest to the inner mold assembly in the large-diameter end 801 of the first rubber plug 8 is spaced apart from the outer surface of the inner mold assembly, and the spacing forms a first gap between the outer surface of the inner mold assembly and the wire mesh tube 5. The wire mesh tube 5 is coaxial with the inner mold assembly. In the embodiment of the present application, the wire mesh tube 5 is made of stainless steel S31603 or S30408 by cutting, rolling, straight seam spot welding, and polishing the welding points to be smooth. The wire mesh tube 5 has a plain or diagonal square mesh pattern with a specification of 60-100 mesh and a wire diameter of 0.2-0.8 mm.

[0089] Step 104, the outer mold assembly is sleeved outside the wire mesh tube, and the first end of the outer mold assembly is embedded into the first rubber plug, so that a second gap exists between the inner surface of the outer mold assembly and the wire mesh tube.

[0090] Specifically, the outer mold assembly is sleeved outside the wire mesh tube 5, and the inner surface of the outer mold assembly is opposite to the outer surface of the wire mesh tube. The first end of the outer mold assembly is embedded into the groove at the outermost part of the large-diameter end 801 of the first rubber plug 8. The groove at the outermost part of the large-diameter end 801 of the first rubber plug 8 is spaced apart from the groove at the innermost part, so that a second gap is formed between the inner surface of the outer mold assembly and the outer surface of the wire mesh tube 5.

[0091] Step 105, the first metal powder is filled into the first gap, and the second metal powder is filled into the second gap; the particle sizes of the first metal powder and the second metal powder are different.

[0092] Specifically, the first metal powder is filled into the first gap, and the second metal powder is filled into the second gap. The larger the mesh number corresponding to the particle size, the smaller the powder particles, that is, the larger the mesh number, the finer the particles, and the smaller the mesh number, the coarser the particles. According to the filtering precision requirements of the metal porous element to be prepared, if the second gap serves as the precision control layer 4 and the first gap serves as the support layer 3, the particle size of the second metal powder filled into the second gap is smaller than the particle size of the first metal powder. If the first gap serves as the precision control layer 4 and the second gap serves as the support layer 3, the particle size of the second metal powder filled into the second gap is larger than the particle size of the first metal powder in the first gap.

[0093] In the embodiment of the present application, the first metal powder and the second metal powder are respectively a mixture of one or two of non-spherical titanium and titanium alloy, stainless steel S31603 or S30408, and Monel alloy powder, and the particle size is 40-500 mesh. According to the precision control requirements of the metal porous element, the required metal powder is screened, graded and mixed to obtain the required particle size interval metal powder. The first gap is used as the support layer 3, and the second gap is used as the precision control layer 4. The particle size of the metal powder in the support layer 3 is 40-100 mesh coarse powder, and the particle size of the metal powder in the precision control layer 4 is 100-500 mesh fine powder. According to the precision requirements of the filter element, the use interval of the coarse and fine powder can be accurately controlled. When filling the metal powder, the coarse powder is first filled into the support layer 3 in a certain amount, and then the fine powder is filled into the precision control layer 4. It should be noted that when the first metal powder and the second metal powder are filled in the first gap and the second gap, a small amount of coarse powder can be first filled into the support layer 3, then a small amount of fine powder is filled into the precision control layer, then a small amount of coarse powder is continuously filled into the support layer 3, and then a small amount of fine powder is filled into the precision control layer 4. By repeatedly filling, it can be avoided that too much coarse powder is filled in the support layer at one time, which causes the metal wire mesh tube to be deformed due to excessive pressure.

[0094] Step 106, the second end of the inner mold assembly is sleeved in the second rubber plug, and the second end of the metal wire mesh tube is embedded in the second rubber plug to seal the first gap and the second gap, thereby obtaining a sealed mold.

[0095] Specifically, after the first gap and the second gap are filled with metal powder, the second end of the inner mold assembly is sleeved in the second rubber plug 9, so that the outer surface of the inner mold assembly tightly fits the inner surface of the second rubber plug 9. The second end of the metal wire mesh tube 5 is embedded in the groove near the inner surface of the large diameter end 801 of the second rubber plug 9, and the second end of the outer mold assembly is embedded in the groove near the outer surface of the large diameter end 801 of the second rubber plug 9. The groove positions of the first rubber plug 8 and the second rubber plug 9 are the same, and after the first rubber plug 8 and the second rubber plug 9 are installed, the coaxiality and the position of the outer mold assembly, the metal wire mesh tube 5 and the inner mold assembly are ensured. In addition, after the second rubber plug 9 is installed, the sealing of the first gap and the second gap is also realized, and then the metal buckle is used to tighten the first rubber plug 8 and the second rubber plug 9, thereby obtaining a sealed mold.

[0096] In addition, the metal wire mesh tube 5 is filled with metal powders of different levels of fineness at the space at the two ends of the metal wire mesh tube 5 in the radial direction and the first gap and the second gap, respectively, and the metal wire mesh tube 5 serves as an intermediate interface to develop a gradient structure of the porous filter element. The mold is tubular, and the inner and outer parts are simultaneously stressed during the pressing process, so that the metal wire mesh tube 5 is uniformly stressed and does not deform during the pressing process. The metal wire mesh tube 5 serves as an intermediate separation layer of coarse and fine powders to achieve accurate positioning of the support layer 3 and the precision control layer 4, and a porous element with higher air permeability and filtering precision can be prepared by adjusting the powder loading, powder particle size, and space ratio at the support layer 3 and the precision control layer 4.

[0097] Step 107: The sealed mold is placed in a cold isostatic pressing machine for pressing, so that the first metal powder, the metal wire mesh tube, and the second metal powder are shaped to obtain a blank element.

[0098] Specifically, the sealed mold is placed in a cold isostatic pressing machine, and the first metal powder and the second metal powder in the mold are pressed by liquid pressure, so that the first metal powder, the metal wire mesh tube 5, and the second metal powder are shaped to obtain a blank element. The blank element is tubular.

[0099] Figure 4 An axial cross-sectional structure schematic diagram of a blank element provided by an embodiment of the present application is shown.

[0100] As shown in Figure 4 , the inner surface and the outer surface of the metal wire mesh tube 5 are the support layer 3 and the precision control layer 4, respectively. The coarse powder particles of the support layer 3 and the fine particles of the precision control layer 4 have a certain mechanical interlocking strength at the mesh holes of the metal wire mesh tube 5, and the metal wire mesh tube 5 is also embedded in the coarse and fine powders and combined with them, which has a higher pre-pressing force compared with a simple metal powder filter element.

[0101] Step 108: After the second rubber plug, the outer mold assembly, and the first rubber plug are sequentially disassembled, the blank element is taken out.

[0102] Specifically, after being pressed in the cold isostatic pressing machine, the blank element is taken out of the mold. First, the first metal buckle 10 and the second metal buckle 11 are removed, and then the second rubber plug 9 is removed, so that the first end of the inner mold assembly, the second end of the metal wire mesh tube 5, and the second end of the outer mold assembly are released, and the first rubber plug 8 is loosened. Then, the first end of the outer mold assembly is taken out of the first rubber plug 8, so that the outer mold assembly is disassembled, the blank element is exposed, and the blank element is taken out. The blank element is processed, and the two ends of the blank element are cut flat.

[0103] Step 109: The blank element is sintered to obtain a gradient metal porous element.

[0104] Specifically, the powder particles within the blank element are mechanically interlocked, thus requiring sintering. During sintering, sintering necks are formed between the powder particles, connecting them to form a stable integral structure consisting of the first metal powder, the metal mesh tube 5, and the second metal powder. This stable integral structure is the gradient metal porous element. The gradient metal element consists of a precision control layer 4, a metal mesh tube 5, and a support layer 3.

[0105] Figure 5 This is a schematic diagram of the radial cross-section of a gradient metal porous element provided in an embodiment of the present invention.

[0106] like Figure 5 As shown in this embodiment of the invention, the outermost layer of the gradient metal porous element is a precision control layer 4, with small pores between the powder particles, mainly used to control the filtration precision. The innermost support layer 3 of the gradient metal porous element has larger powder particles. A metal wire mesh tube 5 separates the precision control layer 4 and the support layer 3. Because the coarse powder particles of the support layer 3 and the fine powder particles of the precision control layer 4 have a certain mechanical interlocking strength at the mesh openings of the metal wire mesh tube 5, the pressed blank element has a higher pre-compression force, resulting in a higher bonding strength between the first and second metal powder interfaces after sintering. Furthermore, it is precisely because of the metallurgical bonding of the metal powder at the interface of the metal wire mesh tube 5, rather than the independent existence of the interfaces of the support layer 3, the wire mesh isolation layer, and the precision control layer, that the porous filter element will not crack or detach at any interface during use.

[0107] In one possible implementation, sintering the blank element to obtain a gradient metal porous element specifically includes:

[0108] The blank component is placed in a high-temperature resistant material boat, and the outer surface of the blank component is filled with high-temperature resistant particles;

[0109] The blank element is sintered for 2 to 4 hours in a vacuum, inert gas, or hydrogen sintering atmosphere and at a sintering temperature of 1100 to 1400°C, and then cooled to obtain the gradient metal porous element.

[0110] Specifically, the processed blank component is placed in a high-temperature resistant boat, and then the outer surface of the blank component is filled with high-temperature resistant particles to ensure the roundness and straightness of the metal component during the high-temperature sintering process. The high-temperature resistant boat can be a metal boat or a ceramic tubular boat, and the blank component is placed vertically in the center of the boat.

[0111] The sintering atmosphere is set as vacuum or inert gas or hydrogen atmosphere, and then the sintering temperature is set as 1100-1400℃, and the holding time is 2-4h. If the temperature is low and the time is short, the sintering necks between the metal powders can not be formed. If the temperature is too high and the time is too long, the metal can be over-sintered, the sintering necks are too large to block some pores, and the filtration precision of the finished element is reduced.

[0112] In a possible implementation, the filling of the second metal powder into the second gap comprises:

[0113] After the first end of the mold is fixed and the second end of the mold is tilted by the first angle, the second metal powder is filled into the second gap while the vibration platform is used for vibration.

[0114] Specifically, when the metal powder is filled, the metal powder in the support layer 3 is filled first, and then the metal powder in the precision control layer 4 is filled.

[0115] In the embodiment of the application, the second gap is the precision control layer 4, and the first gap is the support layer 3. After the filling of the first metal powder in the support layer 3 is completed, the second metal powder is filled into the second gap. Before the second metal powder is filled, the first end of the mold is fixed at a point, and the second end of the mold is tilted by a certain angle. The angle has no special requirement, and the first metal powder in the first gap can have a tendency to enter the second gap. The metal wire mesh tube 5 prevents the second metal powder from entering the first gap.

[0116] In the case that the first metal powder in the first gap has a tendency to enter the second gap, when the second metal powder is filled into the second gap, the metal powder entering the second gap has a tendency to move away from the first gap. During the filling of the second metal powder, in order to ensure the uniformity of the powder filling and avoid that a small amount of fine powder is splashed to the support layer 3 area through the wire mesh tube, the mold is rotated, and the vibration platform is used for real-time vibration.

[0117] In a possible implementation, the placing of the sealed mold into the cold isostatic pressing machine for pressing comprises:

[0118] The sealed mold is placed into the cold isostatic pressing machine, and the pressure range of the cold isostatic pressing machine is set as 100-200Mpa.

[0119] The mold is pressed in the pressure range of 100-200Mpa.

[0120] Specifically, after the mold is sealed by the second rubber plug 9, the sealed mold is placed in the liquid of the cold isostatic press, the pressure range is set between 100-200Mpa, and the pressure is set to start pressing under the pressure. The working principle of the cold isostatic press is that the material loaded in the sealed and elastic mold is placed in a container filled with liquid or gas, and the material is pressed into a solid body by applying a certain pressure to the liquid or gas, so as to obtain a raw-shaped blank. The only through hole 12 on the first metal pipe 1 and the second metal pipe 7 in the embodiment of the present application, the pressure in the cold isostatic press is transmitted to the first rubber sleeve 2 and the second rubber sleeve 6 through the through hole 12 to transmit the pressure, so as to realize the pressing of the support layer 3 and the precision control layer 4 powder.

[0121] In a possible implementation, the mold further comprises a first metal buckle and a second metal buckle, the first rubber plug part comprises a small-diameter end and a large-diameter end; after the second end of the outer mold assembly and the second end of the metal wire mesh pipe are embedded in the second rubber plug, the method further comprises:

[0122] The first metal buckle is used to fix the small-diameter end and the inner mold assembly;

[0123] The second metal buckle is used to fix the large-diameter end and the outer mold assembly.

[0124] Specifically, after the second end of the outer mold assembly and the second end of the metal wire mesh pipe 5 are embedded in the groove of the second rubber plug 9, the first metal buckle 10 is used to fasten the small-diameter end 802 of the first rubber plug 8 and the second rubber plug 9, and the second metal buckle 11 is used to fasten the large-diameter end 801 of the first rubber plug 8 and the second rubber plug 9. The first metal buckle 10 mainly fixes the relative positions of the first rubber plug 8, the second rubber plug 9 and the inner mold assembly, and the second metal buckle 11 mainly fixes the relative positions of the first rubber plug 8, the second rubber plug 9, the outer mold assembly and the metal wire mesh pipe 5.

[0125] The embodiment of the present application realizes the design and one-time forming of the gradient porous structure by sandwiching the filter metal wire mesh pipe isolation layer between the support layer 3 and the precision control layer 4, and can ensure the bonding strength of the powders at both ends of the metal wire mesh pipe isolation layer, and realize the integrated forming and preparation of the gradient metal porous element. The integrated gradient porous filter pipe prepared by the embodiment of the present application can improve the air permeability and filtering precision of the porous filter element, while ensuring high use strength and actual production batch preparation efficiency, and can be applied in the fields of polycrystalline silicon, petroleum chemical industry, coal chemical industry and the like, and has great market application value and potential.

[0126] The preparation method of the gradient metal porous element in the present application is illustrated by the following examples:

[0127] Example 1

[0128] Assembled the second rubber sleeve 6, the second metal tube 7, the first rubber plug 8, fixed the first rubber plug 8 and the second rubber sleeve 6 with the first metal buckle 10 and the second metal buckle 11, the wire diameter 0.4mm, 60 mesh, S31603 stainless steel wire mesh tube isolation layer 4 was clamped in the reserved groove of the first rubber plug 8, then the first metal tube 1 and the second rubber sleeve 6 were installed, and the first rubber plug 8 and the first metal tube 1 were fixed with the first metal buckle 10 and the second metal buckle 11. Fill the S31603 stainless steel powder with a particle size of 40-60 mesh into the support layer 3, and then fill the S31603 stainless steel powder with a particle size of 100-160 mesh into the precision control layer 4. During this period, the mold is tilted and rotated to a certain extent, and a vibration platform is used for real-time vibration to ensure the uniformity of the powder filling and prevent fine powder from splashing into the support layer 3 area. A small amount of fine powder splashed into the support layer 3 is screened into the precision control layer 4 through the wire mesh isolation layer during real-time vibration. Seal with the second rubber plug 9, and then fix the second rubber plug 9 with the first metal tube 1 and the second rubber sleeve 6 with the first metal buckle 10 and the second metal buckle 11 respectively. Put the mold into the cold isostatic pressing machine for pressing and molding, and the pressing pressure is 160MPa. After pressing and molding, disassemble the mold and take out the blank powder pipe. Place the blank pipe in a carbon steel tubular boat, fill the inner wall of the boat with 1-3mm corundum sand on the outer wall of the blank, and sinter in a hydrogen atmosphere, with a sintering temperature of 1350℃ and a holding time of 3h. After sintering, take out the porous element, and finally obtain a one-step forming gradient metal porous element.

[0129] Example 2

[0130] Assembling the second rubber sleeve 6, the second metal tube 7, the first rubber plug 8, fixing the first rubber plug 8 and the second rubber sleeve 6 with the first metal buckle 10 and the second metal buckle 11, clamping the wire mesh tube isolation layer 4 with a wire diameter of 0.4 mm, 60 meshes and S31603 stainless steel in the reserved groove of the first rubber plug 8, then adding the first metal tube 1 and the second rubber sleeve 6, and fixing the first rubber plug 8 and the first metal tube 1 with the first metal buckle 10 and the second metal buckle 11. Fill the S31603 stainless steel powder with a particle size of 40-60 meshes into the support layer 3, and then fill the S31603 stainless steel powder with a particle size of 200-300 meshes into the precision control layer 4. During this period, the mold is tilted and rotated to a certain extent, and a vibration platform is used for real-time vibration to ensure the uniformity of powder filling and prevent fine powder from splashing into the support layer 3 area. A small amount of fine powder splashed into the support layer 3 is screened into the precision control layer 4 through the wire mesh isolation layer during real-time vibration. Seal with the second rubber plug 9, and then fix the second rubber plug 9 with the first metal tube 1 and the second rubber sleeve 6 with the first metal buckle 10 and the second metal buckle 11 respectively. Put the mold into the cold isostatic pressing machine for pressing and molding, and the pressing pressure is 170 MPa. After pressing and molding, disassemble the mold and take out the blank powder tube; place the blank tube in a carbon steel tubular boat, fill the inner wall of the boat with 1-3 mm corundum sand on the outer wall of the blank, and sinter in a hydrogen atmosphere, with a sintering temperature of 1330℃ and a holding time of 3h. After sintering, take out the porous element, and finally obtain a one-step forming gradient metal porous element.

[0131] Example 3

[0132] The second rubber sleeve 6, the second metal tube 7 and the first rubber plug 8 are assembled, the first rubber plug 8 and the second rubber sleeve 6 are fixed by the first metal buckle 10 and the second metal buckle 11, the wire diameter is 0.4 mm, the mesh is 60, the S31603 stainless steel wire mesh tube isolation layer 4 is clamped in the reserved groove of the first rubber plug 8, the first metal tube 1 and the second rubber sleeve 6 are additionally installed, and the first rubber plug 8 and the first metal tube 1 are fixed by the first metal buckle 10 and the second metal buckle 11. The S31603 stainless steel powder with a particle size of 40-60 meshes is filled into the support layer 3, and after a certain amount, the S31603 stainless steel powder with a particle size of 300-400 meshes is filled into the precision control layer 4. During this period, the mold is tilted and rotated to a certain extent, and a vibration platform is used for real-time vibration to ensure the uniformity of powder filling and avoid fine powder splashing to the support layer 3 area. A small amount of fine powder splashed to the support layer 3 is screened to the precision control layer 4 through the wire mesh isolation layer during the real-time vibration process. The second rubber plug 9 is sealed, and then the second rubber plug 9 and the first metal tube 1 and the second rubber sleeve 6 are fixed by the first metal buckle 10 and the second metal buckle 11 respectively. The mold is placed in a cold isostatic pressing machine for pressing and forming, and the pressing pressure is 180 MPa. After pressing and forming, the mold is disassembled, and the blank powder tube is taken out. The blank tube is placed in a carbon steel tubular boat, and the inner wall of the boat, i.e. the outer wall of the blank, is filled with 1-3 mm corundum sand for sintering. The sintering temperature is 1310 DEG C, and the holding time is 3 h. After sintering, the porous element is taken out, and finally the one-step forming gradient metal porous element is obtained.

[0133] Although preferred embodiments of the application have been described, those skilled in the art will be able to make additional changes and modifications without departing from the spirit and scope of the application. Therefore, the appended claims are intended to cover all such changes and modifications that fall within the scope of the application.

[0134] Obviously, various modifications and changes can be made to the present application by those skilled in the art without departing from the spirit and scope of the present application. Thus, it is intended that the present application embrace all such changes and modifications as fall within the scope of the appended claims and their equivalents.

Claims

1. A mold for preparing a gradient metal porous element, characterized by, The mold is tubular, comprising an outer mold assembly arranged outside the mold, an inner mold assembly arranged inside the outer mold assembly, a wire mesh tube, a first rubber plug and a second rubber plug; The wire mesh tube is located between the outer mold assembly and the inner mold assembly, and there is a first gap between the wire mesh tube and the inner mold assembly, and a second gap between the wire mesh tube and the outer mold assembly; the first gap is used for filling the first metal powder, and the second gap is used for filling the second metal powder; the particle size of the first metal powder is different from that of the second metal powder; The first rubber plug is located at the first end of the mold; the first end of the mold comprises the first end of the inner mold assembly, the first end of the outer mold assembly and the first end of the wire mesh tube; the inner surface of the first rubber plug is tightly fitted with the outer surface of the first end of the inner mold assembly, and the inner surface and the outer surface of the first end of the outer mold assembly and the inner surface and the outer surface of the first end of the wire mesh tube are tightly fitted, for fixing the first end of the outer mold assembly, the first end of the inner mold assembly and the first end of the wire mesh tube; The second rubber plug is located at the second end of the mold; the second end of the mold comprises the second end of the inner mold assembly, the second end of the outer mold assembly and the second end of the wire mesh tube; the inner surface of the second rubber plug is tightly fitted with the outer surface of the second end of the inner mold assembly, and the inner surface and the outer surface of the second end of the outer mold assembly and the inner surface and the outer surface of the second end of the wire mesh tube are tightly fitted, for fixing the second end of the outer mold assembly, the first end of the inner mold assembly and the second end of the wire mesh tube.

2. The mold of claim 1, wherein The outer mold assembly comprises a first metal pipe and a first rubber sleeve which are tightly fitted, and the first metal pipe is located outside the first rubber sleeve; The inner mold assembly comprises a second metal pipe and a second rubber sleeve which are tightly fitted, and the second rubber sleeve is located outside the second metal pipe; The end surface of the first metal pipe is flush with the end surface of the first rubber sleeve; the end surface of the second metal pipe is flush with the end surface of the second rubber sleeve.

3. The mold of claim 2, wherein, The first metal pipe and the second metal pipe are radially uniformly distributed with through holes.

4. The mold of claim 2, wherein The first rubber plug is an outer diameter variable tubular structure, comprising a small diameter end and a large diameter end; The end surface of the small diameter end is flush with the end surface of the inner mold assembly; the large diameter end is provided with a groove for positioning the outer mold assembly, the inner mold assembly and the wire mesh tube.

5. The mold of claim 4, wherein, Further comprising a first metal buckle and a second metal buckle; The first metal buckle is used for fixing the small diameter end and the inner mold assembly; The second metal buckle is used for fixing the large diameter end and the outer mold assembly.

6. A method of producing a gradient metal porous element, characterized by, The gradient metal porous element is prepared by using the mold of any one of claims 1-5, and the method comprises: Obtaining the inner mold assembly and the outer mold assembly of the mold, the wire mesh tube, the first rubber plug and the second rubber plug; Sleeving the first end of the inner mold assembly in the first rubber plug, so that the outer surface of the inner mold assembly is tightly fitted with the inner surface of the first rubber plug; The metal wire mesh sleeve is arranged outside the inner mold assembly, and the first end of the metal wire mesh tube is embedded in the first rubber plug, so that a first gap exists between the outer surface of the inner mold assembly and the metal wire mesh tube; The outer mold assembly is arranged outside the metal wire mesh tube, and the first end of the outer mold assembly is embedded in the first rubber plug, so that a second gap exists between the inner surface of the outer mold assembly and the metal wire mesh tube; The first metal powder is filled into the first gap, and the second metal powder is filled into the second gap; the particle sizes of the first metal powder and the second metal powder are different; The second end of the inner mold assembly is sleeved in the second rubber plug, and the second end of the outer mold assembly and the second end of the metal wire mesh tube are embedded in the second rubber plug to seal the first gap and the second gap, thereby obtaining a sealed mold; The sealed mold is placed in a cold isostatic pressing machine for pressing, so that the first metal powder, the metal wire mesh tube and the second metal powder are shaped, thereby obtaining a blank element; After the second rubber plug, the outer mold assembly and the first rubber plug are sequentially disassembled, the blank element is taken out; The blank element is sintered to obtain a gradient metal porous element.

7. The method of claim 6, wherein, The blank element is placed in a high-temperature resistant material boat, and the outer surface of the blank element is filled with high-temperature resistant particles; The blank element is sintered in a vacuum or inert gas or hydrogen sintering atmosphere and a sintering temperature of 1100-1400℃ for 2-4 hours, and the gradient metal porous element is obtained after cooling. The second metal powder is filled into the second gap, including:

8. The method of claim 6, wherein, After the first end of the mold is fixed and the second end of the mold is inclined at a first angle, the second metal powder is filled into the second gap, and a vibration platform is used for vibration. The sealed mold is placed in a cold isostatic pressing machine for pressing, including:

9. The method of claim 6, wherein, The sealed mold is placed in a cold isostatic pressing machine, and the pressure range of the cold isostatic pressing machine is set to 100-200Mpa; The mold is pressed in the pressure range of 100-200Mpa. The mold further comprises a first metal buckle and a second metal buckle, and the structure of the first rubber plug part comprises a small diameter end and a large diameter end; after the second end of the outer mold assembly and the second end of the metal wire mesh tube are embedded in the second rubber plug, further comprising:

10. The method of claim 6, wherein, The first metal buckle is used to fix the small diameter end and the inner mold assembly, and the second metal buckle is used to fix the large diameter end and the outer mold assembly. ​

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