Gradient powder sintered porous metal material based on surface micro-area treatment and preparation method thereof

Abstract

The invention discloses a gradient powder sintered porous metal material based on surface micro-area treatment and a preparation method thereof, the material comprises a powder sintered porous metal material body and a gradient layer located on the body, the thickness of the gradient layer does not exceed 100 microns, and the surface aperture size does not exceed 5 microns; the preparation method comprises the following steps: 1, preparing the body through pressing forming, high-temperature sintering and processing; and 2, forming a gradient layer on the surface of the body by utilizing surface micro-area treatment. The material is composed of the powder sintering porous metal material body and the gradient layer, and by controlling the thickness and the surface aperture size of the gradient layer, the material has the advantages of being high in flux, low in cost and easy to blow back; in-situ construction of a gradient layer on the surface of a traditional powder sintering porous metal material body is achieved through surface micro-area treatment, the mechanical strength and the filtering performance of the material are improved, and the material is suitable for the fields of filtering, separation and purification, fluidized conveying control and the like.

Description

Technical Field

[0001] The invention belongs to the field of powder sintered porous metal materials, and in particular relates to a gradient powder sintered porous metal material based on surface micro-area treatment and a preparation method thereof. Background Art

[0002] Since its invention in 1909, powder sintered porous metal materials have become an indispensable core material / device in the national industrial field for filtration, separation, purification, fluidized transport control and other process links due to their internally interconnected three-dimensional pores and their own properties of metal materials such as high temperature resistance, high strength, thermal shock resistance, and weldability. In recent years, with the rapid development of industrial technology, there is an urgent need for high-precision and high-permeability powder sintered porous metal materials for fluid separation and purification. However, the materials prepared from single-particle powders have uniform pore sizes and cannot simultaneously meet the synergistic leaps in the two core technical indicators of separation efficiency and permeation flux.

[0003] In order to solve the above problems, researchers in the field of powder sintered porous metal materials have made great efforts and proposed the idea of ​​using gradient pore structure to achieve the above goals. They have also proposed a variety of manufacturing solutions in terms of pore structure design and preparation process innovation, including: powder wet spraying, centrifugal deposition and multi-layer rolling composite. Among them, powder wet spraying technology has become the mainstream technology for the preparation of gradient powder sintered porous metal materials due to its simple operation and easy engineering promotion.

[0004] However, in order to ensure sufficient mechanical strength of the gradient layer, the powder wet spraying technology usually requires the prefabrication of an intermediate transition layer between the gradient layer and the support, so as to relieve the sintering stress caused by the difference in powder particle size and avoid the cracking of the film layer caused by the shrinkage difference during sintering. At the same time, due to the limitations of the preparation process, the ultrafine powder of the gradient layer will penetrate into the pores of the support under the action of capillary force, forming a particle penetration layer composed of a mixture of coarse and fine particles, which seriously damages the permeation flux of the gradient porous metal material. In addition, when preparing the gradient structure, the above method requires the use of organic additives as adhesives. After the secondary sintering, the interstitial elements such as carbon, nitrogen, and oxygen remain, which will seriously damage the strength and corrosion resistance of the porous metal material. The multiple high-temperature sintering in the preparation process has led to a significant increase in the manufacturing cost of gradient powder sintered porous metal materials. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a gradient powder sintered porous metal material based on surface micro-area treatment in view of the deficiencies of the above-mentioned prior art. The gradient powder sintered porous metal material is composed of a powder sintered porous metal material body and a gradient layer generated in situ by surface micro-area treatment on the body. By controlling the thickness of the gradient layer and the surface pore size, the material has the advantages of high flux, low cost, and easy backflushing, which meets the requirements of filtering and separating ultrafine particles in most industrial links, and solves the problems of impurity element pollution, high cost and insufficient flux in existing gradient powder sintered porous metal materials.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: a gradient powder sintered porous metal material based on surface micro-area treatment, characterized in that it includes a powder sintered porous metal material body and a gradient layer located on the powder sintered porous metal material body, the gradient layer is obtained by performing surface micro-area treatment on the powder sintered porous metal material body, and the thickness of the gradient layer does not exceed 100μm, and the surface pore size does not exceed 5μm.

[0007] The gradient powder sintered porous metal material of the present invention consists of a powder sintered porous metal material body and a gradient layer, and the gradient layer is generated in situ by performing surface micro-area treatment on the powder sintered porous metal material body. By controlling the thickness of the gradient layer to not exceed 100 μm, the gradient layer structure is guaranteed to be complete and the pore distribution is uniform. It has the advantages of high flux, low cost, and easy backblowing, and avoids damage to the permeability of the material caused by an excessively thick gradient layer. By controlling the surface pore size of the gradient layer to not exceed 5 μm, the filtering and separation needs of ultrafine particles in most industrial links are met, and it has broad application prospects in the filtration and separation industries of modern industry.

[0008] The above-mentioned gradient powder sintered porous metal material based on surface micro-area treatment is characterized in that the material of the gradient powder sintered porous metal material is derived from stainless steel, nickel-based alloy, titanium and titanium alloy, and copper alloy. By controlling the material of the gradient powder sintered porous metal material, it can be applied to various working conditions.

[0009] The above-mentioned gradient powder sintered porous metal material based on surface micro-area treatment is characterized in that the structure of the gradient powder sintered porous metal material is flat or tubular. The structure of the gradient powder sintered porous metal material covers all structural forms of powder sintered porous metal materials currently used in the filtration and separation industry, and has a wide range of applications and is simple to operate.

[0010] In addition, the present invention also provides a method for preparing the gradient powder sintered porous metal material as described above, characterized in that the method comprises the following steps:

[0011] Step 1: Using metal powder as raw material, through pressing, high-temperature sintering and processing steps, a powder sintered porous metal material body is prepared;

[0012] Step 2: Using a surface micro-area treatment method, a gradient layer is formed on the surface of the powder sintered porous metal material body obtained in step 1; the process of the surface micro-area treatment method is: using a WC-Co alloy ball as a pressure head to apply a load to the surface of the powder sintered porous metal material body, and controlling the pressure head to continuously move and scan along the surface of the powder sintered porous metal material body until the entire surface of the powder sintered porous metal material body is completed.

[0013] During the research process of the present invention, the evolution mechanism of the pore structure on the surface of the material was obtained by deeply analyzing and studying the local deformation behavior characteristics of the powder porous material under the action of the surface micro-area load, and the control method of the pore structure of the surface gradient layer was mastered, so as to realize the in-situ on-demand construction of the surface gradient layer of the powder sintered porous metal material. Based on this theoretical guidance, the present invention overturns the existing forming method of the gradient powder sintered porous metal material, and then completes the preparation of the powder sintered porous metal material body with a uniform pore structure. After the micro-area load of the surface micro-area treatment is applied, the pores and struts on the surface of the material body are plastically deformed and pushed, and a gradient layer with a brand-new structure is formed in situ, which will not produce the particle penetration layer in the traditional process, avoid the damage to the material penetration flux, and do not need to use adhesives to cause residual interstitial elements to damage the strength and corrosion resistance of the material, thereby greatly reducing the manufacturing cost of the material on the basis of ensuring the mechanical strength and filtration performance of the material.

[0014] In addition, the present invention uses metal powder as raw material, and completes the preparation of a powder sintered porous metal material body with a uniform pore structure through pressing, high-temperature sintering and processing steps. This process is a widely used powder metallurgy process, which has low cost, simple operation, wide applicability and is easy to implement.

[0015] The above method is characterized in that the diameter of the WC-Co alloy ball in step 2 is 10mm to 20mm, the applied load is 30N to 250N, and the speed of the continuous scanning of the indenter is 50m / s to 200m / s. The present invention effectively controls the thickness and pore size of the gradient layer by controlling the core process parameters including load and scanning speed in the surface micro-area processing process, and realizes the on-demand construction of the gradient layer structure to meet the use requirements of different fields, avoiding the problem that too small load and inappropriate scanning speed cannot cause the pores on the surface of the material body to undergo plastic deformation to form a gradient layer, and at the same time avoiding the problem that too large load causes excessive force on the surface of the material body and causes material tearing.

[0016] The above method is characterized in that in step 2, when the structure of the gradient powder sintered porous metal material is flat, the path of the continuous motion scanning of the indenter is S-shaped, and when the structure of the gradient powder sintered porous metal material is tubular, the path of the continuous motion scanning of the indenter is annular, and the scanning interval is 0.05mm to 0.1mm. The present invention is aimed at gradient powder sintered porous metal materials with different structures, and effectively controls the surface micro-area treatment effect by controlling the path and scanning interval of the continuous motion scanning of the indenter.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. The gradient powder sintered porous metal material of the present invention is composed of a powder sintered porous metal material body and a gradient layer. By controlling the thickness of the gradient layer and the surface pore size, the material has the advantages of high flux, low cost, and easy backflushing, which meets the filtration and separation needs of ultrafine particles in most industrial links.

[0019] 2. Based on a full understanding of the evolution law of the surface pore structure of powder sintered porous metal materials under the action of surface micro-area loads, the present invention adopts a surface micro-area treatment method to achieve the in-situ construction of a gradient layer on the surface of the traditional powder sintered porous metal material body, thereby improving the mechanical strength and filtration performance of the gradient powder sintered porous metal material, and completely subverting the manufacturing concept of the traditional preparation process with an additional gradient layer.

[0020] 3. The pore structure of the gradient layer in the gradient powder sintered porous metal material of the present invention does not come from the accumulation of powder particles, but from the plastic deformation and accumulation of pores on the surface of the powder sintered porous material body. Therefore, the gradient layer is thin, the filtration resistance is small, and the surface roughness is much lower than that of the gradient layer formed by the traditional preparation process. This makes the gradient powder sintered porous metal material have a larger permeation flux and a surface morphology that is easier to backwash under the same filtration accuracy conditions.

[0021] 4. The present invention uses surface micro-area treatment to generate a gradient layer in situ on the surface of the powder sintered porous metal material body. No particle penetration layer is generated and no adhesive is required. This solves the problems of impurity element pollution, high cost and insufficient flux in the existing preparation process of gradient powder sintered porous metal materials. The preparation method is simple, easy to operate and has a high yield. It is a minimum process improvement based on the original mature industrial process. It can greatly reduce the manufacturing cost of the material and improve the added value of the product without changing the existing production line or the existing core equipment.

[0022] 5. The preparation method of the present invention has simple procedures and a wide range of applications. It does not require the use of ultrafine metal powders of traditional procedures as raw materials and is suitable for the preparation of gradient structures of pure metals, alloys and intermetallic compounds.

[0023] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the gradient powder sintered porous metal material based on surface micro-area treatment of the present invention.

[0025] Figure 2 This is a physical picture of the gradient powder sintered porous metal material with surface micro-area treatment prepared in Example 1 of the present invention.

[0026] Description of Reference Numerals

[0027] 1—powder sintered porous metal material body; 2—gradient layer. DETAILED DESCRIPTION

[0028] Example 1

[0029] This embodiment is designed to meet the demand for powder sintered porous metal materials in the energy and chemical industry. Figure 1 The gradient powder sintered porous metal material based on surface micro-area treatment shown includes a powder sintered porous metal material body 1 and a gradient layer 2 located on the powder sintered porous metal material body 1, wherein the gradient layer 2 is obtained by performing surface micro-area treatment on the powder sintered porous metal material body 1, and the thickness of the gradient layer 2 is 80 μm and the surface pore size is 4.3 μm.

[0030] The preparation method of this embodiment comprises the following steps:

[0031] Step 1: Using 316L stainless steel powder with a mesh size of -60 to +100 as raw material, a powder sintered porous metal material body 1 with a flat plate structure having a thickness of 4 mm and an average pore size of 25 μm is prepared through isostatic pressing, high-temperature sintering and processing steps;

[0032] Step 2: Using a surface micro-area treatment method, a gradient layer 2 is formed on the surface of the powder sintered porous metal material body 1 obtained in step 1 to obtain a gradient powder sintered porous metal material with a flat structure; the process of the surface micro-area treatment method is as follows: a WC-Co alloy ball with a diameter of 10 mm is used as a pressure head to apply a load of 100N to the surface of the powder sintered porous metal material body 1, and the pressure head is controlled to continuously move and scan along the surface of the powder sintered porous metal material body 1 at a speed of 100m / s until the entire surface of the powder sintered porous metal material body 1 is completed. The path of the continuous movement scanning of the pressure head is S-shaped, and the scanning interval is 0.1mm.

[0033] Figure 2This is a real picture of the gradient powder sintered porous metal material with surface micro-area treatment prepared in this embodiment. Figure 2 It can be seen that after surface micro-area treatment, the morphological characteristics of the original powder particles completely disappear, the surface pore size is uniform, and the pore-edge surface is smooth. Therefore, the material is particularly suitable for backflushing regeneration during the filtration and separation process, and can significantly improve the service life of the material.

[0034] The material of the gradient powder sintered porous metal material of this embodiment can also be derived from nickel-based alloys, titanium and titanium alloys, and copper alloys.

[0035] Example 2

[0036] This embodiment aims at the demand for powder sintered porous metal materials in the field of wastewater treatment, and designs Figure 1 The gradient powder sintered porous metal material based on surface micro-area treatment shown includes a powder sintered porous metal material body 1 and a gradient layer 2 located on the powder sintered porous metal material body 1, wherein the gradient layer 2 is obtained by performing surface micro-area treatment on the powder sintered porous metal material body 1, and the thickness of the gradient layer 2 is 50 μm and the surface pore size is 2.8 μm.

[0037] The preparation method of this embodiment comprises the following steps:

[0038] Step 1: Using 316L stainless steel powder of -60 mesh to +220 mesh as raw material, a powder sintered porous metal material body 1 with a tubular structure having an outer diameter of 50 mm and an average pore diameter of 11 μm is prepared through isostatic pressing, high-temperature sintering and processing steps;

[0039] Step 2: Using a surface micro-area treatment method, a gradient layer 2 is formed on the surface of the powder sintered porous metal material body 1 obtained in step 1 to obtain a gradient powder sintered porous metal material with a tubular structure; the process of the surface micro-area treatment method is as follows: a WC-Co alloy ball with a diameter of 20 mm is used as a pressure head to apply a load of 60N to the surface of the powder sintered porous metal material body 1, and the pressure head is controlled to continuously move and scan along the surface of the powder sintered porous metal material body 1 at a speed of 50m / s until the entire surface of the powder sintered porous metal material body 1 is completed. The path of the continuous movement scanning of the pressure head is annular, and the scanning interval is 0.1mm.

[0040] The material of the gradient powder sintered porous metal material of this embodiment can also be derived from nickel-based alloys, titanium and titanium alloys, and copper alloys.

[0041] Example 3

[0042] This embodiment is designed to meet the demand for powder sintered porous metal materials in the nuclear chemical industry. Figure 1The gradient powder sintered porous metal material based on surface micro-area treatment shown includes a powder sintered porous metal material body 1 and a gradient layer 2 located on the powder sintered porous metal material body 1, wherein the gradient layer 2 is obtained by performing surface micro-area treatment on the powder sintered porous metal material body 1, and the thickness of the gradient layer 2 is 30 μm and the surface pore size is 1.3 μm.

[0043] The preparation method of this embodiment comprises the following steps:

[0044] Step 1: Using 316L stainless steel powder with a mesh size of -300 to +400 as raw material, a powder sintered porous metal material body 1 with a flat plate structure having a thickness of 3 mm and an average pore size of 8 μm is prepared through isostatic pressing, high-temperature sintering and processing steps;

[0045] Step 2: Using a surface micro-area treatment method, a gradient layer 2 is formed on the surface of the powder sintered porous metal material body 1 obtained in step 1 to obtain a gradient powder sintered porous metal material with a flat structure; the process of the surface micro-area treatment method is as follows: a WC-Co alloy ball with a diameter of 15 mm is used as a pressure head to apply a load of 30N to the surface of the powder sintered porous metal material body 1, and the pressure head is controlled to continuously move and scan along the surface of the powder sintered porous metal material body 1 at a speed of 200m / s until the entire surface of the powder sintered porous metal material body 1 is completed. The path of the continuous movement scanning of the pressure head is S-shaped, and the scanning interval is 0.05mm.

[0046] The material of the gradient powder sintered porous metal material of this embodiment can also be derived from nickel-based alloys, titanium and titanium alloys, and copper alloys.

[0047] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the technical essence of the invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. Gradient powder sintered porous metal material based on surface micro-area treatment, characterized in that: The invention comprises a powder sintered porous metal material body (1) and a gradient layer (2) located on the powder sintered porous metal material body (1), wherein the gradient layer (2) is obtained by performing surface micro-area treatment on the powder sintered porous metal material body (1), and the thickness of the gradient layer (2) does not exceed 100 μm, and the surface pore size does not exceed 5 μm.

2. The gradient powder sintered porous metal material based on surface micro-area treatment according to claim 1, characterized in that: The material of the gradient powder sintered porous metal material is stainless steel, nickel-based alloy, titanium and titanium alloy, and copper alloy.

3. The gradient powder sintered porous metal material based on surface micro-area treatment according to claim 1, characterized in that: The structure of the gradient powder sintered porous metal material is flat or tubular.

4. A method for preparing the gradient powder sintered porous metal material according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: Step 1: Using metal powder as raw material, through pressing, high-temperature sintering and processing steps, a powder sintered porous metal material body (1) is prepared; Step 2: Using a surface micro-area treatment method, a gradient layer (2) is formed on the surface of the powder sintered porous metal material body (1) obtained in step 1; the process of the surface micro-area treatment method is: using a WC-Co alloy ball as a pressure head to apply a load to the surface of the powder sintered porous metal material body (1), and controlling the pressure head to continuously move and scan along the surface of the powder sintered porous metal material body (1) until the entire surface of the powder sintered porous metal material body (1) is scanned.

5. The method according to claim 4, characterized in that In step 2, the diameter of the WC-Co alloy ball is 10 mm to 20 mm, the applied load is 30 N to 250 N, and the speed of the continuous scanning of the indenter is 50 m / s to 200 m / s.

6. The method according to claim 4, characterized in that In step 2, when the structure of the gradient powder sintered porous metal material is flat, the path of the continuous movement and scanning of the indenter is S-shaped. When the structure of the gradient powder sintered porous metal material is tubular, the path of the continuous movement and scanning of the indenter is annular, and the scanning interval is 0.05mm~0.1mm.

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