Preparation method of high-performance metal fiber felt

Abstract

The invention discloses a preparation method of a high-performance metal fiber felt. The method comprises the following steps: firstly, selecting a high-purity metal wire, and performing multi-pass wire drawing and annealing treatment to obtain metal fibers; during drawing, a lubricant is used for reducing friction, and internal stress is eliminated through annealing; secondly, metal fibers are pretreated, oil dirt and impurities are removed through cleaning, surface modification is conducted through chemical plating or electroplating or plasma treatment or the like, and the binding force of the fibers and a matrix is enhanced; secondly, the pretreated metal fibers are evenly laid in a forming mold to form a metal fiber net, the thickness and porosity of the metal fiber net are controlled, and then the fibers are bonded with one another through hot press forming; and finally, the formed metal fiber felt is subjected to trimming and heat treatment. The metal fibrofelt prepared by the method is uniform in fiber distribution, good in mechanical property, resistant to high temperature and corrosion, simple in preparation process, high in production efficiency, low in cost and suitable for large-scale industrial production, and has wide application prospects in the fields of filtration, separation and the like.

Description

Technical Field

[0001] The invention relates to the technical field of metal fiber material preparation, and in particular to a method for preparing high-performance metal fiber felt. Background Art

[0002] Metal fiber felt is a porous material made of metal fibers through a specific process. It has excellent properties such as high porosity, large specific surface area, high temperature resistance, and corrosion resistance. It has broad application prospects in filtration, separation, catalysis, electromagnetic shielding and other fields.

[0003] Currently, traditional methods for preparing metal fiber felt have several shortcomings. For example, some methods produce metal fiber felts with poor fiber distribution uniformity, resulting in unstable mechanical properties and prone to localized breakage or deformation during use. Other methods require the use of large amounts of organic binders during preparation, which not only increases production costs but also easily decomposes and volatilizes at high temperatures, affecting the performance and service life of the metal fiber felt. Furthermore, some preparation methods have low production efficiency, making them difficult to meet the needs of large-scale industrial production.

[0004] Therefore, it is of great practical significance to develop a preparation method for metal fiber felt that can produce high performance, uniform fiber distribution and high production efficiency. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing high-performance metal fiber felt. The metal fiber felt prepared by this method has the advantages of uniform fiber distribution, good mechanical properties, high temperature resistance, corrosion resistance, etc., and the preparation process is simple, the production efficiency is high, and the cost is low.

[0006] To achieve the above objectives, the present invention provides the following technical solutions:

[0007] A method for preparing high-performance metal fiber felt comprises the following steps in sequence:

[0008] S1 metal fiber preparation:

[0009] A metal wire with a purity of not less than 99% is selected as raw material, and the metal wire is drawn using a multi-pass drawing die. The deformation of each drawing pass is controlled within the range of 10%-30%. The metal wire is lubricated with a lubricant during the drawing process. The drawn metal fiber is then annealed. The annealing temperature is selected according to the material of the metal wire and is controlled at 50-100°C above the recrystallization temperature of the metal wire. The annealing time is set at 30-120 minutes.

[0010] S2 metal fiber pretreatment:

[0011] The annealed metal fiber is placed in a cleaning solution for cleaning at a temperature of 40-80°C for 10-30 minutes. After cleaning, it is rinsed with clean water and dried. The cleaned metal fiber is then subjected to surface modification treatment.

[0012] S3 Metal Fiber Felt Forming:

[0013] The pretreated metal fibers are evenly laid in a forming mold with the help of a mesh laying machine to form a metal fiber mesh with a specific thickness and porosity, wherein the thickness of the metal fiber mesh is controlled between 0.5-5 mm and the porosity is controlled between 70%-90%. The laid metal fiber mesh is then placed in a hot press for hot pressing. The hot pressing temperature is determined according to the material of the metal fiber and the properties of the surface modification layer, and is controlled to be 50-200°C below the melting point of the metal fiber. The hot pressing pressure is set to 5-30 MPa and the hot pressing time is 5-30 minutes.

[0014] S4 post-processing:

[0015] The metal fiber felt formed by hot pressing is taken out from the forming mold and trimmed; the trimmed metal fiber felt is subjected to heat treatment.

[0016] Furthermore, the lubricant is any one of mineral oil or synthetic lubricant.

[0017] Furthermore, the surface modification treatment adopts any one of chemical plating, electroplating or plasma treatment.

[0018] Furthermore, the chemical plating is specifically chemical nickel plating, and the metal fiber is placed in a chemical nickel plating solution and treated at a temperature of 80-90° C. for 20-40 minutes to plate a uniform nickel layer on the surface of the metal fiber.

[0019] Furthermore, the heat treatment process is any one of solution treatment, aging treatment or a combination of the two.

[0020] Furthermore, when the heat treatment process is a combination of solution treatment and aging treatment, for the nickel-based alloy metal fiber felt, solution treatment is first performed at 1050-1150°C and kept warm for 1-2 hours, and then aging treatment is performed at 700-800°C and kept warm for 4-8 hours.

[0021] The preparation method of the high-performance metal fiber felt of the present invention has the following beneficial effects:

[0022] Uniform fiber distribution: The present invention precisely controls the parameters of the laying machine to evenly lay the metal fibers in the forming mold, so that the prepared metal fiber felt has uniform fiber distribution and stable mechanical properties.

[0023] Excellent performance: After surface modification and heat treatment, the bonding force between the metal fiber and the matrix is ​​enhanced, and the strength, hardness, high temperature resistance, corrosion resistance and other properties of the metal fiber felt are significantly improved.

[0024] High production efficiency: The preparation method of the present invention has a simple process, the various steps are closely connected, the production efficiency is high, and it is suitable for large-scale industrial production.

[0025] Low cost: The present invention does not require the use of a large amount of organic binder during the preparation process, thereby reducing production costs and environmental pollution. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0027] (1) Example 1

[0028] Preparation of the metal fiber: Stainless steel wire with a diameter of 50 μm was used as the raw material and drawn through a drawing die in five passes, with the deformation of each pass controlled at 20%. Mineral oil was used as a lubricant during the drawing process. The drawn metal fiber was annealed at 1100°C for 75 minutes.

[0029] Pretreatment of the metal fiber: Place the annealed metal fiber in an alkaline cleaning solution at 60°C for 20 minutes, then rinse with clean water and dry. Modify the surface of the metal fiber by electroless nickel plating: Place the metal fiber in an electroless nickel plating solution at 85°C for 30 minutes.

[0030] Forming of metal fiber felt: The pre-treated metal fibers are evenly laid in a forming mold using a mesh laying machine to form a metal fiber mesh with a thickness of 2 mm and a porosity of 80%. The laid metal fiber mesh is placed in a hot press and hot-pressed at 950°C and 20 MPa for 15 minutes.

[0031] Post-processing: The metal fiber felt after hot pressing is taken out and trimmed; then the trimmed metal fiber felt is heat treated, firstly solution treated at 1100°C, kept warm for 1.5 hours, and then aged at 750°C, kept warm for 6 hours.

[0032] (II) Example 2

[0033] Preparation of the metal fiber: A nickel-based alloy wire with a diameter of 30 μm was used as the raw material and drawn through a wire drawing die in four passes, with the deformation of each pass controlled at 25%. A synthetic lubricant was used as a lubricant during the drawing process. The drawn metal fiber was annealed at 1080°C for 90 minutes.

[0034] Pretreatment of metal fibers: The annealed metal fibers were placed in an organic solvent and washed at 50°C for 25 minutes, then rinsed with clean water and dried. The surface of the metal fibers was modified by plasma treatment for 15 minutes.

[0035] Forming of metal fiber felt: The pre-treated metal fibers are evenly laid in a forming mold using a mesh laying machine to form a metal fiber mesh with a thickness of 1.5 mm and a porosity of 85%. The laid metal fiber mesh is placed in a hot press and hot-pressed for 20 minutes at 900°C and 15 MPa.

[0036] Post-processing: The metal fiber felt after hot pressing is taken out and trimmed; then the trimmed metal fiber felt is heat treated, firstly solution treated at 1120°C, kept warm for 1 hour, and then aged at 720°C, kept warm for 8 hours.

[0037] (3) Performance testing

[0038] Mechanical properties test: including tensile strength and hardness test. Tensile strength reflects the ability of metal fiber felt to resist fracture when subjected to tensile force, while hardness reflects the ability of its surface to resist local deformation.

[0039] High temperature resistance test: The metal fiber felt is placed in a high temperature environment for a certain period of time to test its strength loss in order to evaluate its stability in the high temperature environment.

[0040] Corrosion resistance test: Immerse the metal fiber felt in a corrosive solution of a specific concentration and measure its corrosion rate to determine its corrosion resistance.

[0041] Test forms and summary

[0042] 1. Mechanical properties test

[0043] Mechanical properties test form

[0044] Test items Example 1 Example 2 Test standards Tensile strength (MPa) 120 135 GB / T228.1-2010 Hardness (HV) 280 300 GB / T4340.1-2009

[0045] Summary: The test results show that the high-performance metal fiber felt prepared in Example 2 surpasses that in Example 1 in both tensile strength and hardness. This is due to differences in the metal wire material, drawing parameters, surface modification method, and heat treatment process used in the preparation of Example 2 compared to Example 1. This results in a denser internal microstructure and stronger inter-fiber bonding, resulting in better mechanical properties. This demonstrates that the mechanical properties of metal fiber felt can be further improved by optimizing the preparation process parameters.

[0046] 2. High temperature resistance test

[0047] High temperature resistance test form

[0048]

[0049] In summary, after being maintained at a higher temperature (850°C) for 100 hours, the metal fiber felt prepared in Example 2 still had a lower strength loss rate than that in Example 1 (strength loss rate at 800°C). This indicates that the preparation method of Example 2 enables the metal fiber felt to have better high-temperature resistance, which is related to the material, surface modification layer, and heat treatment process of the metal fiber. The appropriate surface modification layer and heat treatment process can enhance the stability of the metal fiber in a high-temperature environment and reduce the damage to its internal structure and performance caused by high temperature.

[0050] 3. Corrosion resistance test

[0051] Corrosion resistance test form

[0052]

[0053] Summary: The corrosion rate of the metal fiber felt prepared in Example 2 after being immersed in a 10% hydrochloric acid solution for 72 hours is lower than that in Example 1, indicating that it has better corrosion resistance. This is because the surface modification treatment in Example 2 is more effective, forming a denser and more stable protective layer on the surface of the metal fiber, preventing direct contact between the corrosive medium and the metal fiber, thereby reducing the corrosion rate.

[0054] Summary

[0055] The high-performance metal fiber felts prepared in Examples 1 and 2 were tested for mechanical properties, high-temperature resistance, and corrosion resistance. The results showed that the preparation method of Example 2 outperformed Example 1 in all aspects. This fully demonstrates that by rationally adjusting and optimizing the preparation process parameters of the metal fiber felt, such as the selection of metal wire material, drawing process, surface modification method, and heat treatment process, the overall performance of the metal fiber felt can be significantly improved, enabling it to better meet the application requirements in fields such as filtration, separation, catalysis, and electromagnetic shielding. In actual production, the preparation process can be further optimized according to specific application scenarios and performance requirements to obtain high-performance metal fiber felt products with even better performance.

[0056] The above description of the present invention and its embodiments is non-limiting and the actual implementation is not limited thereto. In short, if a person skilled in the art is inspired by the above description and, without departing from the purpose of the present invention, designs similar to the technical solution without creatively designing, they shall fall within the scope of protection of the present invention.

Claims

1. A method for preparing high-performance metal fiber felt, characterized in that: The following steps are included in sequence: S1 metal fiber preparation: A metal wire with a purity of not less than 99% is selected as raw material, and the metal wire is drawn using a multi-pass drawing die. The deformation of each drawing pass is controlled within the range of 10%-30%. The metal wire is lubricated with a lubricant during the drawing process. The drawn metal fiber is then annealed. The annealing temperature is selected according to the material of the metal wire and is controlled at 50-100°C above the recrystallization temperature of the metal wire. The annealing time is set at 30-120 minutes. S2 metal fiber pretreatment: The annealed metal fiber is placed in a cleaning solution for cleaning at a temperature of 40-80°C for 10-30 minutes. After cleaning, it is rinsed with clean water and dried. The cleaned metal fiber is then subjected to surface modification treatment. S3 Metal Fiber Felt Forming: The pretreated metal fibers are evenly laid in a forming mold with the help of a mesh laying machine to form a metal fiber mesh with a specific thickness and porosity, wherein the thickness of the metal fiber mesh is controlled between 0.5-5 mm and the porosity is controlled between 70%-90%. The laid metal fiber mesh is then placed in a hot press for hot pressing. The hot pressing temperature is determined according to the material of the metal fiber and the properties of the surface modification layer, and is controlled to be 50-200°C below the melting point of the metal fiber. The hot pressing pressure is set to 5-30 MPa and the hot pressing time is 5-30 minutes. S4 post-processing: The metal fiber felt formed by hot pressing is taken out from the forming mold and trimmed; the trimmed metal fiber felt is subjected to heat treatment.

2. The method for preparing a high-performance metal fiber felt according to claim 1, wherein: The lubricant is any one of mineral oil and synthetic lubricant.

3. The method for preparing a high-performance metal fiber felt according to claim 1, wherein: The surface modification treatment adopts any one of chemical plating, electroplating or plasma treatment.

4. The method for preparing a high-performance metal fiber felt according to claim 1, wherein: The chemical plating is specifically chemical nickel plating, and the metal fiber is placed in a chemical nickel plating solution and treated at a temperature of 80-90° C. for 20-40 minutes to plate a uniform nickel layer on the surface of the metal fiber.

5. The method for preparing a high-performance metal fiber felt according to claim 1, wherein: The heat treatment process is any one of solution treatment, aging treatment or a combination of the two.

6. The method for preparing a high-performance metal fiber felt according to claim 5, characterized in that: When the heat treatment process is a combination of solution treatment and aging treatment, for nickel-based alloy metal fiber felt, solution treatment is first performed at 1050-1150°C and kept warm for 1-2 hours, and then aging treatment is performed at 700-800°C and kept warm for 4-8 hours.

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