Preparation method of metal fiber sintered felt base material
The preparation of stainless steel fiber sintered felts through low-temperature hydrothermal reaction and vapor deposition methods, which solved the problem of coarse grains caused by high-temperature sintering, improved the mechanical and corrosion resistance, and achieved an efficient metallurgical combination.
Patent Information
- Application Number
- CN202510479087.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-16
- Publication Date
- 2025-07-08
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The high-temperature sintering temperature of traditionally prepared stainless steel fiber sintering felts leads to the formation of coarse grains and bamboo-like grain boundaries, reducing its mechanical properties and making it difficult to ensure metallurgical bonding at low temperatures.
Hydrothermal reaction is carried out using an appropriate concentration of phosphoric acid aqueous solution to form a rough structure of micro-nano particles. Combined with the vapor deposition method, the sintering temperature is controlled at 1000~1020℃, and the temperature increase rate and atmosphere conditions are optimized.
It improves the mechanical properties of metal fiber sintered felt substrates, enhances metallurgical bonding, and improves corrosion resistance and tensile properties.
Smart Images
Figure CN120273102A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of sintered felts, and particularly relates to a preparation method of a metal fiber sintered felt substrate. Background Art
[0002] A metal fiber sintered felt is a three-dimensional network porous material formed by micron-level metal fibers through processes such as laying and high-temperature sintering. It has a high porosity, a large surface area, and a uniform pore size distribution. The metal fiber sintered felt has excellent filtration performance, and at the same time has properties such as high temperature resistance, corrosion resistance, high precision, and low pressure loss. At present, metal fiber sintered felts have been widely used in many fields such as filtration and separation, high-temperature gas dust removal, sound absorption and noise reduction, and tail gas purification.
[0003] Compared with other metal fiber sintered felts, the stainless steel fiber sintered felt has a high porosity, excellent dirt-holding capacity, and after high-temperature sintering, the formed pores can withstand higher pressures and are not easily deformed, with high structural stability. Therefore, it also has stable service performance and a long service life.
[0004] When preparing a stainless steel fiber sintered felt, high-temperature sintering is one of the key processes, which ensures the metallurgical bonding of sintering nodes. In the current traditional sintering process, the sintering temperature is mostly close to 1200°C. This relatively high sintering temperature will form coarse grains and bamboo-joint-shaped grain boundaries on the stainless steel fibers. The formation of coarse grains and bamboo-joint-shaped grain boundaries reduces the mechanical properties of the stainless steel fiber sintered felt. Therefore, in order to improve the mechanical properties of the obtained stainless steel fiber sintered felt, it is necessary to reduce its sintering temperature. However, when reducing the sintering temperature, the traditional preparation process is difficult to ensure the metallurgical bonding of fiber sintering nodes. Summary of the Invention
[0005] The purpose of the present invention is to provide a preparation method of a metal fiber sintered felt substrate. When the metal fiber sintered felt substrate is prepared by the method of the present invention, the sintering temperature is relatively low, and the prepared metal fiber sintered felt substrate has excellent mechanical properties.
[0006] To achieve the above purpose, the present invention is realized through the following technical solutions: A preparation method of a metal fiber sintered felt substrate includes the following steps: (1) Pretreat the stainless steel short fibers, then place them in a reaction kettle, add a phosphoric acid aqueous solution with a mass fraction of 4.5 - 6%, seal the reaction kettle, raise the temperature to 150 - 165°C for hydrothermal reaction, and then filter, wash with water, and dry to obtain pretreated stainless steel short fibers; lay the pretreated stainless steel short fibers into a fiber web, and then obtain a metal fiber felt blank through pre-pressing; (2) Place the metal fiber felt blank in a sintering furnace and sinter it under a mixed atmosphere of hydrogen and argon. The sintering temperature is 1000 - 1020 °C, and keep it warm for 25 - 32 minutes, then cool it to room temperature with the furnace, obtaining the metal fiber sintered felt substrate to be treated; (3) Place the metal fiber sintered felt substrate to be treated in a chemical vapor deposition furnace. At 830 - 850 °C, deposit pyrolytic carbon on the fiber surface of the metal fiber sintered felt substrate to be treated to obtain the metal fiber sintered felt substrate.
[0007] The phosphoric acid aqueous solution in the present invention is controlled between 4.5 - 6%. Because if the concentration is too high, it will cause excessive hydrothermal etching, thus causing great damage to the strength of the stainless steel short fibers, and further affecting the mechanical properties of the metal fiber sintered felt substrate; while if the concentration is too low, the constructed rough structure is limited, and then when sintering at 1000 - 1020 °C, a good metallurgical bond cannot be formed, resulting in a reduction in the mechanical properties of the metal fiber sintered felt substrate.
[0008] Preferably, in step (1), the time of the hydrothermal reaction is 2 - 3 hours.
[0009] Preferably, in step (2), in the mixed atmosphere of hydrogen and argon, the volume ratio of argon to hydrogen is 7 - 8:1.
[0010] Preferably, in step (2), during sintering, first heat up at a heating rate of 5 - 10 °C / min to 890 - 920 °C, and then heat up at a heating rate of 0.8 - 1.5 °C / min to 1000 - 1020 °C. By heating up at a heating rate of 0.8 - 1.5 °C / min after 890 - 920 °C, compared with directly heating up to 1000 - 1020 °C at a heating rate of 5 - 10 °C / min, the overall mechanical properties of the metal fiber sintered felt substrate will be better.
[0011] Preferably, step (3) specifically includes the following steps: Place the metal fiber sintered felt substrate to be treated in a chemical vapor deposition furnace, and evacuate it, then heat up to 830 - 850 °C, and then introduce a mixed gas of methane and argon. The introduction time is 7 - 10 minutes, and deposit pyrolytic carbon on the fiber surface of the metal fiber sintered felt substrate to be treated; then stop introducing methane, introduce argon and cool it to room temperature under an argon atmosphere with the furnace to obtain the metal fiber sintered felt substrate.
[0012] Preferably, heat up to 830 - 850 °C at a heating rate of 5 - 10 °C / min.
[0013] Preferably, in the mixed gas of methane and argon, the volume flow rate of methane is 40 - 60 sccm, and the volume flow rate of argon is 25 - 40 sccm.
[0014] By reasonably controlling the deposition time of pyrolytic carbon and the amount of methane introduced, etc., an appropriate amount of pyrolytic carbon is deposited on the fiber surface of the metal fiber sintered felt, which can effectively reinforce the fiber without blocking the pores due to excessive deposition of pyrolytic carbon and increasing the production cost.
[0015] Preferably, in step (1), the stainless steel short fibers are 316L stainless steel short fibers, the wire diameter of the stainless steel short fibers is 15 - 30 μm, and the length is 15 - 20 mm.
[0016] Preferably, in step (1), the pretreated stainless steel short fibers are formed into a fiber web by air laying.
[0017] Preferably, the pretreatment of the stainless steel short fibers includes the following steps: first place the stainless steel short fibers in acetone and ultrasonically clean for 10 - 20 min, then place them in deionized water and ultrasonically clean for 3 - 6 min, then place them in a sodium hydroxide solution with a mass fraction of 10 - 15% and ultrasonically clean for 10 - 30 min, then place them in deionized water and ultrasonically clean for 5 - 8 min, and then dry.
[0018] The beneficial effects of the present invention are: When preparing the metal fiber sintered felt substrate of the present invention, first, the stainless steel short fibers are hydrothermally etched with a phosphoric acid aqueous solution of an appropriate concentration to in-situ form a rough structure of micro-nano particles on the surface of the stainless steel short fibers. By constructing this rough structure, the mechanical bite points and contact areas between the stainless steel short fibers are increased, forming a stronger physical anchoring, and then sintering at a temperature of 1000 - 1020 °C can also achieve effective metallurgical bonding. And this micro-nano scale rough structure also facilitates the formation of a dense bond between the fibers, strengthening the metallurgical bonding force. The sintering temperature of 1000 - 1020 °C can effectively avoid the formation of large grains and bamboo joint-shaped grain boundaries on the stainless steel fibers, so that the metal fiber sintered felt substrate as a whole has high mechanical properties.
[0019] After the surface of the stainless steel short fibers of the present invention is etched, its strength will be reduced compared with the unetched fibers. To solve this problem, an appropriate amount of pyrolytic carbon is deposited on the fiber surface of the metal fiber sintered felt substrate to be treated by chemical vapor deposition. This appropriate amount of pyrolytic carbon can cover the holes on the surface of the stainless steel fibers, etc., reducing the risk of subsequent fiber cracking, and the pyrolytic carbon itself can also bear part of the tensile stress, thereby significantly improving the tensile properties of the obtained metal fiber sintered felt substrate. In addition, by depositing pyrolytic carbon on the surface of the stainless steel fibers, a protective layer can be formed on the surface of the stainless steel fibers, making the metal fiber sintered felt substrate exhibit more excellent corrosion resistance.
[0020] The sintering temperature for preparing the metal fiber sintered felt substrate by the method of the present invention is relatively low. The obtained metal fiber sintered felt substrate has excellent yield strength and fracture strength, and has an appropriate elongation at break, enabling the obtained metal fiber sintered felt substrate to be applicable to a variety of application scenarios. Description of the Drawings
[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.
[0022] Figure 1 It is a process flow chart for preparing the metal fiber sintered felt substrate of the present invention. Detailed Embodiments
[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.
[0024] In the following embodiments and comparative examples, the stainless steel short fibers used are 316L stainless steel short fibers, with a wire diameter of 20 μm and a length of 20 mm.
[0025] Example 1: A method for preparing a metal fiber sintered felt substrate, the process flow chart is as Figure 1 shown, and specifically includes the following steps: (1) Pretreatment: Place the stainless steel short fibers in acetone first, ultrasonically clean for 20 min, then place them in deionized water and ultrasonically clean for 5 min, then place them in a sodium hydroxide solution with a mass fraction of 15% and ultrasonically clean for 20 min, then place them in deionized water and ultrasonically clean for 6 min, and then perform drying to obtain the pretreated stainless steel short fibers; Place the pre-treated stainless steel short fibers in a reaction kettle, add a phosphoric acid aqueous solution with a mass fraction of 5.0%, and the mass-volume ratio of the stainless steel short fibers to the phosphoric acid aqueous solution is 1 g: 32 mL; then seal the reaction kettle, heat it up to 155 °C for hydrothermal reaction, the reaction time is 2.5 h, and then filter, wash with water, and dry to obtain pre-treated stainless steel short fibers; use the air-laying method to form a fiber web with the pre-treated stainless steel short fibers, and then through pre-pressing, obtain a metal fiber felt blank with a thickness of 5 mm, and the porosity of the metal fiber felt blank is 85%.
[0026] (2)Place the metal fiber felt blank in a sintering furnace and sinter it in a mixed atmosphere of hydrogen and argon. The volume ratio of argon to hydrogen in the mixed atmosphere is 7:1. When sintering, first heat it up to 910 °C at a heating rate of 8 °C / min, and then heat it up to 110 °C at a heating rate of 4 °C / min, keep it warm for 30 min, and then cool it to room temperature with the furnace to obtain a metal fiber sintered felt substrate to be treated.
[0027] (3)Place the metal fiber sintered felt substrate to be treated in a chemical vapor deposition furnace, evacuate it, then heat it up to 850 °C at a heating rate of 10 °C / min, and then introduce a mixed gas of methane and argon. The volume flow rate of methane is 50 sccm, and the volume flow rate of argon is 30 sccm. The introduction time is 8 min to deposit pyrolytic carbon on the fiber surface of the metal fiber sintered felt substrate to be treated; then stop introducing methane, introduce argon and cool it to room temperature in an argon atmosphere with the furnace to obtain a metal fiber sintered felt substrate.
[0028] Example 2: A preparation method of a metal fiber sintered felt substrate, comprising the following steps: (1)Pretreatment: First place the stainless steel short fibers in acetone, ultrasonically clean for 20 min, then place them in deionized water and ultrasonically clean for 5 min, then place them in a sodium hydroxide solution with a mass fraction of 15% and ultrasonically clean for 20 min, then place them in deionized water and ultrasonically clean for 6 min, and then dry them to obtain pre-treated stainless steel short fibers; Place the pre-treated stainless steel short fibers in a reaction kettle, add a phosphoric acid aqueous solution with a mass fraction of 4.5%, and the mass-volume ratio of the stainless steel short fibers to the phosphoric acid aqueous solution is 1 g: 32 mL; then seal the reaction kettle, heat it up to 150 °C for hydrothermal reaction, the reaction time is 3 h, and then filter, wash with water, and dry to obtain pre-treated stainless steel short fibers; use the air-laying method to form a fiber web with the pre-treated stainless steel short fibers, and then through pre-pressing, obtain a metal fiber felt blank with a thickness of 5 mm, and the porosity of the metal fiber felt blank is 85%.
[0029] (2) Place the metal fiber felt blank in a sintering furnace and sinter it in a mixed atmosphere of hydrogen and argon. The volume ratio of argon to hydrogen in the mixed atmosphere is 8:1. When sintering, first heat it at a heating rate of 5 °C / min to 890 °C, then heat it at a heating rate of 1.5 °C / min to 1020 °C, hold for 30 min, and then cool it in the furnace to room temperature to obtain the metal fiber sintered felt substrate to be treated.
[0030] (3) Place the metal fiber sintered felt substrate to be treated in a chemical vapor deposition furnace, evacuate it, then heat it at a heating rate of 5 °C / min to 840 °C, and then introduce a mixed gas of methane and argon. The volume flow rate of methane is 60 sccm, and the volume flow rate of argon is 35 sccm. The introduction time is 7 min to deposit pyrolytic carbon on the fiber surface of the metal fiber sintered felt substrate to be treated; then stop introducing methane, introduce argon, and cool it in the furnace to room temperature in an argon atmosphere to obtain the metal fiber sintered felt substrate.
[0031] Example 3: A method for preparing a metal fiber sintered felt substrate, comprising the following steps: (1) Pretreatment: First place the stainless steel short fibers in acetone and ultrasonically clean them for 20 min, then place them in deionized water and ultrasonically clean them for 5 min, then place them in a sodium hydroxide solution with a mass fraction of 15% and ultrasonically clean them for 20 min, then place them in deionized water and ultrasonically clean them for 6 min, and then dry them to obtain the pretreated stainless steel short fibers; Place the pretreated stainless steel short fibers in a reaction kettle, add a phosphoric acid aqueous solution with a mass fraction of 4.5%. The mass-volume ratio of the stainless steel short fibers to the phosphoric acid aqueous solution is 1 g:32 mL; then seal the reaction kettle, heat it to 165 °C for hydrothermal reaction, the reaction time is 3 h, then filter, wash with water, and dry to obtain the pretreated stainless steel short fibers; use the air-laying method to lay the pretreated stainless steel short fibers into a web, and then pre-press to obtain a 5-mm-thick metal fiber felt blank. The porosity of the metal fiber felt blank is 86%.
[0032] (2) Place the metal fiber felt blank in a sintering furnace and sinter it in a mixed atmosphere of hydrogen and argon. The volume ratio of argon to hydrogen in the mixed atmosphere is 7:1. When sintering, first heat it at a heating rate of 6 °C / min to 920 °C, then heat it at a heating rate of 0.8 °C / min to 1000 °C, hold for 32 min, and then cool it in the furnace to room temperature to obtain the metal fiber sintered felt substrate to be treated.
[0033] (3) Place the substrate of the metal fiber sintered felt to be treated in a chemical vapor deposition furnace, evacuate it, then heat it up to 845 °C at a heating rate of 8 °C / min, and then introduce a mixed gas of methane and argon. The volume flow rate of methane is 40 sccm, the volume flow rate of argon is 25 sccm, and the introduction time is 10 min to deposit pyrolytic carbon on the fiber surface of the substrate of the metal fiber sintered felt to be treated; then stop introducing methane, introduce argon, and cool it down to room temperature in the argon atmosphere to obtain the substrate of the metal fiber sintered felt.
[0034] Example 4: A method for preparing a substrate of a metal fiber sintered felt, comprising the following steps: (1) Pretreatment: Place the stainless steel short fibers in acetone and ultrasonically clean them for 20 min, then place them in deionized water and ultrasonically clean them for 5 min, then place them in a sodium hydroxide solution with a mass fraction of 15% and ultrasonically clean them for 20 min, then place them in deionized water and ultrasonically clean them for 6 min, and then dry them to obtain the pretreated stainless steel short fibers; Place the pretreated stainless steel short fibers in a reaction kettle, add a phosphoric acid aqueous solution with a mass fraction of 6%, and the mass-to-volume ratio of the stainless steel short fibers to the phosphoric acid aqueous solution is 1 g: 32 mL; then seal the reaction kettle, heat it up to 160 °C for hydrothermal reaction, the reaction time is 2 h, then filter, wash with water, and dry to obtain the pretreated stainless steel short fibers; use the air-laying method to lay the pretreated stainless steel short fibers into a fiber web, and then pre-press to obtain a metal fiber felt blank with a thickness of 5 mm, and the porosity of the metal fiber felt blank is 86%.
[0035] (2) Place the metal fiber felt blank in a sintering furnace and sinter it in a mixed atmosphere of hydrogen and argon. The volume ratio of argon to hydrogen in the mixed atmosphere is 7:1. When sintering, first heat it up to 900 °C at a heating rate of 5 °C / min, then heat it up to 1005 °C at a heating rate of 1 °C / min, keep it warm for 30 min, and then cool it down to room temperature to obtain the substrate of the metal fiber sintered felt to be treated.
[0036] (3) Place the substrate of the metal fiber sintered felt to be treated in a chemical vapor deposition furnace, evacuate it, then heat it up to 835 °C at a heating rate of 7 °C / min, and then introduce a mixed gas of methane and argon. The volume flow rate of methane is 50 sccm, the volume flow rate of argon is 25 sccm, and the introduction time is 9 min to deposit pyrolytic carbon on the fiber surface of the substrate of the metal fiber sintered felt to be treated; then stop introducing methane, introduce argon, and cool it down to room temperature in the argon atmosphere to obtain the substrate of the metal fiber sintered felt.
[0037] Example 5: A method for preparing a substrate of a metal fiber sintered felt, comprising the following steps: (1) Pretreatment: First, place the stainless - steel short fibers in acetone and ultrasonically clean them for 20 min. Then, place them in deionized water and ultrasonically clean for 5 min. Next, place them in a sodium hydroxide solution with a mass fraction of 15% and ultrasonically clean for 20 min. Then, place them in deionized water again and ultrasonically clean for 6 min. After that, perform drying to obtain the pretreated stainless - steel short fibers. Place the pretreated stainless - steel short fibers in a reaction kettle, add a phosphoric acid aqueous solution with a mass fraction of 5.0%, and the mass - to - volume ratio of the stainless - steel short fibers to the phosphoric acid aqueous solution is 1 g:32 mL. Then, seal the reaction kettle, raise the temperature to 160 °C for hydrothermal reaction, and the reaction time is 2.5 h. After that, filter, wash with water, and dry to obtain the pretreated stainless - steel short fibers. Use the air - laid method to form a web with the pretreated stainless - steel short fibers, and then through pre - pressing, obtain a 5 - mm - thick metal fiber felt blank, and the porosity of the metal fiber felt blank is 85%.
[0038] (2) Place the metal fiber felt blank in a sintering furnace and sinter it under a mixed atmosphere of hydrogen and argon. The volume ratio of argon to hydrogen in the mixed atmosphere is 8:1. When sintering, first raise the temperature at a heating rate of 10 °C / min to 900 °C, then raise the temperature at a heating rate of 1.2 °C / min to 1020 °C, hold for 28 min, and then cool to room temperature with the furnace to obtain the metal fiber sintered felt substrate to be treated.
[0039] (3) Place the metal fiber sintered felt substrate to be treated in a chemical vapor deposition furnace, evacuate it, then raise the temperature at a heating rate of 10 °C / min to 850 °C, and then introduce a mixed gas of methane and argon. The volume flow rate of methane is 40 sccm, and the volume flow rate of argon is 30 sccm. The introduction time is 7 min to deposit pyrolytic carbon on the fiber surface of the metal fiber sintered felt substrate to be treated. Then, stop introducing methane, introduce argon, and cool to room temperature with the furnace under an argon atmosphere to obtain the metal fiber sintered felt substrate.
[0040] Comparative Example 1: It is basically the same as Example 5, except that the metal fiber sintered felt substrate to be treated is not subjected to the treatment in step (3), that is, the metal fiber sintered felt substrate to be treated obtained in step (2) is directly used as the metal fiber sintered felt substrate.
[0041] Comparative Example 2: It is basically the same as Example 5, except that the hydrothermal reaction with the phosphoric acid aqueous solution is not carried out on the pretreated stainless - steel short fibers. That is, the pretreated stainless - steel short fibers are directly formed into a web by the air - laid method, and then through pre - pressing, a 5 - mm - thick metal fiber felt blank is obtained; then, through steps (2) and (3), the metal fiber sintered felt substrate is prepared.
[0042] Comparative Example 3: Basically the same as Example 5, except that the mass fraction of the phosphoric acid aqueous solution is 8%.
[0043] Comparative Example 4: Basically the same as Example 5, except that the mass fraction of the phosphoric acid aqueous solution is 2%.
[0044] Comparative Example 5: Basically the same as Example 5, except that in step (2) during sintering, the temperature is directly increased to 1020°C at a heating rate of 10°C / min.
[0045] Cut the metal fiber sintered felt substrates in Examples 1 - 5 and Comparative Examples 1 - 5 into test blocks of 8 cm × 2 cm, then conduct a tensile test at a tensile rate of 1.5 mm / min, test their yield strength and fracture strength, and additionally test the fracture elongation rate of the metal fiber sintered felt substrates. The specific test results are shown in Table 1.
[0046] Table 1: <![CDATA[Yield strength σ 0.2 / MPa]]> <![CDATA[Tensile strength σ b / MPa]]> Elongation at break / % Example 1 22.5 34.9 10.2 Example 2 23.2 35.8 10.7 Example 3 23.5 36.0 11.0 Example 4 22.7 35.2 10.4 Example 5 22.1 34.5 10.0 Comparative Example 1 19.2 30.3 8.7 Comparative Example 2 16.7 27.0 7.6 Comparative Example 3 20.0 32.2 9.2 Comparative Example 4 19.5 31.1 9.0 Comparative Example 5 20.5 32.8 9.5
[0047] As can be seen from Table 1, the metal fiber sintered felt substrate prepared by the present invention has excellent tensile properties and good mechanical properties.
[0048] As can be seen from the comparison between Example 5 and Comparative Example 1, depositing pyrolytic carbon on the fiber surface of the metal fiber sintered felt substrate to be treated can effectively improve the yield strength, fracture strength, and fracture elongation rate of the metal fiber sintered felt substrate.
[0049] As can be seen from the comparison between Example 5 and Comparative Example 2, if the hydrothermal reaction of the pre - treated stainless steel short fibers with the phosphoric acid aqueous solution is not carried out, effective metallurgical bonding cannot be achieved during sintering at 1020°C, thus significantly affecting the mechanical properties.
[0050] As can be seen from the comparison between Example 5 and Comparative Example 3, when hydrothermally etching the stainless steel short fibers, if the concentration of the phosphoric acid aqueous solution is too high, it will cause slightly excessive etching, reduce the strength of the stainless steel short fibers, and thus lead to a decrease in the mechanical properties of the metal fiber sintered felt substrate.
[0051] As can be seen from the comparison between Example 5 and Comparative Example 4, when hydrothermally etching the stainless steel short fibers, if the concentration of the phosphoric acid aqueous solution is too low, the constructed rough structure is limited, and thus good metallurgical bonding cannot be formed during sintering at 1020°C, resulting in a decrease in the mechanical properties of the metal fiber sintered felt substrate.
[0052] As can be seen from the comparison between Example 5 and Comparative Example 5, compared with directly increasing the temperature to 1020°C at a heating rate of 10°C / min, increasing the temperature to 1020°C at a heating rate of 1.2°C / min after 900°C will make the overall mechanical properties of the metal fiber sintered felt substrate better.
[0053] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.
Claims
1. A preparation method of a metal fiber sintered felt substrate, characterized in that, It includes the following steps: (1) Pretreat the stainless steel short fibers, then place them in a reaction kettle, add an aqueous phosphoric acid solution with a mass fraction of 4.5 - 6%, seal the reaction kettle, heat up to 150 - 165 °C for hydrothermal reaction, then filter, wash with water, and dry to obtain pretreated stainless steel short fibers; lay the pretreated stainless steel short fibers into a fiber web, and then obtain a metal fiber felt blank through pre-pressing; (2) Place the metal fiber felt blank in a sintering furnace, sinter it in a mixed atmosphere of hydrogen and argon, the sintering temperature is 1000 - 1020 °C, and keep it warm for 25 - 32 min, then cool it to room temperature with the furnace to obtain a metal fiber sintered felt substrate to be treated; (3) Place the metal fiber sintered felt substrate to be treated in a chemical vapor deposition furnace, deposit pyrolytic carbon on the fiber surface of the metal fiber sintered felt substrate to be treated at 830 - 850 °C to obtain the metal fiber sintered felt substrate.
2. The preparation method of the metal fiber sintered felt substrate according to claim 1, characterized in that, In step (1), the time of the hydrothermal reaction is 2 - 3 h.
3. The preparation method of the metal fiber sintered felt substrate according to claim 1, characterized in that, In step (2), in the mixed atmosphere of hydrogen and argon, the volume ratio of argon to hydrogen is 7 - 8:
1.
4. The preparation method of the metal fiber sintered felt substrate according to claim 1, characterized in that, In step (2), during sintering, first heat up at a heating rate of 5 - 10 °C / min to 890 - 920 °C, and then heat up at a heating rate of 0.8 - 1.5 °C / min to 1000 - 1020 °C.
5. The preparation method of the metal fiber sintered felt substrate according to claim 1, characterized in that, Step (3) specifically includes the following steps: Place the metal fiber sintered felt substrate to be treated in a chemical vapor deposition furnace, evacuate it, then heat up to 830 - 850 °C, and then introduce a mixed gas of methane and argon, the introduction time is 7 - 10 min, deposit pyrolytic carbon on the fiber surface of the metal fiber sintered felt substrate to be treated; then stop introducing methane, introduce argon and cool it to room temperature with the furnace in an argon atmosphere to obtain the metal fiber sintered felt substrate.
6. The preparation method of the metal fiber sintered felt substrate according to claim 5, characterized in that, Heat up to 830 - 850 °C at a heating rate of 5 - 10 °C / min.
7. The preparation method of the metal fiber sintered felt substrate according to claim 5, characterized in that, In the mixed gas of methane and argon, the volume flow rate of methane is 40 - 60 sccm, and the volume flow rate of argon is 25 - 40 sccm.
8. The preparation method of the metal fiber sintered felt substrate according to any one of claims 1 to 7, characterized in that In step (1), the stainless steel short fibers are 316L stainless steel short fibers, the wire diameter of the stainless steel short fibers is 15 - 30 μm, and the length is 15 - 20 mm.
9. The preparation method of the metal fiber sintered felt substrate according to any one of claims 1 to 7, characterized in that, In step (1), the pretreated stainless steel short fibers are laid into a fiber web by the air-laying method.
10. The preparation method of the metal fiber sintered felt substrate according to any one of claims 1 to 7, characterized in that, The pretreatment of the stainless steel short fibers includes the following steps: First place the stainless steel short fibers in acetone, ultrasonically clean for 10 - 20 min, then place them in deionized water and ultrasonically clean for 3 - 6 min, then place them in a sodium hydroxide solution with a mass fraction of 10 - 15% and ultrasonically clean for 10 - 30 min, then place them in deionized water and ultrasonically clean for 5 - 8 min, and then dry them.