Regenerated carbon fiber reinforced metal-based composite material and preparation method and application thereof

Abstract

The invention discloses a preparation method of a regenerated carbon fiber reinforced metal-based composite material, which comprises the following steps: S1, pretreatment of a waste carbon fiber composite material: carrying out three-stage pyrolysis treatment on the waste carbon fiber composite material in an inert gas environment to obtain regenerated carbon fibers; and S2, metal or alloy with excellent physical performance and processability is selected as a base material, metal powder and the regenerated carbon fibers are evenly mixed, the mixture is put into a pressing die to be repressed into a formed blank, the formed blank is put into a heating furnace to be sintered, and a tightly-combined composite material structure is formed. The high-performance carbon fiber reinforced metal-based composite material is successfully prepared through an innovative regenerated carbon fiber surface treatment technology in combination with an advanced composite material preparation process, and a new way is provided for cyclic utilization of carbon fiber resources and improvement of the performance of the composite material.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and in particular to a recycled carbon fiber reinforced metal matrix composite material and a preparation method and application thereof. Background Art

[0002] Carbon fiber metal matrix composites have shown broad application prospects in aerospace, automobile manufacturing, electronic packaging, sporting goods and other fields due to their high specific strength, high specific stiffness, good thermal conductivity and electrical conductivity. However, traditional carbon fiber reinforced metal matrix composites face two major challenges: one is the destruction of the carbon fiber structure under high temperature environment; the other is the insufficient interface bonding between carbon fiber and metal matrix, which limits the full play of the overall performance of the composite material. In particular, the chemical inertness and low number of active functional groups on the surface of carbon fiber seriously affect its wettability and bonding strength with the metal matrix.

[0003] The surface properties of carbon fiber depend on the size of its roughness, the type and number of active functional groups, the size of the microcrystalline structure, and the strength of the acid-base interaction. From the perspective of the surface morphology of carbon fiber, there are many micropores, foreign matter, crystals, etc. on its surface, which are important factors affecting the bonding performance between the matrix and the reinforcement in the composite material. The untreated carbon fiber has a smooth surface, high chemical inertness, low surface energy, and very few active functional groups (polar functional groups such as hydroxyl and carbonyl). It has poor wettability with the matrix in the composite material, thereby reducing the interface bonding ability of the composite material and hindering the maximization of the performance of the reinforced fiber. After surface treatment, the mechanical properties of carbon fiber reinforced materials (such as interlaminar shear strength and interfacial shear strength) will be improved. The commonly used surface treatment methods are: gas phase oxidation method (air, ozone, inert gas), liquid phase oxidation method (concentrated nitric acid, mixed acid and strong oxidant), anodic oxidation method (electrochemical oxidation), plasma oxidation method (plasma oxygen, plasma ammonia), surface coating modification method, and composite surface treatment method using two or more methods to treat the surface of carbon fiber.

[0004] Although the existing carbon fiber surface treatment technology can improve the interface bonding performance to a certain extent, it has problems such as high processing cost, complex operation, and great impact on the environment, and it is difficult to fully explore the high strength potential of carbon fiber. Therefore, developing a new method that is both economical and efficient and can significantly improve the interface bonding strength has become a hot topic in current research. Summary of the invention

[0005] The purpose of the present invention is to provide a recycled carbon fiber reinforced metal matrix composite material and its preparation method and application, aiming to solve the problems of carbon fiber damage and poor interface bonding between carbon fiber and metal in traditional carbon fiber metal matrix composite materials under high temperature environment, and to achieve significant improvement in the performance of composite materials through innovative recycled carbon fiber processing technology and unique composite material preparation process.

[0006] In a first aspect, the present invention provides a method for preparing a recycled carbon fiber reinforced metal matrix composite material, comprising the following steps:

[0007] Step S1, pretreatment of waste carbon fiber composite materials: subjecting the waste carbon fiber composite materials to three-stage pyrolysis treatment in an inert gas environment to obtain recycled carbon fiber;

[0008] Step S2, selecting a metal or alloy with excellent physical properties and processing properties as the matrix material, uniformly mixing the metal powder with the above-mentioned recycled carbon fiber, loading into a die and re-pressing into a molded blank, placing in a heating furnace for sintering to form a tightly bonded composite material structure.

[0009] In certain embodiments, the resin residues on the surface of the regenerated carbon fiber are distributed in clusters, are firmly sintered to the surface of the carbon fiber, and are rich in surface active groups.

[0010] In certain embodiments, the inert gas in step S1 includes one of nitrogen, helium, neon, argon, krypton, and xenon.

[0011] In certain embodiments, step S1 comprises the following three stages:

[0012] Stage 1: fully carried out in the absence of oxygen and low temperature, so that the residue is relatively uniform and the epoxy resin residue accounts for 5-10% by mass;

[0013] Stage 2: Perform oxygen-free high-temperature pyrolysis to reduce the epoxy resin residue to 1-5% by mass;

[0014] Stage 3: Oxidizing the surface with oxygen at a certain temperature to form recycled carbon fiber with a carbon fiber mass content of 98-99%.

[0015] In certain embodiments, the low temperature range of stage 1 is 300-500° C., and the treatment time is 1-3 hours.

[0016] In certain embodiments, the high temperature range of stage 2 is 700-800° C., and the treatment time is 10-30 minutes.

[0017] In certain embodiments, the temperature of stage three ranges from 500 to 700° C., and the treatment time is 10 to 30 seconds.

[0018] Among them: the time and temperature of stages one and two are regulated by the proportion of residues.

[0019] The functions of the three stages are as follows: in stage one, most of the resin is removed non-destructively through anaerobic low-temperature pyrolysis, and the residues on the fiber surface are ensured to be relatively uniform; in stage two, the residues meet the requirements through anaerobic high-temperature pyrolysis to prevent excessive residues; in stage three, the resin residues are combined with the carbon fiber surface by controlling the oxygen flow time and temperature to form incomplete carbonization, which exists on the fiber surface together with the resin residues. The residual resin is distributed in clusters on the carbon fiber surface and is firmly sintered to the carbon fiber surface. The oxidized residual resin surface is extremely rich in active groups. The residual resin in cluster form not only increases the fiber's pull-out resistance, but also the active groups on the oxidized surface of the resin greatly enhance the bonding strength with the metal matrix, further increasing the tensile performance.

[0020] The inventors have found through comparison that the metal-based composite material prepared using this recycled carbon fiber can effectively increase the strength of the fiber being pulled out due to the effect of the agglomerated resin residues, thereby improving the performance of the entire composite material system.

[0021] In certain embodiments, the matrix material includes one of aluminum, copper, and silver.

[0022] In certain embodiments, the sintering temperature in step S2 is 650-850°C.

[0023] In a second aspect, the present invention provides a recycled carbon fiber reinforced metal matrix composite material, which is composed of recycled carbon fiber and a matrix material, wherein the matrix material includes a metal or an alloy; the composite material is prepared by the following method:

[0024] Step S1, pretreatment of waste carbon fiber composite materials: subjecting the waste carbon fiber composite materials to three-stage pyrolysis treatment in an inert gas environment to obtain recycled carbon fiber;

[0025] Step S2, selecting a metal or alloy with excellent physical properties and processing properties as the matrix material, uniformly mixing the metal powder with the above-mentioned recycled carbon fiber, loading into a die and re-pressing into a molded blank, placing in a heating furnace for sintering to form a tightly bonded composite material structure.

[0026] In a third aspect, the recycled carbon fiber reinforced metal matrix composite material provided by the present invention is used in the fields of aerospace, automobile manufacturing, electronic packaging, and sporting goods.

[0027] Beneficial effects: The present invention successfully solves the problems of interface bonding and high temperature stability of traditional carbon fiber metal matrix composite materials through innovative recycled carbon fiber surface treatment technology combined with advanced composite material preparation technology, and opens up a new way for the recycling of carbon fiber resources and the improvement of composite material performance. The composite material not only has significant economic and social benefits, but also provides strong support for promoting technological progress and product upgrades in related industries. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below through embodiments.

[0029] Example 1

[0030] Step S1: Pyrolysis of waste carbon fiber composites in a nitrogen environment. First, pyrolysis is performed at 350°C for 3 hours without oxygen, so that the residue is relatively uniform and the residue mass accounts for about 7%. Then, pyrolysis is performed at 750°C for 20 minutes without oxygen, so that the residual mass of epoxy resin accounts for about 3%. Finally, the surface is oxidized by oxygen at 600°C for 20 seconds to form recycled carbon fiber with a carbon fiber mass content of 98.5%.

[0031] Step S2: Aluminum is selected as the matrix material, aluminum powder is uniformly mixed with the pretreated carbon fiber, loaded into a die and re-pressed into a molded blank, and placed in a heating furnace for sintering at 650° C. to form a tightly bonded composite material structure, in which the carbon fiber mass accounts for 10%.

[0032] Example 2

[0033] Step S1: Pyrolysis of waste carbon fiber composites in an argon environment. First, pyrolysis is performed at 400°C for 2 hours without oxygen, so that the residue is relatively uniform and the residue mass accounts for about 8%. Then, pyrolysis is performed at 780°C for 15 minutes without oxygen, so that the residual mass of epoxy resin accounts for about 2%. Finally, the surface is oxidized by oxygen at 550°C for 25 seconds to form recycled carbon fiber with a carbon fiber mass content of 98.8%.

[0034] Step S2: Copper is selected as the matrix material, aluminum powder is uniformly mixed with the pretreated carbon fiber, loaded into a die to re-press the formed blank, and placed in a heating furnace for sintering at 700° C. to form a tightly bonded composite material structure, in which the carbon fiber mass accounts for 10%.

[0035] Example 3

[0036] Step S1: Pyrolysis of waste carbon fiber composite materials in a neon environment. First, pyrolysis is performed at 450°C for 1.5 hours without oxygen, so that the residue is relatively uniform and the residue mass accounts for about 10%. Then, pyrolysis is performed at 800°C for 10 minutes without oxygen, so that the residual mass of epoxy resin accounts for about 1.8%. Finally, the surface is oxidized by oxygen at 700°C for 10 seconds to form recycled carbon fiber with a carbon fiber mass content of 99%.

[0037] Step S2: silver is selected as the matrix material, aluminum powder is uniformly mixed with the pretreated carbon fiber, loaded into a die and re-pressed into a molded blank, and placed in a heating furnace for sintering at 850°C to form a tightly bonded composite material structure, in which the carbon fiber mass accounts for 10%.

[0038] Comparative Example 1

[0039] Take new carbon fiber and perform oxidation treatment at 500° C. for 15 min (conventional carbon fiber oxidation treatment). The remaining steps are the same as those in Example 1.

[0040] Comparative Example 2

[0041] The regenerated carbon fiber treatment method in Example 2 was used, but the oxygen flow time was 15 minutes.

[0042] Comparative Example 3

[0043] The treatment method of the regenerated carbon fiber in Example 3 was used, but the oxygen-free high-temperature pyrolysis was carried out at 800°C for 30 minutes.

[0044] The composite materials prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests, and the test results are as follows:

[0045]

[0046] It can be seen from the above table:

[0047] The composite materials prepared in Examples 1-3 are superior to those in Comparative Examples 1-3 in terms of interface bonding strength, high temperature stability and overall performance.

[0048] In particular, in Examples 1-3, due to the firm bonding of the agglomerated resin residues on the surface of the regenerated carbon fibers to the surface of the carbon fibers and the abundant active groups, the strength of the fibers when pulled out is significantly improved, thereby improving the performance of the entire composite material system.

[0049] Compared with comparative example 1, the carbon fiber reinforcement effect of the composite material of comparative example 1 without an oxidized resin layer on the surface is worse than that of the carbon fiber with agglomerated resin residue, indicating that the effect of the resin oxidation layer is obvious.

[0050] Compared with Example 2, Example 2 has a longer oxidation time, serious resin decomposition, and a weakened strengthening effect;

[0051] When comparing Example 3 with Comparative Example 3, it is found that when the resin residue in Comparative Example 3 is less, effective reinforcement cannot be formed.

[0052] In summary: The present invention successfully prepared high-performance carbon fiber reinforced metal matrix composites through innovative recycled carbon fiber surface treatment technology combined with advanced composite material preparation technology, providing a new way for the recycling of carbon fiber resources and the improvement of composite material performance.

[0053] The above description is only a preferred embodiment of the present invention. It should be pointed out that, for ordinary technicians in this field, several modifications and improvements can be made without departing from the creative concept of the present invention, and these should also be regarded as within the scope of protection of the invention.

Claims

1. A method for preparing a recycled carbon fiber reinforced metal matrix composite material, characterized in that: The following steps are involved: Step S1, pretreatment of waste carbon fiber composite materials: subjecting the waste carbon fiber composite materials to three-stage pyrolysis treatment in an inert gas environment to obtain recycled carbon fiber; Step S2, selecting a metal or alloy with excellent physical properties and processing properties as the matrix material, uniformly mixing the metal powder with the above-mentioned recycled carbon fiber, loading into a die and re-pressing into a molded blank, placing in a heating furnace for sintering to form a tightly bonded composite material structure.

2. The method for preparing a recycled carbon fiber reinforced metal matrix composite material according to claim 1, characterized in that: In step S1, the inert gas includes one of nitrogen, helium, neon, argon, krypton, and xenon.

3. The method for preparing a recycled carbon fiber reinforced metal matrix composite material according to claim 1, characterized in that: Step S1 includes the following three stages: Stage 1: fully carried out in the absence of oxygen and low temperature, so that the residue is relatively uniform and the epoxy resin residue accounts for 5-10% by mass; Stage 2: Perform pyrolysis without oxygen to reduce the epoxy resin residue to 1-5% by mass; Stage 3: Oxidizing the surface with oxygen at a certain temperature to form recycled carbon fiber with a carbon fiber mass content of 98-99%.

4. The method for preparing a recycled carbon fiber reinforced metal matrix composite material according to claim 3, characterized in that: The low temperature range of stage 1 is 300-500°C and the processing time is 1-3 hours.

5. The method for preparing a recycled carbon fiber reinforced metal matrix composite material according to claim 3, characterized in that: The high temperature range of stage 2 is 700-800°C and the processing time is 10-30 minutes.

6. The method for preparing a recycled carbon fiber reinforced metal matrix composite material according to claim 3, characterized in that: The temperature range of stage three is 500-700°C and the processing time is 10-30s.

7. The method for preparing a recycled carbon fiber reinforced metal matrix composite material according to claim 1, characterized in that: The base material includes one of aluminum, copper and silver.

8. The method for preparing a recycled carbon fiber reinforced metal matrix composite material according to claim 1, characterized in that: The sintering temperature in step S2 is 650-850°C.

9. A recycled carbon fiber reinforced metal matrix composite material obtained by the preparation method according to any one of claims 1 to 8, characterized in that: The composite material consists of recycled carbon fibers and a matrix material, wherein the matrix material comprises a metal or an alloy.

10. Application of the recycled carbon fiber reinforced metal matrix composite material according to claim 9 in the fields of aerospace, automobile manufacturing, electronic packaging, and sporting goods.

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