A composite material integrating the bonding of metal and resin

Abstract

The present invention relates to the technical field of composite materials, and provides a metal-resin bonded integrated composite material. An oxide film is provided on the metal surface bonded to the resin, and the oxide film is obtained by subjecting the metal to plasma electrolytic oxidation treatment, and the water contact angle of the oxide film is ≤ 30°. Through the above technical solution, the problem in the related art that the bonding strength of the metal-resin bonded integrated composite material and the fatigue strength of the metal cannot be taken into account simultaneously is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of composite materials, and specifically, to a metal-resin bonded integrated composite material. Background Art

[0002] Composite materials are materials composed of two or more materials with different properties through physical or chemical methods to form materials with new properties. In the fields of aerospace, automotive industry, and robot manufacturing, the application of composite materials is of great significance. On the one hand, composite materials have the advantages of high strength, high stiffness, and low density, which can effectively reduce their own weight, achieve lightweight, and improve motion efficiency and flexibility; on the other hand, composite materials have good electrical conductivity, thermal conductivity, high temperature resistance, corrosion resistance, and wear resistance, etc., and can adapt to various harsh working environments.

[0003] High-strength metals such as titanium, aluminum, and magnesium are widely used due to their unique performance advantages. For example, aluminum alloys have the characteristics of low density, high strength, specific strength close to high-alloy steels, and specific stiffness exceeding that of steel; titanium alloys have the advantages of high strength and corrosion resistance. Carbon fiber reinforced resin composite materials, abbreviated as CFRP, have the advantages of high specific strength and good chemical stability, but due to the lack of interlayer fiber reinforcement in the layered CFRP structure, their impact resistance is poor. In actual use, they often need to be combined with metals to form composite materials. For example, the metal-resin bonded integrated composite material formed by titanium alloy and CFRP has obvious advantages in aerospace applications such as rocket fuel tanks, leading edges of wings, and engine pods.

[0004] The biggest characteristic of the metal-resin bonded integrated composite material in structure is its multi-layer interface, and the performance of the bonding interface directly affects the final performance of the composite material. If the bonding interface is prone to interface delamination or even cracking during use, it will lead to a decrease in stiffness and strength. Taking the metal-resin bonded integrated composite material formed by titanium alloy and CFRP as an example, due to the strong chemical activity of titanium, it is extremely easy to react with elements such as oxygen and nitrogen at room temperature, and a dense and highly inert passivation film is formed on its surface. This passivation film greatly affects the bonding strength between the titanium alloy and the resin. Currently, before preparing the metal-resin bonded integrated composite material, the metal surface needs to be treated to achieve an ideal bonding state by improving the metal surface morphology.

[0005] Mechanical methods such as sandblasting and grinding with a grinding wheel can increase the surface roughness of the metal and the contact area with the resin, which is beneficial to forming a mechanical connection during bonding and improving the bonding strength. However, during mechanical treatment, as the surface roughness of the metal increases, the defects of surface unevenness will become the starting point of metal fatigue cracking, which will greatly reduce the fatigue strength of the metal. Although chemical treatment methods such as the mixed acid method, the oxalic acid method, and the phosphate chloride method can also increase the surface roughness of the metal through chemical etching and improve the bonding strength, with the dissolution of the metal and the increase of the surface roughness, the fatigue strength of the metal will be reduced, and there are also environmental protection problems such as the treatment of toxic chemicals and wastewater treatment. In addition, although methods such as alkaline anodic oxidation and chromic acid anodic oxidation can improve the bonding strength without significantly increasing the surface roughness, the disadvantages of poor stability and poor resistance to heat and humidity restrict their practical use.

[0006] Therefore, for the integrated composite material of metal and resin, how to improve the bonding strength without affecting the metal fatigue strength is an urgent problem to be solved. Summary of the Invention

[0007] The present invention provides an integrated composite material of metal and resin, which solves the problem that the bonding strength of the integrated composite material of metal and resin in the related art and the fatigue strength of the metal cannot be taken into account at the same time.

[0008] The technical solution of the present invention is as follows:

[0009] The present invention provides an integrated composite material of metal and resin, and an oxide film is provided on the metal surface bonded to the resin. The oxide film is obtained by plasma electrolytic oxidation of the metal, and the water contact angle of the oxide film is ≤30°.

[0010] As a further technical solution, the surface roughness Ra of the oxide film is ≤1μm.

[0011] As a further technical solution, the thickness of the oxide film is 0.3 - 5μm.

[0012] As a further technical solution, the shear bonding strength of the metal and the resin is ≥36MPa.

[0013] As a further technical solution, during the plasma electrolytic oxidation, the voltage is 30 - 450V and the temperature is 10 - 60°C.

[0014] As a further technical solution, during the plasma electrolytic oxidation, the electrolyte includes the following components: alkali metal hydroxide, layered compound, and amino silane coupling agent.

[0015] As a further technical solution, the concentration of the alkali metal hydroxide is 10 to 50 g / L, the concentration of the layered compound is 8 to 10 g / L, and the concentration of the aminosilane coupling agent is 5 to 8 g / L.

[0016] As a further technical solution, the resin is a carbon fiber reinforced resin composite material, and the carbon fiber reinforced resin composite material is a carbon fiber reinforced thermosetting resin composite material or a carbon fiber reinforced thermoplastic resin composite material.

[0017] As a further technical solution, in the carbon fiber reinforced thermosetting resin composite material, the thermosetting resin includes one of phenolic resin, epoxy resin, unsaturated polyester, and thermosetting polyimide;

[0018] In the carbon fiber reinforced thermoplastic resin composite material, the thermoplastic resin includes one of polyamide, polyphenylene sulfide, thermoplastic polyimide, and polyether ether ketone.

[0019] As a further technical solution, the surface of the carbon fiber reinforced resin composite material is processed by atmospheric plasma.

[0020] The working principle and beneficial effects of the present invention are as follows:

[0021] In the present invention, an oxide film obtained by plasma electrolytic oxidation is provided on the metal surface bonded to the resin. By ensuring that the water contact angle of the oxide film is ≤30°, it is beneficial for the resin to better wet and adhere, enabling the metal and the resin to be tightly combined to form a firm interfacial connection, which can significantly improve the bonding strength between the metal and the resin. In addition, different from conventional mechanical treatment methods and chemical treatment methods, the use of plasma electrolytic oxidation treatment can not only improve the bonding strength between the metal and the resin, but also avoid the phenomenon of fatigue strength reduction of the metal caused by the roughening of the metal surface to form fatigue cracking initiation points due to conventional treatment methods. Specific Embodiments

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of the present invention.

[0023] It should be understood that, unless otherwise clearly specified in the context, the terms "comprising", "including" or "having" used in this application mean the presence of an element, but do not exclude the presence or addition of one or more other elements. In addition, "comprising" and / or "including" used herein indicate the presence of a shape, number, step, operation, member, element and / or a combination thereof, and do not exclude the presence or addition of one or more other shapes, numbers, operations, elements and / or a combination thereof.

[0024] In this application, the numerical range represented by "~" means a numerical range including the lower limit value and the upper limit value respectively specified before or after this word. When referring to multiple numerical values of the upper limit or the lower limit of any numerical range, the ranges disclosed herein can be understood as ranges with any one of the multiple upper limit values mentioned as its upper limit value and any one of the multiple lower limit values as its lower limit value.

[0025] Next, a metal-resin integrated composite material according to an embodiment of the present invention will be introduced in detail.

[0026] According to one aspect of the present invention, there is provided a metal-resin integrated composite material, and an oxide film is provided on the metal surface joined to the resin. The oxide film is obtained by subjecting the metal to plasma electrolytic oxidation treatment, and the water contact angle of the oxide film is ≤30°. For example, it can be 0.7°, 2°, 4°, 6.5°, 7.8°, 11.2°, 16.6°, 19.8°, 25°, 30°.

[0027] In the present invention, plasma electrolytic oxidation has the characteristic of high energy density. Through the combined action of plasma chemistry, electrochemistry and thermochemistry, it can endow the metal surface with hydrophilic properties, which helps to improve the interfacial bonding between the metal and the resin and does not generate fatigue cracking points, solving the problem that the bonding strength of the metal-resin integrated composite material and the fatigue strength of the metal cannot be taken into account at the same time.

[0028] In the present invention, the water contact angle of the metal surface can be measured by a commercially available contact angle measuring instrument. For example, the water contact angle of the metal surface can be the value measured by a contact angle measuring instrument (model JC200A).

[0029] In an embodiment of the present invention, the surface roughness Ra of the oxide film is ≤1μm. For example, it can be 0.2μm, 0.4μm, 0.57μm, 0.68μm, 0.73μm, 0.81μm, 1μm.

[0030] In the present invention, when the surface roughness Ra of the metal surface is ≤ 1 μm, on the one hand, it can increase the effective contact area between the metal and the resin, enhance the mechanical biting ability at the joint of the metal and the resin, and improve the bonding strength between the metal and the resin; on the other hand, it can reduce the fatigue cracking points caused by large surface roughness and prevent the decline of the metal fatigue strength.

[0031] In the present invention, the surface roughness Ra of the metal surface can be measured by a commercially available surface roughness tester using the contact measurement method. For example, the surface roughness Ra of the metal surface can be the value measured by moving a TS2200 type surface roughness tester along any direction on the metal surface using the contact measurement method.

[0032] In one embodiment of the present invention, the thickness of the oxide film is 0.3 - 5 μm. For example, it can be 0.3 μm, 0.7 μm, 1.2 μm, 1.7 μm, 2.6 μm, 3.4 μm, 4.5 μm, 5 μm.

[0033] In the present invention, the thickness of the oxide film can be the thickness measured by observing the cross-section of the film with a scanning electron microscope (SEM), or can be the thickness measured using a known thickness gauge.

[0034] In one embodiment of the present invention, the oxide film has sub-micron level irregularities.

[0035] In the present invention, during the plasma electrolytic oxidation process, the plasma discharge can reach a high temperature state of thousands of degrees Celsius in an instant, forming an oxide film with sub-micron level irregularities on the metal surface. The unique microstructure provides good bonding points for the resin, and these sub-micron level irregularities are different from the surface roughening by sandblasting or pickling and will not become the starting point of metal fatigue cracking. While improving the bonding strength between the metal and the resin, it does not affect the fatigue strength of the metal.

[0036] In one embodiment of the present invention, the maximum diameter length of the sub-micron level irregularities is 0.1 - 1 μm. For example, it can be 0.1 μm, 0.2 μm, 0.4 μm, 0.6 μm, 0.8 μm, 1 μm.

[0037] In the present invention, the maximum diameter length of the irregularities can be observed and measured by a scanning electron microscope (SEM).

[0038] In one embodiment of the present invention, the shear bonding strength between the metal and the resin is ≥ 36 MPa. For example, 36 MPa, 36.7 MPa, 37.2 MPa, 39.8 MPa, 40.1 MPa, 40.5 MPa, 41.2 MPa, 41.8 MPa.

[0039] In the present invention, the shear bond strength between the metal and the resin can be tested by a universal testing machine. For example, it can be the value measured by using a commercially available universal testing machine with reference to ASTM D3165-07(2014).

[0040] In one embodiment of the present invention, during plasma electrolytic oxidation, the voltage is 30~450V and the temperature is 10~60°C. For example, the voltage can be 30V, 100V, 200V, 300V, 400V, 450V; the temperature can be 10°C, 20°C, 30°C, 40°C, 50°C, 60°C.

[0041] In the present invention, when the voltage is 30~450V, the stability of plasma electrolytic oxidation can be improved; when the temperature is 10~60°C, it can not only ensure a good film-forming rate, but also prevent burns caused by overly intense plasma electrolytic oxidation.

[0042] In one embodiment of the present invention, the time of plasma electrolytic oxidation is 10~60 min. For example, it can be 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, and can be adjusted according to actual needs.

[0043] In one embodiment of the present invention, during plasma electrolytic oxidation, the cathode material includes one of stainless steel, graphite, and titanium.

[0044] In one embodiment of the present invention, during plasma electrolytic oxidation, the electrolyte includes the following components: alkali metal hydroxide, layered compound, and amino silane coupling agent.

[0045] In the present invention, by optimizing the composition of the electrolyte, the metal surface can have hydroxyl groups and amino silanes, improving the hydrophilicity of the metal surface. The amino silane can act as a bridge between the metal and resin interfaces or directly participate in the subsequent resin cross-linking reaction, which is beneficial to further improving the bond strength between the metal and the resin. In addition, the layered compound and amino silane coupling agent in the electrolyte can act. The amino silane molecules enter the interlayers of the layered compound, inducing and promoting the interlayer peeling of the layered compound through hydrolysis reaction to form a large number of nano-sheet structures with a large specific surface area, increasing the effective contact area between the metal and the resin, and further improving the bond strength between the metal and the resin without affecting the metal fatigue strength.

[0046] In the present invention, the alkali metal hydroxide can be any alkali metal hydroxide, preferably one or two of sodium hydroxide and potassium hydroxide. For example, it can be sodium hydroxide, potassium hydroxide, or a combination of sodium hydroxide and potassium hydroxide.

[0047] In the present invention, the layered compound is preferably a cationic layered compound. The cationic layered compound is charge-compensated by mobile cations between the layers and has characteristics such as a high specific surface area, good ion exchange ability, adjustable interlayer distance, and interlayer exfoliation. The cationic layered compound can be a layered phosphate, a layered silicate, or a layered titanate. The layered phosphate can be zirconium phosphate or titanium phosphate; the layered silicate can be mica, talcum powder, or montmorillonite; the layered titanate can be sodium titanate, potassium titanate, or lithium titanate. For example, it can be disodium titanate, trinodium titanate, potassium tetratitanate, or lithium titanate.

[0048] In the present invention, the aminosilane coupling agent has two active groups, namely an amino group and an alkoxy group. For example, it can be γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane. γ-aminopropyltriethoxysilane can be selected from KH550, WD-50, and A-1100, and N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane can be selected from KH792 and A-1120.

[0049] In one embodiment of the present invention, in the electrolyte, the concentration of the alkali metal hydroxide is 10-50 g / L, the concentration of the layered compound is 8-10 g / L, and the concentration of the aminosilane coupling agent is 5-8 g / L. For example, the concentration of the alkali metal hydroxide can be 10 g / L, 20 g / L, 30 g / L, 40 g / L, or 50 g / L; the concentration of the layered compound can be 8 g / L, 9 g / L, or 10 g / L; the concentration of the aminosilane coupling agent can be 5 g / L, 6 g / L, 7 g / L, or 8 g / L.

[0050] In one embodiment of the present invention, the solvent of the electrolyte is water.

[0051] In one embodiment of the present invention, the metal includes one of titanium, aluminum, magnesium, titanium alloy, aluminum alloy, and magnesium alloy. For example, it can be pure titanium, pure aluminum, pure magnesium, TC4 titanium alloy, TA1 titanium alloy, TA2 titanium alloy, 1000 series aluminum alloy, 2000 series aluminum alloy, 3000 series aluminum alloy, LZ91MA magnesium alloy, AZ91D magnesium alloy, or AZ61A magnesium alloy.

[0052] In one embodiment of the present invention, the resin is a carbon fiber reinforced resin composite material, and the carbon fiber reinforced resin composite material is a carbon fiber reinforced thermosetting resin composite material or a carbon fiber reinforced thermoplastic resin composite material.

[0053] In an embodiment of the present invention, when the carbon fiber reinforced resin composite material is a carbon fiber reinforced thermosetting resin composite material, the thermosetting resin in the carbon fiber reinforced thermosetting resin composite material includes one of phenolic resin, epoxy resin, unsaturated polyester, and thermosetting polyimide, and preferably, it is a carbon fiber reinforced thermosetting epoxy resin composite material.

[0054] In an embodiment of the present invention, when the carbon fiber reinforced resin composite material is a carbon fiber reinforced thermoplastic resin composite material, the thermoplastic resin in the carbon fiber reinforced thermoplastic resin composite material includes one of polyamide, polyphenylene sulfide, thermoplastic polyimide, and polyether ether ketone, and preferably, it is a carbon fiber reinforced thermoplastic polyether ether ketone resin composite material.

[0055] In an embodiment of the present invention, the surface of the carbon fiber reinforced resin composite material is processed by atmospheric plasma.

[0056] In the present invention, the atmospheric plasma surface treatment technology is used to process the carbon fiber reinforced resin composite material, which can generate active ions, react chemically with the atoms on the surface of the carbon fiber reinforced resin composite material, improve its performance, enhance the wettability, adhesiveness, and hydrophilicity of the surface of the carbon fiber reinforced resin composite material, and can avoid the surface layer and subsurface layer damage caused by contact stress, further improving the bonding strength between the metal and the resin. In addition, this treatment method does not require vacuum equipment, has a low processing cost, and is suitable for industrial applications.

[0057] In an embodiment of the present invention, during the atmospheric plasma processing, the power is 1000W, the processing distance is 15mm, the processing time is 60s, and the processing atmosphere is air.

[0058] In an embodiment of the present invention, when the carbon fiber reinforced resin composite material is a carbon fiber reinforced thermosetting resin composite material, when preparing the integrated composite material of metal and resin, a binder needs to be added. For example, the preparation method of the integrated composite material of TC4 titanium alloy and carbon fiber reinforced thermosetting epoxy resin composite material includes the following steps:

[0059] A1. Lay up and mold the unidirectional carbon fiber epoxy prepreg, cure it, and process it by atmospheric plasma to obtain the carbon fiber reinforced thermosetting epoxy resin composite material;

[0060] Among them, the model of the unidirectional carbon fiber epoxy prepreg is NY9200GA / HF10A, purchased from Jiangsu Hengshen Fiber Materials Co., Ltd. The carbon fiber reinforced thermosetting epoxy resin composite material has a total of 12 layers, with a single-layer thickness of 0.125 mm, and the ply is [0 / 90]. During curing, it is heated to 140 °C at a rate of 2 °C / min, pressurized to 0.2 MPa and kept warm for 30 min, then still heated to 180 °C at a rate of 2 °C / min, pressurized to 0.5 MPa and maintained. After keeping warm for 2.5 h, heating is stopped and it is cooled naturally;

[0061] During atmospheric plasma processing, an atmospheric pressure plasma instrument (model RFD-200) is selected, with a power of 1000 W, a processing distance of 15 mm, a processing time of 60 s, and a processing atmosphere of air;

[0062] A2. The TC4 titanium alloy with a thickness of 1.6 mm is subjected to plasma electrolytic oxidation treatment to obtain the treated titanium alloy;

[0063] Among them, during plasma electrolytic oxidation treatment, the electrolyte includes components with the following concentrations: sodium hydroxide 10 g / L, layered zirconium phosphate 8 g / L, γ-aminopropyltriethoxysilane 5 g / L (model KH550), the solvent is water, the constant voltage pulse electrolysis method is adopted, the voltage is 30 V, the temperature is 10 °C, the time is 10 min, the pulse width is 20 ms, and the pulse interval is 5 ms;

[0064] A3. Laminating is carried out in the order of carbon fiber reinforced thermosetting epoxy resin composite material, binder, and treated titanium alloy from top to bottom, and then it is clamped in a flat die and hot-pressed and cured on a flat hot press to obtain a bonded integrated composite material of TC4 titanium alloy and carbon fiber reinforced thermosetting epoxy resin composite material;

[0065] Among them, the binder is a thermosetting epoxy resin film (model AF191K) with a thickness of 0.33 mm, and the hot-pressing and curing process is: the curing pressure is 0.3 MPa, starting from room temperature, the heating rate is 2 °C / min, heated to 177 °C and kept warm for 1 h, then heating is stopped, and it is naturally cooled to below 60 °C to relieve pressure.

[0066] In an embodiment of the present invention, when the carbon fiber reinforced resin composite material is a carbon fiber reinforced thermoplastic resin composite material, when preparing a bonded integrated composite material of metal and resin, the heating and melting method is adopted. For example, the preparation method of a bonded integrated composite material of TC4 titanium alloy and carbon fiber reinforced thermoplastic polyether ether ketone resin composite material includes the following steps:

[0067] B1. The prepreg is laminated and cured, and subjected to atmospheric plasma processing to obtain a carbon fiber reinforced thermoplastic polyether ether ketone resin composite material;

[0068] Among them, the prepreg has a model of APC-2 and a specification of AS4, and is produced by ICI Composites Fiberite of the United Kingdom. When laminating and curing, there are a total of 12 layers, the single-layer thickness is 0.125 mm, and the ply layup is [0 / 90];

[0069] When performing atmospheric plasma processing, an atmospheric pressure plasma instrument (model RFD-200) is selected, the power is 1000 W, the processing distance is 15 mm, the processing time is 60 s, and the processing atmosphere is air;

[0070] B2. Perform plasma electrolytic oxidation treatment on TC4 titanium alloy with a thickness of 1.6 mm to obtain the treated titanium alloy;

[0071] Among them, when performing plasma electrolytic oxidation treatment, the electrolyte includes components with the following concentrations: sodium hydroxide 10 g / L, layered zirconium phosphate 8 g / L, γ-aminopropyltriethoxysilane 5 g / L (model KH550), the solvent is water, the constant voltage pulse electrolysis method is adopted, the voltage is 30 V, the temperature is 10 °C, the time is 10 min, the pulse width is 20 ms, and the pulse interval is 5 ms;

[0072] B3. Lay up in the order of carbon fiber reinforced thermoplastic polyetheretherketone resin composite, polyetheretherketone film, and the treated titanium alloy from top to bottom, and then clamp it in a flat die and hot press and cure it on a flat hot press to obtain a bonded integrated composite material of TC4 titanium alloy and carbon fiber reinforced thermoplastic polyetheretherketone resin composite;

[0073] Among them, the thickness of the polyetheretherketone film is 50 μm, the model is Aptiv 1000 series films, and it is produced by Victrex. The hot press curing process is: heat from room temperature to 390 °C, keep warm for 20 min, and then cool naturally. During the cooling process, apply a pressure of 0.6 MPa to the die.

[0074] The present invention will be described in detail below with reference to examples. The embodiments according to the present invention described below can be modified into various forms, so the scope of the present invention should not be construed as being limited to the embodiments described in detail below. The embodiments are provided to help those skilled in the art understand the present invention more easily.

[0075] Example 1

[0076] A method for preparing a bonded integrated composite material of a metal and a resin, comprising the following steps:

[0077] A1. Lay up and mold a unidirectional carbon fiber epoxy prepreg, and cure it to obtain a carbon fiber reinforced thermosetting epoxy resin composite;

[0078] Among them, the model of the unidirectional carbon fiber epoxy prepreg is NY9200GA / HF10A, purchased from Jiangsu Hengshen Fiber Materials Co., Ltd. The carbon fiber reinforced thermosetting epoxy resin composite material has a total of 12 layers, with a single-layer thickness of 0.125 mm, and the ply is [0 / 90]. During curing, it is heated to 140 °C at a rate of 2 °C / min, pressurized to 0.2 MPa and kept warm for 30 min, then still heated to 180 °C at a rate of 2 °C / min, pressurized to 0.5 MPa and maintained. After keeping warm for 2.5 h, heating is stopped and it is naturally cooled;

[0079] A2. Perform plasma electrolytic oxidation treatment on TC4 titanium alloy with a thickness of 1.6 mm to obtain the treated titanium alloy;

[0080] Among them, during the plasma electrolytic oxidation treatment, the electrolyte includes components with the following concentrations: sodium hydroxide 10 g / L, layered zirconium phosphate 8 g / L, γ-aminopropyltriethoxysilane 5 g / L (model KH550), and the solvent is water. The constant voltage pulse electrolysis method is adopted, with a voltage of 30 V, a temperature of 60 °C, a time of 60 min, a pulse width of 20 ms, and a pulse interval of 5 ms;

[0081] A3. Lay up in the order of carbon fiber reinforced thermosetting epoxy resin composite material, binder, and treated titanium alloy from top to bottom, and then clamp it in a flat die and hot press and cure it on a flat hot press to obtain a bonded integrated composite material of TC4 titanium alloy and carbon fiber reinforced thermosetting epoxy resin composite material;

[0082] Among them, the binder is a thermosetting epoxy resin film (model AF191K) with a thickness of 0.33 mm. The hot press curing process is: the curing pressure is 0.3 MPa, starting from room temperature, the heating rate is 2 °C / min, heated to 177 °C and kept warm for 1 h, then heating is stopped, and it is naturally cooled to below 60 °C and the pressure is released.

[0083] Example 2

[0084] A preparation method of a bonded integrated composite material of metal and resin, comprising the following steps:

[0085] B1. Stack and cure the prepreg to obtain a carbon fiber reinforced thermoplastic polyether ether ketone resin composite material;

[0086] Among them, the model of the prepreg is APC-2, the specification is AS4, produced by ICI Composites Fiberite Company of the UK. During the stacking and curing, there are a total of 12 layers, with a single-layer thickness of 0.125 mm, and the ply is [0 / 90];

[0087] B2. Subject the TC4 titanium alloy with a thickness of 1.6 mm to plasma electrolytic oxidation treatment to obtain the treated titanium alloy;

[0088] Among them, during the plasma electrolytic oxidation treatment, the electrolyte includes components with the following concentrations: 50 g / L of sodium hydroxide, 10 g / L of potassium tetratitanate hydrate, 8 g / L of γ-aminopropyltriethoxysilane (model KH550), the solvent is water, the constant voltage pulse electrolysis method is adopted, the voltage is 450 V, the temperature is 10 °C, the time is 60 min, the pulse width is 20 ms, and the pulse interval is 5 ms;

[0089] B3. Lay up in the order of carbon fiber reinforced thermoplastic polyetheretherketone resin composite, polyetheretherketone film, and the treated titanium alloy from top to bottom, and then clamp it in a flat die and hot press and cure it on a flat hot press to obtain a bonded integrated composite of TC4 titanium alloy and carbon fiber reinforced thermoplastic polyetheretherketone resin composite;

[0090] Among them, the thickness of the polyetheretherketone film is 50 μm, the model is Aptiv 1000 series films, produced by Victrex Corporation, and the hot press curing process is: heat from room temperature to 390 °C, keep warm for 20 min, and then cool naturally. Apply a pressure of 0.6 MPa to the die during the cooling process.

[0091] Example 3

[0092] The difference between this example and Example 2 is only that in this example, the γ-aminopropyltriethoxysilane in the electrolyte is replaced with an equal amount of N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane (model KH792).

[0093] Example 4

[0094] The difference between this example and Example 2 is only that in this example, the N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane in the electrolyte is replaced with an equal amount of γ-mercaptopropyltrimethoxysilane (model KH580).

[0095] Example 5

[0096] The difference between this example and Example 2 is only that in this example, the N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane in the electrolyte is replaced with an equal amount of γ-glycidoxypropyltrimethoxysilane (model KH560).

[0097] Example 6

[0098] The difference between this example and Example 2 is only that in this example, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane in the electrolyte is replaced with 5 g / L of vinyltriethoxysilane (model A-151) in equal amount.

[0099] Example 7

[0100] The difference between this example and Example 2 is only that in this example, the layered potassium tetratitanate in the electrolyte is replaced with an equal amount of tunnel-structured potassium hexatitanate.

[0101] Example 8

[0102] The difference between this example and Example 2 is only that in this example, the layered potassium tetratitanate in the electrolyte is replaced with an equal amount of tunnel-structured potassium octatitanate.

[0103] Example 9

[0104] The difference between this example and Example 2 is only that in this example, after the prepreg is laminated and cured, atmospheric plasma processing is also carried out. When carrying out atmospheric plasma processing, an atmospheric pressure plasma instrument (model RFD-200) is selected, the power is 1000 W, the processing distance is 15 mm, the processing time is 60 s, and the processing atmosphere is air.

[0105] Example 10

[0106] The difference between this example and Example 1 is only that in this example, the material is changed from TC4 titanium alloy to AA2024 aluminum alloy, and the AA2024 aluminum alloy is subjected to plasma electrolytic oxidation to obtain the treated aluminum alloy;

[0107] Among them, when carrying out plasma electrolytic oxidation treatment, the electrolyte includes components with the following concentrations: 5 g / L of sodium hydroxide, 8 g / L of layered zirconium phosphate, 5 g / L of γ-aminopropyltriethoxysilane (model KH550), the solvent is water, the constant voltage pulse electrolysis method is adopted, the voltage is 300 V, the temperature is 60 °C, the time is 30 min, the pulse width is 20 ms, and the pulse interval is 5 ms.

[0108] Comparative Example 1

[0109] The difference between this comparative example and Example 1 is only that in this comparative example, the TC4 alloy is not subjected to plasma electrolytic oxidation, but sulfuric acid anodic oxidation is carried out. When carrying out sulfuric acid anodic oxidation, the electrolyte is 25 g / L of sulfuric acid (mass fraction 98%), the solvent is water, the direct current constant voltage method is adopted, the voltage is 20 V, the temperature is 25 °C, and the time is 15 min.

[0110] Comparative Example 2

[0111] The difference between this comparative example and Example 1 is only that in this comparative example, the TC4 alloy was not subjected to plasma electrolytic oxidation, but was subjected to anodic oxidation with sodium hydroxide. When performing anodic oxidation with sodium hydroxide, the electrolyte was sodium hydroxide at 30 g / L, the solvent was water, the direct current constant voltage method was used, the voltage was 16 V, the temperature was 90 °C, and the time was 25 min.

[0112] Comparative Example 3

[0113] The difference between this comparative example and Example 1 is only that in this comparative example, the TC4 alloy was not subjected to plasma electrolytic oxidation, but was pickled with a mixed aqueous solution of nitric acid and hydrofluoric acid;

[0114] Among them, the mass fraction of nitric acid was 30%, the mass fraction of hydrofluoric acid was 3%, the volume ratio of nitric acid to hydrofluoric acid was 1:1, the pickling temperature was 40 °C, and the pickling time was 10 min.

[0115] Comparative Example 4

[0116] The difference between this comparative example and Example 10 is only that in this comparative example, the AA2024 aluminum alloy was not subjected to plasma electrolytic oxidation, but was subjected to sulfuric acid anodic oxidation. When performing sulfuric acid anodic oxidation, the electrolyte was sulfuric acid at 25 g / L (mass fraction 98%), the solvent was water, the direct current constant voltage method was used, the voltage was 18 V, the temperature was 20 °C, and the time was 30 min.

[0117] The following performance tests were carried out on the metal-resin bonded integrated composites prepared in Examples 1 to 10 and Comparative Examples 1 to 4:

[0118] ① Water contact angle of the oxide film: Measured using a contact angle measuring instrument (model JC200A);

[0119] ② Surface roughness Ra of the oxide film: Measured using a TS2200 type surface roughness tester by moving along the same direction on the metal surface in a contact measurement method;

[0120] ③ Thickness of the oxide film: Determined by observing the cross-section with a scanning electron microscope (model JCM-5000);

[0121] ④ Metal fatigue strength: Measured with reference to GB / T 3075-2021 "Metallic materials - Fatigue testing - Axial force controlled method", using a high-frequency fatigue testing machine, test frequency 90 - 130 Hz, sine wave, stress ratio R of -1, and target number of cycles of 10^7 cycles.

[0122] ⑤ Shear bond strength between metal and resin: Measured using a universal testing machine with reference to ASTM D3165-07(2014);

[0123] The test results are shown in Table 1 below.

[0124] Table 1 Performance Test Results

[0125]

[0126] Comparing Example 1 with Comparative Examples 1 to 3, it can be seen that after the surface of the metal in the metal-resin bonded integrated composite material is treated by plasma electrolytic oxidation, it has hydrophilicity. This not only improves the bonding strength between the metal and the resin, but also avoids the phenomenon of fatigue strength reduction of the metal caused by the roughening of the metal surface formed by the conventional treatment method to form fatigue cracking initiation points.

[0127] Comparing Examples 2 to 3 with Examples 4 to 6 shows that when the components of the electrolyte include an amino silane coupling agent, the bonding strength between the metal and the resin can be further improved without affecting the fatigue strength of the metal.

[0128] Comparing Example 2 with Examples 7 to 8 shows that the layered compound in the electrolyte can produce a synergistic effect with the amino silane coupling agent, and the bonding strength between the metal and the resin can be further improved without affecting the fatigue strength of the metal.

[0129] Comparing Example 2 with Example 9 shows that using the atmospheric plasma surface treatment technology to process the carbon fiber reinforced resin composite material can further improve the bonding strength between the metal and the resin without affecting the fatigue strength of the metal.

[0130] Example 10 shows that when the metal is changed from TC4 titanium alloy to AA2024 aluminum alloy, the bonding strength between the metal and the resin can also be improved without affecting the fatigue strength of the metal.

[0131] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A bonded and integrated composite material of metal and resin, characterized in that, The metal surface bonded to the resin is provided with an oxide film, which is obtained by subjecting the metal to plasma electrolytic oxidation treatment, and the water contact angle of the oxide film is ≤ 30°; When performing the plasma electrolytic oxidation, the electrolyte includes the following components: alkali metal hydroxide, layered compound and amino silane coupling agent; The concentration of the alkali metal hydroxide is 10 - 50 g / L, the concentration of the layered compound is 8 - 10 g / L, and the concentration of the amino silane coupling agent is 5 - 8 g / L.

2. The integrated composite material of metal and resin according to claim 1, wherein The surface roughness Ra of the oxide film is ≤ 1 μm.

3. The integrated composite material of metal and resin according to claim 1, characterized in that, The thickness of the oxide film is 0.3 - 5 μm.

4. The integrated composite material of metal and resin according to claim 1, characterized in that, The shear bonding strength between the metal and the resin is ≥ 36 MPa.

5. The integrated composite material of metal and resin according to claim 1, characterized in that, When performing the plasma electrolytic oxidation, the voltage is 30 - 450 V and the temperature is 10 - 60 °C.

6. A metal-resin integrated composite material according to any one of claims 1 to 5, characterized in that The resin is a carbon fiber reinforced resin composite material, and the carbon fiber reinforced resin composite material is a carbon fiber reinforced thermosetting resin composite material or a carbon fiber reinforced thermoplastic resin composite material.

7. A metal-resin integrated composite material according to claim 6, characterized in that, In the carbon fiber reinforced thermosetting resin composite material, the thermosetting resin includes one of phenolic resin, epoxy resin, unsaturated polyester, and thermosetting polyimide; In the carbon fiber reinforced thermoplastic resin composite material, the thermoplastic resin includes one of polyamide, polyphenylene sulfide, thermoplastic polyimide, and polyether ether ketone.

8. The integrated composite material of metal and resin according to claim 6, characterized in that, The surface of the carbon fiber reinforced resin composite material is processed by atmospheric plasma.

Images