A processing method for alloy composite parts based on nano-injection molding

Abstract

The present invention relates to the field of nano-injection molding technology, and discloses a processing method for an alloy composite part based on nano-injection molding, comprising the following steps: surface pretreatment: degreasing, removing the oxide film, and chemically polishing the surface of the aluminum alloy in sequence; anodic oxidation treatment: subjecting the aluminum alloy after surface pretreatment to first anodic oxidation, removing the oxide film, second anodic oxidation, and oxide film pore expansion in sequence; electrochemical deposition: performing double-potential electro-deposition on the aluminum alloy after anodic oxidation treatment; nano-injection molding: using toughened polyphenylene sulfide resin as the matrix resin to perform nano-injection molding on the surface of the aluminum alloy after electrochemical deposition to obtain an alloy composite part.

Description

Technical Field

[0001] The present invention relates to the technical field of nano-injection molding, and specifically provides a processing method for alloy composite parts based on nano-injection molding. Background Art

[0002] Nano Molding Technology (NMT) is a new technology that integrates metal and plastic. Through this technology, the metal surface undergoes nano-level treatment, such as T treatment or E treatment, to form nano-pores, and then the molten plastic is injected onto the metal surface using an injection molding machine. Under pressure, these plastics enter the nano-pores and cool and solidify, resulting in a strong bonding force called the "anchor bolt effect". This technology not only improves the strength of the metal-plastic bonded parts but also simplifies the manufacturing process and reduces environmental impact.

[0003] NMT technology is widely used in fields such as the communication industry, smart terminals, e-book readers, and tablet computers. In addition, in the fields of smart home appliances and automotive lightweighting, NMT also shows great market potential and is one of the important technologies in the 5G, logistics, and vehicle networking eras. Traditional methods such as adhesive bonding and insert molding have their own advantages, but NMT achieves higher bonding strength and processing efficiency through nano-treatment and injection molding processes.

[0004] Although NMT has significant advantages, there are also some problems in its application. The expansion coefficients of polyester materials and metals differ greatly, which may lead to problems such as poor bonding strength between the resin and the metal, warping, peeling, and insufficient weather resistance after molding. Therefore, it is of great significance to develop a processing method for alloy composite parts that is applicable to nano-injection molding technology and has a strong bonding force with metals. Summary of the Invention

[0005] The purpose of the present invention is to provide a processing method for alloy composite parts based on nano-injection molding to solve the problems raised in the above background art.

[0006] To solve the above technical problems, the present invention provides the following technical solutions:

[0007] A processing method for alloy composite parts based on nano-injection molding, comprising the following steps:

[0008] S1: Surface pretreatment: The aluminum alloy surface is successively degreased, deoxidized, and chemically polished.

[0009] S2: Anodic oxidation treatment: The aluminum alloy after surface pretreatment is successively subjected to the first anodic oxidation, deoxidation, the second anodic oxidation, and oxide film pore expansion.

[0010] S3: Electrochemical deposition: subject the anodized aluminum alloy to double - potential electrodeposition;

[0011] S4: Nano - injection molding: use toughened polyphenylene sulfide resin as the matrix resin to perform nano - injection molding on the surface of the aluminum alloy after electrochemical deposition to obtain an alloy composite.

[0012] Further, the degreasing step includes grinding the surface of the aluminum alloy flat, successively immersing it in acetone and absolute ethanol for ultrasonic cleaning for 5 - 10 min, taking it out, washing with deionized water, and drying.

[0013] Further, the step of removing the oxide film includes immersing the degreased aluminum alloy in a mixed solution composed of 30 - 35 g / L sodium hydroxide and 30 - 35 g / L sodium carbonate, heating to 55 - 60 °C for reaction for 40 - 45 s, taking it out, washing with deionized water, and drying.

[0014] The purpose is to remove the loose, porous and uneven oxide film on the surface of the aluminum alloy to avoid the reduction of the orderliness of the oxide film obtained in the subsequent anodization process.

[0015] Further, the chemical polishing treatment step includes immersing the aluminum alloy after removing the oxide film in a mixed solution composed of 400 - 420 g / L sodium hydroxide, 300 - 320 g / L sodium nitrate, 60 - 65 g / L sodium fluoride, and 100 - 120 g / L sodium silicate, heating to 95 - 100 °C for reaction for 1 - 5 min, taking it out, washing with deionized water, and drying.

[0016] The purpose is to maintain the flatness of the surface of the aluminum alloy to facilitate obtaining a highly ordered oxide film in the subsequent anodization process.

[0017] Further, in the first anodization, the electrolyte is 0.3 - 0.6 mol / L oxalic acid solution, the oxidation voltage is 35 - 45 V, the oxidation temperature is 15 - 25 °C, and the oxidation time is 4 - 4.5 h.

[0018] Further, the step of removing the oxide film includes immersing the aluminum alloy after the first anodization in a mixed solution composed of 6 - 7 wt% phosphoric acid and 1.8 - 2 wt% chromic acid at 60 - 65 °C for reaction for 1 - 2 min.

[0019] The purpose is to remove the relatively disordered oxide film formed in the first anodization and reduce the randomness of the pore size of the nanopores.

[0020] Further, in the second anodization, the oxidation time is 6 - 6.5 h, and the other anodization process parameters are the same as those in the first anodization.

[0021] The purpose is to improve the orderliness and uniformity of the nanopore distribution on the surface of the aluminum alloy oxide film and the aspect ratio of the pore size of the nanopores.

[0022] Further, the step of expanding the pores of the oxide film includes immersing the aluminum alloy after the second anodization in a phosphoric acid solution at 30 - 35°C and 6 - 7 wt% for 15 - 30 minutes for reaction.

[0023] On the one hand, the purpose is to adjust the pore size of the nanopores to make the pore size more uniform and improve the orderliness; through pore expansion, the cylindrical nanopores formed during the anodization process are expanded along the pore growth direction at the bottom of the nanopores to form a "trapezoid"-like frustum structure nanopore, improving the anchoring performance. On the other hand, impurities on the surface of the oxide film are removed to facilitate the subsequent coating of the triazine dithiol polymer on the surface of the porous oxide film.

[0024] Further, the solvent of the oxalic acid solution is anhydrous ethanol and deionized water with a volume ratio of 1:4.

[0025] Further, in the anodization, the anode and the cathode are an aluminum alloy and a graphite plate respectively.

[0026] Further, the distance between the aluminum alloy and the graphite plate is 5 cm.

[0027] Further, in the double potential electrodeposition, the aluminum alloy after anodization treatment is used as the working electrode, the saturated calomel electrode is used as the reference electrode, and the stainless steel sheet is used as the auxiliary electrode.

[0028] Further, the electrolyte is composed of 5 - 6 mmol / L of triazine dithiol and 0.15 - 0.18 mol / L of sodium nitrate solution.

[0029] Further, in the double potential deposition method, the step potential of step 1 is 1.6 V, the step time is 30 s, the step potential of step 2 is 6 V, the step time is 10 s; the deposition temperature is 5 - 10°C.

[0030] The purpose is to form a triazine dithiol metal salt on the surface of the aluminum alloy, which can adsorb negatively charged compounds or react to form chemical bonding, improving the interfacial bonding strength between the plastic and the metal of the alloy composite; during the nano-injection molding process, through the reaction between the aluminum alloy - triazine dithiol metal salt - toughened polyphenylene sulfide resin, an anchoring effect is formed, further improving the interfacial bonding strength and the durability of the interfacial bonding strength.

[0031] Further, the nano-injection molding step includes injection pressurization, pressure holding, cooling, and ejection.

[0032] Further, the injection speed is 250 - 350 mm / s, the injection pressurization pressure is 60 - 80 MPa, the pressure holding pressure is 40 - 60 MPa, and the pressure holding time is 8 - 10 s.

[0033] Objective By controlling the injection speed, injection pressure, and pressure holding, after the toughened polyphenylene sulfide resin molecular chains enter the frustum-shaped holes, under the drag of the molecular chains in the holes and the action of pressure, the resin molecular chains are filled into the frustum-shaped holes. Compared with the cylindrical holes with straight up and down, the frustum-shaped holes can form a mechanical interlocking structure between the plastic and the metal, further improving the interfacial bonding strength.

[0034] Further, the diameter of the nano-injection cylinder is 20 mm.

[0035] Further, the temperatures of each zone of the nano-injection cylinder are 270 °C, 275 °C, 265 °C, 245 °C, 10 °C, 75 °C, and the mold temperature is 140 °C.

[0036] Further, the components in the toughened polyphenylene sulfide resin include polyphenylene sulfide, polybutylene terephthalate, silicon carbide whiskers, ethylene vinyl acrylate resin, glycidyl ester-containing random copolymer, antioxidant, and mold release agent.

[0037] Further, the proportion of each component in the toughened polyphenylene sulfide resin is calculated by mass fraction: 50 - 65 parts of polyphenylene sulfide, 15 - 30 parts of polybutylene terephthalate, 10 - 30 parts of silicon carbide whiskers, 1 - 10 parts of ethylene vinyl acrylate resin, 1 - 10 parts of glycidyl ester-containing random copolymer, 0.1 - 1 part of antioxidant, and 0.1 - 2 parts of mold release agent.

[0038] Further, the glycidyl ester-containing random copolymer is an ethylene acrylate and glycidyl methacrylate random copolymer.

[0039] Further, the antioxidant is antioxidant 1098.

[0040] Further, the mold release agent is mold release agent SEED.

[0041] Further, the preparation method of the silicon carbide whiskers includes the following steps:

[0042] Add carbon-silicon mixed powder, catalyst, aluminum powder, and absolute ethanol into a ball mill, stir evenly, add phenolic resin, stir for 12 - 14 h, press into a blank, heat to 200 - 205 °C and cure for 24 h, heat the cured blank to 1200 - 1400 °C at a heating rate of 5 °C / min under the condition of burying coke, keep warm for 2 - 2.5 h, cool, and grind to obtain silicon carbide whiskers.

[0043] Further, the carbon-silicon molar ratio in the carbon-silicon mixed powder is 1:1, and the catalyst includes any one of cobalt oxide, chromium oxide, and aluminum fluoride trihydrate.

[0044] Further, the addition amount of the catalyst is 2-4 wt% of the mass of the carbon-silicon mixed powder, the addition amount of the aluminum powder is 1-1.5 wt% of the total mass of the silicon carbide mixed powder and the catalyst, and the addition amount of the phenolic resin is 5-6 wt% of the total mass of the carbon-silicon mixed powder, the catalyst and the aluminum powder.

[0045] Further, the carbon-silicon mixed powder is composed of silicon powder and nano carbon black.

[0046] Further, the aluminum alloy includes any one of 6000 series aluminum alloy and 7000 series aluminum alloy.

[0047] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The present invention uses polyphenylene sulfide as the main matrix resin, and uses polybutylene terephthalate, ethylene vinyl acrylate resin, and random copolymer containing glycidyl ester as composite toughening agents to toughen polyphenylene sulfide, improving its own mechanical properties; and uses silicon carbide whiskers with similar polarity, thermal expansion coefficient, and heat resistance to glass fiber to replace glass fiber as reinforcement, enhancing the resin strength, adjusting the thermal expansion coefficient, reducing the internal stress after the combination of metal material and plastic, and enhancing the nano-anchor effect; The self-made silicon carbide whiskers of the present invention have a nano-scale diameter (50-90 nm) and a micro-scale length (5-7 μm), and the size is much smaller than that of glass fiber, solving the problem that the large size of glass fiber cannot enter the nano-pores and only stays in the resin outside the nano-pores, resulting in different thermal expansion coefficients inside and outside the nano-pores and causing the failure of the nano-anchor effect. On this basis, the present invention further combines surface pretreatment, anodic oxidation treatment, and electrochemical deposition steps, so that the prepared alloy composite has excellent interfacial bonding strength. Specific embodiments

[0048] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 shall fall within the protection scope of the present invention.

[0049] In the following examples, nano carbon black was purchased from Tianjin Tianyi Chemical Co., Ltd.; silicon powder was purchased from Qinghe Chaoneng Alloy Materials Co., Ltd.; aluminum powder was purchased from Ruitaima Steel New Materials Technology Co., Ltd.; phenolic resin CAS: 9003-35-4 was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; polyphenylene sulfide model was CXP-500C, purchased from Zhuhai Changxian; polybutylene terephthalate model was 1200-211D; ethylene acrylic acid ethylene resin model was Amplify EA 102, purchased from Dow Chemical Company, USA; ethylene acrylate and glycidyl methacrylate random copolymer model was AX8900, purchased from Arkema, France; glass fiber model was ECS13-4.5-534A, purchased from China National Bluestar (Group) Co., Ltd.; the rest of the raw materials were commercially available.

[0050] Example 1: A processing method of an alloy composite part based on nano-injection molding: S1: Preparation of silicon carbide whiskers: Add carbon-silicon mixed powder, catalyst, aluminum powder, and absolute ethanol into a ball mill, stir evenly, add phenolic resin, stir for 12-14 h, press into a blank, heat to 200-205 °C and cure for 24 h, heat the cured blank to 1200-1400 °C at a heating rate of 5 °C / min under the condition of burying coke, keep warm for 2-2.5 h, cool, and grind to obtain silicon carbide whiskers;

[0051] S2: Surface pretreatment: Grind the surface of the aluminum alloy flat, soak it in acetone and absolute ethanol successively for ultrasonic cleaning for 5 min, take it out, wash it with deionized water, and dry it; Immerse the degreased aluminum alloy in a mixed solution composed of 30 g / L sodium hydroxide and 30 g / L sodium carbonate, heat to 55 °C and react for 40 s, take it out, wash it with deionized water, and dry it; Immerse the aluminum alloy after removing the oxide film into a mixed solution composed of 400 g / L sodium hydroxide, 300 g / L sodium nitrate, 60 g / L sodium fluoride, and 100 g / L sodium silicate, heat to 95 °C and react for 2 min, take it out, wash it with deionized water, and dry it;

[0052] S3: Anodic oxidation treatment: Use the aluminum alloy after surface pretreatment as the anode and a graphite plate as the cathode to carry out the first anodic oxidation in an oxalic acid electrolyte. During the first anodic oxidation, the electrolyte is a 0.3 mol / L oxalic acid solution, the oxidation voltage is 40 V, the oxidation temperature is 20 °C, and the oxidation time is 4 h; Immerse the aluminum alloy after the first anodic oxidation into a mixed solution composed of 6 wt% phosphoric acid and 1.8 wt% chromic acid at 60 °C and react for 1 min to remove the oxide film; Carry out the second anodic oxidation on the aluminum alloy after removing the oxide film, and the oxidation time is 6 h; Immerse the aluminum alloy after the second anodic oxidation into a 6 wt% phosphoric acid solution at 30 °C and react for 15 min to expand the pores of the oxide film;

[0053] S4: Electrochemical deposition: The anodized aluminum alloy is subjected to double - potential electrodeposition; among them, in the double - potential electrodeposition, the anodized aluminum alloy is used as the working electrode, the saturated calomel electrode is used as the reference electrode, and the stainless - steel sheet is used as the auxiliary electrode; a mixed solution composed of 5 mmol / L triazine dithiol and 0.15 mol / L sodium nitrate solution is used as the electrolyte; in the double - potential deposition method, the step - 1 step - potential is 1.6 V, the step - time is 30 s, the step - 2 step - potential is 6 V, the step - time is 10 s; the deposition temperature is 5 °C;

[0054] S5: Nano - injection molding: The surface of the electrochemically deposited aluminum alloy is subjected to nano - injection molding using toughened polyphenylene sulfide resin as the matrix resin to obtain an alloy composite; among them, the toughened polyphenylene sulfide resin is composed of 65 parts of polyphenylene sulfide, 30 parts of polybutylene terephthalate, 10 parts of silicon carbide whiskers, 5 parts of ethylene - vinyl acetate resin, 5 parts of ethylene acrylate - glycidyl methacrylate random copolymer, 0.2 part of antioxidant 1098, and 0.8 part of mold release agent SEED; during the nano - injection molding process, the injection speed is 300 mm / s, the injection pressure is 60 MPa, the holding pressure is 40 MPa, and the holding time is 8 s.

[0055] Example 2: A processing method of an alloy composite based on nano - injection molding: S5: Nano - injection molding: The surface of the electrochemically deposited aluminum alloy is subjected to nano - injection molding using toughened polyphenylene sulfide resin as the matrix resin to obtain an alloy composite; among them, the toughened polyphenylene sulfide resin is composed of 65 parts of polyphenylene sulfide, 30 parts of polybutylene terephthalate, 20 parts of silicon carbide whiskers, 5 parts of ethylene - vinyl acetate resin, 5 parts of ethylene acrylate - glycidyl methacrylate random copolymer, 0.2 part of antioxidant 1098, and 0.8 part of mold release agent SEED; during the nano - injection molding process, the injection speed is 300 mm / s, the injection pressure is 60 MPa, the holding pressure is 40 MPa, and the holding time is 8 s.

[0056] The remaining steps are the same as those in Example 1.

[0057] Example 3: A processing method of an alloy composite based on nano - injection molding: S5: Nano - injection molding: The surface of the electrochemically deposited aluminum alloy is subjected to nano - injection molding using toughened polyphenylene sulfide resin as the matrix resin to obtain an alloy composite; among them, the toughened polyphenylene sulfide resin is composed of 65 parts of polyphenylene sulfide, 30 parts of polybutylene terephthalate, 30 parts of silicon carbide whiskers, 5 parts of ethylene - vinyl acetate resin, 5 parts of ethylene acrylate - glycidyl methacrylate random copolymer, 0.2 part of antioxidant 1098, and 0.8 part of mold release agent SEED; during the nano - injection molding process, the injection speed is 300 mm / s, the injection pressure is 60 MPa, the holding pressure is 40 MPa, and the holding time is 8 s.

[0058] The remaining steps are the same as those in Example 1.

[0059] Comparative Example 1: A processing method for an alloy composite based on nano-injection molding: S3: Anodizing treatment: Using the surface-pretreated aluminum alloy as the anode, a graphite plate as the cathode, and performing the first anodizing in an oxalic acid electrolyte. During the first anodizing process, the electrolyte is a 0.8 mol / L oxalic acid solution, the oxidation voltage is 40 V, the oxidation temperature is 20 °C, and the oxidation time is 4 h; immersing the aluminum alloy after the first anodizing in a mixed solution composed of 6 wt% phosphoric acid and 1.8 wt% chromic acid at 60 °C for 1 min to remove the oxide film; performing the second anodizing on the aluminum alloy after removing the oxide film, with an oxidation time of 6 h; immersing the aluminum alloy after the second anodizing in a 6 wt% phosphoric acid solution at 30 °C for 15 min to expand the pores of the oxide film.

[0060] The remaining steps are the same as those in Example 1.

[0061] Comparative Example 2: A processing method for an alloy composite based on nano-injection molding: S3: Anodizing treatment: Using the surface-pretreated aluminum alloy as the anode, a graphite plate as the cathode, and performing the first anodizing in an oxalic acid electrolyte. During the first anodizing process, the electrolyte is a 0.3 mol / L oxalic acid solution, the oxidation voltage is 60 V, the oxidation temperature is 20 °C, and the oxidation time is 4 h; immersing the aluminum alloy after the first anodizing in a mixed solution composed of 6 wt% phosphoric acid and 1.8 wt% chromic acid at 60 °C for 1 min to remove the oxide film; performing the second anodizing on the aluminum alloy after removing the oxide film, with an oxidation time of 6 h; immersing the aluminum alloy after the second anodizing in a 6 wt% phosphoric acid solution at 30 °C for 15 min to expand the pores of the oxide film.

[0062] The remaining steps are the same as those in Example 1.

[0063] Comparative Example 3: A processing method for an alloy composite based on nano-injection molding: S3: Anodizing treatment: Using the surface-pretreated aluminum alloy as the anode, a graphite plate as the cathode, and performing the first anodizing in an oxalic acid electrolyte. During the first anodizing process, the electrolyte is a 0.3 mol / L oxalic acid solution, the oxidation voltage is 40 V, the oxidation temperature is 30 °C, and the oxidation time is 4 h; immersing the aluminum alloy after the first anodizing in a mixed solution composed of 6 wt% phosphoric acid and 1.8 wt% chromic acid at 60 °C for 1 min to remove the oxide film; performing the second anodizing on the aluminum alloy after removing the oxide film, with an oxidation time of 6 h; immersing the aluminum alloy after the second anodizing in a 6 wt% phosphoric acid solution at 30 °C for 15 min to expand the pores of the oxide film.

[0064] The remaining steps are the same as those in Example 1.

[0065] Comparative Example 4: A processing method of an alloy composite based on nano-injection molding: S3: Anodizing treatment: The surface-pretreated aluminum alloy is used as the anode, the graphite plate is used as the cathode, and the first anodizing is carried out in an oxalic acid electrolyte. During the first anodizing process, the electrolyte is a 0.3 mol / L oxalic acid solution, the oxidation voltage is 40 V, the oxidation temperature is 20 °C, and the oxidation time is 4 h; the aluminum alloy after the first anodizing is immersed in a mixed solution composed of 6 wt% phosphoric acid and 1.8 wt% chromic acid at 60 °C for 1 min to remove the oxide film; the aluminum alloy after removing the oxide film is subjected to the second anodizing, and the oxidation time is 6 h; the aluminum alloy after the second anodizing is immersed in a 6 wt% phosphoric acid solution at 30 °C for 45 min to expand the pores of the oxide film.

[0066] The remaining steps are the same as those in Example 1.

[0067] Comparative Example 5: A processing method of an alloy composite based on nano-injection molding: S1: Preparation of silicon carbide whiskers: Carbon-silicon mixed powder, catalyst, aluminum powder, and absolute ethanol are added to a ball mill, stirred evenly, phenolic resin is added, stirred for 12 - 14 h, pressed into a blank, heated to 200 - 205 °C and cured for 24 h, and the cured blank is heated to 1200 - 1400 °C at a heating rate of 5 °C / min under the condition of being buried in coke, held for 2 - 2.5 h, cooled, and ground to obtain silicon carbide whiskers;

[0068] S2: Surface pretreatment: Grind the surface of the aluminum alloy flat, successively immerse it in acetone and absolute ethanol for ultrasonic cleaning for 5 min, take it out, wash it with deionized water, and dry it; immerse the degreased aluminum alloy in a mixed solution composed of 30 g / L sodium hydroxide and 30 g / L sodium carbonate, heat to 55 °C and react for 40 s, take it out, wash it with deionized water, and dry it; immerse the aluminum alloy after removing the oxide film in a mixed solution composed of 400 g / L sodium hydroxide, 300 g / L sodium nitrate, 60 g / L sodium fluoride, and 100 g / L sodium silicate, heat to 95 °C and react for 2 min, take it out, wash it with deionized water, and dry it;

[0069] S3: Anodizing treatment: The surface-pretreated aluminum alloy is used as the anode, the graphite plate is used as the cathode, and the first anodizing is carried out in an oxalic acid electrolyte. During the first anodizing process, the electrolyte is a 0.3 mol / L oxalic acid solution, the oxidation voltage is 40 V, the oxidation temperature is 20 °C, and the oxidation time is 4 h; the aluminum alloy after the first anodizing is immersed in a mixed solution composed of 6 wt% phosphoric acid and 1.8 wt% chromic acid at 60 °C for 1 min to remove the oxide film; the aluminum alloy after removing the oxide film is subjected to the second anodizing, and the oxidation time is 6 h; the aluminum alloy after the second anodizing is immersed in a 6 wt% phosphoric acid solution at 30 °C for 15 min to expand the pores of the oxide film;

[0070] S4: Nano-injection molding: Using toughened polyphenylene sulfide resin as the matrix resin, nano-injection molding is carried out on the surface of aluminum alloy to obtain an alloy composite; among them, the toughened polyphenylene sulfide resin is composed of 65 parts of polyphenylene sulfide, 30 parts of polybutylene terephthalate, 10 parts of silicon carbide whiskers, 5 parts of ethylene-vinyl acetate resin, 5 parts of ethylene acrylate-glycidyl methacrylate random copolymer, 0.2 part of antioxidant 1098, and 0.8 part of demolding agent SEED; during the nano-injection molding process, the injection speed is 150 mm / s, the injection pressure is 60 MPa, the holding pressure is 40 MPa, and the holding time is 8 s.

[0071] Comparative Example 6: A processing method of an alloy composite based on nano-injection molding: S5: Nano-injection molding: Using toughened polyphenylene sulfide resin as the matrix resin, nano-injection molding is carried out on the surface of aluminum alloy after electrochemical deposition to obtain an alloy composite; among them, the toughened polyphenylene sulfide resin is composed of 65 parts of polyphenylene sulfide, 30 parts of polybutylene terephthalate, 10 parts of silicon carbide whiskers, 5 parts of ethylene-vinyl acetate resin, 5 parts of ethylene acrylate-glycidyl methacrylate random copolymer, 0.2 part of antioxidant 1098, and 0.8 part of demolding agent SEED; during the nano-injection molding process, the injection speed is 300 mm / s, the injection pressure is 60 MPa, the holding pressure is 40 MPa, and the holding time is 8 s.

[0072] The remaining steps are the same as those in Example 1.

[0073] Comparative Example 7: A processing method of an alloy composite based on nano-injection molding: S5: Nano-injection molding: Using toughened polyphenylene sulfide resin as the matrix resin, nano-injection molding is carried out on the surface of aluminum alloy after electrochemical deposition to obtain an alloy composite; among them, the toughened polyphenylene sulfide resin is composed of 65 parts of polyphenylene sulfide, 30 parts of polybutylene terephthalate, 10 parts of silicon carbide whiskers, 5 parts of ethylene-vinyl acetate resin, 5 parts of ethylene acrylate-glycidyl methacrylate random copolymer, 0.2 part of antioxidant 1098, and 0.8 part of demolding agent SEED; during the nano-injection molding process, the injection speed is 500 mm / s, the injection pressure is 60 MPa, the holding pressure is 40 MPa, and the holding time is 8 s.

[0074] The remaining steps are the same as those in Example 1.

[0075] Comparative Example 8: A processing method for an alloy composite based on nano-injection molding: S5: Nano-injection molding: Using toughened polyphenylene sulfide resin as the matrix resin to perform nano-injection molding on the surface of the aluminum alloy after electrochemical deposition to obtain an alloy composite; wherein, the toughened polyphenylene sulfide resin is composed of 65 parts of polyphenylene sulfide, 30 parts of polybutylene terephthalate, 10 parts of glass fiber, 5 parts of ethylene-ethyl acrylate resin, 5 parts of ethylene acrylate-glycidyl methacrylate random copolymer, 0.2 part of antioxidant 1098, and 0.8 part of mold release agent SEED; during the nano-injection molding process, the injection speed is 300 mm / s, the injection pressure is 60 MPa, the holding pressure is 40 MPa, and the holding time is 8 s.

[0076] The remaining steps are the same as those in Example 1.

[0077] Experiment: Plastic-metal bonding strength performance test:

[0078] Prepare a plastic-metal test integral part according to the relevant patent method of Dainippon Ink and Chemicals, Inc. of Japan. The size of the aluminum alloy sheet is 20 mm × 45 mm × 1.5 mm, the size of the plastic part is 10 mm × 45 mm × 3 mm, and the bonding area between the plastic and the metal is 0.5 cm 2 .

[0079] According to the standard in Japanese Dainippon Chemical Patent No. 8057890, conduct a plastic-metal bonding strength performance test on the plastic-metal test integral part.

[0080] Table 1 Data table of plastic-metal bonding strength performance test

[0081]

[0082] Conclusion: The alloy composite prepared by the present invention has excellent interfacial bonding strength.

[0083] In Comparative Example 1, the concentration of oxalic acid during the anodization process was too high, resulting in too large nanopore diameters and pore collapse, leading to a decrease in interfacial bonding force.

[0084] In Comparative Example 2, the oxidation voltage during the anodization process was too high, resulting in an unstable growth process of the nanopore structure, irregular nanopore shapes, and different nanopore diameters, leading to a decrease in interfacial bonding force.

[0085] In Comparative Example 3, the oxidation temperature during the anodization process was too high, resulting in severe electrolyte corrosion, the nanopore structures being connected through, and the porous structure being damaged, leading to a decrease in interfacial bonding force.

[0086] In Comparative Example 4, the pore expansion time during the oxidation film pore expansion process was too long, resulting in severe corrosion of the oxidation film, the pores being connected and collapsed, leading to a decrease in interfacial bonding force.

[0087] In Comparative Example 5, electrochemical deposition was not carried out after anodization, lacking the anchoring effect formed by the reaction between aluminum alloy, triazine dithiol metal salt, and toughened polyphenylene sulfide resin, resulting in a decrease in interfacial bonding strength.

[0088] In Comparative Example 6, the injection speed was too slow during the nano-injection process. Constrained by the metal pore wall during the filling process, distortion was likely to occur, resulting in a decrease in the pore size. The molecular chains accumulated and blocked at the entrance of the nano-pores, leading to a decrease in interfacial bonding strength.

[0089] In Comparative Example 7, the injection speed was too fast during the nano-injection process, reducing the bonding strength of the resin in the nano-pores and resulting in a decrease in interfacial bonding strength.

[0090] In Comparative Example 8, the silicon carbide whiskers in the toughened polyphenylene sulfide resin were replaced with glass fibers. The glass fiber size was too large to enter the nano-pores and was only located in the resin outside the nano-pores, causing a difference in the thermal expansion coefficients inside and outside the nano-pores and the failure of the nano-anchor effect, resulting in a decrease in interfacial bonding strength.

[0091] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for processing alloy composite parts based on nano injection molding, characterized in that: The following steps are involved: S1: Surface pretreatment: Degreasing, removing oxide film and chemical polishing the aluminum alloy surface in sequence; S2: Anodizing treatment: The aluminum alloy after surface pretreatment is subjected to first anodizing, oxide film removal, second anodizing, and oxide film pore expansion in sequence; S3: Electrochemical deposition: The aluminum alloy after anodizing is subjected to double potential electrodeposition; S4: Nano-injection molding: using toughened polyphenylene sulfide resin as a matrix resin to perform nano-injection molding on the surface of the electrochemically deposited aluminum alloy to obtain an alloy composite; In step S1, the degreasing step includes grinding the surface of the aluminum alloy flat, immersing it in acetone and anhydrous ethanol for ultrasonic cleaning for 5-10 minutes, taking it out, washing it with deionized water, and drying it; the oxide film removal step includes immersing the degreased aluminum alloy in a mixed solution composed of 30-35g / L sodium hydroxide and 30-35g / L sodium carbonate, heating it to 55-60°C for reaction for 40-45s, taking it out, washing it with deionized water, and drying it; the chemical polishing step includes placing the aluminum alloy after the oxide film is removed into a mixed solution composed of 400-420g / L sodium hydroxide, 300-320g / L sodium nitrate, 60-65g / L sodium fluoride, and 100-120g / L sodium silicate, heating it to 95-100°C for reaction for 1-5 minutes, taking it out, washing it with deionized water, and drying it; In step S2, the electrolyte in the first anodization is a 0.3-0.6 mol / L oxalic acid solution, the oxidation voltage is 35-45 V, the oxidation temperature is 15-25° C., and the oxidation time is 4-4.5 h; the oxide film removal step comprises immersing the first anodized aluminum alloy in a mixed solution of 6-7 wt% phosphoric acid and 1.8-2 wt% chromic acid at 60-65° C. for 1-2 min; the oxidation time in the second anodization is 6-6.5 h, and the other anodization process parameters are the same as those of the first anodization; the oxide film pore expansion step comprises immersing the aluminum alloy after the second anodization in a 6-7 wt% phosphoric acid solution at 30-35° C. for 15-30 min; In the dual potential electrodeposition, the aluminum alloy after anodization is used as the working electrode, the saturated calomel electrode is used as the reference electrode, and the stainless steel sheet is used as the auxiliary electrode; The electrolyte consists of 5-6 mmol / L triazine dithiol and 0.15-0.18 mol / L sodium nitrate solution; In step S4, the nano injection molding step includes injection pressurization, pressure holding, cooling, and ejection; the injection speed is 250-350 mm / s, the injection pressurization pressure is 60-80 MPa, the pressure holding pressure is 40-60 MPa, and the pressure holding time is 8-10 s; The components of the toughened polyphenylene sulfide resin are 50-65 parts by mass of polyphenylene sulfide, 15-30 parts of polybutylene terephthalate, 10-30 parts of silicon carbide whiskers, 1-10 parts of ethylene acrylic acid resin, 1-10 parts of random copolymer containing glycidyl ester, 0.1-1 parts of antioxidant, and 0.1-2 parts of release agent. The method for preparing the silicon carbide whisker comprises the following steps: Add carbon silicon mixed powder, catalyst, aluminum powder and anhydrous ethanol into a ball mill, stir evenly, add phenolic resin, stir for 12-14 hours, press into billets, heat to 200-205°C and cure for 24 hours, heat the cured billet to 1200-1400°C at a heating rate of 5°C / min under coke conditions and keep warm for 2-2.5 hours, cool and grind to obtain silicon carbide whiskers.

2. The method for processing alloy composite parts based on nano injection molding according to claim 1, characterized in that: The carbon-silicon molar ratio in the carbon-silicon mixed powder is 1:1, and the catalyst includes any one of cobalt trioxide, chromium trioxide, and aluminum fluoride trihydrate; the amount of the catalyst added is 2-4wt% of the mass of the carbon-silicon mixed powder, the amount of aluminum powder added is 1-1.5wt% of the total mass of the silicon carbide mixed powder and the catalyst, and the amount of phenolic resin added is 5-6wt% of the total mass of the carbon-silicon mixed powder, the catalyst, and the aluminum powder.

3. An alloy composite part prepared according to the processing method of an alloy composite part based on nano injection molding according to any one of claims 1-2.

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