Two-component pretreating agent for titanium alloy, preparation method of two-component pretreating agent and titanium alloy surface treatment method

Abstract

The invention relates to the technical field of metal surface treatment, particularly provides a two-component pretreatment agent for a titanium alloy and a preparation method of the two-component pretreatment agent, and meanwhile provides a titanium alloy surface treatment method based on the two-component pretreatment agent. The double-component pretreating agent for the titanium alloy comprises a component A and a component B, the component A comprises the following components: a glycine-hydrochloric acid buffer solution, a dopamine compound and a modified methacrylic acid prepolymer; the component B comprises the following components: an acetic acid-sodium acetate buffer solution and an oxidizing agent. According to the invention, dopamine is self-polymerized on the surface of the titanium alloy to form a polydopamine interface layer with high adhesive force, and catechol groups in the layer can form stable coordinate bonds with the surface of the titanium alloy; meanwhile, the introduced modified methacrylic acid prepolymer can be covalently crosslinked with a paint layer, so that a coordinate bond-covalent bond dual chemical bonding mechanism is constructed at an interface, and the initial adhesive force of the paint layer is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal surface treatment, in particular to a two-component pretreatment agent for titanium alloy and a preparation method thereof, and a titanium alloy surface treatment method. BACKGROUND

[0002] Titanium alloy is widely used in aerospace, marine engineering, medical treatment, electronic devices and other industrial fields due to its high specific strength, good corrosion resistance, high fatigue strength and excellent processing performance. The pursuit of military aircraft performance in the military field increases the use proportion of titanium alloy in aircraft, such as the weight proportion of titanium alloy in the F-22 fighter of the United States is close to 42%. With the special combat performance requirements of the new generation of fighter aircraft, the titanium alloy surface needs to be coated with various functional paint layers, such as wave-absorbing paint layer, high-emissivity paint layer, and aviation primer. However, the titanium metal surface is easy to form a low-surface-energy oxide film, which seriously affects the adhesion between the paint layer and the titanium alloy substrate, resulting in the risk of paint layer falling off during flight, so the titanium alloy needs to be surface treated to enhance the adhesion of the paint layer.

[0003] Traditional surface treatment processes mainly include sandblasting, pickling, anodizing, etc., which essentially improve the adhesion between the paint layer and the titanium alloy by enhancing physical interaction. The adhesion between the coating and the metal surface depends only on intermolecular forces such as van der Waals force and hydrogen bond, and the improvement effect is limited, which is difficult to meet the high performance requirements. New surface treatment processes mainly include phosphating primer method and sol-gel method, which can improve the adhesion between titanium alloy and paint layer by 15% to 20% to a certain extent by forming a chemical conversion film or an inorganic-organic hybrid layer, but there is a problem of insufficient durability. After long-term environmental aging, the adhesion of the paint layer will decrease significantly, and its long-term reliability cannot be fully guaranteed. In summary, a new titanium alloy surface pretreatment technology is urgently needed to long-term improve the adhesion between the paint layer and the titanium alloy. SUMMARY

[0004] In view of the above problems, the present application provides a two-component pretreatment agent for titanium alloy and a preparation method thereof. The pretreatment agent can form a modified polydopamine (PDA) layer with high adhesion on the surface of titanium alloy, which can chemically react with commonly used aviation paint layers to form covalent bonds, achieving long-term enhancement of the adhesion of the paint layer. The present application also provides a titanium alloy surface treatment method.

[0005] In a first aspect, the present application provides a two-component pretreatment agent for titanium alloy, comprising component A and component B. The A component comprises the following components: aminoacetate-hydrochloric acid buffer, dopamine compound, modified methacrylic acid prepolymer; the pH value of the aminoacetate-hydrochloric acid buffer is 1.5-3.0, and the concentration of aminoacetate in the aminoacetate-hydrochloric acid buffer is 20-100 mmol / L; In the A component, the concentration of the dopamine compound is 0.5-20 g / L, and the concentration of the modified methacrylic acid prepolymer is 0.1-2 g / L. The B component comprises the following components: acetic acid-sodium acetate buffer, oxidizing agent; the pH value of the acetic acid-sodium acetate buffer is 5.0-7.0, and the concentration of sodium acetate in the acetic acid-sodium acetate buffer is 20-100 mmol / L. In the B component, the concentration of the oxidizing agent is 10-100 mmol / L.

[0006] After the A component of the pretreatment agent in the application contacts with the B component of the pretreatment agent containing the oxidizing agent, a complex redox reaction is triggered, the dopamine compound is self-polymerized and self-assembled on the surface of the titanium alloy to form a dense polydopamine (PDA) interface layer, and the abundant catechol groups of the dopamine can be complexed with the titanium metal to form a high-energy coordination bond, the strength of which is much higher than the intermolecular force (such as van der Waals force, hydrogen bond, etc.) between the paint layer and the titanium alloy substrate, thereby realizing the strong combination of the PDA layer and the titanium alloy substrate. Meanwhile, the modified methacrylic acid prepolymer introduced in the application is rich in active functional groups such as hydroxyl groups and amine groups, which not only can participate in the self-polymerization of the dopamine to enhance the density of the PDA interface layer, but also can be covalently crosslinked with the functional groups (such as epoxy functional groups and carboxylic acid functional groups, etc.) in the commonly used aviation paint layer, thereby ensuring the bonding force between the PDA layer and the paint layer. In addition, each organic molecule in the A component of the pretreatment agent in the application contains a large number of phenyl groups, which have a strong π-π stacking effect between molecules, further strengthening the intermolecular force of the interface layer, greatly improving the structural stability and overall density of the interface layer, and thereby endowing the overall coating system with excellent durability.

[0007] Preferably, the dopamine compound comprises one or more of dopamine hydrochloride, 6-hydroxydopamine hydrochloride, 6-hydroxydopamine acid hydrobromide, dobutamine hydrochloride, levodopa hydrochloride, 3-methoxytyramine hydrochloride and 3-methylacryldopamine.

[0008] Preferably, the preparation method of the modified methacrylic acid prepolymer comprises the following steps: The hydroxyethyl methacrylate, acrylamide and initiator are added to deionized water for reaction to obtain the modified methacrylic acid prepolymer; the molar ratio of the hydroxyethyl methacrylate to the acrylamide is (1-5):1.

[0009] The molar ratio of hydroxyethyl methacrylate to acrylamide in the present application is preferably (1-5):1. This ratio can accurately regulate the relative density of hydroxyl and amine groups in the polymer chain, ensuring that the modified methacrylate prepolymer has good water phase compatibility and moderate molecular weight, and ensuring that the finally formed interface layer has good compactness, stability and adhesion. Within this range, an appropriate amount of acrylamide unit effectively participates in and promotes the self-polymerization reaction of dopamine through its amine group, anchoring the prepolymer firmly in the polydopamine network; at the same time, the dominant hydroxyethyl methacrylate unit can form efficient covalent crosslinking with the subsequently coated aviation paint layer through the rich hydroxyl groups, forming a firm chemical bridge.

[0010] Preferably, the temperature of the reaction is 50-60℃, and the time is 1-5h.

[0011] Preferably, the initiator is dibenzoyl peroxide.

[0012] Preferably, the oxidizing agent includes one or more of ammonium persulfate (APS), sodium periodate (NaIO4), sodium hypochlorite (NaClO), sodium bromate (NaBrO3), cerium sulfate (Ce2(SO4)3), and potassium monopersulfate (KHSO5).

[0013] Preferably, the mixing mass ratio of the A component and the B component is 1:(1-5).

[0014] The mass ratio of the A component and the B component in the present application is preferably 1:(1-5), which can not only ensure that the oxidizing agent in the B component fully initiates the ordered self-polymerization of dopamine compounds to form a polydopamine network with complete structure, but also stabilize the acid-base degree of the reaction system in the most suitable interval for interface layer growth, thereby synergistically ensuring that the finally formed PDA composite interface layer has excellent compactness, uniformity and stability.

[0015] Preferably, the two-component pretreatment agent for titanium alloys provided by the present application is stored separately in A and B components, which are mixed during use, ensuring that dopamine compounds with reducing properties and strong oxidizing agents do not come into contact during storage, improving the storage stability of the pretreatment agent itself and avoiding the problem of self-polymerization failure of single-component systems.

[0016] In a second aspect, the present application also provides a preparation method of the above-mentioned two-component pretreatment agent for titanium alloys, comprising the following steps: An aminoacetic acid-hydrochloric acid buffer with a pH value of 1.5-3.0 is prepared, deoxygenated, and then the dopamine compound and the modified methacrylic acid prepolymer are added and stirred uniformly to obtain the A component; The acetic acid-sodium acetate buffer solution with pH value of 5.0-7.0 is configured, the oxidant is added, and stirring is uniformly performed to obtain the B component; The A component and the B component are mixed to obtain the two-component pretreatment agent for titanium alloy.

[0017] In an embodiment of the present application, the configuration process of the glycine-hydrochloric acid buffer solution is as follows: The glycine is weighed and dissolved in deionized water, and is uniformly shaken to prepare a glycine solution with a concentration of 1 mol / L; the concentrated hydrochloric acid is weighed and dissolved in deionized water, and is uniformly shaken to prepare a hydrochloric acid solution with a concentration of 1 mol / L; the glycine-hydrochloric acid buffer solution is configured by using the glycine solution and the hydrochloric acid solution, the pH value of the glycine-hydrochloric acid buffer solution is controlled to be 1.5-3.0, and the concentration of glycine is controlled to be 20-100 mmol / L.

[0018] In an embodiment of the present application, the configuration process of the acetic acid-sodium acetate buffer solution is as follows: The sodium acetate is weighed and dissolved in deionized water, and is uniformly shaken to prepare a sodium acetate solution with a concentration of 1 mol / L; the acetic acid is weighed and dissolved in deionized water, and is uniformly shaken to prepare an acetic acid solution with a concentration of 1 mol / L; the acetic acid-sodium acetate buffer solution is configured by using the sodium acetate solution and the acetic acid solution, the pH value of the acetic acid-sodium acetate is controlled to be 5.0-7.0, and the concentration of sodium acetate is controlled to be 20-100 mmol / L.

[0019] In a third aspect, the present application further provides a titanium alloy surface treatment method, which comprises the following steps: The surface of the titanium alloy to be treated is polished, and then is immersed in the two-component pretreatment agent for titanium alloy for soaking; the titanium alloy is taken out, is cleaned and dried, and then a surface-modified titanium alloy is obtained.

[0020] Preferably, the soaking time is 0.5-6 h.

[0021] Preferably, the polishing process specifically comprises: crosswise polishing the surface to be processed of the titanium alloy to be treated by using 80-mesh, 120-mesh and 240-mesh sandpaper in sequence, and then wiping the titanium alloy surface powder and grease by using ethanol or acetone.

[0022] In a fourth aspect, the present application further provides a titanium alloy obtained by using the titanium alloy surface treatment method.

[0023] Compared with the prior art, the present application has the following beneficial effects: (1) The present application utilizes the self-polymerization of dopamine on the surface of titanium alloy to form a high-adhesion polydopamine (PDA) interface layer, and the catechol groups in the layer can form stable coordination bonds with the surface of titanium alloy; at the same time, the introduced modified methacrylic acid prepolymer can be covalently crosslinked with the paint layer, thereby constructing a "coordination bond-covalent bond" double chemical bonding mechanism at the interface, greatly improving the initial adhesion of the paint layer. In addition, the strong π-π stacking effect between organic molecules in the PDA layer further enhances the structural stability of the interface layer, so that the titanium alloy surface modified by the present application has better long-term durability than the traditional processing technology.

[0024] (2) The pretreatment agent provided by the present application uses deionized water as the solvent in the entire preparation process, avoiding the use of common organic solvents in traditional titanium alloy pretreatment agents, and having the advantages of green environmental protection. At the same time, the processing method is simple and convenient, and the conditions are mild, and is suitable for surface treatment of various grades of titanium alloy, such as TA12, TC4, TB6, etc., and has good industrial popularization prospects. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The schematic diagram of the surface modified titanium alloy samples prepared in Examples 1-3 of the present application and the unmodified titanium alloy samples of Controls 1-3; from top to bottom, they are unmodified TA12, unmodified TC4, unmodified TB6, surface modified TA12, surface modified TC4, surface modified TB6; Figure 2 The schematic diagram of each sample after spraying the aviation primer TB06-9; from top to bottom, they are unmodified TA12, unmodified TC4, unmodified TB6, surface modified TA12, surface modified TC4, surface modified TB6; Figure 3 The schematic diagram of each sample after the pull-off test; the first row from left to right is unmodified TA12, unmodified TC4, unmodified TB6; the second row from left to right is surface modified TA12, surface modified TC4, surface modified TB6. DETAILED DESCRIPTION

[0026] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, a brief introduction to the specific embodiments will be given below. Obviously, the examples described below are some embodiments of the present application, and other embodiments can be obtained by those skilled in the art without creative labor on the basis of these examples.

[0027] The specific experimental steps or conditions are not indicated in the embodiments, and the operation or conditions can be carried out according to the conventional experimental steps described in the literature in the art. The raw materials or instruments used are conventional products that can be obtained by purchase, including but not limited to the raw materials or instruments used in the embodiments of the present application.

[0028] In the embodiments of the present application, the preparation method of the modified methacrylic acid prepolymer is as follows: Hydroxyethyl methacrylate and acrylamide are added to deionized water according to a molar ratio of 2:1, then dibenzoyl peroxide (BPO) is added, and the reaction is stirred at 60℃ for 3h. After precipitation treatment, the modified methacrylic acid prepolymer is obtained.

[0029] Embodiment 1 The present embodiment provides a two-component pretreatment agent for titanium alloy, which comprises component A and component B; when used, the mass ratio of component A to component B is 1:2.

[0030] Component A comprises the following components: aminoacetate-hydrochloric acid buffer, dopamine compound, modified methacrylic acid prepolymer; the pH value of the aminoacetate-hydrochloric acid buffer is 2.0, and the concentration of aminoacetate in the aminoacetate-hydrochloric acid buffer is 40mmol / L; In component A, the concentration of dopamine compound is 6g / L, and the concentration of modified methacrylic acid prepolymer is 0.5g / L; The dopamine compound is selected from dopamine hydrochloride, 6-hydroxydopamine hydrochloride, levodopa hydrochloride, and 3-methacryloyl dopamine, and the mass ratio of dopamine hydrochloride, 6-hydroxydopamine hydrochloride, levodopa hydrochloride, and 3-methacryloyl dopamine is 2:2:1:1; Component B comprises the following components: acetic acid-sodium acetate buffer, oxidizing agent; the pH value of the acetic acid-sodium acetate buffer is 6.0, and the concentration of sodium acetate in the acetic acid-sodium acetate buffer is 30mmol / L; In component B, the concentration of oxidizing agent is 30mmol / L; The oxidizing agent is sodium hypochlorite.

[0031] The present embodiment provides a preparation method of the two-component pretreatment agent for titanium alloy described above, comprising the following steps: Take 75 g of aminoacetic acid and dissolve it in 1 L of deionized water, shake well, to prepare 1 mol / L aminoacetic acid solution; take 83 mL of concentrated hydrochloric acid and dissolve it in 1 L of deionized water, shake well, to prepare 1 mol / L hydrochloric acid solution; use the prepared aminoacetic acid solution and hydrochloric acid solution to prepare aminoacetic acid-hydrochloric acid buffer solution, control the pH value in the range of 2.0, and control the aminoacetic acid concentration at 40 mmol / L; pass nitrogen into the aminoacetic acid-hydrochloric acid buffer solution for 20 min to remove oxygen in the solution; add dopamine hydrochloride, 6-hydroxydopamine hydrochloride, madopar hydrochloride, and 3-methacryloyl dopamine into the solution after oxygen removal in a ratio of 2:2:1:1, stir well, and control the total concentration at 6 g / L; add modified methacrylic acid prepolymer, control the concentration at 0.5 g / L, and obtain component A; Take 82 g of sodium acetate and dissolve it in 1 L of deionized water, shake well, to prepare 1 mol / L sodium acetate solution; take 63 mL of acetic acid and dissolve it in 1 L of deionized water, shake well, to prepare 1 mol / L acetic acid solution; use the prepared sodium acetate solution and acetic acid solution to prepare acetic acid-sodium acetate buffer solution, control the pH value at 6.0, and control the sodium acetate concentration at 30 mmol / L; add sodium hypochlorite into the buffer solution, control the concentration at 30 mmol / L, and obtain component B of the pretreatment agent.

[0032] The embodiment provides a surface treatment method of TA12 titanium alloy, which comprises the following steps: Cross the titanium alloy surface to be machined with 80-mesh, 120-mesh, and 240-mesh sandpaper in turn, and then wipe off the titanium alloy surface powder and grease with ethanol; Mix the prepared component A and component B of the pretreatment agent according to the mass ratio of 1:2, stir well, and obtain a two-component pretreatment agent for titanium alloy; Put the TA12 titanium alloy sample after polishing treatment into the two-component pretreatment agent for titanium alloy, soak for 1 h, and keep uniform stirring; rinse the soaked TA12 sample with deionized water and dry, to obtain a surface-modified TA12 titanium alloy.

[0033] Embodiment 2 The embodiment provides a two-component pretreatment agent for titanium alloy, which comprises component A and component B; the mass ratio of component A to component B is 1:1 when used.

[0034] Component A comprises the following components: aminoacetic acid-hydrochloric acid buffer solution, dopamine compound, and modified methacrylic acid prepolymer; the pH value of the aminoacetic acid-hydrochloric acid buffer solution is 2.5, and the concentration of aminoacetic acid in the aminoacetic acid-hydrochloric acid buffer solution is 30 mmol / L; In the A component, the concentration of the dopamine compound is 6 g / L, and the concentration of the modified methacrylic acid prepolymer is 1 g / L. The dopamine compound is selected from 6-hydroxydopamine acid hydrobromide, dopamine hydrochloride, 3-methoxytyramine hydrochloride, and 3-methyl acryl dopamine, and the mass ratio of 6-hydroxydopamine acid hydrobromide, dopamine hydrochloride, 3-methoxytyramine hydrochloride, and 3-methyl acryl dopamine is 2:1:1:1. The B component includes the following components: acetic acid-sodium acetate buffer and oxidizing agent; the pH value of the acetic acid-sodium acetate buffer is 6.5, and in the acetic acid-sodium acetate buffer, the concentration of sodium acetate is 50 mmol / L. In the B component, the concentration of the oxidizing agent is 20 mmol / L. The oxidizing agent is sodium periodate.

[0035] The embodiment provides a preparation method of the two-component pretreatment agent for the titanium alloy. 75 g of aminoacetic acid is weighed and dissolved in 1 L of deionized water to prepare a 1 mol / L aminoacetic acid solution; 83 mL of concentrated hydrochloric acid is weighed and dissolved in 1 L of deionized water to prepare a 1 mol / L hydrochloric acid solution; an aminoacetic acid-hydrochloric acid buffer is prepared by using the prepared aminoacetic acid solution and the hydrochloric acid solution, the pH value is controlled to be 2.5, and the concentration of the aminoacetic acid is controlled to be 30 mmol / L; nitrogen gas is passed into the aminoacetic acid-hydrochloric acid buffer for 20 min to remove oxygen in the solution; after the oxygen is removed, 6-hydroxydopamine acid hydrobromide, dopamine hydrochloride, 3-methoxytyramine hydrochloride and 3-methyl acryl dopamine are added into the solution in a ratio of 2:1:1:1, and are uniformly stirred, so that the total concentration is controlled to be 5 g / L; a modified methacrylic acid prepolymer is added, and the concentration is controlled to be 1 g / L, to obtain the A component. 82 g of sodium acetate is weighed and dissolved in 1 L of deionized water to prepare a 1 mol / L sodium acetate solution; 63 mL of acetic acid is weighed and dissolved in 1 L of deionized water to prepare a 1 mol / L acetic acid solution; an acetic acid-sodium acetate buffer is prepared by using the prepared sodium acetate solution and the acetic acid solution, the pH value is controlled to be 6.5, and the concentration of sodium acetate is controlled to be 50 mmol / L; sodium periodate is added into the buffer, and the concentration is controlled to be 20 mmol / L, to obtain the B component of the pretreatment agent.

[0036] The embodiment provides a surface treatment method of a TC4 titanium alloy. The TC4 titanium alloy sample is crosswise polished on the titanium alloy surface to be processed by using 80-mesh, 120-mesh and 240-mesh sandpaper, and then ethanol is used to wipe off the powder and grease on the titanium alloy surface. The A component and the B component of the pretreatment agent prepared in this embodiment are mixed in a mass ratio of 1:1, and after being stirred uniformly, a two-component pretreatment agent for titanium alloy is obtained. The TC4 titanium alloy sample after polishing treatment is placed into the two-component pretreatment agent for titanium alloy and soaked for 1 h while being stirred uniformly; the TC4 sample after soaking is washed with deionized water and dried to obtain a surface-modified TC4 titanium alloy.

[0037] Embodiment 3 This embodiment provides a two-component pretreatment agent for titanium alloy, which comprises an A component and a B component; the mass ratio of the A component to the B component is 1:2 when used.

[0038] The A component comprises the following components: an aminoacetic acid-hydrochloric acid buffer, a dopamine compound, and a modified methacrylic acid prepolymer; the pH value of the aminoacetic acid-hydrochloric acid buffer is 1.5, and the concentration of aminoacetic acid in the aminoacetic acid-hydrochloric acid buffer is 60 mmol / L; In the A component, the concentration of the dopamine compound is 4 g / L, and the concentration of the modified methacrylic acid prepolymer is 1.5 g / L. The dopamine compound is selected from dopamine hydrochloride, levodopa hydrochloride, 3-methoxytyramine hydrochloride, and 3-methylacryl dopamine, and the mass ratio of dopamine hydrochloride, levodopa hydrochloride, 3-methoxytyramine hydrochloride, and 3-methylacryl dopamine is 1:1:1:1. The B component comprises the following components: an acetic acid-sodium acetate buffer and an oxidizing agent; the pH value of the acetic acid-sodium acetate buffer is 6.5, and the concentration of sodium acetate in the acetic acid-sodium acetate buffer is 30 mmol / L. In the B component, the concentration of the oxidizing agent is 60 mmol / L. The oxidizing agent is sodium periodate and ammonium persulfate, the concentration of sodium periodate is 30 mmol / L, and the concentration of ammonium persulfate is 30 mmol / L.

[0039] This embodiment provides a preparation method of the two-component pretreatment agent for titanium alloy described above, comprising the following steps: Take 75 g of aminoacetic acid and dissolve it in 1 L of deionized water, shake well to prepare 1 mol / L aminoacetic acid solution; take 83 mL of concentrated hydrochloric acid and dissolve it in 1 L of deionized water, shake well to prepare 1 mol / L hydrochloric acid solution; use the prepared aminoacetic acid solution and hydrochloric acid solution to prepare an aminoacetic acid-hydrochloric acid buffer solution, control the pH value at 1.5, and control the aminoacetic acid concentration at 60 mmol / L; pass nitrogen into the aminoacetic acid-hydrochloric acid buffer solution for 20 min to remove oxygen in the solution; add dopamine hydrochloride, madopar hydrochloride, 3-methoxy tyramine hydrochloride and 3-methyl acryl dopamine into the solution after oxygen removal in a ratio of 1:1:1:1, stir well, and control the total concentration at 4 g / L; add modified methacrylic acid prepolymer, control the concentration at 1.5 g / L, and obtain component A; Take 82 g of sodium acetate and dissolve it in 1 L of deionized water, shake well to prepare 1 mol / L sodium acetate solution; take 63 mL of acetic acid and dissolve it in 1 L of deionized water, shake well to prepare 1 mol / L acetic acid solution; use the prepared sodium acetate solution and acetic acid solution to prepare an acetic acid-sodium acetate buffer solution, control the pH value at 6.5, and control the sodium acetate concentration at 30 mmol / L; add sodium periodate and ammonium persulfate into the buffer solution, control the sodium periodate concentration at 30 mmol / L, and control the ammonium persulfate concentration at 30 mmol / L to obtain component B of the pretreatment agent.

[0040] The present embodiment provides a surface treatment method of TB6 titanium alloy, comprising the following steps: Cross the titanium alloy surface to be machined with 80 mesh, 120 mesh and 240 mesh sandpaper in turn, and then wipe off the titanium alloy surface powder and grease with ethanol; Mix the prepared component A and component B of the pretreatment agent according to the mass ratio of 1:2, stir well, and obtain a two-component pretreatment agent for titanium alloy; Put the polished TB6 titanium alloy sample into the two-component pretreatment agent for titanium alloy, soak for 1 h, and keep uniform stirring; rinse the soaked TB6 sample with deionized water and dry to obtain a surface modified TB6 titanium alloy.

[0041] Performance test To verify the treatment effect of the pretreatment agent, select TA12, TC4 and TB6 titanium alloy samples, cross the surfaces to be machined with 80 mesh, 120 mesh and 240 mesh sandpaper in turn, and then remove the surface powder and grease with ethanol, and mark them as control 1, control 2 and control 3. The schematic diagram of the polished TA12 titanium alloy sample, TC4 titanium alloy sample and TB6 titanium alloy sample and the surface modified TA12 titanium alloy, surface modified TC4 titanium alloy and surface modified TB6 titanium alloy prepared in examples 1-3 is as follows:Figure 1 as shown.

[0042] The surface modified titanium alloy samples prepared in Examples 1-3 and the unmodified titanium alloy samples of Controls 1-3 were uniformly sprayed with an aviation primer TB06-9. Subsequently, the adhesion of the titanium alloy to the paint layer in each sample was detected by using a tensile testing machine according to the standard of GB / T 5210-2006 Paint and Varnish Adhesion by Tensile Method, and the results are shown in Table 1 below.

[0043] A schematic diagram of each sample after spraying the aviation primer TB06-9 is shown in Figure 2 . A schematic diagram of each sample after the tensile test is shown in Figure 3 .

[0044] Table 1 Comparison of the adhesion of titanium alloy to paint layer before and after treatment with the pretreatment agent Further, the samples were subjected to a 1500-hour damp heat aging test, and the change in adhesion was tested in a damp heat chamber according to GJB 150.9A-2009 Military Equipment Laboratory Environmental Test Method Damp Heat Test, and the results are shown in Table 2.

[0045] Table 2 Comparison of the adhesion of titanium alloy to paint layer after 1500h damp heat test before and after treatment with the pretreatment agent As shown in Table 1, after the titanium alloy was treated with the two-component pretreatment agent prepared in the application, the adhesion of the three typical titanium alloys to the paint layer was significantly improved, with an improvement of 27.7% to 37.8%, which proves that the pretreatment agent can be widely used for different grades of titanium alloy materials. As shown in Table 2, after 1500 hours of damp heat aging, the adhesion of the untreated control samples decreased significantly (the reduction ratio was higher than 23%), while the adhesion of the samples treated with the pretreatment agent was higher (the reduction ratio was lower than 10%), which showed excellent environmental aging resistance and long-term adhesion stability.

[0046] Obviously, the above examples are merely examples for clarity and do not limit the embodiments. Based on the above description, other different forms of changes or variations can be made by those of ordinary skill in the art. Here, it is not necessary and impossible to exhaust all embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A two-component pretreatment agent for titanium alloys, characterized by comprising: The two-component pretreatment agent for titanium alloy comprises an A component and a B component. The A component comprises the following components: an aminoacetate-hydrochloric acid buffer, a dopamine compound, and a modified methacrylic acid prepolymer; the pH value of the aminoacetate-hydrochloric acid buffer is 1.5-3.0, and the concentration of aminoacetate in the aminoacetate-hydrochloric acid buffer is 20-100 mmol / L. In the A component, the concentration of the dopamine compound is 0.5-20 g / L, and the concentration of the modified methacrylic acid prepolymer is 0.1-2 g / L. The B component comprises the following components: an acetic acid-sodium acetate buffer and an oxidizing agent; the pH value of the acetic acid-sodium acetate buffer is 5.0-7.0, and the concentration of sodium acetate in the acetic acid-sodium acetate buffer is 20-100 mmol / L. In the B component, the concentration of the oxidizing agent is 10-100 mmol / L.

2. The two-part pretreatment for titanium alloys according to claim 1, characterized in that, The dopamine compound comprises one or more of dopamine hydrochloride, 6-hydroxydopamine hydrochloride, 6-hydroxydopamine acid hydrobromide, dobutamine hydrochloride, levodopa hydrochloride, 3-methoxytyramine hydrochloride, and 3-methacryl dopamine.

3. The two-part pretreatment for titanium alloys according to claim 1, characterized in that, The preparation method of the modified methacrylic acid prepolymer comprises the following steps: hydroxyethyl methacrylate, acrylamide, and an initiator are added to deionized water to react, so as to obtain the modified methacrylic acid prepolymer; the molar ratio of the hydroxyethyl methacrylate to the acrylamide is (1-5):

1.

4. The two-part pretreatment for titanium alloys according to claim 3, characterized in that, The reaction temperature is 50-60°C, and the reaction time is 1-5 h.

5. The two-part pretreatment for titanium alloys according to claim 3, characterized in that, The initiator is dibenzoyl peroxide.

6. The two-part pretreatment for titanium alloys according to claim 1, characterized in that, The oxidizing agent comprises one or more of ammonium persulfate, sodium periodate, sodium hypochlorite, sodium bromate, cerium sulfate, and potassium hydrogen persulfate.

7. The two-part pretreatment for titanium alloys according to claim 1, characterized in that, The mixing mass ratio of the A component to the B component is 1:(1-5).

8. A method of producing a two-component pretreatment agent for a titanium alloy according to any one of claims 1 to 7, characterized by, The method comprises the following steps: aminoacetate-hydrochloric acid buffer with a pH value of 1.5-3.0 is prepared, the dopamine compound and the modified methacrylic acid prepolymer are added to the aminoacetate-hydrochloric acid buffer after deoxygenation treatment, and the mixture is stirred uniformly, so as to obtain the A component; acetic acid-sodium acetate buffer with a pH value of 5.0-7.0 is prepared, the oxidizing agent is added to the acetic acid-sodium acetate buffer, and the mixture is stirred uniformly, so as to obtain the B component; the A component and the B component are mixed, so as to obtain the two-component pretreatment agent for titanium alloy.

9. A method of surface treatment of a titanium alloy, characterized in that, The method comprises the following steps: the surface of the titanium alloy to be treated is polished, and then immersed in the two-component pretreatment agent for titanium alloy for soaking; the titanium alloy is taken out, washed, and dried, so as to obtain a surface-modified titanium alloy.

10. A titanium alloy obtained by the method for treating the surface of a titanium alloy according to claim 9.

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