Titanium-aluminum composite metal surface nanometer treatment process for injection molding combination

Abstract

The invention belongs to the technical field of material surface treatment, and particularly relates to a titanium-aluminum composite metal surface nanometer treatment process for injection molding bonding, which comprises the following steps: S1, carrying out surface cleaning treatment on a titanium-aluminum alloy; s2, the titanium-aluminum alloy is subjected to primary etching and primary ultrasonic treatment; s3, the titanium-aluminum alloy is subjected to secondary etching and secondary ultrasonic treatment; s4, the titanium-aluminum alloy is subjected to primary anodic oxidation treatment to form first-class nano holes; and S5, the titanium-aluminum alloy is subjected to secondary anodic oxidation treatment to form second-class nano holes. After the titanium-aluminum alloy treated through the method is subjected to injection molding fusion with plastics such as PPT, PPS and PA, the plastics enter nano holes of the titanium-aluminum alloy, superstrong connection strength (ISO 19095) and IP67 / 68 waterproof performance are obtained through physical anchor bolts and chemical replacement reaction, and the titanium-aluminum alloy is applied to structures such as middle frames and rear covers of 3C electronic products such as mobile phones, watches, tablet personal computers and laptops and has good application prospects. And a connecting piece can be replaced, so that the stability is enhanced, and the structure is simplified.

Description

Technical Field

[0001] The invention belongs to the technical field of material surface treatment, and in particular relates to a nano-treatment process for the surface of titanium-aluminum composite metal used for injection molding. Background Art

[0002] Titanium-aluminum alloy (Ti-Al alloy) is an intermetallic compound material with titanium (Ti) and aluminum (Al) as its main components. It has high strength, low density and high temperature resistance, and has shown great potential in the fields of aerospace, automobile and energy. The density of titanium-aluminum alloy is about 4.0-4.5g / cm 3 , between pure titanium (4.51g / cm 3 ) and aluminum alloy (2.7g / cm 3 ), while its strength approaches that of titanium alloys (yield strength ≥800MPa), making it suitable for weight-sensitive structural parts. Titanium-aluminum alloys have a maximum operating temperature of 600-700°C, far exceeding aluminum alloys (≤300°C), and can replace some nickel-based high-temperature alloys, reducing engine weight. Titanium-aluminum alloys form a dense Al2O3 / TiO2 composite oxide film on their surface, exhibiting superior corrosion resistance compared to titanium alloys in seawater and acidic environments.

[0003] Due to its high strength and low density, titanium-aluminum alloys are widely used in electronic devices, particularly in mobile phone midframes, where they can effectively reduce weight. However, when used as a material for mobile phone midframes, titanium-aluminum alloys must be joined to plastic to form the overall structure. Traditional methods, such as shaft-hole or coordinated connections, require additional connectors or structures, increasing product complexity and reducing reliability.

[0004] Existing X-treatment technology can make the connection between plastic and metal more reliable by performing special surface nano-treatment on metal materials. However, the current market only has nano-treatment technologies for single metals such as aluminum alloys and stainless steel, and no surface nano-treatment technologies specifically for titanium-aluminum composite alloys. Summary of the Invention

[0005] The purpose of the embodiment of the present invention is to provide a nano-processing process for the surface of titanium-aluminum composite metal for injection molding, aiming to solve the surface treatment problem of titanium-aluminum alloy used for connection with plastic and to enhance the connection strength and waterproofness.

[0006] The embodiment of the present invention is implemented as follows: a nano-process for the surface treatment of titanium-aluminum composite metal for injection molding, characterized by comprising the following steps:

[0007] S1. Clean the surface of titanium aluminum alloy;

[0008] S2, etching the titanium aluminum alloy once and performing an ultrasonic treatment once;

[0009] S3, performing secondary etching and secondary ultrasonic treatment on the titanium aluminum alloy;

[0010] S4, performing an anodic oxidation treatment on the titanium aluminum alloy to form a type of nanopores;

[0011] S5. Perform secondary anodizing treatment on the titanium aluminum alloy to form the second type of nanopores.

[0012] The titanium-aluminum alloy treated by the titanium-aluminum composite metal surface nano-treatment process for injection molding provided in an embodiment of the present invention is injected and fused with plastics such as PPT, PPS, and PA. The plastic enters the nanopores of the titanium-aluminum alloy and obtains super strong connection strength (ISO19095) and IP67 / 68 waterproof performance through physical anchor bolts and chemical replacement reactions. It is applied to the middle frame and back cover of 3C electronic products such as mobile phones, watches, tablets, and notebooks, etc., and can replace the use of connectors, enhance stability, and simplify the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a diagram of the use state of the titanium aluminum alloy targeted by the embodiment of the present invention;

[0014] Figure 2 This is a SEM 100000X electron microscope image of the surface nanomorphology of the sample obtained in Example 1 of the present invention;

[0015] Figure 3 This is a SEM 100000X electron microscope image of the surface nanomorphology of the sample obtained in Example 2 of the present invention;

[0016] Figure 4 This is a SEM 100000X electron microscope image of the surface nanomorphology of the sample obtained in Example 3 of the present invention;

[0017] Figure 5 This is a SEM 100000X electron microscope image of the surface nanomorphology of the sample obtained in Example 4 of the present invention;

[0018] Figure 6 This is a SEM 100000X electron microscope image of the surface nanomorphology of the sample obtained in Example 5 of the present invention;

[0019] Figure 7 This is a SEM 100000X electron microscope image of the surface nanomorphology of the sample obtained in Example 6 of the present invention;

[0020] Figure 8 This is a physical picture of the sample obtained by injection molding;

[0021] Figure 9The STS5000 EasyStation electronic tensile testing equipment used in this invention;

[0022] Figure 10 for Figure 9 A graph showing test data obtained by performing a tensile test using the test equipment shown;

[0023] Figure 11 This is a SEM 100000X electron microscope image of the surface nanomorphology of the sample obtained in Example 7 of the present invention;

[0024] Figure 12 This is a SEM 100000X electron microscope image of the surface nanomorphology of the sample obtained in Example 8 of the present invention;

[0025] Figure 13 This is a SEM 100000X electron microscope image of the surface nanomorphology of the sample obtained in Example 9 of the present invention;

[0026] Figure 14 This is a SEM 100000X electron microscope image of the surface nanomorphology of the sample obtained in Example 10 of the present invention;

[0027] Figure 15 This is a SEM 100000X electron microscope image of the surface nanomorphology of the sample obtained in Example 11 of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] The specific implementation of the present invention is described in detail below with reference to specific embodiments.

[0030] Figure 1 This is a diagram of the usage status of the titanium-aluminum alloy targeted by the present invention in the middle frame of a mobile phone. In this usage status, the titanium-aluminum alloy is used to make the skeleton of the middle frame of the mobile phone, and the inner side of the middle frame is made of ADC12 (a die-cast aluminum alloy belonging to the Al-Si-Cu alloy series). The surface of the titanium-aluminum alloy needs to be integrated with plastics such as PPT, PPS, and PA through injection molding. Figure 1 The figure shows a die-cast titanium-aluminum alloy. The present invention is also applicable to the surface treatment of a titanium-aluminum alloy produced by a smelting process or the like and having no titanium-aluminum bonding surface.

[0031] The embodiment of the present invention provides a nano-processing process for the surface of titanium-aluminum composite metal for injection molding, comprising:

[0032] S1. Clean the surface of titanium aluminum alloy;

[0033] S2, etching the titanium aluminum alloy once and performing an ultrasonic treatment once;

[0034] S3, performing secondary etching and secondary ultrasonic treatment on the titanium aluminum alloy;

[0035] S4, performing an anodic oxidation treatment on the titanium aluminum alloy to form a type of nanopores;

[0036] S5. Perform secondary anodizing treatment on the titanium aluminum alloy to form the second type of nanopores.

[0037] In the embodiment of the present invention, the surface of the titanium-aluminum alloy is cleaned mainly to remove impurities, grease and metal oxides on the surface of the alloy to prevent these substances from affecting the subsequent treatment process. S1 is specifically: the titanium-aluminum alloy is immersed in a mixed solution of sodium phosphate Na3PO4, sodium carbonate Na2CO3 and sodium pyrophosphate Na4P2O7 with a mass concentration of 50-80g / L and a temperature of 65-80°C for 5-10 minutes, and ultrasonic treatment is used during the soaking process to remove impurities, foreign matter and oxides on the surface of the titanium-aluminum alloy, and the ultrasonic frequency is 30-40kHz. Among them, the mass ratio of sodium phosphate Na3PO4, sodium carbonate Na2CO3 and sodium pyrophosphate Na4P2O7 is about 1:1:1, and the aqueous solution of the three is highly alkaline. The specific ratio of the three is mainly limited by controlling the total concentration and pH value, and the pH value is above 11. After surface treatment with the mixed solution, the oxides formed by aluminum are mainly dissolved, and at the same time, PO4 3- and P2O7 4- Can be used with Al 3+ 、Ti 4+ Form complexes (such as AlPO4, Ti(PO4)2) to slow down the metal dissolution rate and prevent excessive dissolution.

[0038] In the embodiment of the present invention, the S2 is specifically: preparing OH - The titanium aluminum alloy is immersed in an alkaline etching solution with a concentration of 0.8-1.2 mol / L for 2-4 minutes at a solution temperature of 40-80°C. Ultrasonic treatment is used during the immersion process to refine the microscopic roughness at an ultrasonic frequency of 90-100kHz. 0.8 mol / L OH at 25°C - The concentration corresponds to a pH value of 13.90, and 1.2 mol / L OH - The concentration corresponds to a pH value of 14.08, which is rounded up to about 14. The pH value can be maintained by adjusting the solubility of the solute by controlling the temperature of the solution.

[0039] In an embodiment of the present invention, the S3 is specifically: preparing an acidic etching solution of hydrofluoric acid HF and nitric acid HNO3, or an acidic etching solution of phosphoric acid H3PO4 and hydrofluoric acid HF, and immersing the titanium aluminum alloy for 3-5 minutes, and the solution temperature is not higher than 30°C; during the immersion process, ultrasonic treatment is performed to refine the micro-roughness, and the ultrasonic frequency is not lower than 120kHz. When preparing the acidic etching solution of hydrofluoric acid HF and nitric acid HNO3, the mass fraction of hydrofluoric acid HF is 1-3%, and the mass fraction of nitric acid HNO3 is 10-15%. At the same time, 0.5-1.0% citric acid and a small amount of surfactant (such as 0.01-0.05% OP-10) can also be added. In this formula, HNO3 quickly dissolves aluminum, HF slowly dissolves titanium, and citric acid chelates Al 3+ Prevent precipitation, surfactants reduce surface tension and improve etching uniformity. When preparing the acidic etching solution of phosphoric acid H3PO4 and hydrofluoric acid HF, the mass fraction of phosphoric acid H3PO4 is 15-20%, the mass fraction of hydrofluoric acid HF is 0.5-1.0%, and in addition, 0.3-0.6% of tartaric acid and 0.1-0.3% of hydrogen peroxide H2O2 can be added. In this formula, phosphoric acid provides an acidic environment and reacts with Al 3+ HF etches titanium, and hydrogen peroxide accelerates the oxidation reaction, inhibiting excessive corrosion of titanium. Ammonium fluoride (NH4F) can also be added to this formula within 0.01% to enhance the etching selectivity of titanium.

[0040] In the embodiment of the present invention, the S4 is specifically as follows: placing the titanium aluminum alloy in a solution of sulfuric acid H2SO4 with a concentration of 150g / L, and passing a current density of 0.6A to 1.8A / cm 2 , the temperature is controlled at 30-50°C. In this embodiment, the treatment time is about 3-5 minutes. As a further optimization treatment solution, the current density is increased from 0.6A / cm 2 Gradually increase to 1.8A / cm 2 , and the increase rate is nonlinear, the increase rate of the latter unit time is at least twice that of the previous unit time, and the current density is increased from 0.6A / cm 2 to 1.8A / cm 2 Thus, at low currents, the oxidation rate is low, and oxidation sites mainly occur on rough spots on the metal surface. As the current density increases, the oxidation capacity improves, and the oxidation sites generated at low currents further expand. The increased current density growth rate can reduce the appearance of new oxidation sites, allowing them to quickly expand to the required size rather than generating a large number of new oxidation sites, resulting in large differences in pore size.

[0041] In this embodiment, the average diameter of the nanopores obtained in step S4 is no greater than 40 nm. The diameter of the pores can be controlled by controlling the current density and the processing time.

[0042] In the embodiment of the present invention, the S5 is specifically prepared as follows: a solution containing 8-40 wt.% electrolyte and 0.1-1.2 wt.% silane coupling agent is prepared, and the solution is heated at 30-40°C at a temperature of 0.1-10 A / dm 2 The current density is 1000 ms and the positive duration of the pulse is 400 ms for 1-3 minutes; wherein, in the electrolyte solution, NaOH, KOH, Ca(OH)2 and NaHCO3 are mixed in a ratio of 3:2:1:1.

[0043] In this embodiment, the average diameter of the second type of nanopores obtained in step S5 is no greater than 40 nm. It should be noted that the first type of nanopores and the second type of nanopores are formed by the corrosion of aluminum and titanium, respectively, and are structurally indistinguishable, being distinguishable only during the generation process. The pores obtained in step S4 are first type of nanopores, and the pores obtained in step S5 based on the first type of nanopores are second type of nanopores.

[0044] Example 1:

[0045] Take a sample with a length of 6 cm, a width of 2 cm, and a thickness of 0.2 cm and process it as follows:

[0046] S1: Soak the titanium-aluminum alloy in a mixed solution of sodium phosphate Na3PO4, sodium carbonate Na2CO3 and sodium pyrophosphate Na4P2O7 at a mass concentration of 50-80 g / L and a temperature of 65-80°C for 5-10 minutes, and perform ultrasonic treatment during the soaking process to remove impurities, foreign matter and oxides on the surface of the titanium-aluminum alloy. The ultrasonic frequency is 30-40 kHz.

[0047] S2: Preparation of OH - The titanium aluminum alloy is immersed in an alkaline etching solution with a concentration of 0.8-1.2 mol / L for 2-4 minutes at a solution temperature of 40-80°C. Ultrasonic treatment is performed during the immersion process to refine microscopic roughness at a frequency of 90-100 kHz.

[0048] S3: preparing an acidic etching solution of hydrofluoric acid HF and nitric acid HNO3, or an acidic etching solution of phosphoric acid H3PO4 and hydrofluoric acid HF, and immersing the titanium aluminum alloy for 3-5 minutes at a solution temperature not higher than 30°C; during the immersion process, ultrasonic treatment is performed to refine microscopic roughness, with an ultrasonic frequency of not less than 120kHz;

[0049] S4: Place the titanium-aluminum alloy in a solution of sulfuric acid H2SO4 with a concentration of 150 g / L and pass a current density of 0.6 A to 1.8 A / cm 2 , temperature control 30~50℃;

[0050] S5: Prepare a solution with 8-40 wt.% electrolyte and 0.1-1.2 wt.% silane coupling agent, and conduct the reaction at 0.1-10 A / dm at 30-40 °C. 2 The current density is 1000 ms and the positive duration of the pulse is 400 ms for 1-3 minutes; wherein, in the electrolyte solution, NaOH, KOH, Ca(OH)2 and NaHCO3 are mixed in a ratio of 3:2:1:1.

[0051] Example 2:

[0052] Take a sample with a length of 6 cm, a width of 2 cm, and a thickness of 0.2 cm and process it as follows:

[0053] S1: no treatment;

[0054] S2: Preparation of OH - The titanium aluminum alloy is immersed in an alkaline etching solution with a concentration of 0.8-1.2 mol / L for 2-4 minutes at a solution temperature of 40-80°C. Ultrasonic treatment is performed during the immersion process to refine microscopic roughness at a frequency of 90-100 kHz.

[0055] S3: preparing an acidic etching solution of hydrofluoric acid HF and nitric acid HNO3, or an acidic etching solution of phosphoric acid H3PO4 and hydrofluoric acid HF, and immersing the titanium aluminum alloy for 3-5 minutes at a solution temperature not higher than 30°C; during the immersion process, ultrasonic treatment is performed to refine microscopic roughness, with an ultrasonic frequency of not less than 120kHz;

[0056] S4: Place the titanium-aluminum alloy in a solution of sulfuric acid H2SO4 with a concentration of 150 g / L and pass a current density of 0.6 A to 1.8 A / cm 2 , temperature control 30~50℃;

[0057] S5: Prepare a solution with 8-40 wt.% electrolyte and 0.1-1.2 wt.% silane coupling agent, and conduct the reaction at 0.1-10 A / dm at 30-40 °C. 2 The current density is 1000 ms and the positive duration of the pulse is 400 ms for 1-3 minutes; wherein, in the electrolyte solution, NaOH, KOH, Ca(OH)2 and NaHCO3 are mixed in a ratio of 3:2:1:1.

[0058] Example 3:

[0059] Take a sample with a length of 6 cm, a width of 2 cm, and a thickness of 0.2 cm and process it as follows:

[0060] S1: Soak the titanium-aluminum alloy in a mixed solution of sodium phosphate Na3PO4, sodium carbonate Na2CO3 and sodium pyrophosphate Na4P2O7 at a mass concentration of 50-80 g / L and a temperature of 65-80°C for 5-10 minutes, and perform ultrasonic treatment during the soaking process to remove impurities, foreign matter and oxides on the surface of the titanium-aluminum alloy. The ultrasonic frequency is 30-40 kHz.

[0061] S2: no treatment;

[0062] S3: preparing an acidic etching solution of hydrofluoric acid HF and nitric acid HNO3, or an acidic etching solution of phosphoric acid H3PO4 and hydrofluoric acid HF, and immersing the titanium aluminum alloy for 3-5 minutes at a solution temperature not higher than 30°C; during the immersion process, ultrasonic treatment is performed to refine microscopic roughness, with an ultrasonic frequency of not less than 120kHz;

[0063] S4: Place the titanium-aluminum alloy in a solution of sulfuric acid H2SO4 with a concentration of 150 g / L and pass a current density of 0.6 A to 1.8 A / cm 2 , temperature control 30~50℃;

[0064] S5: Prepare a solution with 8-40 wt.% electrolyte and 0.1-1.2 wt.% silane coupling agent, and conduct the reaction at 0.1-10 A / dm at 30-40 °C. 2 The current density is 1000 ms and the positive duration of the pulse is 400 ms for 1-3 minutes; wherein, in the electrolyte solution, NaOH, KOH, Ca(OH)2 and NaHCO3 are mixed in a ratio of 3:2:1:1.

[0065] Example 4:

[0066] Take a sample with a length of 6 cm, a width of 2 cm, and a thickness of 0.2 cm and process it as follows:

[0067] S1: Soak the titanium-aluminum alloy in a mixed solution of sodium phosphate Na3PO4, sodium carbonate Na2CO3 and sodium pyrophosphate Na4P2O7 at a mass concentration of 50-80 g / L and a temperature of 65-80°C for 5-10 minutes, and perform ultrasonic treatment during the soaking process to remove impurities, foreign matter and oxides on the surface of the titanium-aluminum alloy. The ultrasonic frequency is 30-40 kHz.

[0068] S2: Preparation of OH -The titanium aluminum alloy is immersed in an alkaline etching solution with a concentration of 0.8-1.2 mol / L for 2-4 minutes at a solution temperature of 40-80°C. Ultrasonic treatment is performed during the immersion process to refine microscopic roughness at a frequency of 90-100 kHz.

[0069] S3: no treatment;

[0070] S4: Place the titanium-aluminum alloy in a solution of sulfuric acid H2SO4 with a concentration of 150 g / L and pass a current density of 0.6 A to 1.8 A / cm 2 , temperature control 30~50℃;

[0071] S5: Prepare a solution with 8-40 wt.% electrolyte and 0.1-1.2 wt.% silane coupling agent, and conduct the reaction at 0.1-10 A / dm at 30-40 °C. 2 The current density is 1000 ms and the positive duration of the pulse is 400 ms for 1-3 minutes; wherein, in the electrolyte solution, NaOH, KOH, Ca(OH)2 and NaHCO3 are mixed in a ratio of 3:2:1:1.

[0072] Embodiment 5:

[0073] Take a sample with a length of 6 cm, a width of 2 cm, and a thickness of 0.2 cm and process it as follows:

[0074] S1: Soak the titanium-aluminum alloy in a mixed solution of sodium phosphate Na3PO4, sodium carbonate Na2CO3 and sodium pyrophosphate Na4P2O7 at a mass concentration of 50-80 g / L and a temperature of 65-80°C for 5-10 minutes, and perform ultrasonic treatment during the soaking process to remove impurities, foreign matter and oxides on the surface of the titanium-aluminum alloy. The ultrasonic frequency is 30-40 kHz.

[0075] S2: Preparation of OH - The titanium aluminum alloy is immersed in an alkaline etching solution with a concentration of 0.8-1.2 mol / L for 2-4 minutes at a solution temperature of 40-80°C. Ultrasonic treatment is performed during the immersion process to refine microscopic roughness at a frequency of 90-100 kHz.

[0076] S3: preparing an acidic etching solution of hydrofluoric acid HF and nitric acid HNO3, or an acidic etching solution of phosphoric acid H3PO4 and hydrofluoric acid HF, and immersing the titanium aluminum alloy for 3-5 minutes at a solution temperature not higher than 30°C; during the immersion process, ultrasonic treatment is performed to refine microscopic roughness, with an ultrasonic frequency of not less than 120kHz;

[0077] S4: no treatment;

[0078] S5: Prepare a solution with 8-40 wt.% electrolyte and 0.1-1.2 wt.% silane coupling agent, and conduct the reaction at 0.1-10 A / dm at 30-40 °C. 2 The current density is 1000 ms and the positive duration of the pulse is 400 ms for 1-3 minutes; wherein, in the electrolyte solution, NaOH, KOH, Ca(OH)2 and NaHCO3 are mixed in a ratio of 3:2:1:1.

[0079] Example 6:

[0080] Take a sample with a length of 6 cm, a width of 2 cm, and a thickness of 0.2 cm and process it as follows:

[0081] S1: Soak the titanium-aluminum alloy in a mixed solution of sodium phosphate Na3PO4, sodium carbonate Na2CO3 and sodium pyrophosphate Na4P2O7 at a mass concentration of 50-80 g / L and a temperature of 65-80°C for 5-10 minutes, and perform ultrasonic treatment during the soaking process to remove impurities, foreign matter and oxides on the surface of the titanium-aluminum alloy. The ultrasonic frequency is 30-40 kHz.

[0082] S2: Preparation of OH - The titanium aluminum alloy is immersed in an alkaline etching solution with a concentration of 0.8-1.2 mol / L for 2-4 minutes at a solution temperature of 40-80°C. Ultrasonic treatment is performed during the immersion process to refine microscopic roughness at a frequency of 90-100 kHz.

[0083] S3: preparing an acidic etching solution of hydrofluoric acid HF and nitric acid HNO3, or an acidic etching solution of phosphoric acid H3PO4 and hydrofluoric acid HF, and immersing the titanium aluminum alloy for 3-5 minutes at a solution temperature not higher than 30°C; during the immersion process, ultrasonic treatment is performed to refine microscopic roughness, with an ultrasonic frequency of not less than 120kHz;

[0084] S4: Place the titanium-aluminum alloy in a solution of sulfuric acid H2SO4 with a concentration of 150 g / L and pass a current density of 0.6 A to 1.8 A / cm 2 , temperature control 30~50℃;

[0085] S5: No action is taken.

[0086] In the above examples 1-5, the specific operations of each step are performed with reference to the above contents of the specification. The above is only listed as steps, and does not limit the detailed processing of each step. The sample obtained after treatment was measured with an upright scanning electron microscope (Elextron Microscope, abbreviated as SEM) at a magnification of 100,000 times to obtain the nano-morphology of the product surface, and the following was obtained: Figure 2-7The hole structure shown in the figure is shown in the figure. The diameter of the holes in each image was counted, and the average diameter and the standard deviation of the diameter distribution were calculated to measure the uniformity of the holes. The results are shown in the following table:

[0087]

[0088]

[0089] The five samples were then injected with other plastics such as PPT, PPS, and PA using NMT (Nona Molding Technology) technology. During the injection molding process, the PPT, PPS, and PA plastics will enter the nanopores, generating physical anchors and chemical replacement reactions. The resulting composite has ultra-high strength and waterproof properties. Figure 8 The following are pictures of the actual samples. Five injection molding samples were obtained by the same injection molding process. Figure 9 The tensile testing equipment shown in the figure performs tensile tests on five samples. Figure 10 As shown, the tensile force when the plastic and titanium aluminum alloy are separated is recorded in the following table:

[0090] serial number Separation force / kN Example 1 2054 Example 2 1452 Example 3 1841 Example 4 1869 Example 5 1673 Example 6 1691

[0091] It can be seen from Examples 1 to 6 that steps S1-S5 are indispensable for obtaining nanopores that meet the requirements, but the impact of different steps varies. Specifically, the absence of step S1 will result in larger pores and the worst pore size uniformity; the absence of step S2 or S3 will result in a larger average pore diameter, but the pore diameter uniformity is acceptable, which is the role played by steps S4 and S5; and although the absence of steps S4 and S5 has a smaller impact on the average pore diameter than steps S2 and S3, the uniformity of the resulting pores is poor.

[0092] In addition, the effect of current changes in steps S4 and S5 on the holes was tested:

[0093] Example 7: Compared with Example 1, in step S4, the current density is increased from 0.6 A / cm to 2 to 1.8A / cm 2 The increase is nonlinear, and the speed of increase is at least twice that of the previous unit time. Similarly, in step S5, the current density is increased from 0.1A / dm 2 Up to 10A / dm 2 The increase is nonlinear, and the speed of increase is at least twice that of the previous unit time. In the first embodiment, the current density in steps S4 and S5 is the middle value of the given corresponding range.

[0094] Example 8: Compared with Example 7, the current density in step S4 is fixed at 0.6 A / cm 2 In step S5, the current density is fixed at 0.1A / dm 2 , other conditions are the same.

[0095] Example 9: Compared with Example 7, the current density in step S4 is fixed at 1.8 A / cm 2 In step S5, the current density is fixed at 0.1A / dm 2 , other conditions are the same.

[0096] Example 10: Compared with Example 7, the current density in step S4 is fixed at 0.6 A / cm 2 In step S5, the current density is fixed at 10A / dm 2 , other conditions are the same.

[0097] Example 11: Compared with Example 7, the current density in step S4 is fixed at 1.8 A / cm 2 In step S5, the current density is fixed at 10A / dm 2 , other conditions are the same.

[0098] The results are as follows Figure 11-15 As shown, the diameter of the holes in each image was counted, and the average diameter and the standard deviation of the diameter distribution were calculated to measure the uniformity of the holes. The results are shown in the following table:

[0099] serial number Diameter range / nm Average diameter / nm Standard deviation / nm Example 7 31.7-39.8 37.3 2.9 Example 8 29.8-53.4 41.6 8.7 Embodiment 9 23.9-47.6 38.4 9.2 Example 10 32.9-53.3 42.6 7.9 Example 11 33.4-47.8 41.7 8.4

[0100] It can be seen from Examples 7 to 11 that using a variable current density can make the average diameter of the holes smaller and the holes more uniform.

[0101] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A nano-processing process for the surface of titanium-aluminum composite metal for injection molding, characterized in that: The following steps are involved: S1. Clean the surface of titanium aluminum alloy; S2, etching the titanium aluminum alloy once and performing an ultrasonic treatment once; S3, performing secondary etching and secondary ultrasonic treatment on the titanium aluminum alloy; S4, performing an anodic oxidation treatment on the titanium aluminum alloy to form a type of nanopores; S5. Perform secondary anodizing treatment on the titanium aluminum alloy to form the second type of nanopores.

2. The surface nano-processing process for titanium-aluminum composite metal for injection molding according to claim 1, characterized in that: S1 is specifically: The titanium aluminum alloy is immersed in a mixed solution of sodium phosphate Na3PO4, sodium carbonate Na2CO3 and sodium pyrophosphate Na4P2O7 with a mass concentration of 50-80g / L and a temperature of 65-80°C for 5-10 minutes. During the immersion process, ultrasonic treatment is performed to remove impurities, foreign matter and oxides on the surface of the titanium aluminum alloy. The ultrasonic frequency is 30-40kHz.

3. The surface nano-processing process for titanium-aluminum composite metal for injection molding according to claim 1, characterized in that: The S2 is specifically: Prepare an alkaline etching solution with an OH- concentration of 0.8-1.2 mol / L, and immerse the titanium-aluminum alloy in it for 2-4 minutes at a solution temperature of 40-80°C. The soaking process is supplemented by ultrasonic treatment to refine the micro roughness, and the ultrasonic frequency is 90-100kHz.

4. The nano-processing process for the surface of titanium-aluminum composite metal for injection molding according to claim 1, characterized in that: The S3 is specifically: Prepare an acidic etching solution of hydrofluoric acid HF and nitric acid HNO3, or phosphoric acid H3PO4 and hydrofluoric acid HF, and immerse the titanium aluminum alloy for 3-5 minutes. The solution temperature is not higher than 30°C. During the soaking process, ultrasonic treatment is used to refine the microscopic roughness, and the ultrasonic frequency is not less than 120kHz.

5. The surface nano-processing process for titanium-aluminum composite metal for injection molding according to claim 1, characterized in that: The S4 is specifically: The titanium-aluminum alloy was placed in a solution of sulfuric acid H2SO4 with a concentration of 150 g / L and a current density of 0.6 A to 1.8 A / cm 2 , the temperature is controlled at 30~50℃.

6. The nano-processing process for the surface of titanium-aluminum composite metal for injection molding according to claim 5, characterized in that: The average diameter of the nanopores obtained in step S4 is no greater than 40 nm.

7. The nano-processing process for the surface of titanium-aluminum composite metal for injection molding according to claim 1, characterized in that: The S5 is specifically: Prepare a solution with 8-40wt% electrolyte and 0.1-1.2wt% silane coupling agent, and conduct it at 0.1-10A / dm at 30-40℃. 2 The current density and the positive duration of the pulse were 400 ms for 1-3 minutes; Wherein, in the electrolyte solution, NaOH, KOH, Ca(OH)2 and NaHCO3 are mixed in a ratio of 3:2:1:

1.

8. The nano-processing process for the surface of titanium-aluminum composite metal for injection molding according to claim 7, characterized in that: The average diameter of the second type of nanopores obtained in step S5 is no greater than 40 nm.

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