Corrosion-resistant titanium-copper alloy and preparation method thereof

Abstract

The invention discloses a preparation method of a corrosion-resistant titanium-copper alloy and the alloy prepared by the preparation method, and aims to solve the technical problem that the corrosion resistance of the existing titanium alloy still needs to be improved. In order to achieve the purpose, the technical scheme adopted by the invention comprises the following steps: firstly, adopting a wire-powder synergistic additive manufacturing process, taking a titanium wire as a matrix, and synchronously feeding copper powder to prepare a titanium-copper alloy block; then, pulse laser is adopted for machining the surface of the titanium-copper alloy block, so that a groove-shaped or mastoid-shaped micro-nano structure is constructed; and finally, hydrophobic chemical treatment is conducted on the titanium-copper alloy block with the micro-nano structure, and the super-hydrophobic surface with the static contact angle larger than 150 degrees is obtained. Additive manufacturing, laser surface micro-nano structuring and super-hydrophobic treatment are combined, the corrosion resistance of the titanium-copper alloy is synergistically improved, the titanium-copper alloy shows the corrosion tendency and corrosion rate remarkably reduced in the corrosion environment, especially in the chloride environment, and the titanium-copper alloy has important application prospects.

Description

Technical Field

[0001] This invention relates to the field of metallic materials technology, specifically to a corrosion-resistant titanium-copper alloy and its preparation method. Background Technology

[0002] Titanium alloys have gained increasingly widespread application in marine engineering, shipbuilding, and other fields due to their high specific strength, excellent impact resistance, fatigue resistance, and good corrosion resistance. However, with the continuous development of marine resources, the working environments of the deep sea and deep drilling place more stringent demands on the corrosion resistance of materials, and there is still room for improvement in the corrosion resistance of existing titanium alloys.

[0003] To improve the corrosion resistance of titanium alloys, existing technologies have mainly explored two aspects. One is through alloying modification. For example, studies have shown that adding Cu to titanium can effectively improve its corrosion resistance. Zhu et al.'s research (using selective laser melting to prepare pure Ti and Ti-3Cu alloys) found that in 0.9 wt.% NaCl solution, the self-corrosion potential of the Ti-3Cu alloy (-0.99 V) was higher than that of commercial pure titanium (CP-Ti) (-1.07 V), and its self-corrosion current density (2.81 × 10⁻⁶) was also higher. -7 A·cm -2 (This is lower than that of commercially pure titanium (3.56×10)) -7 A·cm -2 This indicates that the Ti-3Cu alloy has a lower corrosion tendency and corrosion rate.

[0004] On the other hand, surface modification techniques are used. For example, micro / nanostructures with specific wettability are constructed on alloy surfaces. Xu et al.'s research used nanosecond lasers to fabricate biomimetic papillary micro / nanostructures on the surface of nickel-titanium (NiTi) alloys and then constructed a superhydrophobic surface through chemical treatment. Tests showed that in a 3.5 wt% NaCl solution, this treatment reduced the alloy's self-corrosion current density from (4.42 ± 0.5) × 10⁻⁶. -7 A·cm -2 It decreased significantly to (3.21 ± 0.5) × 10 -9 A·cm -2 It exhibits excellent corrosion resistance.

[0005] However, current technologies have not effectively combined the two approaches of titanium-copper alloying and surface micro / nano-structure formation. Specifically, there are currently no publicly available publications reporting a technical solution for further constructing micro / nano structures on the surface of titanium-copper alloys prepared by additive manufacturing technology and applying superhydrophobic treatment to synergistically improve their corrosion resistance. Summary of the Invention

[0006] To address the shortcomings of the prior art, the present invention aims to provide a method for preparing a corrosion-resistant titanium-copper alloy and the corrosion-resistant titanium-copper alloy prepared by the method. The aim is to significantly improve the corrosion resistance of the titanium-copper alloy in corrosive environments (especially chloride environments) through the synergistic effect of additive manufacturing, surface micro / nano structuring, and superhydrophobic treatment.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention provides a method for preparing a corrosion-resistant titanium-copper alloy, comprising the following steps: a) using a wire-powder co-additive manufacturing process, with titanium wire as the matrix and copper powder being fed in simultaneously to prepare a titanium-copper alloy block, wherein the mass fraction of copper is 2-10%; b) using a pulsed laser to process the surface of the titanium-copper alloy block to construct a micro / nano structure; c) subjecting the titanium-copper alloy block treated in step b) to a hydrophobic chemical treatment to obtain a superhydrophobic surface.

[0009] Preferably, the process parameters for the above-mentioned wire-powder co-additive manufacturing of the titanium-copper alloy bulk material are as follows: plasma arc additive manufacturing, protective gas flow rate 12.5 L / min, ion gas 2.5 L / min, tungsten electrode-substrate spacing 13 mm, deposition current 100-110 A, titanium wire feeding speed 13.2 g / min, copper powder feeding speed 0.25-1.5 g / min, and interlayer cooling time 4-10 min.

[0010] Preferably, in the above-mentioned titanium-copper alloy block, the mass fraction of copper is 2.5%, and the process parameters of the wire-powder co-additive manufacturing are as follows: plasma arc additive manufacturing, protective gas flow rate 12.5L / min, ion gas 2.5L / min, tungsten electrode-substrate spacing 13mm, deposition current 105A, titanium wire feeding speed 13.2g / min, copper powder feeding speed 0.35g / min, and interlayer cooling time 4min.

[0011] Preferably, the laser used in step b) above is a nanosecond pulsed laser.

[0012] Preferably, the above-mentioned micro / nano structure is a groove structure or a papillary structure.

[0013] Preferably, the above-mentioned micro / nano structure is a papillary structure prepared using an 80 μm scanning interval.

[0014] Preferably, the hydrophobic chemical treatment in step c) above includes: immersing the above titanium-copper alloy block in a 20mM fluorinated silane hydrophobic agent for 12 hours, and then baking it at 75°C for 120 minutes.

[0015] Preferably, the above-mentioned fluorinated silane hydrophobic agent is a perfluorosilane-based trichlorosilane ethanol solution.

[0016] Preferably, the static contact angle of the superhydrophobic surface is greater than 150°.

[0017] This invention also provides a corrosion-resistant titanium-copper alloy, which is prepared by the above-described method.

[0018] The beneficial effects of this invention are as follows:

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. This invention combines wire-powder co-additive manufacturing, laser surface micro / nano processing technology, and superhydrophobic chemical treatment to form a complete and synergistic corrosion-resistant alloy preparation scheme. The wire-powder co-additive manufacturing process combines the advantages of high wire deposition efficiency and flexible powder composition adjustment, providing an efficient route for preparing titanium-copper alloys with specific compositions.

[0021] 2. The titanium-copper alloy prepared by the method of this invention exhibits significantly improved corrosion resistance. Experimental data show that in a 3.5 wt% NaCl solution, compared with an untreated titanium-copper alloy (self-corrosion potential -0.384 V, self-corrosion current density 3.28 × 10⁻⁶), the corrosion resistance is significantly improved. -8 A·cm -2 Compared to the previous method, the self-corrosion potential of the samples treated with this invention shifts significantly in the positive direction (up to 0.172V), and the self-corrosion current density is significantly reduced (down to 2.65×10⁻⁶). -10 A·cm -2 This indicates that its corrosion tendency and corrosion rate have both decreased significantly.

[0022] 3. The alloy surface prepared by this invention has superhydrophobic properties with a static contact angle greater than 150°. This superhydrophobic surface can form a stable air barrier between the alloy and the corrosive medium, effectively hindering the erosion of corrosive ions, thereby providing long-lasting corrosion protection. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the filament-powder co-additive manufacturing process in this invention.

[0024] Figure 2 These are photographs of actual products from the filament-powder co-additive manufacturing process described in this invention.

[0025] Figure 3 This is a physical image of the titanium-copper alloy block prepared in an embodiment of the present invention.

[0026] Figure 4 This is a schematic diagram of the laser scanning path in this invention, where (a) is the scanning path for constructing the groove structure and (b) is the scanning path for constructing the papillary structure.

[0027] Figure 5 These are the 3D topography results of the surface micro-nano structure formed after laser processing when the surface micro-nano structure of the present invention is a groove structure, where (a) is a scanning distance of 40μm and (b) is a scanning distance of 80μm.

[0028] Figure 6 These are 3D topography results of the surface micro-nano structure formed after laser processing when the surface micro-nano structure of the present invention is a papillary structure, where (a) is a scanning interval of 40 μm and (b) is a scanning interval of 80 μm.

[0029] Figure 7 These are electron microscope images of the present invention, wherein (a) and (b) are images of the groove structure taken with scanning intervals of 40 μm and 80 μm, respectively; and (c) and (d) are images of the papillary structure taken with scanning intervals of 40 μm and 80 μm, respectively.

[0030] Figure 8 These are photographs of the superhydrophobic surface of the present invention. (a) and (b) are photographs of the superhydrophobic surface with a groove structure, and the static contact angles are 150.9° and 155.4° when the scanning spacing is 40 μm and 80 μm, respectively. (c) and (d) are photographs of the superhydrophobic surface with a papillary structure, and the static contact angles are 155.1° and 164.5° when the scanning spacing is 40 μm and 80 μm, respectively.

[0031] Figure 9 This is a polarization curve of the groove structure of the present invention in 3.5wt% NaCl solution, with scanning spacing of 40, 80, and 100 μm. The vertical axis represents Log |i| (A·cm). -2 The horizontal axis represents the logarithm of the absolute value of the current density; the horizontal axis represents E (V). SCE The numbers represent potentials, with the gray line representing the control group (untreated group), and the red, blue, and green lines representing the d=40μm group, d=80μm group, and d=100μm group, respectively.

[0032] Figure 10 The image shows polarization curves of samples with papillary structures and scanning spacing of 40, 80, and 100 μm in 3.5 wt% NaCl solution, where the vertical axis represents Log |i| (A·cm). -2 The horizontal axis represents the logarithm of the absolute value of the current density; the horizontal axis represents E (V). SCE The numbers represent potentials, with the gray line representing the control group (untreated group), and the red, blue, and green lines representing the d=40μm group, d=80μm group, and d=100μm group, respectively. Detailed Implementation

[0033] The present invention will be described in more detail below with reference to the embodiments. It should be understood that the implementation of the present invention is not limited to the embodiments below, and any modifications or alterations made to the present invention fall within the protection scope of the present invention; and the methods in the following embodiments, unless otherwise specified, are conventional methods in the art.

[0034] Example 1:

[0035] This invention provides a method for preparing a corrosion-resistant titanium-copper alloy. The method involves preparing an alloy matrix using a specific additive manufacturing process, followed by laser surface processing and chemical treatment to impart excellent corrosion resistance. The specific embodiments of this invention will be described in detail below with reference to the accompanying drawings.

[0036] Preparation of titanium-copper alloy blocks

[0037] This step employs a wire-powder co-additive manufacturing process to prepare titanium-copper alloy bulk materials. For example... Figure 1 and Figure 2 As shown, the process system mainly includes a wire feeding mechanism, a powder feeding mechanism, and a heat source (e.g., an electric arc). In this embodiment, titanium wire is used as the base material and is continuously fed into the molten pool via the wire feeding mechanism. Simultaneously, copper powder is fed into the molten pool synchronously and precisely via the powder feeding mechanism. The electric arc, acting as a heat source, melts the titanium wire and copper powder together, and they are deposited layer by layer on a CP-Ti substrate, eventually solidifying to form a titanium-copper alloy block (As-built specimen) with a preset composition. By precisely controlling the powder feeding speed and airflow, the amount of copper powder fed can be flexibly adjusted, thereby achieving precise control of the copper content in the alloy, resulting in a copper mass fraction of 2.5% in the final titanium-copper alloy block. The parameters for the wire-powder co-additive manufacturing process used to prepare the titanium-copper alloy bulk material are as follows: plasma arc additive manufacturing, protective gas flow rate 12.5 L / min, ion gas 2.5 L / min, tungsten electrode-substrate spacing 13 mm, deposition current 105 A, titanium wire feed speed 13.2 g / min, copper powder feed speed 0.35 g / min, and interlayer cooling time 4 min. Figure 3 Photographs of the titanium-copper alloy bulk material prepared by this method are shown. This process combines the high deposition efficiency of wire additive manufacturing with the flexible composition design of powder additive manufacturing, providing an effective way to prepare high-performance, compositionally tunable metallic materials.

[0038] Construction of surface micro and nano structures

[0039] This step uses a nanosecond laser to process the surface of the titanium-copper alloy bulk material prepared in step a), in order to construct specific micro / nano structures. The laser processing system includes a nanosecond pulsed laser and a corresponding scanning galvanometer system. By controlling the scanning path and spacing of the laser beam through a computer program, a preset geometric shape can be etched onto the alloy surface. For example... Figure 4 As shown, by setting parallel linear scan paths ( Figure 4 (a)) can construct a series of parallel trench structures; by setting orthogonal grid-like scanning paths ( Figure 4 (b) can construct an array of papillary structures. When lasers interact with materials, rapid melting, vaporization, and resolidification processes occur, resulting in the superposition of finer nanoscale structures on micrometer-scale grooves or papillae, which together constitute composite micro / nano structures.

[0040] In the surface processing step b), a nanosecond laser was used. Using this nanosecond laser, two different scanning schemes were employed to construct two typical micro / nano structures:

[0041] (1) Preparation of the trench structure: Using Figure 4 (a) shows a unidirectional parallel scanning path. In this embodiment, the laser scanning spacing is set to 40 μm and 80 μm, respectively, and the results are as shown in Figure (a). Figure 5 (a) and Figure 5 (b) shows the periodic trench array structure.

[0042] (2) Preparation of the papillary structure: using Figure 4 (b) shows the orthogonal grid scanning path, which involves first performing a parallel scan along the X direction, then rotating the sample by 90 degrees or rotating the scanning path by 90 degrees to perform a second parallel scan along the Y direction. Similarly, with scanning intervals of 40 μm and 80 μm, the following results were obtained: Figure 6 (a) and Figure 6 (b) shows the papillary array structure.

[0043] like Figure 7 As shown, the images of the papillary and groove structures obtained under an electron microscope reveal that nanoscale structures exist on top of micron-scale structures, i.e., the aforementioned micro-nano structures.

[0044] Formation of superhydrophobic surfaces

[0045] This step involves performing a hydrophobic chemical treatment on the laser-processed titanium-copper alloy block to form a low surface energy chemical film on its surface, thereby obtaining a superhydrophobic surface. Specifically, the sample is immersed in an organic solvent containing a hydrophobic agent, causing the hydrophobic agent molecules to chemically adsorb or react on the alloy surface, forming a dense molecular film. Subsequently, a heat treatment process is used to further stabilize this molecular film. This chemical film significantly reduces the surface energy, and combined with the roughness provided by the micro / nano structure constructed in step b), it achieves a superhydrophobic effect, meaning that the static contact angle of a water droplet on this surface is greater than 150°. This superhydrophobic surface can effectively trap an air cushion between the alloy substrate and the corrosive medium, greatly hindering the contact and erosion of corrosive ions, which is key to improving corrosion resistance.

[0046] (1) Perfluorosilyl trichlorosilane, chemically named (3,3,4,4,5,5,6,6,7,7,8,8,8-tridecylfluorooctyl)trichlorosilane, is a commonly used hydrophobic modifier. First, prepare a 20 mM perfluorosilyl trichlorosilane ethanol solution;

[0047] (2) The laser-processed titanium-copper alloy sample was completely immersed in the above solution and soaked at room temperature for 12 hours;

[0048] (3) After soaking, take out the sample, wash it with ethanol, blow it dry, and then bake it on a heating table at 75°C for 120 minutes;

[0049] (4) Performance characterization measurement: After the above complete preparation steps, the static water contact angle of the final obtained sample surface is measured. For example... Figure 8 As shown in the figure, the results show that the static contact angle of both the groove structure and the papillary structure is greater than 150°, which meets the superhydrophobic standard.

[0050] Corrosion resistance test

[0051] To verify the beneficial effects of the corrosion-resistant titanium-copper alloy prepared in this invention, the aforementioned prepared sample and a 2.5wt% Cu titanium-copper alloy prepared only by step a) without surface treatment (as a control sample) were subjected to electrochemical corrosion performance tests.

[0052] The testing system was a three-electrode electrochemical workstation, with a saturated calomel electrode (SCE) as the reference electrode, a platinum sheet as the auxiliary electrode, and the sample under test as the working electrode. The corrosive medium was a 3.5 wt% NaCl solution, simulating a seawater environment. The self-corrosion potential (Ecorr) and self-corrosion current density (Icorr) of the sample were determined using the polarization curve method. The self-corrosion potential reflects the material's corrosion tendency; the higher the potential, the lower the corrosion tendency. The self-corrosion current density reflects the material's corrosion rate; the lower the density, the slower the corrosion rate.

[0053] The test results are summarized in the table below, and as follows: Figure 9 and Figure 10 As shown:

[0054]

[0055] from Figure 9 , Figure 10 As can be seen from the data in the table above, all samples treated with surface micro / nano structuring and superhydrophobicity exhibit higher self-corrosion potentials and lower self-corrosion current densities than the control samples. This indicates that the treatment method of the present invention significantly improves the corrosion resistance of titanium-copper alloys.

[0056] In particular, the papillary structure sample prepared using an 80 μm scanning interval exhibited the best corrosion resistance, with a self-corrosion potential of 0.172 V, an increase of approximately 0.556 V compared to the control sample; its self-corrosion current density decreased to 2.65 × 10⁻⁶. -10 A·cm -2 Compared to the control sample, the corrosion resistance was reduced by more than two orders of magnitude. This fully demonstrates the significant beneficial effect of the technical solution of the present invention in improving the corrosion resistance of titanium-copper alloys.

[0057] Example 2

[0058] The preparation method and parameters in this embodiment are basically the same as those in Example 1, except that the copper content is 10%.

[0059] The titanium-copper alloy bulk material was prepared using the same equipment system as in Example 1. To obtain a titanium-copper alloy with a copper mass fraction of 10%, the process parameters for wire-powder co-additive manufacturing were adjusted in this example. Specifically, the following methods were adopted:

[0060] Additive manufacturing method: Plasma arc additive manufacturing;

[0061] Protective gas flow rate: 12.5 L / min;

[0062] Ionizing gas flow rate: 2.5 L / min;

[0063] Tungsten electrode-substrate spacing: 13 mm;

[0064] Deposition current: 105 A;

[0065] Titanium wire feeding speed: 13.2 g / min;

[0066] Copper powder feeding rate: 1.5 g / min;

[0067] Interlayer cooling time: 5 minutes for the first 3 layers, gradually increasing the cooling time thereafter, 7 minutes for the fourth layer, and 10 minutes for the fifth layer.

[0068] The prepared titanium-copper alloy block has good shape, and the mass fraction of copper is 10.47% according to the composition analysis.

[0069] The surface micro / nano structures were constructed by using nanosecond pulsed lasers to create papillary structures on the alloy surface. To verify the best results, the same parameters as those in Example 1 were selected, namely, a scanning spacing of 80 μm and an orthogonal grid scanning path.

[0070] The chemical treatment steps for forming the superhydrophobic surface are the same as in Example 1: soaking in a 20mM perfluorosilicone-based trichlorosilane ethanol solution for 12 hours and baking at 75°C for 120 minutes.

[0071] Performance testing showed that the static contact angle of the sample surface was 161.6°, exhibiting excellent superhydrophobicity. Electrochemical testing in a 3.5 wt% NaCl solution showed a self-corrosion potential (Ecorr) of 0.189 V and a self-corrosion current density (Icorr) of 2.55 × 10⁻⁶. -9 A·cm -2 The results show that even with high copper content, the surface treatment of this invention can maintain and further enhance excellent corrosion resistance.

[0072] Example 3:

[0073] The preparation method and parameters in this embodiment are basically the same as those in Example 1, except that the copper content is 2%.

[0074] The titanium-copper alloy block was prepared using the same equipment system as in Example 1. Specifically, to obtain a titanium-copper alloy with a copper mass fraction of 2%, the following methods were employed:

[0075] Additive manufacturing method: Plasma arc additive manufacturing;

[0076] Protective gas flow rate: 12.5 L / min;

[0077] Ionizing gas flow rate: 2.5 L / min;

[0078] Tungsten electrode-substrate spacing: 13 mm;

[0079] Deposition current: 105A (corresponding to the lower limit of the range described in claim 2);

[0080] Titanium wire feeding speed: 13.2 g / min;

[0081] Copper powder feeding rate: 0.3 g / min (corresponding to the lower limit of the range described in claim 2, to achieve a copper content of approximately 2%).

[0082] Interlayer cooling time: 4 min (corresponding to the lower limit of the range described in claim 2).

[0083] The prepared titanium-copper alloy block, after compositional analysis, showed that the mass fraction of copper was 2.1% (within the range of 2-10%).

[0084] The surface micro / nano structures were constructed by using nanosecond pulsed lasers to create groove structures on the alloy surface (to verify the feasibility of the different micro / nano structures in claim 1). The laser scanning interval was set to 80 μm, and a unidirectional parallel scanning path was used.

[0085] The chemical treatment steps for forming the superhydrophobic surface are the same as in Example 1.

[0086] Performance testing showed that the static contact angle of the sample surface was 154.8°. Electrochemical testing in a 3.5 wt% NaCl solution showed a self-corrosion potential (Ecorr) of 0.052 V and a self-corrosion current density (Icorr) of 1.6 × 10⁻⁶. -8 A·cm -2 Although the corrosion resistance of the grooved structure is slightly lower than that of the papillary structure, it is still significantly improved compared to the untreated control sample.

[0087] In summary, a copper mass fraction of 2.5% in the titanium-copper alloy block is the optimal solution of this invention.

[0088] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for preparing a corrosion-resistant titanium-copper alloy, characterized in that, Includes the following steps: a) Using a wire-powder co-additive manufacturing process, titanium wire is used as the matrix and copper powder is fed in simultaneously to prepare titanium-copper alloy blocks with a copper mass fraction of 2-10%. b) The surface of the titanium-copper alloy block is processed using a pulsed laser to construct micro-nano structures, which are groove structures or papillary structures. c) The titanium-copper alloy block treated in step b) is subjected to hydrophobic chemical treatment to obtain a hydrophobic surface.

2. The method according to claim 1, characterized in that, The process parameters for the wire-powder co-additive manufacturing used to prepare the titanium-copper alloy bulk body are as follows: plasma arc additive manufacturing, protective gas flow rate 12.5L / min, ion gas 2.5L / min, tungsten electrode-substrate spacing 13mm, deposition current 100-110A, titanium wire feeding speed 13.2g / min, copper powder feeding speed 0.25-1.5g / min, and interlayer cooling time 4-10min.

3. The method according to claim 1, characterized in that, In the titanium-copper alloy block, the mass fraction of copper is 2.5%.

4. The method according to claim 3, characterized in that, The parameters for the wire-powder co-additive manufacturing process used to prepare the titanium-copper alloy bulk body are as follows: plasma arc additive manufacturing, protective gas flow rate 12.5 L / min, ion gas 2.5 L / min, tungsten electrode-substrate spacing 13 mm, deposition current 105 A, titanium wire feeding speed 13.2 g / min, copper powder feeding speed 0.35 g / min, and interlayer cooling time 4 min.

5. The method according to claim 1, characterized in that, The laser used in step b) is a nanosecond pulse laser.

6. The method according to claim 1, characterized in that, The micro / nano structure is a papillary structure prepared using an 80 μm scanning interval.

7. The method according to claim 1, characterized in that, The hydrophobic chemical treatment in step c) includes immersing the titanium-copper alloy block in a 20 mM fluorinated silane hydrophobic agent for 12 hours, and then baking it at 75°C for 120 minutes.

8. The method according to claim 7, characterized in that, The fluorinated silane hydrophobic agent is a perfluorosilane-based trichlorosilane ethanol solution.

9. The method according to claim 1, characterized in that, The static contact angle of the hydrophobic surface is greater than 150°.

10. A corrosion-resistant titanium-copper alloy, characterized in that, It is prepared by the method described in any one of claims 1-9.

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