Preparation method of gradient nano-structure anti-fouling titanium alloy

Abstract

The application discloses a kind of preparation methods of gradient nanostructure antifouling titanium alloy, which includes the following steps: (1) workpiece preparation: the surface of titanium alloy plate is polished with sandpaper to remove surface oxide layer;(2) workpiece cleaning: the workpiece is cleaned with ultrasonic after polishing;(3) shot peening: the cleaned workpiece is placed in the shot peening device, the height is adjusted according to the actual processing intensity, the shot peening parameters are set, the shot peening chamber is added with shot peening, copper powder;The workpiece is taken out after shot peening treatment.The application can provide better biological fouling resistance while improving the mechanical properties of titanium alloy by adding copper powder during shot peening treatment.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of alloy material preparation, in particular to a preparation method of gradient nanostructure antifouling titanium alloy. BACKGROUND

[0002] Metal materials are widely used in different fields, including construction, aerospace, automobile manufacturing and marine engineering, etc. However, in these applications, metal materials often face challenges from environmental factors such as microorganisms, seawater and soil. In the natural environment, microorganisms can adhere to the surface of the metal, causing biofouling. Marine biofouling not only increases the maintenance cost of marine underwater facilities, but also causes damage to marine observation facilities, resulting in failure of instrument transmission mechanism, signal distortion, reduced reliability, and even safety hazards. Therefore, improving the anti-biofouling ability of materials has great safety and economic significance.

[0003] The current marine biofouling protection scheme is mainly antifouling paint. Antifouling paint is a special variety of marine paint, and its main purpose is to prevent marine organisms from adhering to marine structures and causing fouling, and to keep the ship bottom or marine structure smooth and clean. Whether based on low surface energy or self-polishing concept, antifouling paint needs to add "toxin" - antifouling agent. There are many types of traditional antifouling paint, including inorganic types such as cuprous oxide (also other copper compounds such as cuprous thiocyanate), mercuric oxide (although effective but pollutes the environment, has been banned), zinc chloride (auxiliary antifouling agent), etc., and organic types including organotin compounds (tributyltin TBT or triphenyltin compound TPT, which has been banned), organic oxygen compounds (DDT, which is effective against barnacles, but DDT is too stable and not easy to degrade, pollutes the environment, and has been banned). In addition, antifouling paint cannot improve the mechanical properties of the material. SUMMARY

[0004] In order to overcome the shortcomings of the prior art, the present application provides a gradient nanostructure antifouling titanium alloy and a preparation method thereof.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is:

[0006] The first aspect of the present application provides a preparation method of gradient nanostructure antifouling titanium alloy, comprising the following steps:

[0007] (1) Workpiece preparation: polish the surface of the titanium alloy plate with sandpaper to remove the surface oxide layer;

[0008] (2) Workpiece cleaning: clean the polished workpiece with ultrasonic cleaning to remove surface oil and other residues;

[0009] (3) shot blasting: the cleaned workpiece is placed in a shot blasting device, the height is adjusted according to the actual processing intensity, the shot blasting parameters are set, and copper powder is added into the shot blasting chamber; the workpiece is taken out after shot blasting.

[0010] The application prepares a copper-containing protective layer on the material surface through shot blasting to inhibit biofouling during use, and the shot blasting can prepare a grain refinement layer on the alloy surface to improve the mechanical properties and surface hardness of the material.

[0011] Preferably, in step (1), the surface of the titanium alloy plate is mechanically polished with 180-mesh, 600-mesh and 1000-mesh sandpaper in sequence to remove the surface oxide layer.

[0012] Preferably, in step (2), the ultrasonic cleaning time is 5-15 min, and the ultrasonic cleaning solution is acetone and alcohol in sequence; further preferably, the ultrasonic cleaning time is 8-12 min.

[0013] Preferably, in step (3), the particle size of the copper powder is 40-60 μm; further preferably, the particle size of the copper powder is 45-55 μm.

[0014] Preferably, in step (3), the added amount of the copper powder is 0.5-1.5 g; further preferably, the added amount of the copper powder is 0.8-1.2 g.

[0015] Preferably, in step (3), the copper powder can be replaced by silver powder and / or zinc powder.

[0016] Preferably, in step (3), the shot blasting time is 2-8 min; further preferably, the shot blasting time is 4-6 min.

[0017] Preferably, in step (3), the shot blasting parameters are as follows: the shot blasting distance is 12-18 mm, the frequency is 18-22 kHz, and the amplitude is 70-76 μm; further preferably, the shot blasting distance is 14-16 mm, the frequency is 19-21 kHz, and the amplitude is 72-74 μm.

[0018] Preferably, in step (3), the shot blasting uses bearing steel, and the diameter of the shot blasting is 3-5 mm; further preferably, the diameter of the shot blasting is 4 mm.

[0019] The second aspect of the application provides the gradient nano-structured anti-fouling titanium alloy prepared by the preparation method of the gradient nano-structured anti-fouling titanium alloy.

[0020] Compared with the prior art, the application has the following beneficial effects:

[0021] The application produces a gradient structure by adding copper powder during shot peening, which can well improve the mechanical properties, and the introduction of copper element on the surface provides certain anti-biofouling ability. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 A schematic diagram of the device used for shot peening in the examples;

[0023] Figure 2 A metallographic photograph of the cross section of the ultrasonic shot peening sample;

[0024] Figure 3 A backscattering photograph of the gradient nanostructure antifouling titanium alloy surface and corresponding element distribution information;

[0025] Figure 4 A surface fluorescence spectrum of TA2 alloy in different processing states;

[0026] Figure 5 A comparison diagram of the tensile property curves of TA2 alloy before and after ultrasonic shot peening;

[0027] The accompanying drawings are included to provide a further understanding of the application, and are incorporated herein and constitute a part of this application. Figure 1 In the drawings, 1 is a workpiece, 2 is shot peening, 3 is a shot peening cavity, 4 is a tool head, 5 is an amplitude bar, 6 is a transducer, and 7 is a digital display controller. DETAILED DESCRIPTION

[0028] The specific embodiments of the application will be further described below. It should be noted that the description of these embodiments is used to help understand the application, but does not constitute a limitation on the application. In addition, the technical features involved in each embodiment of the application described below can be combined with each other as long as they do not conflict with each other.

[0029] The experimental methods in the following examples are all conventional methods unless otherwise specified. The test materials used in the following examples are all commercially available unless otherwise specified.

[0030] Example 1

[0031] The shot peening device is used to prepare the gradient nanostructure antifouling titanium alloy, which specifically includes the following steps: Figure 1

[0032] 1. Workpiece preparation: The surface of the purchased TA2 alloy plate is mechanically polished with 180 mesh, 600 mesh and 1000 mesh sandpaper in sequence to remove the surface oxide layer.

[0033] 2. Workpiece cleaning: The mechanically polished workpiece is cleaned with deionized water for 10 minutes to remove surface dirt, and then wiped and dried.

[0034] ​3. Ultrasonic shot peening: The workpiece is attached to the bottom of the adjustable sample rod with adhesive tape. The height is adjusted according to the actual processing intensity. The shot peening parameters are: peening distance 15mm, frequency 20kHz, amplitude 73μm, and shot peening time 5min. The shot used is bearing steel with a diameter of 4mm. Before starting the shot peening process, 1g of copper powder with a diameter of 50μm is added to the shot peening chamber.

[0035] 4. After 5 minutes of processing, the workpiece is removed to obtain a gradient nanostructured antifouling titanium alloy.

[0036] Figure 2 The image shows a cross-sectional metallographic photograph of the ultrasonically shot-peened sample. The alloy surface has a grain refinement layer of about 300 μm, and the grain size gradually increases from the surface to the inside.

[0037] The surface backscattered image and elemental distribution of the prepared gradient nanostructured antifouling titanium alloy are shown in the attached image. Figure 3 As shown, attached Figure 3 In the middle (a)-(d), we see (a) - surface backscattering image, (b) - titanium element distribution, (c) - copper element distribution, and (d) - iron element distribution, respectively.

[0038] Comparative Example 1

[0039] Based on Example 1, an untreated TA2 alloy sheet was used as a control. Additionally, based on Example 1, a conventional shot peening treatment without the addition of copper powder was used as a control.

[0040] The antifouling effect of the prepared gradient nanostructured antifouling titanium alloy was tested, and the specific test method is as follows:

[0041] After culturing samples in *Pseudomonas aeruginosa* culture dishes for 14 days, the adhesion of bacteria on the surface of the slides immersed in the test medium was observed using a Leica DM2500 LED fluorescence microscope. SYTO9+PI staining agent was used to demonstrate the adhesion of microorganisms (*Pseudomonas aeruginosa*) on the slide surface. SYTO9+PI staining agent makes live bacteria appear green and dead bacteria appear red. The staining procedure was as follows: After incubation, the metal slides were removed, and the surface of the metal sample was gently rinsed with 0.85 wt.% NaCl. Then, 0.5 μL SYTO9 + 0.5 μL PI was used for staining in the dark for 15 min. After staining, the metal sample was rinsed three times with sterile distilled water. Finally, the microbial adhesion on the surface of the alloy sample was tested under a fluorescence microscope. The test results are attached. Figure 4 As shown in the figure, green represents live cells, red represents dead cells, and yellow represents a combination of both. The figure indicates that the surface of the copper-peened sample contains more dead cells, demonstrating that copper-containing surfaces have a good bactericidal effect.

[0042] Figure 5The tensile property curves of TA2 alloy before and after ultrasonic peening are compared, and the yield strength and tensile strength of TA2 alloy are both improved after ultrasonic peening, wherein the yield strength is improved by about 20%.

[0043] The above detailed the embodiments of the present application, but the present application is not limited to the described embodiments. For those skilled in the art, various changes, modifications, replacements and variations of the embodiments are made without departing from the principles and spirits of the present application, and still fall within the protection scope of the present application.

Claims

1. A method for preparing a gradient nanostructured anti-fouling titanium alloy, characterized in that, The method comprises the following steps: (1) Workpiece preparation: polish the surface of the titanium alloy plate with sandpaper to remove the surface oxide layer; (2) Workpiece cleaning: clean the polished workpiece with ultrasonic cleaning to remove surface oil and other residues; (3) Shot blasting treatment: place the cleaned workpiece in a shot blasting device, adjust the height according to the actual processing intensity, set the shot blasting parameters, add shot blasting, copper powder, to the shot blasting chamber; take out the workpiece after shot blasting treatment; the particle size of the copper powder is 40-60 μm; the shot blasting treatment time is 2-8 min; the shot blasting parameters are: shot blasting distance is 12-18 mm, frequency is 18-22 kHz, and amplitude is 70-76 μm; the shot blasting used in the shot blasting treatment is bearing steel, and the diameter of the shot blasting is 3-5 mm.

2. The method of claim 1, wherein the gradient nanostructured anti-fouling titanium alloy is prepared by the steps of: In step (1), the surface of the titanium alloy plate is mechanically polished with 180 mesh, 600 mesh, and 1000 mesh sandpaper in sequence to remove the surface oxide layer. ​ 3. The method of claim 1, wherein the gradient nanostructured anti-fouling titanium alloy is prepared by the steps of: In step (2), the ultrasonic cleaning time is 5-15 min, and the ultrasonic cleaning solution is acetone and alcohol in sequence. ​ 4. The method of claim 1, wherein the gradient nanostructured anti-fouling titanium alloy is prepared by the steps of: In step (3), the amount of copper powder added is 0.5-1.5 g. ​ 5. The method of claim 1, wherein the gradient nanostructured anti-fouling titanium alloy is prepared by the steps of: a) preparing a titanium alloy; b) preparing a nanostructured titanium alloy by a mechanical alloying process; c) preparing a gradient nanostructured titanium alloy by a mechanical alloying process. In step (3), the copper powder can be replaced by silver powder and / or zinc powder.

6. The gradient nano-structured anti-fouling titanium alloy prepared by the method according to any one of claims 1-5.

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