Surface treatment method for improving antifouling performance of inner surface of connector in underwater environment

Abstract

The invention discloses a surface treatment method for improving the antifouling performance of the inner surface of an underwater environment connector. The invention particularly relates to a surface treatment method for improving the antifouling performance of the inner surface of an underwater connector. According to the electroplating copper layer and the electroplating nickel layer designed by the invention, cupronickel components appear on the nickel-plated layer in cooperation with heat treatment, so that the antifouling performance of the inner surface is improved.

Description

Technical Field

[0001] The present invention relates to the surface treatment of aluminum alloys, and in particular to a surface treatment method for improving the anti-fouling performance of the inner surface of underwater environment connectors. Background Art

[0002] With the gradual development of the activity areas of underwater weapon combat systems and ocean engineering towards the deep sea, underwater connectors have become indispensable components in underwater engineering such as weapon equipment systems and ocean resource development. It is mainly used to connect cables or optical fibers underwater. The connector consists of two parts, a plug and a socket, which can be conveniently connected together by divers, remotely operated vehicles or underwater robots to achieve the purpose of fast, efficient and reliable operation, greatly improving the reliability and maintainability of the entire underwater system.

[0003] It should be noted that marine biofouling refers to the process in which animals, plants or microorganisms in the ocean attach, colonize, grow and corrode on the surface of marine structures, which will cause corrosion of marine monitoring instruments, submarine pipelines, coastal structures, ships and even cross-sea bridges. Marine biofouling is mainly caused by microbial corrosion and biological deposition. Fouling reduces the accuracy of underwater connectors and leads to a decline in the reliability of underwater weapon combat systems. Summary of the Invention

[0004] Aiming at the problem of marine non-damage on the inner wall of the underwater connector housing, the present invention combines surface electroplating treatment and heat treatment to achieve efficient anti-fouling in the limited space of the inner wall of the connector housing. The implementation steps of the present invention are as follows:

[0005] (1) The inner wall of the connector housing is successively treated by surface treatment processes of electroplating tantalum, electroplating copper and electroplating nickel;

[0006] (2) The inner wall of the connector treated by electroplating is heat-treated to achieve efficient thermal diffusion of electroplated copper and electroplated nickel, and then the cupronickel effect is achieved;

[0007] The surface treatment method for improving the anti-fouling performance of the inner surface of an underwater environment connector of the present invention has the following beneficial effects:

[0008] (1) The cupronickel structure on the inner wall of the present invention is easy to obtain and does not change the traditional electroplating process.

[0009] (2) The cupronickel on the inner wall of the present invention does not add anti-fouling paint and does not change the inner wall size, ensuring the function of the connector. Description of the Drawings

[0010] Figure 1 It is a schematic diagram of electroplating copper and electroplating nickel;

[0011] Figure 2 It is a schematic diagram of heat treatment and achieving thermal diffusion.

[0012] Figure 3 are the anti-fouling properties of the electroplated surface and the heat-treated surface prepared in the comparative examples. Detailed implementation manners

[0013] Aiming at the existing problems, the present invention provides a surface treatment method for improving the anti-fouling performance of the inner surface of an underwater environment connector. The present invention will be further described below in conjunction with embodiments and drawings. The embodiments are for more clearly explaining the implementation manners of the present invention, rather than limiting the present invention.

[0014] Detailed implementation manner 1: This implementation manner is a surface treatment method for improving the anti-fouling performance of the inner surface of an underwater environment connector, and is implemented according to the following steps:

[0015] The titanium alloy matrix on the inner wall of the connector housing is sandblasted with 200-mesh alumina sand, and the surface roughness Ra is 3.2 - 6.3 μm to enhance the surface bonding force of the coating. Soak it in 3% hydrofluoric acid solution for two minutes to remove the surface oxide film, and soak it in a mixed acid melting solution with a volume ratio of 10% hydrofluoric acid + 20% nitric acid + 70% water for five minutes for surface activation treatment to form micron-sized pits. Ultrasonically clean it with acetone, ethanol, and deionized water for 10 minutes each in sequence to complete the surface pretreatment of the titanium alloy matrix on the inner surface of the connector.

[0016] Adopt the fluoro-tantalate system, and configure the electroplating solution according to K2TaF7 100 g / L, H2SO4 30 g / L, and ammonium citrate 10 g / L. The temperature of the electroplating solution is maintained at 60 ± 2 °C, and the pH value is adjusted to 2.5 - 3.0. Use a current density of 4 A / dm 2 for pulsed current electroplating treatment for 25 minutes, and control the coating thickness within 1.5 - 2 μm. Immediately after electroplating, use high-pressure deionized water to clean for 10 seconds to remove fluoride residues, and then quickly dry with hot air at 60 °C to complete the tantalum barrier layer electroplating.

[0017] Adopt nickel sulfamate electroplating solution, and configure the electroplating solution according to Ni(NH2SO3)2 400 g / L, H3BO3 40 g / L, and wetting agent 0.5 mL / L. The temperature of the electroplating solution is maintained at 55 ± 2 °C, and the pH value is adjusted to 4.0 - 4.5. Use a moving cathode device, and the current density is 3 A / dm 2 , for DC current electroplating treatment for 40 minutes, and control the coating thickness within 10 - 12 μm. After electroplating, immerse the connector in 5% H2SO4 solution for 10 seconds to remove nickel oxide, and then rinse and dry with deionized water to complete the nickel electroplating layer.

[0018] An environmentally friendly pyrophosphate plating solution is used. The electroplating solution is prepared according to 60 g / L of Cu2P2O7 and 300 g / L of K4P2O7, and 0.1 g / L of 2-mercaptobenzothiazole (MBT) is added as a grain refiner. The pH value of the electroplating solution is adjusted to 8.5 - 9.5. A current density of 1.5 A / dm 2 is used for direct current electroplating treatment for 90 minutes, and the coating thickness is controlled at 20 - 25 μm. After electroplating, the connector is immersed in a 5% H2SO4 solution for 10 seconds to remove the copper oxide film, and then rinsed and dried with deionized water to complete the electroplated copper layer.

[0019] The connector after electroplating treatment is placed in a tube furnace, and high-purity argon with an oxygen content < 50 ppm is introduced. It is heated to 600 °C at a rate of 10 °C / min and held for two hours to promote the initial interdiffusion of copper and nickel. It is then heated to 750 °C and held for 30 minutes to form a cupronickel layer. The furnace temperature is slowly cooled to room temperature at a rate of ≤ 5 °C / min to complete the gradient heat treatment of the connector.

Claims

1. An anti-fouling coating structure for the inner surface of an underwater environment connector, characterized in that: The coating comprises: A tantalum barrier layer, a copper layer and a nickel layer are sequentially deposited on the surface of the titanium alloy substrate; The white copper composite layer is formed by thermal diffusion between the copper layer and the nickel layer through gradient heat treatment.

2. The anti-fouling coating structure according to claim 1, characterized in that: The thickness of the tantalum barrier layer is 1.5-2 μm, the thickness of the copper layer is 20-25 μm, and the thickness of the nickel layer is 10-12 μm.

3. The anti-fouling coating structure according to claim 1, characterized in that: The white copper composite layer is formed by the following heat treatment process: under the protection of inert gas, the temperature is increased to 600-750° C. in a gradient manner, kept at this temperature for 0.5-2 hours, and then cooled to room temperature at a rate of ≤5° C. / min.

4. The anti-fouling coating structure according to claim 3, characterized in that: The inert gas is high-purity argon gas with an oxygen content of less than 50 ppm.

5. The anti-fouling coating structure according to claim 1, characterized in that: The surface roughness Ra of the white copper composite layer is 3.2-6.3 μm.

6. The anti-fouling coating structure according to claim 1, characterized in that: The plating layer does not require the addition of an additional antifouling coating and does not change the original size of the inner wall of the connector.

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