Nickel-plated layer structure on aerospace aluminum alloy part

Abstract

The utility model discloses a nickel plating layer structure on an aerospace aluminum alloy part, which comprises an aluminum alloy substrate, and a chemical zinc deposition layer, a chemical nickel pre-plating layer, a nickel-copper alloy plating layer, a bright nickel plating layer and a nano polymer protective film which are sequentially prepared on the aluminum alloy substrate from inside to outside. According to GB / T 5270-2005 Metal Covering Layer Electro-Deposition and Chemical Deposition Layer Adhesive Strength Test Method Assessment on Metal Matrix, the binding force of the plating layer is measured by a thermal shock test method, and the measurement result meets the standard requirement. The corrosion resistance of the plating layer is measured according to GB / T 10125-2021 Artificial Atmosphere Corrosion Test Salt Spray Test, no corrosives are generated on the surface of a plating piece after a neutral salt spray test is carried out for 132 hours, and the corrosion resistance of the plating layer meets the special requirements of aerospace accessories.

Description

Technical Field

[0001] The utility model belongs to the field of metal electroplating, and in particular relates to a nickel-plated layer structure on an aerospace aluminum alloy part. Background Art

[0002] Electrical parts in the domestic aerospace field generally use cadmium plating to prepare protective layers. In order to reduce the pollution caused by cadmium plating, some electrical parts have now replaced cadmium plating with chemical nickel plating. The process of chemical nickel plating of aluminum alloy parts is usually to prepare a chemical zinc deposition layer, a chemical pre-plating nickel layer, and a chemical nickel plating layer on the aluminum alloy substrate in sequence. The prepared protective layer requires no rust in a neutral salt spray test for 96 hours. However, the chemical nickel plating layer is a cathodic coating relative to the aluminum alloy substrate. When the coating is damaged, galvanic corrosion will occur and destroy the aluminum alloy substrate. Therefore, the corrosion resistance of this coating structure is not high.

[0003] Nickel-copper alloy coating has good mechanical properties, corrosion resistance, electrical and catalytic properties, and has been increasingly valued by domestic peers. [1] The performance of nickel-copper alloy plating is better than that of nickel plating. It is currently mainly used as a decorative plating, but less used as a functional plating.

[0004] According to traditional processes, protective decorative coatings such as nickel plating need to be post-treated with chromate electrolytic protection or chromic acid passivation to improve their anti-discoloration and corrosion resistance. However, the use of hexavalent chromium has the problem of high pollution.

[0005] References: [1] Yang Ruisong, Li Mingtian, Wang Ying, et al., Effect of process parameters on the composition and phase structure of electroplated nickel-copper alloy coatings [J]. Electroplating and Finishing, 2014, 33(15): 633-635. Utility Model Content

[0006] In order to overcome the technical defect that chemical nickel plating of aerospace aluminum alloy parts does not have electrochemical protection, the utility model provides a nickel plating layer structure on aerospace aluminum alloy parts. In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0007] A nickel-plated layer structure on an aerospace aluminum alloy part comprises an aluminum alloy substrate, and a chemical zinc deposition layer, a chemical pre-plated nickel layer, a nickel-copper alloy plating layer, a bright nickel plating layer, and a nano-polymer protective film, which are sequentially prepared from the inside to the outside on the aluminum alloy substrate.

[0008] Preferably, the thickness of the chemical pre-plated nickel layer is 0.5-2 μm.

[0009] Preferably, the thickness of the nickel-copper alloy plating layer is 6 to 15 μm.

[0010] Preferably, the thickness of the bright nickel plating layer is 6 to 15 μm.

[0011] The electrode potential of nickel is obviously negative than that of nickel-copper alloy. A bright nickel-plated layer is prepared on the nickel-copper alloy coating. The bright nickel-plated layer is an anodic coating, which has an electrochemical protective effect on the nickel-copper alloy coating and can effectively prevent the corrosive medium from corroding the substrate.

[0012] Compared with the prior art, the utility model has the following beneficial effects:

[0013] 1. The nickel plating structure on the aerospace aluminum alloy parts disclosed in the utility model is to plate bright nickel on the nickel-copper alloy plating layer, and the surface plating layer has an electrochemical protection effect on the bottom plating layer, thus overcoming the defect that the chemical nickel plating layer prepared on the aluminum alloy parts does not have an electrochemical protection effect;

[0014] 2. The nickel plating structure on the aerospace aluminum alloy parts disclosed in the utility model prepares a nano polymer protective film on the surface plating layer, which overcomes the high pollution problem of traditional chromate electrolytic protection or chromic acid passivation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of the present application, and do not constitute an improper limitation of the present invention. In the drawings:

[0016] Figure 1 It is a schematic diagram of the coating structure of Example 1 and Example 2 of the utility model. DETAILED DESCRIPTION

[0017] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. The schematic embodiments and descriptions of the present invention are used to explain the present invention but are not intended to limit the present invention.

[0018] The aluminum alloy parts are subjected to degreasing, alkali corrosion, polishing, slag removal and micro-corrosion activation according to the current pre-treatment process.

[0019] After the aluminum alloy parts are pre-treated, the chemical zinc deposition layer is prepared by the current aluminum alloy chemical zinc deposition process.

[0020] Preferably, the chemical zinc deposition layer is prepared using ALBUME AS-699 cyanide-free aluminum zinc deposition agent produced by Chaobang Chemical:

[0021] ALBUME AS-699 cyanide-free aluminum zinc precipitation agent 140 ~ 180mL / L, the working solution contains zinc ions 6 ~ 9g / L, copper ions 0.16 ~ 0.20g / L, the operating temperature is 20 ℃ ~ 30 ℃, the zinc precipitation time is 60 ~ 120s.

[0022] Preferably, the chemical zinc deposition layer is prepared using AZIN-113 acidic aluminum zinc deposition agent produced by Chaobang Chemical:

[0023] AZIN-113 acidic aluminum zinc precipitation agent 150 ~ 250mL / L, working temperature 15 ℃ ~ 30 ℃, bath pH value 3.4 ~ 4.5, zinc precipitation time 30 ~ 90s.

[0024] After chemical zinc deposition on aluminum alloy parts, the current low-temperature chemical nickel plating process is used to prepare a chemical pre-nickel plating layer.

[0025] Preferably, the thickness of the chemical pre-plated nickel layer is 0.5-2 μm.

[0026] Preferably, the chemical pre-plated nickel layer is prepared by using the GG-178 alkaline chemical nickel plating process of Chaobang Chemical:

[0027] GG-178 A additive 25~50mL / L, GG-178 B reducing agent 25~40mL / L, GG-178 C stabilizer 30~60mL / L, operating temperature 25℃~38℃, plating solution pH 8.5~9.5.

[0028] Preferably, the chemical pre-plated nickel layer is prepared by using the GG-158 alkaline chemical nickel plating process of Chaobang Chemical:

[0029] GG-158 A opener 140~160mL / L, GG-158 B supplement 90~110mL / L, GG-158 C supplement 90~110mL / L, operating temperature 30℃~45℃, plating solution pH 7.5~8.5.

[0030] The aluminum alloy parts are chemically pre-nickel plated and then the nickel-copper alloy coating is prepared by the current nickel-copper alloy plating process.

[0031] Preferably, the thickness of the nickel-copper alloy plating layer is 6 to 15 μm.

[0032] Preferably, the nickel-copper alloy plating layer is prepared by using the Nistar 6070 bright nickel-copper alloy plating process of Chaobang Chemical:

[0033] Nickel sulfate hexahydrate 180-220 g / L, copper sulfate pentahydrate 8-12 g / L, trisodium citrate 50-70 g / L, disodium hydroxyethylidene diphosphonate 20-30 g / L, boric acid 28-35 g / L, sodium chloride 5-8 g / L, NISTAR 6070 brightener 0.3-0.7 mL / L, NISTAR 6071 auxiliary agent 6-10 mL / L, NI-35 wetting agent 0.3-1.0 mL / L, plating solution pH 4.3-4.8, plating tank temperature 50°C-55°C, cathode current density 2.6-3.2 A / dm 2 , the cathode moves 3 to 5 m / min.

[0034] After the aluminum alloy parts are plated with nickel-copper alloy, the current bright nickel plating process is used to prepare a bright nickel plating layer.

[0035] Preferably, the thickness of the bright nickel plating layer is 6 to 15 μm.

[0036] The nano polymer protective film is prepared by the current electrolytic protection process after the aluminum alloy parts are plated with bright nickel.

[0037] Preferably, the nano polymer protective film is prepared by using the PROTEZVY 1126 electrolytic protection process of Chaobang Chemical:

[0038] PROTEZVY 1126 MUP tank opener 30-40 mL / L, PROTEZVY 1126 ADDITIVE C additive 70-90 mL / L, sodium hydroxide 0.15-0.25 g / L, bath pH 3.4-4.0, operating temperature 55°C-65°C, cathode current density 0.05-0.1 A / dm 2 , electrolysis time is 3 to 10 minutes.

[0039] Aluminum alloy parts are electrolytically protected and then washed and dried. Example

[0040] like Figure 1 As shown, a nickel-plated layer structure on an aerospace aluminum alloy part includes an aluminum alloy substrate 1, and a chemical zinc deposition layer 2, a chemical pre-plated nickel layer 3, a nickel-copper alloy plating layer 4, a bright nickel plating layer 5, and a nano-polymer protective film 6 prepared in sequence from the inside to the outside on the aluminum alloy substrate 1.

[0041] 1. Pre-treatment:

[0042] According to the current aluminum alloy pretreatment process, the aluminum alloy substrate 1 is subjected to "chemical degreasing → water washing → ultrasonic degreasing → water washing → alkaline corrosion → water washing → polishing → water washing → descaling → water washing → micro-corrosion → water washing".

[0043] 2. Chemical zinc precipitation:

[0044] After pre-treatment of the aluminum alloy parts, the chemical zinc deposition layer 2 was prepared using ALBUME AS-699 cyanide-free aluminum zinc deposition agent produced by Chaobang Chemical.

[0045] ALBUME AS-699 cyanide-free aluminum zinc precipitation agent 150mL / L, the working solution contains zinc ions 8g / L, copper ions 0.18g / L, the operating temperature is 23℃, and the zinc precipitation time is 100s. The specific process flow is as follows:

[0046] First zinc precipitation → water washing → zinc removal → water washing → second zinc precipitation → water washing.

[0047] 3. Chemical pre-nickel plating:

[0048] After chemical zinc deposition on the aluminum alloy part, the chemical pre-plating nickel layer 3 is prepared by using the GG-178 alkaline chemical nickel plating process of Chaobang Chemical, and the coating thickness is 1.2 μm.

[0049] GG-178 A additive 42mL / L, GG-178 B reducing agent 32mL / L, GG-178 C stabilizer 45mL / L, operating temperature 33℃, plating solution pH 9.2.

[0050] 4. Nickel-plated copper alloy:

[0051] After chemical pre-nickel plating, the aluminum alloy part is subjected to Nistar 6070 bright nickel-copper alloy plating process of Chaobang Chemical to prepare a nickel-copper alloy coating 4, and the coating thickness is 10 μm.

[0052] Nickel sulfate hexahydrate 200g / L, copper sulfate pentahydrate 10g / L, trisodium citrate 60g / L, disodium hydroxyethylidene diphosphonate 25g / L, boric acid 31g / L, sodium chloride 6g / L, NISTAR 6070 brightener 0.5mL / L, NISTAR 6071 auxiliary agent 8mL / L, NI-35 wetting agent 0.6mL / L, plating solution pH 4.5, plating tank temperature 53℃, cathode current density 3A / dm 2 , cathode moves 4m / min.

[0053] 5. Bright nickel plating:

[0054] After the aluminum alloy part is plated with nickel-copper alloy, a bright nickel-plated layer 5 is prepared by using the current bright nickel-plating process, and the thickness of the plating layer is 10 μm.

[0055] 6. Electrolytic protection:

[0056] After the aluminum alloy parts are plated with bright nickel, the nano-polymer protective film 6 is prepared using the PROTEZVY 1126 electrolytic protection process of Chaobang Chemical.

[0057] PROTEZVY 1126 MUP tank opener 35mL / L, PROTEZVY 1126 ADDITIVE C additive 80mL / L, sodium hydroxide 0.2g / L, bath pH 3.5, operating temperature 60℃, cathode current density 0.08A / dm 2 , electrolysis time 7min.

[0058] 7. Drying:

[0059] After electrolytic protection, the aluminum alloy parts are subjected to “water washing → pure water washing → drying”. Example

[0060] like Figure 1As shown, a nickel-plated layer structure on an aerospace aluminum alloy part includes an aluminum alloy substrate 1, and a chemical zinc deposition layer 2, a chemical pre-plated nickel layer 3, a nickel-copper alloy plating layer 4, a bright nickel plating layer 5, and a nano-polymer protective film 6 prepared in sequence from the inside to the outside on the aluminum alloy substrate 1.

[0061] 1. Pre-treatment:

[0062] According to the current aluminum alloy pretreatment process, the aluminum alloy substrate 1 is subjected to "chemical degreasing → water washing → ultrasonic degreasing → water washing → alkaline corrosion → water washing → polishing → water washing → descaling → water washing → micro-corrosion → water washing".

[0063] 2. Chemical zinc precipitation:

[0064] After pre-treatment of aluminum alloy parts, the chemical zinc deposition layer is prepared using Chaobang Chemical's AZIN-113 acid aluminum zinc deposition process.

[0065] AZIN-113 acidic aluminum zinc precipitation agent 200mL / L, working temperature 25℃, bath pH 4.0, zinc precipitation time 60s. The specific process flow is as follows:

[0066] First zinc precipitation → water washing → zinc removal → water washing → second zinc precipitation → water washing.

[0067] 3. Chemical pre-nickel plating:

[0068] After chemical zinc deposition on the aluminum alloy part, a chemical pre-plated nickel layer 2 is prepared by using the GG-158 alkaline chemical nickel plating process of Chaobang Chemical, and the coating thickness is 1.5 μm.

[0069] GG-158 A opener 150mL / L, GG-158 B supplement 100mL / L, GG-158 C supplement 100mL / L, operating temperature 35℃, plating solution pH 8.2.

[0070] 4. Nickel-plated copper alloy:

[0071] After chemical pre-nickel plating, the aluminum alloy part is subjected to Nistar 6070 bright nickel-copper alloy plating process of Chaobang Chemical to prepare a nickel-copper alloy coating 4, and the coating thickness is 10 μm.

[0072] Nickel sulfate hexahydrate 220g / L, copper sulfate pentahydrate 12g / L, trisodium citrate 70g / L, disodium hydroxyethylidene diphosphonate 30g / L, boric acid 35g / L, sodium chloride 8g / L, NISTAR 6070 brightener 0.5mL / L, NISTAR 6071 auxiliary agent 8mL / L, NI-35 wetting agent 0.6mL / L, plating solution pH 4.5, plating tank temperature 52℃, cathode current density 3A / dm 2 , cathode moves 4m / min.

[0073] 5. Bright nickel plating:

[0074] After the aluminum alloy part is plated with nickel-copper alloy, a bright nickel-plated layer 5 is prepared by using the current bright nickel-plating process, and the thickness of the plating layer is 10 μm.

[0075] 6. Electrolytic protection:

[0076] After the aluminum alloy parts are plated with bright nickel, the nano-polymer protective film 6 is prepared using the PROTEZVY 1126 electrolytic protection process of Chaobang Chemical.

[0077] PROTEZVY 1126 MUP tank opener 40mL / L, PROTEZVY 1126 ADDITIVE C additive 90mL / L, sodium hydroxide 0.25g / L, bath pH 3.8, operating temperature 58℃, cathode current density 0.08A / dm 2 , electrolysis time 6min.

[0078] 7. Drying:

[0079] After electrolytic protection, the aluminum alloy parts are subjected to “water washing → pure water washing → drying”.

[0080] Test Example 1:

[0081] Aluminum alloy nickel-plated samples were prepared according to the process of Example 1 and Example 2. According to GB / T 5270-2005 "Review of test methods for adhesion strength of electrodeposited and chemically deposited metal coatings on metal substrates", the samples were placed in a heating furnace and heated to 220°C for 30 minutes. They were taken out and quenched in water at room temperature. The coating did not bubble or fall off, and the prepared coating had good bonding strength.

[0082] Test Example 2:

[0083] Aluminum alloy nickel-plated samples were prepared according to the process of Example 1 and Example 2, and the corrosion resistance of the coating was tested according to GB / T 10125-2021 "Artificial atmosphere corrosion test salt spray test". The sample was subjected to a neutral salt spray test for 132 hours, and no white corrosion products were generated on its surface. The prepared coating has excellent corrosion resistance.

[0084] Test Example 3:

[0085] The aluminum alloy nickel-plated samples prepared according to the process of Example 1 and Example 2 were subjected to a constant humidity test according to GB / T 2423.3-1993 "Basic Environmental Test Procedure for Electrical and Electronic Products Test Ca: Constant Humidity Test Method". The test was performed for 500 hours at a temperature of 40°C and a relative humidity of 93%. There was no visible change in the coating. The anti-discoloration ability of the coating prepared by the utility model fully meets customer requirements.

[0086] The technical solutions provided by the embodiments of the present utility model are described in detail above. The principles and implementation methods of the embodiments of the present utility model are described in detail in this article using specific examples. The description of the above embodiments is only applicable to help understand the principles of the embodiments of the present utility model. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present utility model, which all belong to the protection scope of the present utility model.

Claims

1. A nickel-plated layer structure on an aerospace aluminum alloy part, characterized in that: The invention comprises an aluminum alloy substrate, and a chemical zinc deposition layer, a chemical pre-plating nickel layer, a nickel-copper alloy plating layer, a bright nickel plating layer, and a nano polymer protective film which are sequentially prepared from the inside to the outside on the aluminum alloy substrate.

2. The nickel-plated layer structure on the aerospace aluminum alloy part according to claim 1, characterized in that: The thickness of the chemical pre-plated nickel layer is 0.5-2 μm.

3. The nickel plating layer structure on the aerospace aluminum alloy part according to claim 1, characterized in that: The thickness of the nickel-copper alloy plating layer is 6-15 μm.

4. The nickel plating layer structure on the aerospace aluminum alloy part according to claim 1, characterized in that: The thickness of the bright nickel plating layer is 6-15 μm.

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