Electroplating bath and process for processing standard cadmium-titanium embrittlement rods

Abstract

The application discloses a kind of electroplating tank liquid and electroplating process for processing standard cadmium-titanium hydrogen embrittlement rod, belongs to the field of civil aviation detection.The cadmium-titanium hydrogen embrittlement rod coating layer obtained by controlling the content of tank liquid component and electroplating process has titanium metal content in the range of 0.2% to 0.7%.The cadmium-titanium hydrogen embrittlement rod loaded with 75% ultimate tensile strength does not break for 200 hours at room temperature, and the coating surface is free of corrosion and white spots after 120 hours of neutral salt spray test.The cadmium-titanium hydrogen embrittlement rod can pass the hydrogen embrittlement sensitivity test, has good batch stability, and is suitable for detecting the hydrogen embrittlement performance of cadmium-titanium high-strength steel, such as civil aviation aircraft maintenance chemicals, including aircraft cabin and cargo compartment disinfectant, aircraft engine cleaner, and aircraft paint remover.The application has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of civil aviation inspection, specifically relating to an electroplating bath and electroplating process for processing standard cadmium-titanium hydrogen embrittlement rods. Background Technology

[0002] Hydrogen embrittlement occurs when freely diffusing hydrogen atoms in high-strength steel migrate to stress concentration areas under stress. These hydrogen atoms accumulate in the stress concentration areas, forming cracks, which then propagate under stress, eventually leading to fracture. If substandard aircraft maintenance chemicals are used during routine maintenance of civil aircraft, hydrogen embrittlement can occur on cadmium-titanium plated high-strength steel components. In particular, the extensive and prolonged use of cabin and cargo hold disinfectants in the last three years has led to hydrogen embrittlement and corrosion of cadmium-titanium plated high-strength steel components within the aircraft cabin. Therefore, it is necessary to conduct hydrogen embrittlement tests on aviation maintenance chemicals (such as cabin disinfectants, cargo hold disinfectants, and aircraft cleaning agents) using standard cadmium-titanium plated hydrogen embrittlement rods to determine whether they cause hydrogen embrittlement in cadmium-titanium plated high-strength steel components.

[0003] Currently, standard hydrogen embrittlement rods are typically manufactured from AMS 6414 or AMS 6415 ultra-high strength steel bars, which are then plated with cadmium-titanium to produce standard cadmium-titanium hydrogen embrittlement rods. However, the current process for preparing these rods suffers from several problems. These include unstable plating baths, precipitation and turbidity during electroplating, easy deactivation of titanium active compounds, and improper cadmium-titanium plating techniques. Consequently, the titanium content in the plating layer fluctuates significantly during the cadmium-titanium electroplating process, hydrogen permeation occurs, plating defects are present, and plating adhesion is poor. These issues make the standard cadmium-titanium hydrogen embrittlement rods prone to brittle fracture and unable to pass hydrogen embrittlement sensitivity tests. Therefore, when using these standard cadmium-titanium hydrogen embrittlement rods for hydrogen embrittlement testing, the test results are inaccurate.

[0004] The literature (Application of Cadmium-Titanium Plating Process for Low-Hydrogen Embrittlement of High-Strength Steel, Tu Guisheng et al., Proceedings of the 2010 (Guiyang) Academic Forum on Low-Carbon and Environmentally Friendly Surface Engineering) reports a cadmium-titanium plating process for high-strength steel. Following the bath formulation and electroplating process shown in the table below, this literature applied cadmium-titanium plating to high-strength steels such as 300M steel, 4340 steel, and 16Co14Ni10Cr2Mo steel. Static load notched tensile tests were conducted on the cadmium-titanium-plated products, and all results showed no fracture after more than 200 hours. The hydrogen embrittlement resistance of the cadmium-titanium plating also passed the test. However, on the one hand, the standard hydrogen embrittlement rod has a very small V-shaped notch structure in the middle. This literature does not mention or address the problem of darkening and scorching of the plating at the edges and tips of the V-shaped notch of the standard hydrogen embrittlement rod due to the dispersion ability of the electroplating solution. On the other hand, the standard hydrogen embrittlement bars are made of AMS6414, AMS6415, and MIL-S-5000 ultra-high strength steels, which are most sensitive to hydrogen and electroplating processes. However, the steels used in this literature are 300M steel, 4340 steel, and 16Co14Ni10Cr2Mo steel. These steels are less sensitive to hydrogen than AMS6414, AMS6415, and MIL-S-5000 ultra-high strength steels, and their cadmium-titanium plating processes are not compatible with those for standard hydrogen embrittlement bars. This invention also experimentally verified that hydrogen embrittlement bars made by cadmium-titanium plating of AMS6415 ultra-high strength steel using the bath formulation and electroplating process reported in this literature failed the hydrogen embrittlement sensitivity test.

[0005] Table of plating bath formulations and electroplating processes reported in the literature

[0006]

[0007] In summary, developing a standard cadmium-titanium hydrogen embrittlement rod that can pass the hydrogen embrittlement sensitivity test and has good batch stability is of great significance. Summary of the Invention

[0008] To address the aforementioned problems, the present invention aims to provide an electroplating bath and process for processing standard cadmium-titanium hydrogen embrittlement bars, as well as standard cadmium-titanium hydrogen embrittlement bars prepared using the cadmium-titanium plating bath and process, for testing the hydrogen embrittlement performance of cadmium-titanium high-strength steel using chemicals used in civil aviation aircraft maintenance, such as aircraft cabin and cargo hold disinfectants, aircraft engine cleaners, and aircraft paint removers.

[0009] This invention provides an electroplating bath for preparing cadmium-titanium hydrogen embrittlement rods. The electroplating bath comprises cadmium metal, NaCN, NaOH, Na2CO3, a titanium active compound solution, and water, wherein the concentration of cadmium metal is 22.0 g / L to 25.0 g / L, the concentration of NaCN is 100.0 g / L to 120.0 g / L, the concentration of NaOH is 16.0 g / L to 20.0 g / L, the concentration of sodium carbonate is 30.0 g / L to 50.0 g / L, and the concentration of the titanium active compound solution is 12.0 g / L to 24.0 g / L.

[0010] Further, the concentration of cadmium metal is 22.5 g / L to 24.5 g / L, the concentration of NaCN is 106.0 g / L to 118.0 g / L, the concentration of NaOH is 17.5 g / L to 19.0 g / L, the concentration of sodium carbonate is 32.0 g / L to 42.0 g / L, and the concentration of titanium active compound solution is 14.0 g / L to 22.5 g / L.

[0011] Furthermore, the titanium active compound solution is obtained by filtering a liquid containing titanium active compounds, wherein the liquid containing titanium active compounds is composed of mineral clay, titanium oxide salt, NaOH, H2O2 aqueous solution and water; wherein the concentration of mineral clay is 55.0 g / L ~ 75.0 g / L, the concentration of titanium oxide salt is 140.0 g / L ~ 200.0 g / L, the concentration of NaOH is 8.0 g / L ~ 12.0 g / L, and the concentration of H2O2 aqueous solution is 18.0 g / L ~ 24.0 g / L.

[0012] Furthermore, the mineral soil is diatomaceous earth or montmorillonite, the titanium oxide salt is TiOSO4 or TiOCl2, and the H2O2 aqueous solution is 35% H2O2;

[0013] The concentration of the mineral soil is 65.0 g / L to 74.0 g / L, the concentration of the titanium oxide salt is 155.0 g / L to 195.0 g / L, the concentration of NaOH is 8.5 g / L to 11.0 g / L, and the concentration of the H2O2 aqueous solution is 20.0 g / L to 23.0 g / L.

[0014] The present invention also provides an electroplating process for preparing cadmium-titanium hydrogen-brittle rods, which includes the following steps:

[0015] (a) Preparation of electroplating bath solution: The electroplating bath solution is as described above;

[0016] (b) Activation of the plating bath: The cathode plate is placed in the electroplating bath at a current density of 0.45 Amp / dm³. 2 ~0.65Amp / dm 2Electroplating was performed for 30 to 60 minutes under the specified conditions to obtain the activated plating solution.

[0017] (c) Electroplating of cadmium-titanium: The hydrogen embrittlement rod is electroplated in the activated bath to obtain cadmium-titanium hydrogen embrittlement rod.

[0018] Further, in step (b), the current density is 0.50 Amp / dm. 2 ~0.60 Amp / dm 2 The electroplating time is 35 min to 50 min.

[0019] Further, in step (c), the electroplating method is as follows: first, at a current density of 6.5 Amp / dm 2 ~10.5 Amp / dm 2 Electroplating was performed for 10-40 seconds under the specified conditions, followed by electroplating at a current density of 2.5 Amp / dm². 2 ~4.0 Amp / dm 2 Electroplating for 10-16 minutes under the specified conditions;

[0020] Preferably, in step (c), the electroplating method is as follows: first, at a current density of 6.8 Amp / dm 2 ~9.5Amp / dm 2 Electroplating was performed for 15-30 seconds under the specified conditions, followed by electroplating at a current density of 2.8 Amp / dm². 2 ~3.6Amp / dm 2 Electroplating for 12-15 minutes under the specified conditions.

[0021] Further, in step (c), the hydrogen-brittle rod is high-strength steel, preferably ultra-high-strength steel, and more preferably AMS6414, AMS6415 or MIL-S-5000.

[0022] The present invention also provides a cadmium-titanium hydrogen embrittlement rod prepared by the above electroplating process.

[0023] The present invention also provides the use of the above-mentioned cadmium-plated titanium hydrogen brittle rod in the preparation of standard cadmium-plated titanium hydrogen brittle rod.

[0024] In this invention, the titanium active compound solution refers to the titanium complex ion solution.

[0025] In this invention, the cadmium metal in the cadmium-titanium plating bath refers to the cadmium content corresponding to cadmium oxide added to the bath.

[0026] H2O2 aqueous solution refers to an aqueous solution of H2O2, where 30%H2O2 refers to an aqueous solution of H2O2 with a mass concentration of 30%.

[0027] High-strength steel refers to low-alloy steel that has been heat-treated to an ultimate tensile strength greater than 1240 MPa. Ultra-high-strength steel refers to low-alloy steel that has been heat-treated to an ultimate tensile strength greater than 1650 MPa. Ultra-high-strength steel includes AMS6414 steel, AMS6415 steel, and MIL-S-5000 steel.

[0028] This invention effectively removes trace impurities from the plating bath by controlling the content of the bath components and the electroplating process, activates the bath, and ensures that the titanium content in the resulting coating is within the range of 0.2% to 0.7%, thereby avoiding coating defects and improving the adhesion and salt spray resistance of the coating.

[0029] The present invention provides a cadmium-titanium plating process for processing standard cadmium-titanium hydrogen-brittle rods, λ pc value (λ) pc The value is an indicator used to test the hydrogen embrittlement performance of the electroplating bath and process using a Lawrence hydrogen analyzer. It is generally considered that λ is significant during cadmium-titanium plating. pc The value should not exceed 120s, otherwise severe hydrogen embrittlement will occur (less than 80s). The cadmium-titanium hydrogen embrittlement rods obtained using the cadmium-titanium plating bath and process of this invention have a titanium metal content in the range of 0.2%~0.7%, and under a load of 75% ultimate tensile strength, they do not crack after 200 hours at room temperature. After a 120-hour neutral salt spray test, the coating surface shows no corrosion or white spots. These cadmium-titanium hydrogen embrittlement rods can pass the hydrogen embrittlement sensitivity test and have good batch stability. They are suitable for testing the hydrogen embrittlement performance of cadmium-titanium high-strength steel by chemicals used in civil aviation aircraft maintenance, such as aircraft cabin and cargo hold disinfectants, aircraft engine cleaners, and aircraft paint removers, and have broad application prospects.

[0030] Obviously, based on the above description of the present invention, and according to common technical knowledge and conventional methods in the field, various other modifications, substitutions or alterations can be made without departing from the basic technical concept of the present invention.

[0031] The following detailed embodiments further illustrate the above-described content of the present invention. However, this should not be construed as limiting the scope of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Attached Figure Description

[0032] Figure 1 Schematic diagram of dimensional requirements for cadmium-plated titanium hydrogen brittle rods.

[0033] Figure 2 Schematic diagram of hydrogen embrittlement experiment of cadmium-titanium plated hydrogen embrittlement rod. Detailed Implementation

[0034] The raw materials and equipment used in this invention are all known products, obtained by purchasing commercially available products.

[0035] In the embodiments and comparative examples of the present invention, the hydrogen-embrittled rods before treatment were made of AMS 6415 ultra-high strength steel according to... Figure 1 The standard test pieces are manufactured according to the standard requirements.

[0036] The cathode plates used in the embodiments and comparative examples of the present invention are inert cathode plates for electroplating, such as graphite plates.

[0037] Example 1: An electroplating bath and process for processing standard cadmium-titanium hydrogen-brittle rods.

[0038] Prepare standard cadmium-titanium hydrogen embrittlement rods according to the following steps:

[0039] (1) Preparation of titanium active compound: Montmorillonite: 66.0 g / L, TiOSO4: 192 g / L; NaOH: 9.0 g / L; 35%H2O2: 21.0 g / L; After preparation, stir thoroughly and filter out the clear liquid to obtain titanium active compound solution.

[0040] (2) Preparation of cadmium-titanium plating bath: In the cadmium-titanium plating bath, the concentration of cadmium metal is 23.5 g / L, the concentration of NaCN is 112.0 g / L, the concentration of NaOH is 17.5 g / L, the concentration of sodium carbonate is 35.0 g / L, and the concentration of titanium active compound solution is 19.0 g / L (referring to the amount of titanium active compound solution added to the bath is 19.0 g / L); the weight ratio of NaCN to cadmium metal is 4.8:1.

[0041] (3) Activation of the plating bath: Place the cathode plate in the cadmium-titanium plating bath and activate it at a current density of 0.5 Amp / dm. 2 Electroplating for 35 minutes under the specified conditions;

[0042] (4) Electroplating cadmium-titanium: The hydrogen embrittlement rod is placed in the activated bath, and firstly at a current density of 8.7 Amp / dm 2 Under these conditions, electroplating was performed for 25 seconds; then, electroplating was carried out at a current density of 3.5 Amp / dm². 2 Electroplating for 12 minutes under the specified conditions.

[0043] Example 2: An electroplating bath and process for processing standard cadmium-titanium hydrogen-brittle rods.

[0044] To prepare standard cadmium-titanium hydrogen-embrittled rods, follow these steps:

[0045] (1) Preparation of titanium active compound: Montmorillonite: 72.0 g / L, TiOCl2: 168 g / L; NaOH: 10.5 g / L; 35% H2O2: 20.0 g / L. After preparation, stir thoroughly and filter out the clear liquid to obtain titanium active compound solution.

[0046] (2) Preparation of cadmium-titanium plating bath: In the cadmium-titanium plating bath, the concentration of cadmium metal is 24.0 g / L, the concentration of NaCN is 106.0 g / L, the concentration of NaOH is 17.5 g / L, the concentration of sodium carbonate is 42.5 g / L, the concentration of titanium active compound solution is 22.5 g / L, and the weight ratio of NaCN to cadmium metal is 4.4:1.

[0047] (3) Activation of the plating bath: Place the cathode plate in the cadmium-titanium plating bath and activate it at a current density of 0.55 Amp / dm. 2 Electroplating for 45 minutes under the specified conditions;

[0048] (4) Electroplating cadmium-titanium: The hydrogen embrittlement rod is placed in the activated bath, and firstly, the current density is 9.5 Amp / dm 2 Under these conditions, electroplating was performed for 15 seconds; then, electroplating was carried out at a current density of 3.0 Amp / dm². 2 Electroplating for 15 minutes under the specified conditions.

[0049] Example 3: An electroplating bath and process for processing standard cadmium-titanium hydrogen-brittle rods.

[0050] To prepare standard cadmium-titanium hydrogen-embrittled rods, follow these steps:

[0051] (1) Preparation of titanium active compound: Diatomaceous earth: 74.0 g / L, TiOSO4: 195 g / L; NaOH: 8.5 g / L; 35% H2O2: 21.8 g / L. After preparation, stir thoroughly and filter out the clear liquid to obtain titanium active compound solution.

[0052] (2) Preparation of cadmium-titanium plating bath: In the cadmium-titanium plating bath, the concentration of cadmium metal is 22.5 g / L, the concentration of NaCN is 113.0 g / L, the concentration of NaOH is 19.0 g / L, the concentration of sodium carbonate is 40.0 g / L, the concentration of titanium active compound solution is 16.0 g / L, and the weight ratio of NaCN to cadmium metal is 5.0:1.

[0053] (3) Activation of the plating bath: Place the cathode plate in the cadmium-titanium plating bath and activate it at a current density of 0.50 Amp / dm. 2 Electroplating for 50 minutes under the specified conditions;

[0054] (4) Electroplating cadmium-titanium: The hydrogen embrittlement rod is placed in the activated bath, and firstly, the current density is 6.8 Amp / dm 2 Under these conditions, electroplating was performed for 30 seconds; then, electroplating was carried out at a current density of 3.6 Amp / dm². 2 Electroplating for 15 minutes under the specified conditions.

[0055] Example 4: An electroplating bath and process for processing standard cadmium-titanium hydrogen-brittle rods.

[0056] To prepare standard cadmium-titanium hydrogen-embrittled rods, follow these steps:

[0057] (1) Preparation of titanium active compound: Diatomaceous earth: 65.0 g / L, TiOCl2: 155 g / L; NaOH: 9.6 g / L; 35%H2O2: 21.0 g / L. After preparation, stir thoroughly and filter out the clear liquid to obtain titanium active compound solution.

[0058] (2) Preparation of cadmium plating bath: In the cadmium-titanium plating bath, the concentration of cadmium metal is 24.5 g / L, the concentration of NaCN is 118.0 g / L, the concentration of NaOH is 19.0 g / L, the concentration of sodium carbonate is 32.0 g / L, the concentration of titanium active compound solution is 20.0 g / L, and the weight ratio of NaCN to cadmium metal is 4.8:1.

[0059] (3) Activation of the plating bath: The cathode plate is placed in the cadmium-titanium plating bath, and the current density is 0.60 Amp / dm. 2 Electroplating for 50 minutes under the specified conditions;

[0060] (4) Electroplating cadmium-titanium: The hydrogen embrittlement rod is placed in the activated bath, and firstly, the current density is 9.5 Amp / dm 2 Under these conditions, electroplating was performed for 25 seconds; then, electroplating was carried out at a current density of 2.8 Amp / dm². 2 Electroplating for 15 minutes under the specified conditions.

[0061] Example 5: An electroplating bath and process for processing standard cadmium-titanium hydrogen-brittle rods.

[0062] To prepare standard cadmium-titanium hydrogen-embrittled rods, follow these steps:

[0063] (1) Preparation of titanium active compound: Diatomaceous earth: 72.0 g / L, TiOCl2: 155 g / L; NaOH: 11.0 g / L; 35%H2O2: 23.0 g / L. After preparation, stir thoroughly and filter out the clear liquid to obtain titanium active compound solution.

[0064] (2) Preparation of cadmium-titanium plating bath: In the cadmium-titanium plating bath, the concentration of cadmium metal is 23.8 g / L, the concentration of NaCN is 109.5 g / L, the concentration of NaOH is 17.5 g / L, the concentration of sodium carbonate is 40.0 g / L, the concentration of titanium active compound solution is 14.0 g / L, and the weight ratio of NaCN to cadmium metal is 4.6:1.

[0065] (3) Activation of the plating bath: Place the cathode plate in the cadmium-titanium plating bath and activate it at a current density of 0.60 Amp / dm. 2 Electroplating for 35 minutes under the specified conditions;

[0066] (4) Electroplating cadmium-titanium: The hydrogen embrittlement rod is placed in the activated bath, and firstly, the current density is 9.5 Amp / dm 2 Under these conditions, electroplating was performed for 20 seconds; then, electroplating was carried out at a current density of 3.6 Amp / dm². 2 Electroplating for 12 minutes under the specified conditions.

[0067] Comparative Example 1

[0068] To prepare standard cadmium-titanium hydrogen-embrittled rods, follow these steps:

[0069] (1) Preparation of titanium active compound: Montmorillonite: 70.0 g / L, TiOSO4: 190 g / L; NaOH: 10.0 g / L; 35% H2O2: 15.0 g / L. After preparation, stir thoroughly and filter out the clear liquid to obtain titanium active compound solution.

[0070] (2) Preparation of cadmium-titanium plating bath: In the cadmium-titanium plating bath, the concentration of cadmium metal is 20.0 g / L, the concentration of NaCN is 116.0 g / L, the concentration of NaOH is 18.0 g / L, the concentration of sodium carbonate is 60.0 g / L, the concentration of titanium active compound solution is 10.0 g / L, and the weight ratio of NaCN to cadmium metal is 5.8:1.

[0071] (3) Activation of the plating bath: Place the cathode plate in the cadmium-titanium plating bath and activate it at a current density of 0.50 Amp / dm. 2 Electroplating for 50 minutes under the specified conditions;

[0072] (4) Electroplating cadmium-titanium: The hydrogen embrittlement rod is placed in the activated bath, and first at a current density of 8.5 Amp / dm 2 Under these conditions, electroplating was performed for 25 seconds; then, electroplating was carried out at a current density of 3.4 Amp / dm². 2 Electroplating for 14 minutes under the specified conditions.

[0073] Comparative Example 2

[0074] (1) Preparation of titanium active compound: diatomaceous earth: 45.0 g / L, TiOCl2: 120 g / L; NaOH: 9.0 g / L; 35%H2O2: 15.0 g / L. After preparation, stir thoroughly and filter out the clear liquid to obtain titanium active compound solution.

[0075] (2) Preparation of cadmium-titanium plating bath: In the cadmium-titanium plating bath, the concentration of cadmium metal is 24.0 g / L, the concentration of NaCN is 115.2 g / L, the concentration of NaOH is 18.0 g / L, the concentration of sodium carbonate is 40.0 g / L, the concentration of titanium active compound solution is 10.0 g / L, and the weight ratio of NaCN to cadmium metal is 4.8:1.

[0076] (3) Activation of the plating bath: The cathode plate is placed in the cadmium-titanium plating bath and activated at a current density of 0.80 Amp / dm. 2 Electroplating for 40 minutes under the specified conditions;

[0077] (4) Electroplating cadmium-titanium: The hydrogen embrittlement rod is placed in the activated bath, and first at a current density of 4.5 Amp / dm 2 Under these conditions, electroplating was performed for 60 seconds; then, electroplating was carried out at a current density of 3.5 Amp / dm². 2 Electroplating for 15 minutes under the specified conditions.

[0078] Comparative Example 3

[0079] (1) Preparation of titanium active compound: Montmorillonite: 65.0 g / L, TiOCl2: 170 g / L; NaOH: 10.0 g / L; 35%H2O2: 20.0 g / L. After preparation, stir thoroughly and filter out the clear liquid to obtain titanium active compound solution.

[0080] (2) Preparation of cadmium-titanium plating bath: In the cadmium-titanium plating bath, the concentration of cadmium metal is 28.5 g / L, the concentration of NaCN is 111.0 g / L, the concentration of NaOH is 18.5 g / L, the concentration of sodium carbonate is 40.0 g / L, the concentration of titanium active compound solution is 30.0 g / L, and the weight ratio of NaCN to cadmium metal is 3.9:1.

[0081] (3) Activation of the plating bath: Place the cathode plate in the cadmium-titanium plating bath and activate it at a current density of 0.55 Amp / dm. 2 Electroplating for 50 minutes under the specified conditions;

[0082] (4) Electroplating cadmium-titanium: The hydrogen embrittlement rod is placed in the activated bath, and firstly, the current density is 9.5 Amp / dm 2 Under these conditions, electroplating was performed for 15 seconds; then, electroplating was carried out at a current density of 1.5 Amp / dm². 2 Electroplating for 20 minutes under the specified conditions.

[0083] The following experimental examples demonstrate the beneficial effects of the present invention.

[0084] Experimental Example 1: Effect Test of Cadmium-Titanium Plated Rods Obtained by the Cadmium-Titanium Plating Process of the Present Invention

[0085] 1. Experimental Methods

[0086] The cadmium-plated titanium hydrogen embrittlement rods obtained by the cadmium-plating process according to Examples 1-5 and Comparative Examples 1-3 were subjected to the following tests.

[0087] (1) Appearance: Visual inspection with a 5x magnifying glass;

[0088] (2) Salt spray test: ASTM B117, neutral salt spray test;

[0089] (3) Hydrogen embrittlement sensitivity test: ASTM F519 sensitivity test;

[0090] (4) Titanium content test in cadmium-titanium coating: Titanium content test in section 5.8 of MIL-STD-1500;

[0091] (5) Hydrogen embrittlement test evaluation of aviation chemicals: in accordance with Figure 2 The hydrogen embrittlement test of cadmium-titanium hydrogen embrittlement rods was conducted using the experimental method shown. The test used 3.0% hydrogen peroxide aircraft disinfectant as the corrosive medium and applied 45% notched fracture strength for hydrogen embrittlement testing. Imported cadmium-titanium hydrogen embrittlement rods from Green Specialty Service Inc. in the United States and cadmium-titanium hydrogen embrittlement rods prepared in Comparative Examples 1-3 were used as controls.

[0092] 2. Experimental Results

[0093] Table 1. Test results of the effects of cadmium-titanium coated hydrogen embrittlement rods

[0094]

[0095] Table 2. Evaluation results of hydrogen embrittlement tests on aircraft disinfectant products using various cadmium-plated titanium hydrogen embrittlement rods.

[0096]

[0097]

[0098] As can be seen from Table 1, the cadmium-titanium plating processes in Examples 1, 2, 3, 4 and 5 resulted in uniform and flawless cadmium-titanium hydrogen embrittlement rod coatings with good adhesion, and no obvious corrosion points were observed after 120 hours of testing.

[0099] The cadmium-titanium hydrogen embrittlement rods obtained by the cadmium-titanium plating processes in Examples 1, 2, 3, 4 and 5 all passed the hydrogen embrittlement sensitivity test; while the cadmium-titanium hydrogen embrittlement rods obtained by the cadmium-titanium plating processes in Comparative Examples 1 and 3 failed the hydrogen embrittlement sensitivity test.

[0100] Tests on the titanium content in the cadmium-titanium hydrogen embrittlement rod coatings of Examples 1, 2, 3, 4, and 5 revealed that the titanium content in the coatings obtained by these processes was within the range of 0.2% to 0.7%, while the titanium content in the coatings obtained by the processes in Comparative Examples 1 and 2 was less than 0.1%. Statistical analysis of long-term hydrogen embrittlement test results indicates that a low titanium content in the cadmium-titanium hydrogen embrittlement rod coating reduces its resistance to hydrogen embrittlement corrosion, leading to inaccurate test results.

[0101] As shown in Table 2, when using 3.0% hydrogen peroxide aircraft disinfectant for testing, compared with imported cadmium-plated titanium hydrogen embrittlement rods from Green Specialty Service Inc. in the United States, the hydrogen embrittlement test results of the cadmium-plated titanium hydrogen embrittlement rods obtained by the cadmium-plating process in Examples 1, 2, 3, 4, and 5 were all accurate and showed good batch stability; while the hydrogen embrittlement test results of the cadmium-plated titanium hydrogen embrittlement rods obtained by the cadmium-plating process in Comparative Examples 1, 2, and 3 were all inaccurate.

[0102] The above experimental results show that, by controlling the content of the bath components and the electroplating process, the cadmium-titanium hydrogen embrittlement rods obtained in Examples 1, 2, 3, 4 and 5 of this invention show no obvious corrosion points after 120 hours of salt spray testing, can pass the hydrogen embrittlement sensitivity test, and have good batch stability. They can be used as standard cadmium-titanium hydrogen embrittlement rods to evaluate the hydrogen embrittlement performance of high-strength steel by aviation chemicals such as aircraft disinfectants.

[0103] Experimental Example 2: Performance test of cadmium-titanium brittle rods obtained by the cadmium-titanium plating process of the present invention compared with cadmium-titanium brittle rods obtained by other known cadmium-titanium plating processes.

[0104] 1. Experimental Methods

[0105] Using AMS 6415 ultra-high strength steel as the hydrogen embrittlement rod before treatment, standard cadmium-titanium hydrogen embrittlement rods were prepared according to the processes in Examples 1, 2, and 5.

[0106] Using AMS 6415 ultra-high strength steel as the hydrogen embrittlement rod before treatment, standard cadmium-titanium hydrogen embrittlement rods were prepared according to the bath formula and electroplating process recorded in the literature "Application of Low Hydrogen Embrittlement Cadmium-Titanium Plating Process for High Strength Steel" (Tu Guisheng et al., Proceedings of the 2010 (Guiyang) Low Carbon and Environmental Protection Surface Engineering Academic Forum).

[0107] Using AMS 6415 ultra-high strength steel as the hydrogen embrittlement bar before treatment, a standard cadmium-titanium hydrogen embrittlement bar was prepared according to the process described in "HB / Z 107-1986 Low Hydrogen Embrittlement Cadmium-Titanium Plating Process for High Strength Steel Parts".

[0108] The following tests were performed respectively:

[0109] (1) Appearance: The test method is the same as in Experiment 1;

[0110] (2) Hydrogen embrittlement sensitivity test: The test method is the same as in Experiment Example 1;

[0111] (3) Hydrogen embrittlement test evaluation of aviation chemicals: The test method is the same as in Experiment 1.

[0112] 2. Experimental Results

[0113] Table 3. Appearance and hydrogen embrittlement sensitivity test results of various cadmium-plated titanium hydrogen embrittlement rods.

[0114]

[0115] Table 4 Evaluation results of hydrogen embrittlement tests on various cadmium-plated titanium hydrogen embrittlement rods in corrosive media.

[0116]

[0117]

[0118] The experimental data shows that the cadmium-titanium hydrogen embrittlement rods prepared using the electroplating processes described in "Application of Low-Hydrogen Embrittlement Cadmium-Titanium Plating Process for High-Strength Steel" and "HB / Z 107-1986 Low-Hydrogen Embrittlement Cadmium-Titanium Plating Process for High-Strength Steel Parts" exhibit very large dispersion in the test results, leading to inaccurate results. Even aircraft disinfectants that meet the requirements will show unqualified results, making it impossible to determine the hydrogen embrittlement performance of aircraft disinfectant products. In contrast, the cadmium-titanium hydrogen embrittlement rods prepared using the invented electroplating process show less dispersion and more accurate results.

[0119] In the cadmium-titanium plating bath of this invention, titanium salts are less prone to decomposition and precipitation, making bath maintenance simpler. The titanium content in the plating layer is controlled by adjusting the amount of hydrogen peroxide added to the bath, making titanium content control more convenient. Furthermore, the cyanide electroplating bath provides better dispersibility. The cadmium-titanium hydrogen-brittle rods processed by this invention exhibit more uniform plating at the notches, resulting in more accurate test results.

[0120] The process of this invention not only ensures the adhesion of the coating, but also reduces the amount of hydrogen permeation during electroplating, and the prepared standard cadmium-titanium hydrogen embrittlement rods are more likely to pass the hydrogen embrittlement sensitivity test.

[0121] In summary, the standard cadmium-titanium hydrogen embrittlement bars processed using the cadmium-titanium plating bath and process of this invention exhibit a fracture time of over 200 hours under 45% ultimate tensile strength loading in 3.0% hydrogen peroxide aircraft disinfectant, and no fracture after 200 hours under 75% ultimate tensile strength loading at room temperature. The cadmium-titanium hydrogen embrittlement bars prepared using the cadmium-titanium plating bath and process of this invention demonstrate good batch stability and can be used to test the hydrogen embrittlement properties of cadmium-titanium high-strength steel in civil aircraft maintenance chemicals such as aircraft cabin and cargo hold disinfectants, aircraft engine cleaners, and aircraft paint removers, showing broad application prospects.

Claims

1. An electroplating process for preparing cadmium-titanium embrittled rods, characterized in that: It comprises the following steps: (a) preparing an electroplating bath; (b) Bath activation: The cathode plate was placed in the electroplating bath and electroplated for 30 min ~ 60 min at a current density of 0.45 Amp / dm 2 0.65 Amp / dm 2 to obtain the activated bath. (c) electroplating cadmium-titanium: electroplating the hydrogen embrittlement rod in the activated bath to obtain a cadmium-titanium plated hydrogen embrittlement rod; The hydrogen embrittlement rod is an ultrahigh-strength steel; The electroplating bath comprises cadmium metal, NaCN, NaOH, Na2CO3, a titanium activating compound solution and water, wherein the cadmium metal concentration is 22.0 g / L-25.0 g / L, the NaCN concentration is 100.0 g / L-120.0 g / L, the NaOH concentration is 16.0 g / L-20.0 g / L, the sodium carbonate concentration is 30.0 g / L-50.0 g / L, and the titanium activating compound solution concentration is 12.0 g / L-24.0 g / L; The titanium activating compound solution is obtained by filtering a liquid containing a titanium activating compound, and the liquid containing the titanium activating compound is composed of mineral soil, a titanyl salt, NaOH, an H2O2 aqueous solution and water; wherein the mineral soil concentration is 55.0 g / L-75.0 g / L, the titanyl salt concentration is 140.0 g / L-200.0 g / L, the NaOH concentration is 8.0 g / L-12.0 g / L, and the H2O2 aqueous solution concentration is 18.0 g / L-24.0 g / L; The mineral soil is diatomite or montmorillonite, and the titanyl salt is TiOSO4 or TiOCl2; In step (c), the electroplating is performed by first electroplating for 10s~40s at a current density of 6.5 Amp / dm 2 ~10.5 Amp / dm 2 and then electroplating for 10min~16min at a current density of 2.5 Amp / dm 2 ~4.0 Amp / dm 2 .

2. The electroplating process of claim 1, wherein: The cadmium metal concentration is 22.5 g / L-24.5 g / L, the NaCN concentration is 106.0 g / L-118.0 g / L, the NaOH concentration is 17.5 g / L-19.0 g / L, the sodium carbonate concentration is 32.0 g / L-42.0 g / L, and the titanium activating compound solution concentration is 14.0 g / L-22.5 g / L.

3. The electroplating process of claim 1, wherein: The H2O2 aqueous solution is 35% H2O2; The mineral soil concentration is 65.0 g / L-74.0 g / L, the titanyl salt concentration is 155.0 g / L-195.0 g / L, the NaOH concentration is 8.5 g / L-11.0 g / L, and the H2O2 aqueous solution concentration is 20.0 g / L-23.0 g / L.

4. The electroplating process of claim 1, wherein: In step (b), the current density is 0.50 Amp / dm 2 0.60 Amp / dm 2 and the plating time is 35 min to 50 min.

5. The electroplating process of claim 1, wherein: In step (c), the electroplating is performed by first electroplating for 15s~30s at a current density of 6.8 Amp / dm 2 ~9.5 Amp / dm 2 and then electroplating for 12min~15min at a current density of 2.8 Amp / dm 2 ~3.6 Amp / dm 2 .

6. The electroplating process according to any one of claims 1 to 5, characterized in that: In step (c), the hydrogen embrittlement rod is AMS6414, AMS6415 or MIL-S-5000.

7. A cadmium-titanium plated hydrogen embrittlement rod prepared by the electroplating process according to any one of claims 1-6.

8. Use of the cadmium-titanium plated hydrogen embrittlement rod according to claim 7 in the preparation of a standard cadmium-titanium plated hydrogen embrittlement rod.

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