Corrosion-resistant process for structural component of low-altitude aircraft

Abstract

According to the low-altitude aircraft structural part corrosion-resistant technology, nanometer is applied to electroplating, compared with a traditional electroplating coating, a nanometer porous material with titanium and silicon elements as main elements serves as an electroplating catalyst, and by means of the catalytic performance of the nanometer porous material and gaps formed among all atoms, the corrosion resistance of the low-altitude aircraft structural part is improved, and the corrosion resistance of the low-altitude aircraft structural part is improved. And ions needing to be electroplated are adsorbed on the electroplated metal surface layer, so that the metal ions are embedded in gaps of the nano-porous catalyst to form a uniform coating with good compactness. And an electroplated coating is better in corrosion resistance, and the service life of the zinc-nickel alloy is longer.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of metal surface treatment, in particular to a preparation method of a low-altitude aircraft structural member surface nano coating. BACKGROUND

[0002] Traditional electroplating is a surface treatment technology that uses the principle of electrolysis to deposit a layer of metal or alloy coating on the surface of a conductive substrate (such as metal or specially treated plastic). Its history can be traced back to the early 19th century, when an Italian scientist conducted a gold plating experiment using an electric pile (Volta cell) in 1805. With the invention of a direct current generator, electroplating technology began to be industrialized in the mid-19th century. Its core principle is electrochemical deposition: the workpiece to be plated (cathode) and the metal to be plated (anode) are immersed in an electrolyte containing metal ions to be plated, and a direct current is passed through. The anode metal dissolves to replenish the metal ions in the electrolyte, and these ions are reduced to metal atoms on the surface of the cathode workpiece, forming a coating. The coating obtained by traditional electroplating is usually a micron-sized grain structure. The grain size is relatively large (usually > 1 μm), there are many defects (such as dislocations and grain boundaries), and the structure is relatively loose, which may have pores. The micron-sized structure of traditional electroplating will result in a "ceiling" for the hardness, wear resistance, and corrosion resistance of the coating, and when the coating is thick, internal stress may cause peeling and cracking. SUMMARY

[0003] To solve the above problems, the present application provides a technical solution: a preparation method of a low-altitude aircraft structural member surface nano coating, characterized by the following process flow: oil removal → water washing → acid pickling → water washing → acid pickling → water washing → activation → electroplating → water washing.

[0004] (1) The zinc-nickel alloy plating solution formula is: sodium hydroxide 100 g / L, zinc oxide 10 g / L, nickel sulfate hexahydrate 12 g / L, tetraethylenepentamine 13 g / L, and brightener 4 ml / L.

[0005] (2) Temperature 23-27 ℃, plating solution pH: 12, cathode current density 3 A / dm 2 , electroplating time 10 minutes According to the low-altitude aircraft structural member corrosion-resistant process of claim 1, characterized in that: (1) The nano additive is: titanium-silicon molecular sieve (titanium-silicon ratio 50-60): polyethylene glycol: cetyltrimethylammonium bromide = 6:2:1; the total amount of nano additive is 2.55 g.

[0006] (2) The preparation process is as follows: a. Weigh an appropriate amount of nano additive into beaker 1, add appropriate deionized water, and magnetically stir to mix the solution thoroughly; b. The selected dispersant polyethylene glycol and cetyltrimethylammonium bromide capable of dispersing nanoparticles are weighed and added to beaker 1, and fully stirred until the solution is fully mixed; c. The stirred solution is ultrasonically stirred for 1 h.

[0007] Preferably, a nickel sheet is used as the anode during electroplating.

[0008] Preferably, the brightener is DPE-III alkaline zinc plating brightener.

[0009] Compared with the conventional electroplating coating, the present application uses titanium-silicon element-based nanoporous material as an electroplating catalyst, utilizes the catalytic performance of the nanoporous material and the interspace formed among the atoms to adsorb the ions requiring electroplating on the surface layer of the metal to be electroplated, and embeds the metal ions in the interspace of the nanoporous catalyst to form a uniform coating with good compactness. The electroplating coating has better corrosion resistance, and the service life of the zinc-nickel alloy is longer. - Among the numerous complexing agents, the tetraethylenepentamine molecules can be selectively adsorbed on the microconvex or high-peak surface of the plated part. The current density of these areas is usually higher, and the deposition speed is faster. The adsorption of the tetraethylenepentamine inhibits the reduction deposition of the metal ions in the area, and forces the metal to be more deposited in the microconcave or low-lying area, so the leveling ability of the tetraethylenepentamine is the most outstanding. In the present application, the metal ions are adsorbed in the pores of the nanomaterial to fill and level the coating, so it is very reasonable and necessary to use tetraethylenepentamine as a complexing agent. The use of tetraethylenepentamine as a complexing agent in the basic plating solution helps to control the growth of the crystal grains, so that a finer grain structure is obtained, the flatness of the coating is improved, and the grain refinement can make the coating more compact, reduce the pores and defects, and thus improve the corrosion resistance and wear resistance of the coating.

[0010] According to the experiment, the corrosion resistance of the coating is best when the content of the nanocatalyst is 1.75 g.

[0011] The present application uses nanoscale titanium-silicon molecular sieve as an additive in the electroplating process, and under specific electroplating process conditions, the nanoparticles are adsorbed on the surface of the coating; with the help of the pore structure constructed by titanium-silicon atoms, the nickel ions are guided to occur electrodeposition in the pore system through the adsorption of the nanoparticles. The technical scheme aims to optimize the surface flatness of the coating and simultaneously improve the comprehensive use performance of the coating.

[0012] A kind of nano nickel plating liquid is disclosed in patent CN114808050A.Compared with the prior art, the present application significantly reduces the amount of complexing agent by utilizing the pores formed by titanium-silicon ions, which exhibits more excellent technical effects: not only realizes the efficient and stable adsorption of nickel ions, but also can deposit a nano nickel coating on the surface of the workpiece, which has significantly better density, structural stability and corrosion resistance than traditional coatings.

[0013] Compared with the prior art, the present application has the following significant technical advantages: on the one hand, the selective adsorption of metal ions by nanopores can regulate the crystal morphology of the coating to develop in a more fine direction, thereby improving the corrosion resistance of the coating; on the other hand, by introducing a nano catalyst into the plating solution system, the chemical stability of metal ions in the electrolyte can be effectively improved, and the electrochemical performance of the electroplating solution (such as conductivity and uniformity) can be optimized, thereby significantly improving the overall quality of the coating - specifically, the corrosion resistance and microhardness of the coating are simultaneously improved, the porosity is effectively reduced, and the adhesion and protection performance between the coating and the substrate are enhanced. DETAILED DESCRIPTION

[0014] The embodiments of the present application are described below through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the disclosure. The present application can also be implemented or applied in different specific embodiments, and various modifications or changes can be made to the details in this specification without departing from the spirit of the present application.

[0015] The present application provides a technical solution: a method for preparing a nano coating on the surface of a low-altitude aircraft structural member, characterized by the following process flow: oil removal → water washing → acid pickling → water washing → acid pickling → water washing → activation → electroplating → water washing.

[0016] (1) The zinc-nickel alloy plating solution formulation is: sodium hydroxide 100 g / L, zinc oxide 10 g / L, nickel sulfate hexahydrate 12 g / L, tetraethylenepentamine 13 g / L, brightener 4 ml / L.

[0017] (2) Temperature 23-27 ℃, plating solution pH: 12, cathode current density 3 A / dm 2 , electroplating time 10 minutes According to the corrosion-resistant process for a low-altitude aircraft structural member according to claim 1, characterized by: (1) The nano additive is: titanium-silicon molecular sieve (titanium-silicon ratio 50-60): polyethylene glycol: cetyltrimethylammonium bromide = 6:2:1; the total amount of nano additive is 2.55 g.

[0018] (2) The preparation process is as follows: a. Weigh an appropriate amount of nano additives into beaker 1, add appropriate deionized water and stir with a magnetic stirrer to fully mix the solution; b. Select the required dispersant capable of dispersing nanoparticles, polyethylene glycol and cetyltrimethylammonium bromide, weigh and add to beaker 1, stir until the solution is fully mixed; c. Stir the solution after stirring for 1 h. Example

[0019] a. Weigh 10 g of zinc oxide and 100 g of sodium hydroxide into beaker 1, stir with a glass rod until fully mixed, then add 50 ml of ionized water and stir until fully dissolved; b. Weigh 6 g of nickel sulfate hexahydrate into beaker 2, add 50 ml of ionized water and stir until fully dissolved; c. Select the molar mass ratio of nickel sulfate hexahydrate and tetraethylenepentamine, calculate the mass of tetraethylenepentamine according to the ratio, add 13 g of tetraethylenepentamine to beaker 2, and stir with a magnetic stirrer until the solution is clear; d. Slowly add the solution in beaker 1 to beaker 2, the mixed solution should be clear; e. Add 2 ml of primary brightener and 2 ml of secondary brightener to beaker 2, stir with a magnetic stirrer until the solution is fully mixed; f. Select the required dispersant capable of dispersing nanoparticles, 0.58 g of polyethylene glycol and 0.29 g of cetyltrimethylammonium bromide, weigh and add to beaker 3, add 50 ml of ionized water and stir until fully mixed; g. Weigh 1.75 g of nano additives, add to beaker 3 and stir with a magnetic stirrer until the solution is fully mixed; h. Slowly add the solution in beaker 3 to beaker 2, and then add deionized water to a final volume of 250 ml, and stir with a magnetic stirrer for 3 h; i. Stir the solution after stirring for 1 h. j. Take Q235 steel plate as the cathode plate, and perform pretreatment according to the steps of base oil removal → water washing → acid pickling → water washing → acid pickling → water washing → activation; k. Electroplating time 10 minutes, turn on the power, use 3 A / dm 2 Electroplating.

[0020] a. Weigh 10 g of zinc oxide and 100 g of sodium hydroxide into beaker 1, stir with a glass rod until fully mixed, then add 50 ml of ionized water and stir until fully dissolved; b. Weigh 6 g of nickel sulfate hexahydrate into beaker 2, add 50 ml of ionized water and stir until fully dissolved; c. Select the molar mass ratio of nickel sulfate hexahydrate and tetraethylenepentamine, calculate the mass of tetraethylenepentamine according to the ratio, and add 13 g of tetraethylenepentamine to beaker 2, and perform magnetic stirring until the solution is clear; d. Slowly add the solution in beaker 1 to beaker 2, and the mixed solution should be clear; e. Add 2 ml of primary brightener and 2 ml of secondary brightener to beaker 2, and perform magnetic stirring to fully mix the solution; f. Select the required dispersant capable of dispersing nanoparticles, 0.5 g of polyethylene glycol and 0.25 g of cetyltrimethylammonium bromide, weigh and add to beaker 3, add 50 ml of ionized water, and fully stir until fully mixed; g. Weigh 1.5 g of nano additive, add to beaker 3, and perform magnetic stirring to fully mix the solution; h. Slowly add the solution in beaker 3 to beaker 2, and perform magnetic stirring for 3 h after being diluted to 250 ml; i. Perform ultrasonic stirring on the stirred solution for 1 h; j. Take a Q235 steel plate as the cathode plate, and perform pretreatment according to the steps of base oil removal→water washing→acid pickling→water washing→acid pickling→water washing→activation; k. Electroplating time is 10 minutes, turn on the power, and use 3 A / dm 2 for electroplating.

[0021] a. Weigh 10 g of zinc oxide and 100 g of sodium hydroxide, and place them in beaker 1, fully mix with a glass rod, add 50 ml of ionized water, and stir to fully dissolve; b. Weigh 6 g of nickel sulfate hexahydrate, and place it in beaker 2, add 50 ml of ionized water, and stir to fully dissolve; c. Select the molar mass ratio of nickel sulfate hexahydrate and complexing agent, calculate the mass of tetraethylenepentamine according to the ratio, and add 13 g of tetraethylenepentamine to beaker 2, and perform magnetic stirring until the solution is clear; d. Slowly add the solution in beaker 1 to beaker 2, and the mixed solution should be clear; e. Add 2 ml of primary brightener and 2 ml of secondary brightener to beaker 2, and perform magnetic stirring to fully mix the solution; f. Select the required dispersant capable of dispersing nanoparticles, 0.67 g of polyethylene glycol and 0.33 g of cetyltrimethylammonium bromide, weigh and add to beaker 3, add 50 ml of ionized water, and fully stir until fully mixed; g. Weigh 2 g of nano additive, add to beaker 3, and perform magnetic stirring to fully mix the solution; h. The solution in beaker 3 is slowly added to beaker 2, and after constant volume to 250 ml, magnetic stirring is carried out for 3 h; i. The stirred solution is ultrasonically stirred for 1 h; j. The Q235 steel plate is taken as the cathode plate, and the pretreatment is carried out according to the steps of base oil removal→water washing→acid pickling rust removal→water washing→acid pickling rust removal→water washing→activation; k. The plating time is 10 minutes, the power is turned on, and 3 A / dm 2 plating is carried out.

[0022] Results comparison: The electrochemical test results show that, by optimizing the plating solution composition system in Example 1, a passivation film with higher density and stronger interfacial adhesion is successfully formed on the surface of the workpiece. This passivation film can effectively block the penetration path of corrosive media (such as ions), thereby inhibiting the occurrence of anodic dissolution reaction; at the same time, its preparation process significantly reduces the micro defects such as surface micro cracks and pores—such defects as “active sites” in the self-corrosion process, the reduction of their number directly cuts off the conduction channel of the corrosion current. In addition, the charge transfer resistance at the electrode-electrolyte interface is significantly improved, which weakens the electron transfer efficiency of the self-corrosion reaction, effectively inhibiting the corrosion process from the kinetic level. The hardness test data show that the microhardness value of Example 1 is significantly higher than that of Comparative Example 1 and Comparative Example 2, and this difference is closely related to its dense microstructure. This high hardness characteristic endows the coating with excellent anti-friction and anti-wear ability, especially suitable for engineering application scenarios such as low-altitude aircraft structural parts which have precise structure and high wear intensity in service environment.

Claims

1. A corrosion resistant process for low altitude aircraft structures, characterized by: The nano-additive is titanium-silicon molecular sieve with titanium-silicon ratio of 50-60, polyethylene glycol, and cetyl trimethyl ammonium bromide = 6:2:1; the total amount of the nano-additive is 2.55 g; the zinc-nickel alloy plating solution formula is: sodium hydroxide 100 g / L, zinc oxide 10 g / L, nickel sulfate hexahydrate 12 g / L, tetraethylenepentamine 13 g / L, and brightener 4 ml / L; the process flow is as follows: oil removal→water washing→acid pickling→water washing→acid pickling→water washing→activation→electroplating→water washing; the temperature is 23-27 ℃, the plating solution pH is 12, the electroplating time is 10 minutes, and the cathode current density is 3 A / dm 2 .