Functionalized hot galvanizing liquid as well as preparation method and application thereof

Abstract

The invention provides a functionalized hot galvanizing solution and a preparation method and application thereof, and relates to the field of hot galvanizing, the functionalized hot galvanizing solution comprises the following components: 1.0%-2.5% of Al, 0.05%-0.15% of Ni, 0.05%-0.3% of Bi, 0.01%-0.1% of Sb, 0.01%-0.08% of Mg, 0.001%-0.02% of rare earth oxide, 0.01%-0.1% of functionalized nanocapsules, and the balance of Zn. According to the hot galvanizing liquid provided by the invention, through alloying of Al, Ni, Bi, Sb and Mg, the problems of coating binding force, thickness control, wettability, basic corrosion resistance and the like are solved. Rare earth oxide and functionalized nanocapsules are introduced, key weak links such as the grain boundary and the phase boundary of the coating are modified and strengthened, and structure refinement and intelligent function release are achieved.

Description

Technical Field

[0001] This invention relates to the field of hot-dip galvanizing, and more specifically, to a functionalized hot-dip galvanizing solution, its preparation method, and its application. Background Technology

[0002] Hot-dip galvanizing, also known as hot-dip zinc plating, is a process in which cleaned and activated steel products are immersed in molten zinc. Through the reaction and diffusion between iron and zinc, a well-adhesive zinc alloy coating is formed on the steel surface. Hot-dip galvanizing offers advantages such as uniform coating, strong adhesion, and long service life, making it an effective means of delaying environmental corrosion of steel materials. The hot-dip galvanizing process generally includes the following steps: pickling, cleaning, fluxing, hot-dip galvanizing, cooling, and passivation.

[0003] Traditional hot-dip galvanizing solutions generally suffer from the following problems: First, lead is often added to improve fluidity, but lead is toxic, posing a barrier to the environment and product exports; second, the adhesion between the coating and the substrate is greatly affected by pretreatment and the uniformity of zinc liquid composition, resulting in insufficient stability; third, existing technologies often use complex and expensive alloy systems (such as adding rare earth elements like thulium and cobalt) or require extremely high melting temperatures (exceeding 1400℃) in pursuit of high performance, leading to high costs and difficulties in industrial production.

[0004] Chinese patent CN119980111A discloses a hot-dip galvanizing solution containing lead and various rare earth elements (thulium, cobalt, and antimony). Although it exhibits excellent bonding strength, its lead content, expensive components, and extremely high processing temperature make it difficult to promote. Chinese patent CN120366686A effectively reduces zinc consumption and viscosity by increasing the aluminum content and adding nickel and rare earth elements; however, its process relies on dynamic, high-frequency additions and online monitoring, placing stringent requirements on production process control.

[0005] While lead-free alloy systems have solved environmental issues, existing technologies still have room for improvement in certain extremely corrosive environments, situations requiring specific surface gloss levels, or applications where it is necessary to suppress the formation of extremely thick coatings. For example, the long-term corrosion resistance of the coating, its adaptability to steels with exceptionally high silicon content, and the further suppression of zinc dross during production are all ongoing goals pursued in the hot-dip galvanizing industry. Summary of the Invention

[0006] The purpose of this invention is to provide a functionalized hot-dip galvanizing solution that solves problems such as coating adhesion, thickness control, wettability, and basic corrosion resistance through alloying with Al, Ni, Bi, Sb, and Mg.

[0007] Another objective of this invention is to provide a method for preparing a functionalized hot-dip galvanizing solution, by adding intermediate alloys in stages to ensure that various alloying elements are fully and uniformly dissolved and to reduce burn-off and segregation.

[0008] The third objective of this invention is to provide an application of a functionalized hot-dip galvanizing solution, by applying an external pulsed electric field and actively intervening in the solidification process of the coating through the high-voltage pulsed electric field, thereby achieving in-situ self-healing and improving the density of the coating.

[0009] The technical problem solved by this invention is achieved by the following technical solution.

[0010] On one hand, embodiments of the present invention provide a functionalized hot-dip galvanizing solution, comprising the following components by mass fraction: Al: 1.0%-2.5%, Ni: 0.05%-0.15%, Bi: 0.05%-0.3%, Sb: 0.01%-0.1%, Mg: 0.01%-0.08%, rare earth oxides: 0.001%-0.02%, functionalized nanocapsules: 0.01%-0.1%, balance Zn.

[0011] Zn (zinc): The base element, forming the main body of the coating. Molten zinc reacts with the steel substrate to form a metallurgically bonded coating.

[0012] Al (aluminum): Effectively inhibits the formation of brittle and thick ζ-phase and δ-phase between Fe and Zn, resulting in a thinner and tougher coating. The coating surface is smoother and more aesthetically pleasing. It forms a dense Al2O3 film on the zinc bath surface, reducing zinc oxidation and burn-off. During the zinc plating process, aluminum preferentially reacts with iron to form an inhibitory layer of Fe2Al5 or FeAl3, hindering the vigorous diffusion reaction between iron and zinc.

[0013] Ni (Ni): Effectively inhibits excessive coating growth, resulting in a dull and rough finish. Ni forms an Fe-Zn-Ni composite phase at the reaction interface, altering the kinetics of the iron-zinc reaction and slowing the zinc diffusion rate. This leads to finer coating grains, improving uniformity and density.

[0014] Bismuth (Bi): Bismuth atoms accumulate at the interface, lowering the energy of the liquid-solid interface and thus improving wettability. This manifests as a reduction in the surface tension of the zinc bath, increasing the wettability of the zinc bath on the workpiece, and reducing plating defects. It also lowers the melting point, forming a eutectic with zinc, slightly reducing the operating temperature of the zinc bath and saving energy.

[0015] Sb (antimony): Antimony segregates at zinc grain boundaries, inhibiting grain growth and playing a role in grain refinement and strengthening. This makes the zinc grains in the coating smaller, and the refined grains can block corrosion channels and make the corrosion products more compact.

[0016] Mg (magnesium): Magnesium promotes the formation of a stable, dense, and low-solubility protective film, which significantly improves corrosion resistance. Its corrosion products (such as MgZn2 and basic zinc magnesium carbonate) can effectively block the intrusion of corrosive media.

[0017] Rare earth oxides: Rare earth elements have high chemical activity and can adsorb at phase boundaries and grain boundaries, altering interfacial energy. Simultaneously, the oxides they form are very stable. They preferentially accumulate at active sites such as grain boundaries and defects, inhibiting preferential corrosion in these areas. As heterogeneous nucleation sites, they promote zinc grain nucleation, refining the coating structure. They also improve thermal stability, reducing oxidation and evaporation of zinc at high temperatures.

[0018] Functionalized nanocapsules: When the coating solidifies, under the action of an applied pulsed electric field, the capsule shell ruptures, releasing a low-melting-point liquid indium-tin alloy. This alloy fills the microscopic pores and cracks in the coating, playing a self-healing role and optimizing the surface morphology. In the core indium-tin alloy, indium and tin are elements that significantly improve the coating's fluidity and corrosion resistance. At the high temperature of molten zinc, the alloy core melts, but due to the protection of the outer shell, it does not immediately fail.

[0019] The outer shell is a porous SiO2 loaded with CeO2. This porous SiO2 shell remains stable in the molten zinc, protecting the core from failure before it reaches the coating layer. Secondly, the CeO2 nanoparticles loaded on the SiO2 shell are slowly released in the molten zinc, providing continuous grain boundary passivation and grain refinement. The solid nano-SiO2 particles themselves can act as a reinforcing phase in the coating, improving its hardness and wear resistance.

[0020] In some embodiments of the present invention, the rare earth oxide is cerium oxide and / or lanthanum oxide nanoparticles with a particle size of 10-100 nm.

[0021] In some embodiments of the present invention, the functionalized nanocapsules have a core-shell structure, with the core being an indium tin alloy and the outer shell being porous nano-silica loaded with cerium oxide.

[0022] In some embodiments of the present invention, the method for preparing the functionalized nanocapsules includes the following steps: Indium tin alloy nanoparticles were dispersed in a mixed solution of ethanol and water, and a surfactant was added and ultrasonically dispersed for 30 min to obtain a suspension. Ammonia water was added dropwise while stirring, followed by an anhydrous ethanol solution of tetraethyl orthosilicate. The mixture was reacted at 35 °C for 12 hours. After centrifugation and washing, a core-shell intermediate was obtained. The core-shell intermediate was dispersed in Ce(NO3)3 ethanol solution, ultrasonically dispersed for 30 min, and stirred at low speed for 5-6 hours; centrifuged to separate the solid product, and vacuum dried at 60℃ for 6 hours; calcined under an inert atmosphere; the calcined powder was sieved to obtain the functionalized nanocapsules.

[0023] In some embodiments of the present invention, the atomic ratio of the indium-tin alloy is indium:tin = 52:48.

[0024] In some embodiments of the present invention, the concentration of the Ce(NO3)3 ethanol solution is 0.1-0.15M; the volume ratio of tetraethyl orthosilicate to anhydrous ethanol in the anhydrous ethanol solution is 1:(4-5).

[0025] In some embodiments of the present invention, the temperature is increased to 350°C at a rate of 1°C / min under a nitrogen atmosphere and held for 2 hours.

[0026] On the other hand, embodiments of the present invention provide a method for preparing a functionalized hot-dip galvanizing solution, comprising the following steps: S1: Heat the zinc pot to 450-480℃, add zinc ingots, and obtain a molten zinc base; S2: Add the preheated Zn-Al master alloy and rare earth oxides to the molten zinc base and stir until dissolved; S3: Add the preheated Zn-Ni and Zn-Sb master alloys and stir until dissolved; S4: Add Zn-Bi-Mg master alloy and stir until dissolved; stop stirring, let stand and keep warm for 20-30 minutes, and skim off the surface scum; keep warm at 440-460℃ for more than 1 hour. S5: Mix the functionalized nanocapsules with flux preheated to 150-200℃ to obtain a nanocapsule suspension; while stirring, add the nanocapsule suspension to a zinc pot. After the nanocapsules are added, continue stirring for 30-60 minutes; then stir at low speed for 1-2 hours. S6: Let stand for 30-60 minutes, skim off the surface scum, and you will get the hot-dip galvanizing solution.

[0027] Thirdly, embodiments of the present invention provide an application of a functionalized hot-dip galvanizing solution, comprising: immersing a workpiece in the hot-dip galvanizing solution for 1-3 minutes; removing the workpiece from the hot-dip galvanizing solution while simultaneously applying a high-voltage pulsed electric field to the workpiece; and then transferring the workpiece to a cooling zone to cool to room temperature.

[0028] In some embodiments of the present invention, the field strength of the high-voltage pulsed electric field is 1-5kV / cm, the pulse frequency is 50-100Hz, the workpiece lifting speed is 1-3m / min, and the processing time is 5-30s.

[0029] The method for preparing zinc plating solution provided in this embodiment of the invention The intermediate alloy is added in steps from S2 to S4. First, Zn-Al is added because its high content forms the basis for the inhibition layer. Then Ni and Sb are added. Finally, Zn-Bi-Mg is added because Mg is highly reactive and easily oxidized; adding it last minimizes its loss into the slag. This ensures that all alloying elements are fully and uniformly dissolved, reducing burn-off and segregation.

[0030] Intermediate alloys, rather than pure metals, are used because pure metals (such as Mg) have low density, high melting point, and are easily oxidized, making direct addition difficult and resulting in extremely low yields. Intermediate alloys (such as Zn-Mg) allow them to sink into molten zinc and dissolve slowly, improving yield and uniformity.

[0031] The static heat preservation and slag removal process allows the alloying reaction to proceed fully and causes oxides and impurities generated by the addition of alloys to float to the surface and form slag, which is easy to remove and ensures the purity of the zinc liquid.

[0032] When adding functionalized nanocapsules, they are first mixed with the flux. The preheated flux (a mixture of chlorides and fluorides) wets the nanocapsules and forms a protective layer when they are added to the molten zinc, preventing the nanocapsules from being bounced off by the zinc or from instantly oxidizing and agglomerating. High-speed stirring is used first to ensure that the nanocapsules are quickly dispersed throughout the zinc pot; then low-speed stirring is used to ensure that they are evenly distributed while avoiding excessive stirring that could cause the capsules to rupture prematurely or the molten zinc to oxidize excessively.

[0033] Preferably, in step S5, an inert gas carrier gas is used to directly deliver the functionalized nanocapsules deep into the zinc liquid, thereby further improving the dispersion effect and further preventing oxidation.

[0034] When using the hot-dip galvanizing solution provided in this embodiment of the invention, the workpiece is first immersed in the hot-dip galvanizing solution for 1-3 minutes to ensure that the workpiece reaches the zinc solution temperature and completes the alloying reaction between Fe-Al and Fe-Zn, forming a firmly bonded coating. During the workpiece lifting process, a high-voltage pulsed electric field is applied to the workpiece. The electric field induces nucleation, causing a large number of crystal nuclei to be generated during the solidification of the coating. The electro-migration effect can reduce interdendritic segregation and micro-shrinkage. Applying a pulsed electric field during the solidification of the coating metal will produce electro-supercooling and Joule heating effects, significantly increasing the nucleation rate. Furthermore, the electric field can affect the migration of charged atoms (ions), change the solute distribution at the solidification front, and inhibit the growth of coarse dendrites.

[0035] On the other hand, during the final stage of coating solidification, the shrinkage of zinc generates significant contraction stress on the nanocapsules encapsulated within. At this point, the capsule shell is simultaneously subjected to contraction pressure from the outside and hydrostatic pressure from the internal liquid alloy. Applying a pulsed electric field at this stage generates additional stress that causes the shell to become unstable and rupture. The released liquid metal, under capillary action, automatically flows into the micro-pores, grain boundary cracks, and interfacial gaps caused by the volume shrinkage of zinc solidification, achieving self-healing. This in-situ repair mechanism actively blocks the channels for corrosive media penetration, thereby significantly reducing the coating porosity and enhancing the barrier protection function of the coating from the source.

[0036] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects: The hot-dip galvanizing solution provided by this invention solves problems such as coating adhesion, thickness control, wettability, and basic corrosion resistance through alloying of Al, Ni, Bi, Sb, and Mg. The introduction of rare earth oxides and functionalized nanocapsules modifies and strengthens key weak points in the coating, such as grain boundaries and phase boundaries, achieving structural refinement and intelligent functional release.

[0037] During hot-dip galvanizing, an external pulsed electric field is applied to actively intervene in the solidification process of the coating through the high-voltage pulsed electric field, thereby achieving in-situ self-healing and improving the density of the coating. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0039] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to specific embodiments.

[0040] Examples 1-5 Functionalized nanocapsules were prepared using the following steps: Step 1: In 48 Sn 32 Low-melting-point alloy nanopowders were prepared by high-energy mechanical ball milling to obtain micro- and nano-scale alloy powders.

[0041] Master alloy smelting: In a vacuum arc melting furnace under argon protection, in an ingot containing 52 at.% indium and 48 at.% tin, a homogeneous In48Sn32 alloy ingot is formed. The melting process is repeated 3-4 times to ensure uniform composition.

[0042] Pre-crushing: Mechanically crushing the alloy ingot into coarse particles with a particle size of less than 1 mm.

[0043] High-energy ball milling: Coarse alloy particles are placed in a ball mill jar along with an appropriate amount of 2 wt.% anhydrous ethanol. Carbide grinding balls are used, with a ball-to-particle ratio of 10:1 to 20:1. Ball milling is performed under argon protection. To prevent cryogenic melting, the ball mill jar must be connected to a cooling system to control the temperature between 0-10℃. An intermittent ball milling mode is adopted (30 minutes of milling followed by a 15-minute rest), with a total milling time of approximately 20-50 hours. The specific time is determined by periodically sampling and measuring the particle size. The final product is a near-spherical alloy powder with a particle size distribution between 200 nm and 2 μm.

[0044] Vacuum drying: The ball-milled powder was dried at 60°C under vacuum for 4 hours to remove ethanol, yielding dried In. 48 Sn 32 Nano-alloy powder.

[0045] 100 mg In 48 Sn32 nano-alloy powder was dispersed in a mixed solution of 200 mL anhydrous ethanol and 50 mL deionized water, and 500 mg of surfactant CTAB was added. The mixture was sonicated for 30 minutes using an ultrasonic cell disruptor to form a homogeneous suspension. The suspension was transferred to a three-necked flask, and 10 mL of ammonia (catalyst) was slowly added dropwise under magnetic stirring. Subsequently, 20 mL of anhydrous ethanol solution of tetraethyl orthosilicate (TEOS) (volume ratio 1:4) was added dropwise at a very slow rate (approximately 1 drop / second) using a constant-pressure dropping funnel. The reaction was carried out with gentle stirring at 35 °C for 12 hours. CTAB acted not only as a dispersant but also as a mesoporous template, guiding the formation of a porous structure from SiO2. After the reaction, the solid product was separated by high-speed centrifugation and washed three times alternately with ethanol and deionized water to obtain In. 48 Sn 32 @CTAB / SiO2 core-shell intermediate.

[0046] CeO2 loading and curing: The above core-shell intermediate was redispersed in 100 mL of 0.1 M Ce(NO3)3 ethanol solution. The mixture was sonicated for 30 minutes, followed by low-speed stirring for 6 hours to allow CeO2 loading and curing to proceed. 3+ Ions are fully adsorbed and impregnated into the mesopores of the SiO2 shell through capillary action. The product is then centrifuged again and the solid product is collected. The product is then vacuum dried at 60°C for 6 hours.

[0047] Template Removal and Crystallization (Calcination): The dried powder is placed in a muffle furnace and calcined under a programmed temperature rise in air. Temperature program: Increase to 350°C at 1°C / min and hold for 2 hours. The CTAB template is slowly and thoroughly removed, leaving uniform mesopores in the SiO2 shell. The impregnated Ce(NO3)3 is decomposed and oxidized to generate nano-CeO2 particles, which are firmly anchored on the SiO2 framework.

[0048] Screening: The calcined powder is sieved to select nanocapsules with the target particle size range (e.g., 500 nm - 2 μm).

[0049] The amounts of each raw material used in the functionalized nanocapsules of Examples 1-5 are shown in Table 1.

[0050] Table 1

[0051] Examples 6-10 The hot-dip galvanizing solution was prepared using the following steps: S1 Smelting Base: Industrial zinc ingots are added to a zinc pot and heated to 460°C until they are completely melted.

[0052] S2 Add Al and rare earth: Add Zn-5Al master alloy preheated to 150℃ and nano CeO2 powder (particle size ~50nm), and mechanically stir (300 rpm) for 30 minutes.

[0053] S3 Adding Ni and Sb: Add preheated Zn-2Ni and Zn-4Sb master alloys and stir until completely dissolved.

[0054] S4 Add Bi and Mg: Finally, add the preheated Zn-4Bi-1Mg master alloy, stir to dissolve, then stop stirring and let stand for 25 minutes to thoroughly remove surface scum. Hold at 455℃ for 1.5 hours.

[0055] S5 Nanocapsule Addition: Mix the specified amount of functionalized nanocapsules with ZnCl2·NH4Cl composite flux (3:1) preheated to 180℃ to form a slurry, and add it to the zinc pot while stirring. After the addition is complete, continue stirring for 40 minutes, then switch to low-speed stirring (80 rpm) for 1.5 hours.

[0056] S6 final treatment: Let stand for 40 minutes, remove the scum, and obtain the hot-dip galvanizing liquid ready for use.

[0057] The proportions of each component in the hot-dip galvanizing solution of Examples 6-10 are shown in Table 2; Table 2

[0058] In the hot-dip galvanizing solutions of Examples 6-10, the functionalized nanocapsules prepared in Example 2 were used. Based on the hot-dip galvanizing solutions prepared in Examples 6-10, hot-dip galvanizing treatment was carried out according to the following steps.

[0059] A standard Q235 steel plate (100mm×50mm×2mm) was pickled, washed, and fluxed before being immersed in hot zinc liquid for 2 minutes. It was then lifted at a speed of 2m / min, and a high-voltage pulsed electric field of 3kV / cm and 80Hz was applied simultaneously as the workpiece was removed from the zinc liquid surface. This treatment lasted for 15 seconds, followed by air cooling to room temperature. Comparative Example 1: Based on Example 10, without the addition of functionalized nanocapsules. Comparative Example 2: Based on Example 10, without the addition of rare earth oxides. Comparative Example 3: Based on Example 10, without the application of a high-voltage pulsed electric field. The remaining components and processes of Comparative Examples 1, 2, and 3 were completely identical to those of Example 10. The zinc plating process of Comparative Examples 1-2 was the same as that of Example 10, while the zinc plating process of Comparative Example 3 did not apply an electric field; all other aspects were the same as in Example 10.

[0060] The performance of the zinc-plated samples prepared in all the above embodiments and comparative examples was tested, and the results are shown in Table 3.

[0061] Table 3

[0062] As can be seen from Table 3, the hot-dip galvanizing solutions provided in Examples 6-10 combine appropriate alloy composition, sufficient functional additives, and optimized electric field processes, achieving an optimal balance in corrosion resistance (1680h), coating uniformity (3.8μm standard deviation), adhesion (5B), and surface quality. Their microstructure is extremely dense and fine, perfectly embodying the design objectives.

[0063] Comparative Example 1 (without nanocapsules): Corrosion resistance decreased by approximately 37%, indicating that the self-healing and synergistic enhancement effects of nanocapsules are crucial for long-term corrosion protection. Microscopic defects also confirm their function of filling gaps.

[0064] Comparative Example 2 (without rare earth oxides): This showed the worst corrosion resistance, a dull surface, and coarse grains. This demonstrates the fundamental role of rare earth oxides in refining grains and inhibiting grain boundary corrosion, making them indispensable microstructure modulators.

[0065] Comparative Example 3 (without high-voltage electric field): The coating is the thickest and has the worst uniformity, exhibiting runs and nodules, with a microstructure of coarse dendrites. This highlights the decisive role of the high-voltage pulsed electric field in refining the solidification structure and improving coating uniformity and surface morphology. Without an electric field, even with the correct composition, it is impossible to obtain the optimal structure.

[0066] In summary, rare earth oxides, functionalized nanocapsules, and high-voltage pulsed electric fields work synergistically to improve the mechanical properties of the coating.

[0067] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A functionalized hot dip galvanizing bath, characterized in that, By mass fraction, comprising the following components: Al: 1.0%-2.5%, Ni: 0.05%-0.15%, Bi: 0.05%-0.3%, Sb: 0.01%-0.1%, Mg: 0.01%-0.08%, rare earth oxide 0.001%-0.02%, functionalized nanocapsule 0.01%-0.1%, the balance is Zn. The rare earth oxide is a nano-powder of cerium oxide and / or lanthanum oxide, with a particle size of 10-100 nm.

2. The functionalized hot dip galvanizing bath according to claim 1, characterized in that, The functionalized nanocapsule is of core-shell structure, with indium-tin alloy as the core and porous nanosilica loaded with cerium oxide as the shell.

3. The functionalized hot dip galvanizing fluid of claim 1, wherein, The preparation method of the functionalized nanocapsule comprises the following steps:

4. The functionalized hot dip galvanizing bath according to claim 3, wherein, Disperse indium-tin alloy nano-powder in a mixed solution of ethanol and water, add a surfactant and ultrasonically disperse for 30 min to obtain a suspension; under stirring, dropwise add ammonia water and then dropwise add anhydrous ethanol solution of tetraethyl orthosilicate, and react at 35℃ for 12 hours; centrifugally separate and wash to obtain a core-shell intermediate; Disperse the core-shell intermediate in Ce(NO3)3 ethanol solution, ultrasonically disperse for 30 min, and stir at low speed for 5-6 hours; centrifugally separate, collect the solid product, and vacuum dry at 60℃ for 6 hours; calcine under inert atmosphere; sieve the calcined powder to obtain the functionalized nanocapsule. The atomic ratio of the indium-tin alloy is indium:tin=52:

48.

5. The functionalized hot dip galvanizing bath of claim 4, wherein, The concentration of the Ce(NO3)3 ethanol solution is 0.1-0.15M; 6. The functionalized hot dip galvanizing fluid of claim 4, wherein, In the dropwise addition of the anhydrous ethanol solution of tetraethyl orthosilicate, the volume ratio of tetraethyl orthosilicate to anhydrous ethanol is 1: (4-5). The calcining comprises: under nitrogen atmosphere, heat to 350℃ at 1℃ / min, and keep for 2 hours.

7. The functionalized hot dip galvannealing bath according to claim 4, wherein, Comprise the following steps:

8. A process for the preparation of a functionalized hot dip galvanizing bath according to any one of claims 1 to 7, characterized in that, S1: heat a zinc pot to 450-480℃, add zinc ingot to obtain a molten zinc liquid base; S2: add preheated Zn-Al intermediate alloy and rare earth oxide to the molten zinc liquid base, and stir until dissolved; S3: further add preheated Zn-Ni, Zn-Sb intermediate alloy, and stir until dissolved; S4: further add Zn-Bi-Mg intermediate alloy, and stir until dissolved; stop stirring, keep for 20-30 min, and fish the surface dross; keep at 440-460℃ for more than 1h; S5: mix the functionalized nanocapsule with a flux preheated to 150-200℃ to obtain a nanocapsule suspension; under stirring, add the nanocapsule suspension to the zinc pot, continue stirring for 30-60 min after the addition of the nanocapsule is completed, and then stir at low speed for 1-2h; S6: keep for 30-60 min, fish the surface dross, and obtain the hot-dip galvanizing liquid. Comprise, 9. Use of a functionalized hot dip galvanizing bath according to any one of claims 1 to 7, characterized in that, Submerge the workpiece into the hot-dip galvanizing liquid, and immerse for 1-3 min; Take out the workpiece from the hot-dip galvanizing liquid, and at the same time, apply a high-voltage pulsed electric field to the workpiece; Subsequently, transfer the workpiece to a cooling zone, and cool to room temperature. The high-voltage pulsed electric field has a field strength of 1-5kV / cm, a pulse frequency of 50-100Hz, a workpiece lifting rate of 1-3m / min, and a treatment time of 5-30s.

10. Use of a functionalized hot galvanizing bath according to claim 9, characterized in that, ​