KR102388789B1 - Anti-plating agent and selective hot-dip plating method using the same - Google Patents

Abstract

The present invention relates to a plating inhibitor and a selective hot-dip plating method using the same for preventing metal from being selectively plated, such as a part that requires welding on a body to be plated during hot-dip plating. The selective hot-dip plating method according to the present invention comprises the steps of preparing an anti-plating agent containing iron oxide, coating the anti-plating agent on a body to be plated, plating the body coated with the anti-plating agent, and plated body. Including the step of removing the plating inhibitor.

Description

Anti-plating agent and selective hot-dip plating method using the same

The present invention relates to a plating inhibitor, and more particularly, to a plating inhibitor and a selective hot-dip plating method using the same for selectively preventing metal from being selectively plated, such as a portion requiring welding on a body to be plated during hot-dip plating.

Hot-dip galvanizing technology is representative of hot-dip galvanizing, and by plating zinc (Zn) on steel, it has a barrier effect through shielding from the corrosive environment and corrosion resistance through a sacrificial method with a lower corrosion potential than the object to be plated. Its main purpose is to improve.

In addition, the plating material used for hot-dip galvanizing may improve plating adhesion by reacting the body to be plated with zinc to form an intermetallic compound between the body to be plated and zinc. The intermetallic compound formed at this time is a Fe-Zn alloy phase from iron (Fe) to Γ-Zn ₁₀ Fe ₃ /Zn ₄₀ Fe _ll , δ-Zn ₉ Fe. It is composed of ζ-Zn ₁₃ Fe and η-Zn in order and is used for automobiles, ships, home appliances and construction materials.

In particular, welding is essential for fastening between steel plates in ship manufacturing, construction, and automobile manufacturing processes in which hot-dip galvanizing is mainly used. However, if zinc is plated during welding, fumes harmful to the human body may be generated, which may harm the health of field workers, and poor welding occurs due to the low boiling point of zinc.

Because of this problem, plated zinc is peeled off with a grinder and used, but the process of peeling off plated zinc with a grinder is inefficient because it takes a lot of time, money and labor, and it is applied to products with complicated shapes such as bolts and tubes. hard to do

In order to solve this problem, Korean Patent No. 10-0956026 discloses a laser welding method of a galvanized steel sheet. In the disclosed welding method, the galvanized by-product remains in the galvanized steel sheet by burning the galvanized layer in the weld zone with a laser and peeling it off. At this time, there was a problem that the by-product removal process must be additionally performed because the loose by-products affect weldability.

Therefore, in industrial sites currently performing hot dip plating, an intermediate layer is placed between the body to be plated and zinc to suppress the above-mentioned intermetallic compound, and as a temporary measure to separate the body and zinc from the body to be plated, masking using primer paint or tape on the welded area (Masking) method is mainly implemented. However, they all have a low melting point and cause a reaction in a galvanizing bath at a high temperature (about 430 ~ 470 °C), leaving by-products on the surface of the object to be plated, which is inconvenient to perform an additional process using a grinder.

In order to solve this problem, Korean Patent Registration No. 10-1988631 discloses a method for manufacturing a hot-dip galvanizing partial inhibitor for selectively performing plating. The disclosed anti-partial agent consists of a polycarbonate-based urethane binder and a polytetrafluoroethylene and Molybdenum Disulphide-based compound as a release agent. However, the disclosed compound is economically disadvantageous to commercialize using expensive raw materials, and there is a problem in that plating prevention efficiency is lowered in the case of a complex structure.

In addition, U.S. Patent No. 4,421,793 proposes a method in which calcium carbonate is applied alone or mixed with chloride before being immersed in a molten zinc bath. However, the disclosed compound has a problem in that unnecessary residues exist on the object to be plated because a technology for separating the body to be plated and calcium carbonate is not presented.

Accordingly, it is an object of the present invention to provide a plating inhibitor and a selective hot-dip plating method using the same for preventing metal from being selectively plated, such as a portion requiring welding on a body to be plated during hot-dip plating.

In particular, an object of the present invention is to provide an anti-plating agent that is inexpensive, has a simplification of a process, has a high anti-plating effect, and is easy to remove.

The selective hot-dip plating method using the anti-plating agent according to the present invention comprises the steps of preparing a plating inhibitor including iron oxide and a solvent, coating the anti-plating agent on a body to be plated, and plating the body coated with the anti-plating agent. and removing the plating inhibitor from the plated object to be plated.

In the selective hot-dip plating method using the plating inhibitor according to the present invention, the manufacturing step is characterized in that the preparation of the plating inhibitor comprising the iron oxide, aluminum oxide, silicon oxide and a solvent.

In the selective hot-dip plating method using the anti-plating agent according to the present invention, in the step of preparing the anti-plating agent, the anti-plating agent comprises 2 to 50 wt % of the iron oxide, 20 to 70 wt % of the aluminum oxide, and the remainder of silicon oxide and a solvent. characterized by including.

In the selective hot-dip plating method using the anti-plating agent according to the present invention, in the step of preparing the anti-plating agent, the ratio of the mixture containing the iron oxide, the aluminum oxide and the silicon oxide to the solvent is 1 < mixture (g )/solvent (ml) < 2.5.

In the selective hot-dip plating method using the plating inhibitor according to the present invention, the coating step is characterized in that the plating inhibitor is selectively coated with the plating inhibitor by immersing or coating the object to be plated in the plating inhibitor.

In the selective hot-dip plating method using the plating inhibitor according to the present invention, the plating step is characterized in that the plating is performed by immersing the object to be plated selectively coated with the plating inhibitor in the molten metal at 300 to 650°C.

In the selective hot-dip plating method using the plating inhibitor according to the present invention, the molten metal is characterized in that it comprises zinc (Zn), aluminum (Al) or magnesium (Mg).

In the selective hot-dip plating method using the anti-plating agent according to the present invention, the step of removing the anti-plating agent comprises: removing the portion coated with the anti-plating agent from the plated body to be plated; It characterized in that it comprises the step of washing the plating body.

In the selective hot-dip plating method using the plating inhibitor according to the present invention, the removing step is characterized in that the portion coated with the anti-plating agent is removed by applying an external impact to the plated object to be plated or by scraping it. .

The anti-plating agent according to the present invention is characterized in that it contains iron oxide.

In the plating inhibitor according to the present invention, it is characterized in that it contains iron oxide, aluminum oxide, silicon oxide and a solvent.

In the anti-plating agent according to the present invention, the composition ratio of the anti-plating agent is 2 to 50 wt % of the iron oxide, 20 to 70 wt % of the aluminum oxide, and the remainder of the silicon oxide.

In the anti-plating agent according to the present invention, the ratio of the mixture containing the iron oxide, the aluminum oxide, and the silicon oxide to the solvent is 1 < mixture (g)/solvent (ml) < 2.5.

In the anti-plating agent according to the present invention, it is characterized in that it further comprises at least one of magnesium oxide, potassium oxide, titanium oxide, and copper oxide.

The anti-plating agent according to the present invention prevents metal from being selectively plated on a body to be plated, such as a part requiring welding, during hot-dip plating, while being low-cost, simplifies the process, has a high anti-plating effect, and is easy to remove.

1 is a flowchart illustrating a selective plating method using a plating inhibitor according to the present invention.
FIG. 2 is a flowchart illustrating in detail the removing step of FIG. 1 .
3 is a table showing characteristics according to the composition of the anti-plating agent according to Examples and Comparative Examples of the present invention.
4 to 6 are views showing the performance of the plating inhibitor according to the embodiment of the present invention.
7 is a graph showing the results of surface component analysis (GDS) after removing the plating inhibitor of FIG. 6 .

It should be noted that, in the following description, only the parts necessary for understanding the embodiments of the present invention will be described, and descriptions of other parts will be omitted in the scope not disturbing the gist of the present invention.

The terms or words used in the present specification and claims described below should not be construed as being limited to their ordinary or dictionary meanings, and the inventors have appropriate concepts of terms to describe their invention in the best way. It should be interpreted as meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined in Accordingly, the embodiments described in this specification and the configurations shown in the drawings are only preferred embodiments of the present invention, and do not represent all of the technical spirit of the present invention, so various equivalents that can be substituted for them at the time of the present application It should be understood that there may be variations and variations.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

First, the anti-plating agent according to the present invention includes iron oxide (Fe Oxide). Preferably, the anti-plating agent according to the present invention may be prepared by mixing iron oxide, aluminum oxide (Al Oxide), silicon oxide (Si Oxide) and a solvent.

Hereinafter, the selective plating method using the plating inhibitor according to the present invention will be described in detail.

1 is a flowchart illustrating a selective plating method using a plating inhibitor according to the present invention, and FIG. 2 is a flowchart illustrating the removing step of FIG. 1 in detail.

1 to 2, first, in step S10, a solvent is added to a mixture including aluminum oxide, iron oxide, and silicon oxide to prepare an anti-plating agent.

At this time, 2 to 50 wt% of iron oxide, 20 to 70 wt% of aluminum oxide, and the remainder of silicon oxide may be mixed to prepare a mixture. Here, in addition to iron oxide, aluminum oxide, and silicon oxide, trace elements such as magnesium oxide, potassium oxide, titanium oxide, copper oxide, and the like may be included in an amount of 0 to 2 wt%.

Here, when the aluminum oxide content is lower than 20 wt%, the oxide layer on the surface of the object to be plated is not sufficiently formed, so the molten zinc and iron form an alloy phase through an interfacial reaction, and zinc is plated on the part requiring an anti-plating agent. can be generated, and accordingly, a problem of causing harmful gases (fumes) during welding occurs. In addition, when the aluminum oxide exceeds 70 wt%, the concentration of the anti-plating agent is increased, and the plating-preventing efficiency is good, but there is a problem of separation in terms of cost.

In addition, when the content of iron oxide is lower than 2 wt%, the oxide is not formed on the surface of the object to be plated and falls off, so that it cannot serve as a plating inhibitor. When the content of iron oxide exceeds 50 wt %, silicon oxide and aluminum oxide are locally dispersed on the object to be plated, so that the object to be plated cannot be uniformly coated.

In addition, the preparation ratio of the mixture and the solvent may be 1 < mixture (g)/solvent (ml) < 2.5, and the anti-plating agent may be prepared by mixing the mixture and the solvent and then stirring. For example, a polar solvent including water may be applied as the solvent.

Meanwhile, among the components of the anti-plating agent, stable silicon oxide and aluminum oxide are compounds that interfere with the reaction between the object to be plated and zinc, and the molten zinc cannot directly contact the object to be plated, and the interfacial reaction is suppressed to form an alloy phase. , and there is no reaction with the anti-plating agent surface, so that zinc is separated from the body to be plated.

In addition, among the components of the anti-plating agent, iron oxide plays a role in controlling the viscosity of the anti-plating agent, helping the mixing of silicon oxide and aluminum oxide, and adhering the anti-plating agent together with the solvent to the surface of the object to be plated.

Next, in step S20, a plating inhibitor is coated on the object to be plated. That is, in step S20, before performing hot-dip plating, a plating inhibitor is coated on a portion where plating is unnecessary.

For example, in step S20, coating may be performed by dipping the object to be plated in a plating inhibitor bath, or coating may be performed by applying an anti-plating agent to the surface of the object to be plated. and the content of silicon oxide may be determined. That is, the concentration of the plating inhibitor can be determined.

After that, the plated body coated with the anti-plating agent is dried. At this time, the drying temperature is not limited to 100 ~ 140 ℃, which is a drying temperature at which the solvent evaporates, and may vary depending on the type of the solvent.

Next, in step S30, the plated body coated with the anti-plating agent may be plated. That is, the plating is performed by immersing the object to be plated with the anti-plating agent in the molten metal. Meanwhile, in the following description, although hot-dip plating using zinc is described, the present invention is not limited thereto, and various plating methods such as aluminum (Al) and magnesium (Mg) may be applied.

At this time, when plating is performed by immersing the object to be plated in the hot-dip metal plating bath, the hot-dip plating bath temperature is determined according to the temperature of the metal to be plated. For example, it can be applied variously from 430 to 480°C, which is the hot-dip galvanizing temperature, to 650°C, which is the hot-dip aluminum plating temperature.

And in step S40, the plating inhibitor is removed from the plated object.

Here, step S40 includes, as shown in FIG. 2 , removing the portion coated with the anti-plating agent from the plated body to be plated (S41) and washing the body from which the anti-plating agent has been removed (S42). .

In step S41, the plating inhibitor formed on the surface of the object to be plated may be removed by applying a physical chuck shock or scraping it using a scraper or the like.

In step S42, a part of the plating inhibitor remaining on the object to be plated is completely removed.

Hereinafter, the characteristics of the anti-plating agent according to the present invention will be described in more detail through Examples.

3 is a table showing characteristics according to the composition of the anti-plating agent according to Examples and Comparative Examples of the present invention.

Referring to FIG. 3, the CQ material having the thickness, width and length of the object to be plated is 0.8mm * 150mm * 30mm, respectively, by washing it with acetone, methanol, and ethanol to remove foreign substances and oil on the surface to prepare the specimen and then degreasing did. Here, degreasing was performed by immersion in 10% NaOH solution at 60° C. for 10 minutes to remove oil that was not washed in the washing step.

After that, the degreased body to be plated was immersed in 10% HCL at room temperature for 10 minutes to perform pickling treatment. Here, the pickling treatment removes rust from the surface of the object to be plated to make a clean plating surface.

Thereafter, the pickled object is subjected to flux treatment. Flux was prepared by mixing ZnCl ₂ and NH ₄ CL in a 1:3 ratio to prepare a 10% flux solution, immersed at 60° C. for 10 seconds, and then dried. Flux reacts with the oxide film on the surface of the molten metal during hot-dip plating to offset it, thereby improving the plating surface.

Thereafter, the flux-treated body to be plated was treated to prevent plating by varying the composition of silicon oxide, iron oxide, and aluminum oxide.

After that, hot-dip galvanizing was performed, and the coating film characteristics (surface adhesion) of the object to be plated with anti-plating treatment were checked and whether or not plating was prevented.

As shown in FIG. 3 , when the iron oxide content was 2% or less, it was confirmed that the anti-plating agent had a low viscosity and did not adhere to the surface of the object to be plated and fell. On the other hand, when the iron oxide content was 50 wt% or more, it was confirmed that the plating prevention efficiency was lowered due to the local formation of silicon oxide and aluminum oxide.

In addition, when the content of silicon oxide and aluminum oxide is low, no oxide is formed on the surface, so the plating prevention effect is significantly reduced, and when the content is high, there is a problem in that it is difficult to remove the plating inhibitor.

4 to 6 are diagrams showing the performance of the anti-plating agent according to an embodiment of the present invention, and FIG. 7 is a graph showing the results of surface component analysis (GDS) after removing the anti-plating agent of FIG. 6 .

4 to 7, in order to examine the properties of the anti-plating agent according to the embodiment of the present invention, primer painting (a), an adhesive tape (b) and the anti-plating agent (c) according to the embodiment of the present invention are used. After forming a plating prevention layer on an iron (Fe) material to be plated, hot-dip plating was performed, and after removing the plating prevention layer by applying a physical impact, the surface properties were observed. Here, the anti-plating agent (c) according to an embodiment of the present invention was prepared using 48 wt% of iron oxide, 21% of aluminum oxide, and the remainder of silicon oxide.

As a result of the experiment, as shown in FIG. 6 , it can be observed that, in the case of the primer (a), plating prevention is not performed even though the plating prevention layer is formed, and in the case of the adhesive tape (b), plating Although some prevention was performed, it can be confirmed that impurities are present on the surface.

On the other hand, when the anti-plating layer is formed using the anti-plating agent (c) according to the embodiment of the present invention, a clean surface such as the surface before hot-dip plating can be confirmed.

Also, referring to FIG. 7 , as a result of performing surface component analysis (GDS) after removing the plating inhibitor, it can be confirmed that carbon (C), a residue, remains on the surface in the case of the primer (a) and the adhesive tape (b), In the case of the anti-plating agent (c) according to the embodiment of the present invention, silicon was partially detected, but it can be confirmed that the galvanized layer was completely removed to expose a uniform surface of the steel sheet.

On the other hand, the embodiments disclosed in the present specification and drawings are merely presented as specific examples to aid understanding, and are not intended to limit the scope of the present invention. It is apparent to those of ordinary skill in the art to which the present invention pertains that other modifications based on the technical spirit of the present invention can be implemented in addition to the embodiments disclosed herein.

Claims (14)

Preparing an anti-plating agent comprising iron oxide, aluminum oxide, the remainder silicon oxide and a solvent;
coating the anti-plating agent on a body to be plated;
plating the object to be plated onto which the anti-plating agent is coated;
removing the plating inhibitor from the plated object; including,
In the step of preparing the anti-plating agent,
The plating inhibitor is a selective hot-dip plating method using a plating inhibitor, characterized in that it comprises 2 to 50 wt% of the iron oxide, 20 to 70 wt% of the aluminum oxide, the remainder of the silicon oxide and the solvent. delete delete The method of claim 1,
In the step of preparing the anti-plating agent,
The selective hot-dip plating method using a plating inhibitor, characterized in that the ratio of the mixture containing the iron oxide, the aluminum oxide, and the silicon oxide to the solvent is 1 < mixture (g)/solvent (ml) < 2.5. The method of claim 1,
The coating step is
A selective hot-dip plating method using a plating inhibitor, characterized in that the plating inhibitor is selectively coated with the plating inhibitor by immersing or applying the plating inhibitor in the plating inhibitor. 6. The method of claim 5,
The plating step is
Selective hot-dip plating method using an anti-plating agent, characterized in that the plating by immersing the object to be plated selectively coated with the anti-plating agent in molten metal at 300 ~ 650 ℃. 7. The method of claim 6,
The molten metal is a selective hot-dip plating method using a plating inhibitor, characterized in that it comprises zinc (Zn), aluminum (Al) or magnesium (Mg). The method of claim 1,
The step of removing the plating inhibitor is,
removing the portion coated with the anti-plating agent from the plated body;
washing the object to be plated from which the plating inhibitor has been removed;
Selective hot-dip plating method using a plating inhibitor comprising a. 9. The method of claim 8,
The removing step is
Selective hot-dip plating method using an anti-plating agent, characterized in that removing the portion coated with the anti-plating agent by applying an external impact to the plated object to be plated or by scraping it. delete An anti-plating agent comprising 2 to 50 wt% of iron oxide, 20 to 70 wt% of aluminum oxide, and the remainder of silicon oxide and a solvent. delete 12. The method of claim 11,
The preparation ratio of the mixture containing the iron oxide, the aluminum oxide, and the silicon oxide to the solvent is 1 < mixture (g)/solvent (ml) < 2.5. 14. The method of claim 13,
Magnesium oxide, potassium oxide, titanium oxide, and at least one of copper oxide is characterized in that it further comprises an anti-plating agent.

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