JP2021063283A - Coating formation method - Google Patents

Abstract

To improve a corrosion resistance of a surface of a member.SOLUTION: A coating formation method includes a step where zinc powder or zinc alloy powder and a shot particle are impacted to a surface of a member to deform the zinc powder or the zinc alloy powder and bond each other to from a zinc coating or a zinc alloy coating on the surface of the member, a first step where solution containing organosiloxane, alkoxysilane oligomer, or colloidal silica is applied on a surface of the zinc coating or the zinc alloy coating and then is dried, and a second step where after the first step, solution containing organosiloxane, alkoxysilane oligomer, or colloidal silica is applied on the surface of the zinc coating or the zinc alloy coating and then is dried.SELECTED DRAWING: Figure 1

Description

The present invention relates to a film forming method, for example, a film forming method having a step of forming a zinc film or a zinc alloy film.

It is known that corrosion such as rust is suppressed by providing a silica film on a metal surface such as a zinc film or a zinc alloy film (for example, Patent Documents 1 to 4). It is known to form a silica film using an alcohol solution containing an alkoxysilane oligomer (for example, Patent Document 1). It is known to form a silica film using an aqueous solution containing aqueous colloidal silica (for example, Patent Document 2). It is known that a mixed film of zinc, aluminum, and a silica compound is baked and coated on an electroplated film of zinc or a zinc alloy, and a polyorganosiloxane thin film is fired to form a silica film (for example, Patent Document 3). It is known that a silica film is formed after treatment with an alkali metal silicate solution (for example, Patent Document 4).

Japanese Patent No. 4128969 Japanese Patent No. 5364390 Japanese Patent No. 5840278 Japanese Patent No. 6347531

In the methods of Patent Documents 1 to 4, corrosion resistance can be improved without using chromium. However, sufficient corrosion resistance may not be obtained by the methods of Patent Documents 1 to 4.

The present invention has been made in view of the above problems, and an object of the present invention is to improve the corrosion resistance of the surface of a member.

In the present invention, when zinc powder or zinc alloy powder and a shot ball collide with the surface of a member, the zinc powder or zinc alloy powder is crushed and bonded to each other, and a zinc film or zinc alloy film is formed on the surface of the member. A step of forming, a first step of applying a solution containing organosiloxane, an alkoxysilane oligomer or colloidal silica on the surface of the zinc film or the zinc alloy film and drying, and after the first step, the zinc film or the said. This is a film forming method including a second step of applying a solution containing organosiloxane, alkoxysilane oligomer or colloidal silica to the surface of a zinc alloy film and drying it.

In the above configuration, the first step is a step of applying an organic solution containing an alkoxysilane oligomer obtained by hydrolyzing and shrink-polymerizing tetraalkoxysilane to the surface of the zinc film or the zinc alloy film and drying it. The second step includes a step of applying an aqueous solution containing an aqueous colloidal silica and a mixed solvent of alcohol and water to the surface of the zinc film or the zinc alloy film and drying the surface of the zinc film or the zinc alloy film. A step of applying an organic solution containing an alkoxysilane oligomer obtained by hydrolyzing and shrink-polymerizing tetraalkoxysilane and drying it, or a mixed solvent of aqueous colloidal silica, alcohol and water on the surface of the zinc film or the zinc alloy film. The configuration may include a step of applying and drying an aqueous solution containing and.

In the above configuration, the first step includes a step of applying an aqueous solution containing an aqueous colloidal silica and a mixed solvent of alcohol and water to the surface of the zinc film or the zinc alloy film and drying the zinc film, and the second step is , The zinc film or the surface of the zinc alloy film may be configured to include a step of applying an organic solution containing an alkoxysilane oligomer obtained by hydrolyzing and shrink-polymerizing tetraalkoxysilane and drying it.

In the above configuration, the first step includes a step of applying an organic solution containing an alkoxysilane oligomer obtained by hydrolyzing and shrink-polymerizing tetraalkoxysilane to the surface of the zinc film or the zinc alloy film and drying the zinc film or the zinc alloy film. The second step can be configured to include a step of applying an aqueous solution containing an aqueous colloidal silica and a mixed solvent of alcohol and water to the surface of the zinc film or the zinc alloy film and drying the mixture.

In the above configuration, the zinc powder or the zinc alloy powder may be configured to contain zinc, magnesium and aluminum.

In the above configuration, the average particle size of the zinc powder or the zinc alloy powder can be 150 μm or less.

In the above configuration, the member may be a metal member.

In the above configuration, the surface of the metal member may be made of iron or an iron alloy.

In the above configuration, the weight average molecular weight of the alkoxysilane oligomer can be 1000 to 10000.

According to the present invention, the corrosion resistance of the metal surface can be improved.

FIG. 1 is a flowchart showing a film forming method according to the first embodiment. 2 (a) to 2 (d) are schematic cross-sectional views showing the film forming method according to the first embodiment.

As in Patent Documents 1 to 4, by forming a metal film such as a zinc film or a zinc alloy film on the surface of a member such as a metal member and forming a silica film on the surface of the metal film, corrosion such as rust is suppressed. it can. In particular, as in Patent Document 4, when the surface of the metal film is treated with an alkali metal silicate solution and then a silica film is formed, the rust prevention property is improved. However, corrosion resistance such as rust prevention is not sufficient. For example, when the member is deformed by bending or caulking, the metal film and / or the silica film is peeled off. As a result, corrosion resistance such as rust prevention is reduced.

As a film resistant to deformation of the member, a method of forming a metal film by colliding powder such as zinc powder or zinc alloy powder with the member by using a shot peening method or the like and crushing the powder and joining them to each other can be considered. .. In this method, the adhesion between the member and the metal film is strong. Therefore, even if the member is deformed, the metal film does not easily come off. On the other hand, in the metal film formed by the shot peening method, there may be a gap at the bonding interface of the powder. This deteriorates the corrosion resistance. Therefore, it is conceivable to form a silica film on the metal film as in Patent Documents 1 to 4. However, even if a silica film is formed on the metal film formed by the shot peening method, the corrosion resistance is not significantly improved. Hereinafter, embodiments that solve such problems will be described.

[Embodiment 1]
FIG. 1 is a flowchart showing a film forming method according to the first embodiment. 2 (a) to 2 (d) are schematic cross-sectional views showing the film forming method according to the first embodiment. As shown in FIGS. 1 and 2 (a), the metal member 10 is prepared (step S10). The metal member 10 is, for example, iron (Fe) or an iron alloy, and is a member used for, for example, bolts, nuts, reinforcing bars, or caulking. The iron alloy contains 50% by weight or more of iron. The metal member 10 may be a member other than iron or an iron alloy, and may be a metal material such as copper, aluminum or an alloy thereof, or a hard resin.

As shown in FIGS. 1 and 2B, a metal film 14 is formed on the metal member 10 by using a shot peening method (step S12). The shot sphere 11 and the powder 12 are projected onto the surface of the metal member 10 at room temperature. The shot sphere 11 is a metal or insulator harder than the powder 12, for example stainless steel. The shot sphere 11 is, for example, spherical, and the average particle size of the shot sphere 11 is, for example, 10 μm or more and 150 μm or less, for example, 100 μm or less. The powder 12 is, for example, zinc powder or zinc alloy powder. Zinc powder intentionally does not contain elements other than zinc (Zn). The zinc alloy powder contains, for example, 50% by weight or more of zinc and contains at least one element of aluminum (Al), magnesium (Mg) and nickel (Ni). An example of the powder 12 is, for example, a zinc alloy containing 50% by weight or more of zinc and containing aluminum and magnesium. The zinc alloy preferably contains 70% by weight or more of zinc. The powder 12 is, for example, spherical, and the particle size of the powder 12 is, for example, 10 μm or more and 150 μm or less, for example, 100 μm or less. For example, by throwing the powder 12 and the shot ball 11 into the barrel and rotating the barrel, the powder 12 and the shot ball 11 are projected at high speed on the metal member arranged in the barrel.

As shown in FIG. 2C, when the shot sphere 11 and the powder 12 collide with the surface of the metal member 10, the kinetic energy of the powder 12 or the kinetic energy of the shot sphere 11 and the powder 12 causes the powder 12 Is crushed. The crushed powder 13 adheres to the surface of the metal member 10. The plurality of crushed powders 13 are joined to each other. As a result, the crushed powder 13 becomes a bonded metal film 14. The metal film 14 has an interface 16 to which the crushed powder 13 is bonded. Further, since the shot sphere 11 collides with the upper surface of the metal film 14, the unevenness becomes large. When the powder 12 is zinc powder, the metal film 14 becomes a zinc film, and when the powder 12 is a zinc alloy powder, the metal film 14 becomes a zinc alloy film. The thickness of the metal film 14 is, for example, 1 μm or more and 10 μm or less, and for example, 2 μm or more and 5 μm or less. As the energy for striking the shot ball 11 and the powder 12 against the metal member 10, energy other than heat such as centrifugal force using a barrel or air pressure is mainly used.

The metal film 14 formed in this way has good adhesion to the metal member 10 because the shot sphere 11 collides with the powder 13, and the metal film 14 is difficult to peel off even if the metal member 10 is bent or crimped. The peening effect improves the mechanical properties of the metal member 10. Since it is processed at room temperature, problems such as thermal stress are unlikely to occur. Further, since the plating treatment or the acid treatment is not performed, the problem of deterioration due to hydrogen embrittlement due to the remaining hydrogen is unlikely to occur.

As shown in FIG. 1, a solution for forming a silica film is applied to the metal film 14 (step S14). The silica film forming solution is an organic solution containing an organosiloxane, an organic solution containing an alkoxysilane oligomer, or an aqueous solution containing an aqueous colloidal silica.

The organic solution containing organosiloxane or the organic solution containing an alkoxysilane oligomer is, for example, an alcohol solution of an alkoxysilane oligomer as in Patent Document 1. The alkoxysilane oligomer has, for example, a weight average molecular weight of 1000 to 10000 obtained by hydrolyzing and polycondensing tetraalkoxysilane. The concentration in the organic solvent is, for example, 8% by weight to 25% by weight in terms of silica component. Organic solvents include alcohols such as methanol, ethanol and / or isopropyl alcohol. The organic solvent may contain ethers such as propylene fricol monomethyl ether and / or ethylene glycol monobutyl ether. The organic solvent may include a silane coupling agent such as tetraethoxycitane and / or triethoxyvinylsilane. Further, the organic solvent may contain titanium oxide powder and / or a resin soluble in the organic solvent.

The aqueous solution containing the aqueous colloidal silica is, for example, an aqueous solution containing the aqueous colloidal silica as in Patent Document 2 and a mixed solvent of alcohol and water. Aqueous colloidal silica is, for example, acidic and stable. The mixed solvent contains, for example, 3% to 40% by weight of alcohol. Alcohols are, for example, methanol, ethanol and / or isopropyl alcohol. The aqueous solution may contain a silane coupling agent, a titanium chelate compound, and / or a resin soluble in the aqueous solution.

For the application of the silica film forming solution, for example, a method of immersing in the solution and then pulling up, a method of immersing and then using a spin method to shake off the residual liquid, a method of spraying the solution, or the like is used. Pretreatment may be performed before applying the silica film forming solution. For example, an alkali metal silicate solution may be applied to the surface of the metal film 14 and dried.

The applied silica film forming solution is dried (step S16). Drying is carried out, for example, in an atmosphere furnace, an atmosphere furnace or a warm air drying furnace at a temperature of 80 ° C. to 150 ° C. for about 10 to 30 minutes.

Next, the silica film forming solution is reapplied to the metal film 14 (step S18). As the silica film forming solution and coating method, the solution and method exemplified in step S14 are used. The applied silica film forming solution is dried (step S20). As the drying method, the method exemplified in step S16 is used.

As shown in FIG. 2D, a silica film 18 is formed on the metal film 14. The film thickness of the silica film 18 is, for example, 0.5 μm to 20 μm, and for example, 1 μm to 2 μm. The size of silica or oligomer in the silica film forming solution is, for example, 20 nm or less, but the size of silica particles in the silica film 18 is, for example, 100 nm to 2000 nm. The silica particles may be larger than 2000 nm. Silica 17 permeates the bonding interface 16 of the powder 13 and closes the gap between the bonding interfaces 16.

Since the metal film 14 contains zinc, the adhesion between the metal film 14 and the silica film 18 is improved. Assuming that the thickness of the metal film 14 is 2 μm to 5 μm and the thickness of the silica film 18 is 1 μm to 2 μm, the total thickness of the metal film 14 and the silica film 18 is 3 μm to 5 μm, which is a very thin film.

In the first embodiment, the steps of applying the solution and drying are performed twice. This improves corrosion resistance. This means that the silica film forming solution permeates the interface 16 of the powder 13 in the metal film 14 in the step S14. In step S16, silica 17 is formed in the interface 16 to close the gap between the interfaces 16. As a result, the metal film 14 is not exposed to air. In steps S18 and S20, a silica film is further formed on the metal film 14 in a state where the gap of the interface 16 is closed. As a result, the gap between the interfaces 16 is completely closed, so that it is considered that the corrosion resistance is further improved as compared with the first embodiment.

The following experiments were performed as examples and comparative examples.
[Comparative Example 1]
Twenty rivet-shaped carbon steels (SWCH10R) were prepared as the metal member 10 of step S10 of FIG. 1 and FIG. 2 (a).

In step S12 and FIG. 2B of FIG. 1, the shot sphere 11 was a spherical stainless steel sphere having a diameter of about 100 μm, and the powder 12 was a spherical zinc alloy powder having a diameter of about 100 μm. The zinc alloy powder is an alloy composed of zinc, aluminum and magnesium and contains 50% by weight or more of zinc. The thickness of the metal film 14 is 2 μm to 3 μm. Steps S14 to S20 have not been performed.

[Comparative Example 2]
Steps S10 and S12 are the same as in Comparative Example 1.

As step S14, an organic solution containing an alkoxysilane oligomer having a weight average molecular weight of 1000 to 10000 obtained by hydrolyzing and polycondensing tetraalkoxysilane was applied. The coating conditions are as follows.
Solution P: ZEC-Premium manufactured by Discharge Precision Machining Laboratory Co., Ltd.
It mainly contains silicon compounds, titanium compounds, isopropyl alcohol, silane coupling agents and resins.
Coating method: Immerse in solution Solution temperature: Room temperature

As step S16, the applied solution was dried. The conditions are as follows.
Drying temperature: 120 ° C
Drying time: 15 minutes Steps S18 and S20 have not been performed.

[Comparative Example 3]
Steps S10 and S12 are the same as in Comparative Example 1.

As step S14, an aqueous solution containing aqueous colloidal silica and a mixed solvent of alcohol and water was applied. The coating conditions are as follows.
Solution W: ZEC-W manufactured by Discharge Precision Machining Laboratory Co., Ltd.
It mainly contains silicon compounds, titanium compounds, isopropyl alcohol, silane coupling agents, resins and water.
Coating method: Immerse in solution Solution temperature: Room temperature

As step S16, the applied solution was dried. The conditions are as follows.
Drying temperature: 100 ° C
Drying time: 20 minutes Steps S18 and S20 have not been performed.

[Example 1]
Steps S10 and S12 are the same as in Comparative Example 1.
Steps S14 and S16 are the same as in Comparative Example 2.
Steps S18 and S20 are the same as steps S14 and S16 of Comparative Example 3.

[Example 2]
Steps S10 and S12 are the same as in Comparative Example 1.
Steps S14 and S16 are the same as in Comparative Example 3.
Steps S18 and S20 are the same as steps S14 and S16 of Comparative Example 2.

A salt spray test was conducted using 20 samples of Comparative Examples 1 to 3 and Examples 1 and 2 respectively. The conditions for the salt spray test are as follows.
Compliant with JIS-Z2371 Laboratory temperature: 35 ± 2 ° C
Spray: 5% sodium chloride solution Spray amount: 1.5 ± 0.5 ml / hour

Table 1 is a table summarizing the production conditions of Comparative Examples 1 to 3 and Examples 1 and 2 and the results of the salt spray test. In Table 1, item "S12" indicates the presence or absence of the metal film 14. The items "S14" and "S18" indicate the solutions in steps S14 and S18, respectively, "W" indicates the solution W, and "P" indicates the solution P. [-] Indicates that no processing has been performed. The item "Rust generation time" indicates the time when rust started to occur in at least one of the 20 samples. The item "Number of rusts generated after 1000 hours" indicates the number of rusts generated after the salt spray test was performed for 1000 hours. The item "front" indicates the number of rusts on the front side of the sample out of 20 samples, and the item "back" indicates the number of rusts on the back side of the sample out of 20 samples.

As shown in Table 1, in Comparative Example 1, rust started to occur after 550 hours, and rust occurred on all the samples after 1000 hours. In Comparative Example 2, rust started to occur after 600 hours, and after 1000 hours, rust had formed on 13 pieces on the front side and 18 pieces on the back side. In Comparative Example 3, rust started to occur after 520 hours, and rust occurred on all the samples after 1000 hours. In this way, in Comparative Examples 2 and 3 in which the silica film was formed once, the occurrence of rust was about the same as in Comparative Example 1 in which the silica film was not formed. As described above, even if the silica film is formed on the metal film 14, the anticorrosion property is not improved.

In Example 1, rust started to occur after 800 hours, and after 1000 hours, rust was generated on 5 pieces on the front side and 7 pieces on the back side. In Example 2, rust started to occur after 900 hours, and after 1000 hours, 9 pieces of rust were formed on the front side and 8 pieces were formed on the back side. As described above, the generation of rust is suppressed in Examples 1 and 2 in which the silica film is formed twice as compared with Comparative Examples 2 and 3 in which the silica film is formed once.

According to the first embodiment and the embodiment, as in step S12, the powder 12 (zinc powder or zinc alloy powder) and the shot sphere 11 are made to collide with the surface of the metal member 10, so that the powder 12 is crushed and crushed with each other. They are joined to form a metal film 14 (zinc film or zinc alloy film) on the surface of the metal member 10. As a result, even if the metal member is deformed, the film is less likely to peel off. Next, as in steps S14 and S16, as a first step, a solution containing organosiloxane, alkoxysilane oligomer or colloidal silica is applied to the surface of the metal film 14 and dried. As in steps S18 and S20, after the first step, as a second step, a solution containing organosiloxane, alkoxysilane oligomer or colloidal silica is applied to the surface of the metal film 14 and dried.

As a result, the corrosion resistance of the metal film 14 formed by colliding the powder 12 (zinc powder or zinc alloy powder) with the surface of the metal member 10 can be improved.

In the first step, an organic solution (solution P) containing an alkoxysilane oligomer obtained by hydrolyzing and polycondensing tetraalkoxysilane is applied to the surface of the metal film 14 and dried, or the surface of the metal film 14 is aqueous. A step of applying an aqueous solution (solution W) containing colloidal silica and a mixed solvent of alcohol and water and drying the mixture is performed. In the second step, the solution P or the solution W is applied to the surface of the metal film 14 and dried. Thereby, the corrosion resistance can be further improved.

As in Example 1, solution P may be used as the first step, and solution W may be used as the second step. As in Example 2, solution W may be used as the first step, and solution P may be used as the second step.

To form the metal film 14, the powder 12 and the shot ball 11 are made to collide with the surface of the metal member 10, so that the powder 12 is crushed and joined to each other to form the metal film 14 on the surface of the metal member 10. Is preferable. As a result, the powder 12 collides with the metal member 10 due to the kinetic energy of the shot ball 11, so that the adhesion between the metal film 14 and the metal member 10 can be further improved.

The powder 12 preferably contains zinc, magnesium and aluminum. Thereby, the corrosion resistance due to the metal film 14 can be improved. The average particle size of the powder 12 is preferably 150 μm or less. Thereby, the corrosion resistance due to the metal film 14 can be improved. The member forming the metal film 14 may be an insulating member other than the metal member, but the metal member is easily corroded. Therefore, when the member is a metal member, it is preferable to form a metal film and perform the solution treatment twice. The surface of the metal member 10 is iron or an iron alloy. Thereby, the corrosion resistance of the metal member 10 can be improved.

Although the examples of the present invention have been described in detail above, the present invention is not limited to such specific examples, and various modifications and modifications are made within the scope of the gist of the present invention described in the claims. It can be changed.

10 Metal members 11 Shot spheres 12, 13 Powder 14 Metal film 16 Interface 17 Silica 18 Silica film

Claims (9)

By colliding the zinc powder or the zinc alloy powder with the shot ball on the surface of the member, the zinc powder or the zinc alloy powder is crushed and joined to each other to form a zinc film or a zinc alloy film on the surface of the member. ,
The first step of applying a solution containing organosiloxane, alkoxysilane oligomer or colloidal silica to the surface of the zinc film or the zinc alloy film and drying the mixture.
After the first step, a second step of applying a solution containing organosiloxane, alkoxysilane oligomer or colloidal silica on the surface of the zinc film or the zinc alloy film and drying the mixture.
Film forming method including. The first step is a step of applying an organic solution containing an alkoxysilane oligomer obtained by hydrolyzing and shrink-polymerizing tetraalkoxysilane to the surface of the zinc film or the zinc alloy film and drying it, or the zinc film or the above. The step of applying an aqueous solution containing an aqueous colloidal silica and a mixed solvent of alcohol and water to the surface of the zinc alloy film and drying the zinc alloy film is included.
The second step is a step of applying an organic solution containing an alkoxysilane oligomer obtained by hydrolyzing and polycondensing tetraalkoxysilane to the surface of the zinc film or the zinc alloy film and drying it, or the zinc film or the above. The film forming method according to claim 1, further comprising a step of applying an aqueous solution containing an aqueous colloidal silica and a mixed solvent of alcohol and water to the surface of the zinc alloy film and drying the zinc alloy film. The first step includes a step of applying an aqueous solution containing aqueous colloidal silica and a mixed solvent of alcohol and water to the surface of the zinc film or the zinc alloy film and drying the mixture.
The second step according to claim 1, further comprising a step of applying an organic solution containing an alkoxysilane oligomer obtained by hydrolyzing and polycondensing tetraalkoxysilane to the surface of the zinc film or the zinc alloy film and drying the zinc film. Film forming method. The first step includes a step of applying an organic solution containing an alkoxysilane oligomer obtained by hydrolyzing and polycondensing tetraalkoxysilane to the surface of the zinc film or the zinc alloy film and drying the zinc film.
The film forming method according to claim 1, wherein the second step includes a step of applying an aqueous solution containing aqueous colloidal silica and a mixed solvent of alcohol and water to the surface of the zinc film or the zinc alloy film and drying the solution. The film forming method according to any one of claims 1 to 4, wherein the zinc powder or the zinc alloy powder contains zinc, magnesium and aluminum. The film forming method according to any one of claims 1 to 5, wherein the zinc powder or the zinc alloy powder has an average particle size of 150 μm or less. The film forming method according to any one of claims 1 to 6, wherein the member is a metal member. The film forming method according to any one of claims 1 to 6, wherein the surface of the member is iron or an iron alloy. The film forming method according to any one of claims 2 to 4, wherein the alkoxysilane oligomer has a weight average molecular weight of 1000 to 10000.

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