WO2024111661A1 - Film and film formation method - Google Patents

Film and film formation method Download PDF

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WO2024111661A1
WO2024111661A1 PCT/JP2023/042194 JP2023042194W WO2024111661A1 WO 2024111661 A1 WO2024111661 A1 WO 2024111661A1 JP 2023042194 W JP2023042194 W JP 2023042194W WO 2024111661 A1 WO2024111661 A1 WO 2024111661A1
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Prior art keywords
coating
zinc
alloy
film
powder
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PCT/JP2023/042194
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French (fr)
Japanese (ja)
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鈴木弘朗
合田裕一
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株式会社鈴木商店
株式会社ビー・ビー・エム
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Publication of WO2024111661A1 publication Critical patent/WO2024111661A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/02—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by baking
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
    • B05D3/12—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials by mechanical means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
    • B05D7/24—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials for applying particular liquids or other fluent materials
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C28/00—Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D

Definitions

  • the present invention relates to a coating and a method for forming the coating, for example, a coating having a zinc or zinc alloy coating and a method for forming the coating.
  • Patent Document 1 In order to improve the corrosion resistance of zinc or zinc alloy coatings, it is known to bake a coating containing zinc, aluminum and a silica compound onto the zinc or zinc alloy coating, and then form a porous silica coating on top of that (e.g., Patent Document 1).
  • Patent Document 1 can improve corrosion resistance. However, under harsh conditions, the coating may peel off. This may result in a decrease in corrosion resistance. In this way, when multiple zinc or zinc alloy coatings are laminated, the coatings may peel off.
  • the present invention was developed in consideration of the above problems, and aims to improve the adhesion of coatings that have zinc or zinc alloy coatings.
  • the present invention is a method for forming a coating comprising the steps of forming a second coating, which is a zinc or zinc alloy coating and has an uneven surface, by colliding a plurality of powders containing zinc or a zinc alloy onto the surface of a first coating, which is a zinc or zinc alloy coating formed on a base material, and forming a third coating, which contains zinc or a zinc alloy, on the surface of the second coating.
  • the multiple powders can be configured to include a rigid powder that is harder than the zinc or zinc alloy.
  • the multiple powders may include an alloy containing zinc and iron, or an alloy containing zinc, magnesium, and aluminum.
  • the process of forming the third coating can include a process of applying a solution containing zinc powder and an organosilicon compound to the surface of the second coating, and then performing a heat treatment to form the third coating.
  • the step of forming the third coating can include a step of applying a solution containing zinc powder, aluminum powder, and at least one of alkoxysilane and its hydrolysate to the surface of the second coating, and then performing a heat treatment to form the third coating.
  • the first coating can be a zinc-nickel alloy coating.
  • the above configuration may include a step of forming the first coating on a base material using an electroplating method.
  • the above configuration may include a step of performing a chromate treatment on the surface of the first coating using a solution containing trivalent chromium before the step of forming the second coating.
  • the above configuration may include a step of forming a silica coating on the surface of the third coating.
  • the present invention is a method for forming a coating comprising the steps of forming a first coating, which is a zinc-nickel alloy coating, on a base material using an electroplating method, forming a second coating, which is a zinc alloy coating and has an uneven surface, by colliding a plurality of powders, which include zinc or a zinc alloy and a rigid powder harder than the zinc or zinc alloy, on the surface of the first coating, and applying a solution, which includes zinc powder, aluminum powder, and at least one of an alkoxysilane and a hydrolyzate thereof, to the surface of the second coating, and then heat-treating the solution to form a mixed coating.
  • the present invention is a coating comprising a base material, a first coating which is a zinc or zinc alloy coating formed on the base material, a second coating which is a zinc or zinc alloy coating formed on the surface of the first coating and has a structure in which a plurality of powders containing zinc or a zinc alloy are crushed and bonded together, and has an uneven surface, and a third coating which is formed on the surface of the second coating and contains zinc or a zinc alloy.
  • the first coating is a zinc-nickel alloy coating
  • the multiple powders include an alloy containing zinc and iron, or an alloy containing zinc, magnesium, and aluminum
  • the third coating can be configured to include zinc and aluminum.
  • FIG. 1(a) to 1(e) are cross-sectional views showing a coating formation method according to a first embodiment.
  • 2(a) to 2(c) are cross-sectional views showing a method for forming the second coating in the first embodiment.
  • FIG. 3 is a photograph of the surface of the bolt of Treatment 2 after the vibration test in Comparative Example 2.
  • FIG. 1(a) to 1(e) are cross-sectional views showing a coating formation method according to a first embodiment.
  • a base material 10 is prepared.
  • the base material 10 is, for example, iron (Fe) or an iron alloy, and is, for example, a bolt, a nut, or the like.
  • the iron alloy contains iron at 50 mass% or more.
  • the base material 10 may be a member other than iron or an iron alloy, and may be, for example, a metal material such as copper, aluminum, or an alloy thereof, or a hard resin.
  • a first coating 12 is formed on a base material 10.
  • the first coating 12 is a zinc or zinc alloy coating.
  • the first coating 12 is, for example, a zinc coating, a zinc-nickel alloy coating, a zinc-iron alloy coating, or a zinc-tin alloy coating.
  • the zinc coating does not intentionally contain any elements other than zinc.
  • the zinc content in the zinc alloy coating is, for example, 70 to 99% by mass, and the content of metal elements other than zinc that are intentionally contained is, for example, 1 to 30% by mass.
  • the content of unavoidable metal elements that are not intentionally contained is 1% by mass or less.
  • the zinc content in the zinc-nickel alloy coating is preferably 70% by mass or more and 99% by mass or less, and the nickel content is preferably 1% by mass or more and 30% by mass or less, and more preferably the zinc content is 85% by mass or more and 90% by mass or less, and the nickel content is 10% by mass or more and 15% by mass or less.
  • the zinc-nickel alloy coating may or may not intentionally contain metal elements other than zinc and nickel. The content (mass%) of metal elements other than zinc and nickel contained in the zinc-nickel alloy coating is smaller than the content (mass%) of nickel.
  • the content (mass%) of metal elements other than zinc and nickel contained in the zinc-nickel alloy coating is preferably 1/10 or less of the content (mass%) of nickel, for example, 5 mass% or less, and more preferably 1 mass% or less.
  • the first coating 12 may be formed by electroplating or hot-dip plating. It is preferable to use electroplating in order to control the thickness and form a smooth surface.
  • the plating solution may contain a brightener.
  • the thickness of the first coating 12 is, for example, 1 ⁇ m to 20 ⁇ m, and is, for example, 6 ⁇ m.
  • a chromate treatment may be performed. This forms a chromate film on the first film 12.
  • a treatment liquid containing, for example, trivalent or hexavalent chromium is used to treat the surface of the first film 12.
  • the treatment liquid contains, for example, chromic acid. From the viewpoint of not using hexavalent chromium, which has a large environmental impact, it is preferable that the treatment liquid contains trivalent chromium and contains almost no hexavalent chromium.
  • a passive film containing chromium i.e., a chromate film
  • the thickness of the chromate film is, for example, 0.05 ⁇ m to 1 ⁇ m, and is 0.2 ⁇ m as an example.
  • a second coating 14 is formed on the surface of the first coating 12.
  • Fig. 2(a) to Fig. 2(c) are cross-sectional views showing a method of forming the second coating in embodiment 1.
  • a first coating 12 is formed on a base material 10.
  • the second film 14 is formed on the first film 12 by using a mechanical dry plating method.
  • a plurality of powders 20 are collided with the surface of the first film 12 at room temperature.
  • the powders 20 include, for example, zinc powder or zinc alloy powder.
  • the zinc powder does not intentionally include any elements other than zinc (Zn).
  • the zinc alloy powder includes, for example, 50% by mass or more of zinc and at least one element of iron (Fe), nickel (Ni), aluminum (Al) and magnesium (Mg).
  • One example of the powders 20 is a zinc alloy including 50% by mass or more of zinc and including iron.
  • Another example of the powders 20 is a zinc alloy including 50% by mass or more of zinc and including aluminum and magnesium.
  • the zinc alloy includes 70% by mass or more of zinc.
  • the powders 20 are, for example, spherical, and the particle size of the powders 20 is, for example, 10 ⁇ m or more and 150 ⁇ m or less, for example, 100 ⁇ m or less.
  • the powder 20 is injected into a barrel and centrifugal force generated when the barrel is rotated, or energy other than heat, such as air pressure, is mainly used to project the powder 20 onto the surface of the first coating 12 at high speed.
  • the powder 20 collides with the surface of the first coating 12
  • the powder 20 is crushed by the kinetic energy of the powder 20.
  • the crushed powder 13 adheres to the surface of the first coating 12.
  • the crushed powder 13 are bonded to each other and stacked.
  • the second coating 14 has an interface where the crushed powder 13 are bonded.
  • the upper surface of the second coating 14 becomes uneven because the powder 20 collides with it.
  • the powder 20 is zinc powder
  • the second coating 14 becomes a zinc coating
  • the second coating 14 becomes a zinc alloy coating.
  • the thickness of the second coating 14 is, for example, 0.1 ⁇ m or more and 3 ⁇ m or less, for example, 0.2 ⁇ m or more and 0.5 ⁇ m or less.
  • the powder 20 may have a core harder than zinc or a zinc alloy, and a zinc layer or a zinc alloy layer around the core.
  • the core is, for example, a metal or an insulator, for example, iron or an iron alloy.
  • the preferred composition of the zinc layer or zinc alloy layer is the same as the preferred composition of the zinc powder or zinc alloy powder described above.
  • a plurality of powders 20 and a plurality of shot balls may be collided with the surface of the first coating 12.
  • the shot balls are, for example, a metal or an insulator harder than the powder 20, for example, iron or an iron alloy.
  • the shot balls are, for example, spherical, and the average particle size of the shot balls is, for example, 10 ⁇ m or more and 150 ⁇ m or less, for example, 100 ⁇ m or less.
  • the second coating 14 formed as shown in Figures 2(a) to 2(c) has good adhesion between the second coating 14 and the first coating 12 because the powder 20 collides with the first coating 12.
  • the core or shot ball collides with the surface of the crushed powder 13, so that the crushed powder 13 adheres more firmly to the surface of the first coating 12.
  • a plurality of crushed powders 13 are firmly bonded to each other.
  • the surface of the second coating 14 has greater irregularities.
  • the powder 20 may contain metal powders other than zinc and zinc alloys, such as titanium powder, and ceramic powders, such as aluminum oxide.
  • a third coating 16 containing zinc or a zinc alloy is formed on the surface of the second coating 14.
  • the zinc compound contains zinc and at least one of aluminum, nickel, tin, iron, and magnesium.
  • the third coating 16 may contain a silicon compound in addition to zinc or a zinc alloy.
  • a solvent for the third coating is applied onto the second coating 14 and then heated (baked).
  • the solvent for the third coating contains zinc powder, an organosilicon compound, and a solvent.
  • the solution for the third coating may contain at least one type of metal powder, such as aluminum powder, nickel powder, tin powder, iron powder, and magnesium powder, in addition to zinc powder.
  • the solution for the third coating contains zinc powder and aluminum powder.
  • the shape of the zinc powder and the metal powder may be, for example, spherical or scaly.
  • the powder has a short diameter of, for example, 0.05 ⁇ m to 5 ⁇ m, and a long diameter of, for example, 0.5 ⁇ m to 100 ⁇ m.
  • the zinc powder contains, for example, 90% by mass or more or 99% by mass or more of zinc.
  • the metal powder other than zinc (for example, aluminum powder) contains, for example, 90% by mass or more or 99% by mass or more of a metal element other than zinc (for example, aluminum).
  • the ratio of the mass of zinc powder to the total powder mass of zinc powder and metal powder other than zinc (e.g. aluminum powder) is preferably 50% by mass or more, more preferably 70% by mass or more.
  • the ratio of the mass of metal powder other than zinc (e.g. aluminum) to the total powder mass of zinc powder and metal powder other than zinc (e.g. aluminum powder) is preferably 1% by mass or more, more preferably 5% by mass or more.
  • the organosilicon compound includes, for example, at least one of an alkoxysilane and a hydrolyzate thereof.
  • the alkoxysilane is preferably a tetraalkoxysilane having 3 or less carbon atoms, such as tetramethoxysilane, tetraethoxysilane, or tetrapropoxysilane.
  • the solvent of the third coating solution is, for example, an alcohol, ester, glycol, or ether.
  • the solvent is preferably an alcohol, such as methanol, ethanol, propanol, isopropanol, butanol, hexanol, methoxybutanol, or methoxymethylbutanol.
  • the total content of the zinc powder and metal powder in the third coating solution is, for example, 20 to 60 mass %.
  • the content of the organosilicon compound in the solution is, for example, 5 to 40 mass %.
  • the content of the organic solvent in the third coating solution is, for example, 10 to 60 mass %.
  • the third coating solution is applied to the surface of the second coating 14 by, for example, dipping, spraying, or spin coating.
  • the temperature of the heat treatment after applying the third coating solution is, for example, 100°C to 400°C.
  • the temperature of the heat treatment is equal to or higher than the temperature at which the solvent in the third coating solution evaporates.
  • the heat treatment time is, for example, 10 minutes to 120 minutes.
  • the third coating 16 is formed on the surface of the second coating 14.
  • the thickness of the third coating 16 is, for example, 1 ⁇ m to 20 ⁇ m, and is, for example, 8 ⁇ m.
  • the total content of zinc powder and metal powder other than zinc e.g.
  • aluminum powder) in the third coating 16 is, for example, 70 mass% or more and 95 mass% or less, and the content of silicon compounds is, for example, 5 mass% or more and 30 mass% or less.
  • the ratio of the mass of zinc powder to the total powder mass of zinc powder and metal powder other than zinc (e.g. aluminum powder) is preferably 50% or more, and more preferably 70% or more.
  • the zinc powder content in the third coating 16 is 70% by mass
  • the aluminum powder content is 15% by mass
  • the silicon compound content is 15% by mass.
  • a porous silica film 18 is formed on the third film 16.
  • the porous silica film 18 is formed by applying a silica film solution onto the third film 16 and performing a heat treatment (baking treatment).
  • the silica film solution contains a silicon compound and a solvent.
  • the silicon compound is, for example, at least one of an organosiloxane and a silane coupling agent.
  • the silicon compound may contain an alkali metal silicate.
  • the silica film solution may contain a titanium compound.
  • the titanium compound is, for example, an organic titanate compound.
  • the solvent of the silica film solution is, for example, water, alcohols, esters, glycols, or ethers.
  • the content of the silicon compound in the silica film solution is, for example, 40% by mass or more and 90% by mass or less, and the content of the solvent is, for example, 10% by mass or more and 60% by mass or less.
  • the silica film solution is applied to the surface of the third film 16 by, for example, dipping, spraying, or spin coating.
  • the temperature of the heat treatment after applying the silica film solution is, for example, 100°C to 400°C.
  • the temperature of the heat treatment is equal to or higher than the temperature at which the solvent in the silica film solution evaporates.
  • the heat treatment time is, for example, 10 minutes to 120 minutes.
  • a porous silica film 18 is formed on the surface of the third film 16.
  • the thickness of the silica film 18 is, for example, 0.1 ⁇ m to 10 ⁇ m, and is, for example, 1 ⁇ m.
  • the content of the silicon compound is, for example, 50 mass% or more and 95 mass% or less
  • the content of the titanium compound is, for example, 5 mass% or more and 50 mass% or less
  • the content of the silicon compound and the titanium compound are 75 mass% and 25 mass%, respectively.
  • peeling may occur between the zinc or zinc alloy coating and the mixed coating under harsh conditions.
  • a plurality of powders 20 containing zinc or zinc alloy are collided with the surface of the first coating 12, which is a zinc or zinc alloy coating formed on the base material 10, to form the second coating 14, which is a zinc or zinc alloy coating and has an uneven surface.
  • a third coating 16 containing zinc or zinc alloy is formed on the surface of the second coating 14. The plurality of powders 20 collide with the surface of the first coating 12, so that the first coating 12 and the second coating 14 are firmly bonded to each other.
  • the second coating 14 formed in this manner has a structure in which multiple powder particles 13 containing zinc or a zinc alloy are crushed and bonded to each other, as shown in FIG. 2(c).
  • the multiple powders 20 include rigid powder (nuclei or shot balls) that are harder than zinc or zinc alloy.
  • the rigid powder collides with the zinc or zinc alloy attached to the surface of the first coating 12. This makes the first coating 12 and the second coating 14 more firmly bonded together, and the surface of the second coating 14 becomes more uneven, so that the second coating 14 and the third coating 16 are more firmly bonded together. This can further improve the adhesion between the first coating 12 and the third coating 16.
  • the powder 20 contains an alloy containing zinc and iron, or an alloy containing zinc, magnesium, and aluminum. This can further improve the adhesion between the first coating 12 and the third coating 16.
  • a solution containing zinc powder and an organosilicon compound is applied to the surface of the second coating 14, and then heat-treated to form the third coating 16.
  • forming the third coating 16 on the first coating 12 can improve corrosion resistance.
  • forming the third coating 16 on the first coating 12 reduces the adhesion between the first coating 12 and the third coating 16. Therefore, it is preferable to form the second coating 14.
  • a solution containing zinc powder, aluminum powder, and at least one of alkoxysilane and its hydrolysate is applied to the surface of the second coating 14, and then heat-treated to form the third coating 16.
  • the third coating 16 on the first coating 12 in this way, corrosion resistance can be improved.
  • forming the third coating 16 on the first coating 12 reduces the adhesion between the first coating 12 and the third coating 16. Therefore, it is preferable to form the second coating 14.
  • the third coating 16 formed in this way contains zinc and aluminum.
  • the first coating 12 is a zinc-nickel alloy coating.
  • the first coating 12 is formed on the base material 10 by electroplating. In this case, if the second coating 14 is not provided, the adhesion between the first coating 12 and the third coating 16 may decrease. Therefore, it is preferable to form the second coating 14.
  • the first coating 12 is chromated using a solution containing trivalent chromium. This further improves the adhesion between the first coating 12 and the second coating 14.
  • a silica film 18 may be formed on the third film 16. This further improves corrosion resistance.
  • Step 1 An M24 hexagonal bolt, an M24 nut and an M24 washer made of SPCC-SD steel were prepared as the base material 10.
  • Step 2 The base material 10 was electroplated to form a zinc-nickel alloy coating as the first coating 12.
  • a plating solution was used in which zinc and nickel were dissolved in an aqueous sodium hydroxide solution with a mass ratio of 20:3.
  • the surface of the first coating 12 was washed with water.
  • the thickness of the first coating 12 was approximately 6 ⁇ m, and the zinc content in the first coating 12 was 87 to 92 mass %, and the nickel content was 8 to 13 mass %.
  • a chromate treatment was performed using a solution containing trivalent chromium. The thickness of the chromate coating after the chromate treatment was approximately 0.2 ⁇ m.
  • Step 3 A second coating 14 was formed on the surface of the first coating 12.
  • the powder 20 was a spherical zinc alloy powder with a diameter of approximately 100 ⁇ m.
  • the zinc alloy powder was an alloy of zinc, aluminum, and magnesium with a diameter of approximately 100 ⁇ m, and contained 50% or more by mass of zinc.
  • Spherical stainless steel balls with a diameter of approximately 100 ⁇ m were used as shot balls.
  • the thickness of the second coating 14 was approximately 0.2 ⁇ m to 0.3 ⁇ m.
  • Step 4 A third coating 16 was formed on the surface of the second coating 14.
  • Metas YC-B17J and Metas YC-B3 manufactured by Yuken Kogyo Co., Ltd. were mixed in a volume ratio of 25:3 and applied to the surface of the first coating 12. Then, a heat treatment was performed for 30 minutes or more at 250°C to 290°C. The above application and heat treatment were repeated twice.
  • YC-B17J contains zinc powder, aluminum powder as a metal powder other than zinc, and tetraethoxysilane as an organosilicon compound.
  • the thickness of the third coating 16 is about 8 ⁇ m, and the zinc, aluminum, and silicon compound contents in the third coating 16 are 70 mass%, 15 mass%, and 15 mass%, respectively.
  • Step 5 A porous silica film 18 was formed on the surface of the third film 16. Metas YC-T, Lubras C14 or Lubras C24 manufactured by Yuken Kogyo Co., Ltd. was used as a silica film solution and applied to the surface of the third film 16. Then, a heat treatment was performed at 110°C to 160°C for 10 minutes or more. The thickness of the porous silica film 18 was about 1 ⁇ m, and the content of the silicon compound and the titanium compound was 75% by mass and 25% by mass, respectively.
  • Comparative Example 1 As Comparative Example 1, a sample was prepared without carrying out step 3. As Comparative Example 2, a sample was prepared by carrying out an alkaline roughening treatment instead of step 3.
  • the alkaline roughening treatment is a treatment in which the surface of the first coating 12 is exposed to a strong alkaline solution, and the surface of the first coating 12 can be made rough.
  • the strong alkaline solution used was an aqueous solution of NaOH with a concentration of 100 g/L.
  • the treatment temperature was 20°C to 30°C, and the treatment time was 5 to 10 minutes.
  • Table 1 shows the results of the adhesion evaluation by the cross-cut method test in Comparative Examples 1 and 2 and Example 1.
  • Comparative Example 1 is classified as 4 by the cross-cut method and has low adhesion. Comparative Example 2 and Example 1 are classified as 0 by the cross-cut method and have high adhesion. Comparative Example 1 has high corrosion resistance, but the adhesion between the first film 12 and the third film 16 is low, and the third film 16 is easily peeled off from the first film 12. As in Comparative Example 2, when the third film 16 is formed on the first film 12 after performing an alkaline roughening treatment to increase the unevenness of the surface of the first film 12, the adhesion between the first film 12 and the third film 16 is improved.
  • Example 1 when the second film 14 is formed on the first film 12 and the third film 16 is formed on the second film 14, the adhesion between the first film 12 and the third film 16 is improved. In the adhesion evaluation using the cross-cut method, both Comparative Example 2 and Example 1 are good.
  • Figure 3 is a photograph of the surface of the bolt of treatment 2 after the vibration test in Comparative Example 2. As shown in Figure 3, the coating has peeled off due to the vibration test at dashed circle 30. In this way, when a box containing bolts, washers, and nuts is subjected to vibration during transportation, each sample may be hit or rubbed, causing the coating to peel off. Each sample was evaluated for the presence or absence of coating peeling after the vibration test.
  • Table 2 shows the results of the adhesion evaluation by vibration test in Comparative Example 2 and Example 1.
  • A, B, and C different silica coating solutions were used when forming the silica coating 18 in step 5.
  • Example 1 As shown in Table 2, peeling was observed frequently in Comparative Example 2. Peeling was hardly observed in Example 1.
  • the adhesion between the first coating 12 and the third coating 16 is improved.
  • the adhesion of Comparative Example 2 may be insufficient.
  • Example 1 by providing the second coating 14, the adhesion between the first coating 12 and the third coating 16 can be improved, and peeling of the third coating 16 from the first coating 12 can be suppressed even if a large impact is applied to the sample.
  • Example 1 in Example 1, the powder 20 is collided with the surface of the first coating 12 to improve the adhesion between the crushed powder 13 and the first coating 12. Therefore, the results of the Example are considered to be generalizable to cases where the first coating 12 is zinc or a zinc alloy.
  • the surface unevenness of the second coating 14 increases, improving the adhesion between the second coating 14 and the third coating 16. Therefore, the results of the Example are considered to be generalizable to cases where the third coating 16 is zinc or a zinc alloy.
  • the silica coating 18 contributes to improving corrosion resistance, it is considered not to contribute much to the adhesion between the first coating 12 and the third coating 16. Therefore, the results of Example 1 are also generalizable to cases where the silica coating 18 is not used.

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Abstract

This film formation method comprises: a step for forming a second film 14, which is a zinc or zinc alloy film and has an uneven surface, by colliding a plurality of zinc- or zinc alloy-containing powders with the surface of a first film 12, which is a zinc or zinc alloy film and formed on a base material 10; and a step for forming a zinc- or zinc alloy-containing third film 16 on the surface of the second film 14.　

Description

皮膜および皮膜形成方法Coating and coating formation method
　本発明は、皮膜および皮膜形成方法に関し、例えば亜鉛または亜鉛合金皮膜を有する皮膜および皮膜形成方法に関する。 The present invention relates to a coating and a method for forming the coating, for example, a coating having a zinc or zinc alloy coating and a method for forming the coating.
　亜鉛または亜鉛合金皮膜の耐食性向上のため、亜鉛または亜鉛合金皮膜上に、亜鉛、アルミニウムおよびシリカ化合物を含む皮膜を焼付塗装し、その上に多孔質シリカ皮膜を形成することが知られている（例えば特許文献１） In order to improve the corrosion resistance of zinc or zinc alloy coatings, it is known to bake a coating containing zinc, aluminum and a silica compound onto the zinc or zinc alloy coating, and then form a porous silica coating on top of that (e.g., Patent Document 1).
特開２０１６－８４５１０号公報JP 2016-84510 A
　特許文献１の方法によれば、耐食性を高めることができる。しかしながら、過酷な条件下では皮膜に剥がれが生じることがある。これにより、耐食性が低下することがある。このように、亜鉛または亜鉛合金皮膜を複数積層するときに、皮膜が剥がれることがある。 The method of Patent Document 1 can improve corrosion resistance. However, under harsh conditions, the coating may peel off. This may result in a decrease in corrosion resistance. In this way, when multiple zinc or zinc alloy coatings are laminated, the coatings may peel off.
　本発明は、上記課題に鑑みなされたものであり、亜鉛または亜鉛合金皮膜を有する皮膜の密着性を向上させることを目的とする。 The present invention was developed in consideration of the above problems, and aims to improve the adhesion of coatings that have zinc or zinc alloy coatings.
　本発明は、下地材上に形成された亜鉛または亜鉛合金皮膜である第１皮膜の表面に、亜鉛または亜鉛合金を含む複数の粉体を衝突させることで、亜鉛または亜鉛合金皮膜であり表面が凹凸状である第２皮膜を形成する工程と、前記第２皮膜の表面に、亜鉛または亜鉛合金を含む第３皮膜を形成する工程と、を含む皮膜形成方法である。 The present invention is a method for forming a coating comprising the steps of forming a second coating, which is a zinc or zinc alloy coating and has an uneven surface, by colliding a plurality of powders containing zinc or a zinc alloy onto the surface of a first coating, which is a zinc or zinc alloy coating formed on a base material, and forming a third coating, which contains zinc or a zinc alloy, on the surface of the second coating.
　上記構成において、前記複数の粉体は、前記亜鉛または亜鉛合金より硬い剛体紛を含む構成とすることができる。 In the above configuration, the multiple powders can be configured to include a rigid powder that is harder than the zinc or zinc alloy.
　上記構成において、前記複数の粉体は、亜鉛および鉄を含有する合金、または、亜鉛、マグネシウムおよびアルミニウムを含有する合金を含む構成とすることができる。 In the above configuration, the multiple powders may include an alloy containing zinc and iron, or an alloy containing zinc, magnesium, and aluminum.
　上記構成において、前記第３皮膜を形成する工程は、前記第２皮膜の表面に亜鉛粉体および有機ケイ素化合物を含む溶液を塗布し、加熱処理することにより前記第３皮膜を形成する工程を含む構成とすることができる。 In the above configuration, the process of forming the third coating can include a process of applying a solution containing zinc powder and an organosilicon compound to the surface of the second coating, and then performing a heat treatment to form the third coating.
　上記構成において、前記第３皮膜を形成する工程は、前記第２皮膜の表面に亜鉛粉体、アルミニウム粉体、並びにアルコキシシランおよびその加水分解物の少なくとも一方を含む溶液を塗布し、加熱処理することにより前記第３皮膜を形成する工程を含む構成とすることができる。 In the above configuration, the step of forming the third coating can include a step of applying a solution containing zinc powder, aluminum powder, and at least one of alkoxysilane and its hydrolysate to the surface of the second coating, and then performing a heat treatment to form the third coating.
　上記構成において、前記第１皮膜は、亜鉛ニッケル合金皮膜である構成とすることができる。 In the above configuration, the first coating can be a zinc-nickel alloy coating.
　上記構成において、下地材上に、電気めっき法を用い前記第１皮膜を形成する工程を含む構成とすることができる。 The above configuration may include a step of forming the first coating on a base material using an electroplating method.
　上記構成において、前記第２皮膜を形成する工程の前に、前記第１皮膜の表面に三価クロムを含む溶液を用いクロメート処理を行う工程を含む構成とすることができる。 The above configuration may include a step of performing a chromate treatment on the surface of the first coating using a solution containing trivalent chromium before the step of forming the second coating.
　上記構成において、前記第３皮膜の表面にシリカ皮膜を形成する工程を含む構成とすることができる。 The above configuration may include a step of forming a silica coating on the surface of the third coating.
　本発明は、下地材上に、電気めっき法を用い亜鉛ニッケル合金皮膜である第１皮膜を形成する工程と、前記第１皮膜の表面に、亜鉛または亜鉛合金と前記亜鉛または亜鉛合金より硬い剛体紛とを含む複数の粉体を衝突させることで、亜鉛合金皮膜であり表面が凹凸状である第２皮膜を形成する工程と、前記第２皮膜の表面に、亜鉛粉体、アルミニウム粉体、並びにアルコキシシランおよびその加水分解物の少なくとも一方を含む溶液を塗布し、加熱処理することで混合皮膜を形成する工程と、を含む皮膜形成方法である。 The present invention is a method for forming a coating comprising the steps of forming a first coating, which is a zinc-nickel alloy coating, on a base material using an electroplating method, forming a second coating, which is a zinc alloy coating and has an uneven surface, by colliding a plurality of powders, which include zinc or a zinc alloy and a rigid powder harder than the zinc or zinc alloy, on the surface of the first coating, and applying a solution, which includes zinc powder, aluminum powder, and at least one of an alkoxysilane and a hydrolyzate thereof, to the surface of the second coating, and then heat-treating the solution to form a mixed coating.
　本発明は、下地材と、前記下地材上に形成された亜鉛または亜鉛合金皮膜である第１皮膜と、前記第１皮膜の表面に設けられ、亜鉛または亜鉛合金を含む複数の粉体が潰れ互いに接合した構造を有する亜鉛または亜鉛合金皮膜であり表面が凹凸状である第２皮膜と、前記第２皮膜の表面に設けられ、亜鉛または亜鉛合金を含む第３皮膜と、を備える皮膜である。 The present invention is a coating comprising a base material, a first coating which is a zinc or zinc alloy coating formed on the base material, a second coating which is a zinc or zinc alloy coating formed on the surface of the first coating and has a structure in which a plurality of powders containing zinc or a zinc alloy are crushed and bonded together, and has an uneven surface, and a third coating which is formed on the surface of the second coating and contains zinc or a zinc alloy.
　上記構成において、前記第１皮膜は亜鉛ニッケル合金皮膜であり、前記複数の粉体は、亜鉛および鉄を含有する合金、または、亜鉛、マグネシウムおよびアルミニウムを含有する合金を含み、前記第３皮膜は、亜鉛およびアルミニウムを含む構成とすることができる。 In the above configuration, the first coating is a zinc-nickel alloy coating, the multiple powders include an alloy containing zinc and iron, or an alloy containing zinc, magnesium, and aluminum, and the third coating can be configured to include zinc and aluminum.
　本発明によれば、亜鉛または亜鉛合金皮膜を有する皮膜の密着性を向上させることができる。 According to the present invention, it is possible to improve the adhesion of a coating having a zinc or zinc alloy coating.
図１（ａ）から図１（ｅ）は、実施形態１に係る皮膜形成方法を示す断面図である。1(a) to 1(e) are cross-sectional views showing a coating formation method according to a first embodiment. 図２（ａ）から図２（ｃ）は、実施形態１における第２皮膜の形成方法を示す断面図である。2(a) to 2(c) are cross-sectional views showing a method for forming the second coating in the first embodiment. 図３は、比較例２における振動試験後の処理２のボルトの表面の写真である。FIG. 3 is a photograph of the surface of the bolt of Treatment 2 after the vibration test in Comparative Example 2.
［実施形態１］
　図１（ａ）から図１（ｅ）は、実施形態１に係る皮膜形成方法を示す断面図である。 [Embodiment 1]
1(a) to 1(e) are cross-sectional views showing a coating formation method according to a first embodiment.
［工程１：下地材の準備］
　図１（ａ）に示すように、下地材１０を準備する。下地材１０は、例えば鉄（Ｆｅ）または鉄合金であり、例えばボルト、ナット等である。鉄合金は、鉄を５０質量％以上含む。下地材１０は鉄または鉄合金以外の部材でもよく、例えば銅、アルミニウムまたはこれらの合金等の金属材料または硬めの樹脂でもよい。 [Step 1: Preparation of base material]
As shown in Fig. 1(a), a base material 10 is prepared. The base material 10 is, for example, iron (Fe) or an iron alloy, and is, for example, a bolt, a nut, or the like. The iron alloy contains iron at 50 mass% or more. The base material 10 may be a member other than iron or an iron alloy, and may be, for example, a metal material such as copper, aluminum, or an alloy thereof, or a hard resin.
［工程２：第１皮膜１２の形成］
　図１（ｂ）に示すように、下地材１０上に、第１皮膜１２を形成する。第１皮膜１２は、亜鉛または亜鉛合金皮膜である。第１皮膜１２は、例えば亜鉛皮膜、亜鉛ニッケル合金皮膜、亜鉛鉄合金皮膜、亜鉛錫合金皮膜である。亜鉛皮膜は亜鉛以外の元素を意図的に含まない。亜鉛合金皮膜における亜鉛の含有量は例えば７０～９９質量％であり、亜鉛以外の意図的に含有する金属元素の含有量は例えば１～３０質量％である。意図的に含有しない不回避金属元素の含有率は１質量％以下である。亜鉛系皮膜が亜鉛ニッケル合金皮膜のとき、亜鉛ニッケル合金皮膜における亜鉛の含有率は７０質量％以上かつ９９質量％以下でありニッケルの含有率は１質量％以上かつ３０質量％以下であることが好ましく、亜鉛の含有率は８５質量％以上かつ９０質量％以下でありニッケルの含有率は１０質量％以上かつ１５質量％以下であることがより好ましい。亜鉛ニッケル合金皮膜は亜鉛およびニッケル以外の金属元素を意図的に含んでもよいし、意図的に含まなくてもよい。亜鉛ニッケル合金皮膜に含まれる亜鉛およびニッケル以外の金属元素の含有率（質量％）はニッケルの含有率（質量％）より小さい。亜鉛ニッケル合金皮膜に含まれる亜鉛およびニッケル以外の金属元素の含有率（質量％）はニッケルの含有率（質量％）の１／１０以下がより好ましく、例えば５質量％以下であり、１質量％ 以下である。第１皮膜１２の形成方法は電気めっき法を用い形成してもよいし、溶融めっき法を用い形成してもよい。膜厚の制御性および表面を滑らかに形成するため電気めっき法を用いることが好ましい。めっき液には光沢剤を含んでもよい。第１皮膜１２の膜厚は例えば１μｍ～２０μｍであり、一例として６μｍである。 [Step 2: Formation of first coating 12]
As shown in FIG. 1B, a first coating 12 is formed on a base material 10. The first coating 12 is a zinc or zinc alloy coating. The first coating 12 is, for example, a zinc coating, a zinc-nickel alloy coating, a zinc-iron alloy coating, or a zinc-tin alloy coating. The zinc coating does not intentionally contain any elements other than zinc. The zinc content in the zinc alloy coating is, for example, 70 to 99% by mass, and the content of metal elements other than zinc that are intentionally contained is, for example, 1 to 30% by mass. The content of unavoidable metal elements that are not intentionally contained is 1% by mass or less. When the zinc-based coating is a zinc-nickel alloy coating, the zinc content in the zinc-nickel alloy coating is preferably 70% by mass or more and 99% by mass or less, and the nickel content is preferably 1% by mass or more and 30% by mass or less, and more preferably the zinc content is 85% by mass or more and 90% by mass or less, and the nickel content is 10% by mass or more and 15% by mass or less. The zinc-nickel alloy coating may or may not intentionally contain metal elements other than zinc and nickel. The content (mass%) of metal elements other than zinc and nickel contained in the zinc-nickel alloy coating is smaller than the content (mass%) of nickel. The content (mass%) of metal elements other than zinc and nickel contained in the zinc-nickel alloy coating is preferably 1/10 or less of the content (mass%) of nickel, for example, 5 mass% or less, and more preferably 1 mass% or less. The first coating 12 may be formed by electroplating or hot-dip plating. It is preferable to use electroplating in order to control the thickness and form a smooth surface. The plating solution may contain a brightener. The thickness of the first coating 12 is, for example, 1 μm to 20 μm, and is, for example, 6 μm.
　亜鉛ニッケル合金を形成した後クロメート処理を行ってもよい。これにより、第１皮膜１２上にクロメート皮膜が形成される。クロメート処理としては、例えば三価または六価を含む処理液を用い、第１皮膜１２の表面を処理する。処理液は例えばクロム酸を含む。環境負荷の大きい六価クロムを用いない観点から処理液は三価クロムを含み六価クロムをほとんど含まないことが好ましい。第１皮膜１２が形成された下地材１０を処理液に浸漬することで、第１皮膜１２の表面にクロムを含む不動態皮膜（すなわちクロメート皮膜）が形成される。クロメート皮膜の膜厚は例えば０．０５μｍ～１μｍであり、一例として０．２μｍである。 After forming the zinc-nickel alloy, a chromate treatment may be performed. This forms a chromate film on the first film 12. For the chromate treatment, a treatment liquid containing, for example, trivalent or hexavalent chromium is used to treat the surface of the first film 12. The treatment liquid contains, for example, chromic acid. From the viewpoint of not using hexavalent chromium, which has a large environmental impact, it is preferable that the treatment liquid contains trivalent chromium and contains almost no hexavalent chromium. By immersing the base material 10 on which the first film 12 is formed in the treatment liquid, a passive film containing chromium (i.e., a chromate film) is formed on the surface of the first film 12. The thickness of the chromate film is, for example, 0.05 μm to 1 μm, and is 0.2 μm as an example.
［工程３：第２皮膜１４の形成］
　次に、図１（ｃ）に示すように、第１皮膜１２の表面に第２皮膜１４を形成する。図２（ａ）から図２（ｃ）は、実施形態１における第２皮膜の形成方法を示す断面図である。図２（ａ）に示すように、下地材１０上に第1皮膜１２が形成されている。 [Step 3: Formation of second coating 14]
Next, as shown in Fig. 1(c), a second coating 14 is formed on the surface of the first coating 12. Fig. 2(a) to Fig. 2(c) are cross-sectional views showing a method of forming the second coating in embodiment 1. As shown in Fig. 2(a), a first coating 12 is formed on a base material 10.
　図２（ｂ）に示すように、メカニカル乾式メッキ法を用い第１皮膜１２上に第２皮膜１４を形成する。メカニカル乾式メッキ法としては、常温において第１皮膜１２の表面に複数の粉体２０を衝突させる。粉体２０は、例えば亜鉛紛または亜鉛合金紛を含む。亜鉛粉は亜鉛（Ｚｎ）以外の元素を意図的に含まない。亜鉛合金粉は、例えば亜鉛を５０質量％以上含み、鉄（Ｆｅ）、ニッケル（Ｎｉ）、アルミニウム（Ａｌ）およびマグネシウム（Ｍｇ）の少なくとも１つの元素を含む。粉体２０の一例は、亜鉛を５０質量％以上含み、鉄を含む亜鉛合金である。粉体２０の別の一例は、亜鉛を５０質量％以上含み、アルミニウムおよびマグネシウムを含む亜鉛合金である。亜鉛合金は亜鉛を７０質量％以上含むことが好ましい。粉体２０は例えば球形であり、粉体２０の粒径は例えば１０μｍ以上かつ１５０μｍ以下であり、例えば１００μｍ以下である。例えば、粉体２０をバレル内に投入しバレルを回転させたときの遠心力、または空気圧等の熱以外のエネルギーを主に用い、粉体２０を第１皮膜１２の表面に高速に投射する。 As shown in FIG. 2(b), the second film 14 is formed on the first film 12 by using a mechanical dry plating method. In the mechanical dry plating method, a plurality of powders 20 are collided with the surface of the first film 12 at room temperature. The powders 20 include, for example, zinc powder or zinc alloy powder. The zinc powder does not intentionally include any elements other than zinc (Zn). The zinc alloy powder includes, for example, 50% by mass or more of zinc and at least one element of iron (Fe), nickel (Ni), aluminum (Al) and magnesium (Mg). One example of the powders 20 is a zinc alloy including 50% by mass or more of zinc and including iron. Another example of the powders 20 is a zinc alloy including 50% by mass or more of zinc and including aluminum and magnesium. It is preferable that the zinc alloy includes 70% by mass or more of zinc. The powders 20 are, for example, spherical, and the particle size of the powders 20 is, for example, 10 μm or more and 150 μm or less, for example, 100 μm or less. For example, the powder 20 is injected into a barrel and centrifugal force generated when the barrel is rotated, or energy other than heat, such as air pressure, is mainly used to project the powder 20 onto the surface of the first coating 12 at high speed.
　図２（ｃ）に示すように、粉体２０が第１皮膜１２の表面に衝突すると、粉体２０の運動エネルギーにより、粉体２０が潰れる。潰れた粉体１３は第１皮膜１２の表面に凝着する。複数の潰れた粉体１３は互いに接合し、積層する。これにより、潰れた粉体１３が接合した第２皮膜１４となる。第２皮膜１４には、潰れた粉体１３の接合した界面が存在する。また、第２皮膜１４の上面は粉体２０が衝突するため、凹凸が大きくなる。粉体２０が亜鉛粉のとき、第２皮膜１４は亜鉛皮膜となり、粉体２０が亜鉛合金粉のとき、第２皮膜１４は亜鉛合金皮膜となる。第２皮膜１４の厚さは例えば０．１μｍ以上かつ３μｍ以下であり、例えば０．２μｍ以上かつ０．５μｍ以下である。 As shown in FIG. 2(c), when the powder 20 collides with the surface of the first coating 12, the powder 20 is crushed by the kinetic energy of the powder 20. The crushed powder 13 adheres to the surface of the first coating 12. The crushed powder 13 are bonded to each other and stacked. This forms the second coating 14 in which the crushed powder 13 are bonded. The second coating 14 has an interface where the crushed powder 13 are bonded. In addition, the upper surface of the second coating 14 becomes uneven because the powder 20 collides with it. When the powder 20 is zinc powder, the second coating 14 becomes a zinc coating, and when the powder 20 is zinc alloy powder, the second coating 14 becomes a zinc alloy coating. The thickness of the second coating 14 is, for example, 0.1 μm or more and 3 μm or less, for example, 0.2 μm or more and 0.5 μm or less.
　図２（ｂ）において、粉体２０は、亜鉛または亜鉛合金より硬い核と、核の周囲に亜鉛層または亜鉛合金層と、を有してもよい。核は、例えば金属または絶縁体であり、例えば鉄または鉄合金のである。亜鉛層または亜鉛合金層の好ましい組成は上記した亜鉛紛または亜鉛合金紛の好ましい組成と同じである。図２（ｂ）において、粉体２０を第１皮膜１２の表面に衝突させるときに、複数の粉体２０と複数のショット球とを第１皮膜１２の表面に衝突させてもよい。ショット球は粉体２０より硬い金属または絶縁体であり、例えば鉄または鉄合金のである。ショット球は例えば球形であり、ショット球の平均粒径は例えば１０μｍ以上かつ１５０μｍ以下であり、例えば１００μｍ以下である。 In FIG. 2(b), the powder 20 may have a core harder than zinc or a zinc alloy, and a zinc layer or a zinc alloy layer around the core. The core is, for example, a metal or an insulator, for example, iron or an iron alloy. The preferred composition of the zinc layer or zinc alloy layer is the same as the preferred composition of the zinc powder or zinc alloy powder described above. In FIG. 2(b), when the powder 20 is collided with the surface of the first coating 12, a plurality of powders 20 and a plurality of shot balls may be collided with the surface of the first coating 12. The shot balls are, for example, a metal or an insulator harder than the powder 20, for example, iron or an iron alloy. The shot balls are, for example, spherical, and the average particle size of the shot balls is, for example, 10 μm or more and 150 μm or less, for example, 100 μm or less.
　図２（ａ）から図２（ｃ）のように形成した第２皮膜１４は、粉体２０が第１皮膜１２に衝突するため第２皮膜１４と第１皮膜１２との密着性がよい。特に、粉体２０が硬い核を有する場合、またはショット球と粉体２０とを第１皮膜１２に衝突させる場合、核またはショット球が潰れた粉体１３の表面に衝突するため、潰れた粉体１３は第１皮膜１２の表面により強固に凝着する。複数の潰れた粉体１３は互いに強固に接合する。さらに、第２皮膜１４の表面は凹凸はより大きくなる。粉体２０は、チタン粉体等の亜鉛および亜鉛合金以外の金属粉体、酸化アルミニウム等のセラミック粉体を含んでもよい。 The second coating 14 formed as shown in Figures 2(a) to 2(c) has good adhesion between the second coating 14 and the first coating 12 because the powder 20 collides with the first coating 12. In particular, when the powder 20 has a hard core, or when the shot ball and the powder 20 are collided with the first coating 12, the core or shot ball collides with the surface of the crushed powder 13, so that the crushed powder 13 adheres more firmly to the surface of the first coating 12. A plurality of crushed powders 13 are firmly bonded to each other. Furthermore, the surface of the second coating 14 has greater irregularities. The powder 20 may contain metal powders other than zinc and zinc alloys, such as titanium powder, and ceramic powders, such as aluminum oxide.
［工程４：第３皮膜１６の形成］
　次に、図１（ｄ）に示すように、第２皮膜１４の表面に亜鉛または亜鉛合金を含む第３皮膜１６を形成する。亜鉛化合物は、亜鉛に例えばアルミニウム、ニッケル、錫、鉄およびマグネシウムの少なくも１つを含む。第３皮膜１６は、亜鉛または亜鉛合金に加えケイ素化合物を含んでもよい。 [Step 4: Formation of third coating 16]
1(d), a third coating 16 containing zinc or a zinc alloy is formed on the surface of the second coating 14. The zinc compound contains zinc and at least one of aluminum, nickel, tin, iron, and magnesium. The third coating 16 may contain a silicon compound in addition to zinc or a zinc alloy.
　第３皮膜１６の形成方法の一列としては、第２皮膜１４上に第３皮膜用溶剤を塗布し、加熱処理（焼付け処理）することで形成する。第３皮膜用溶剤は、亜鉛粉体、有機ケイ素化合物および溶媒を含む。第３皮膜用溶液は、亜鉛粉体に加え、アルミニウム粉体、ニッケル粉体、錫粉体、鉄粉体およびマグネシウム粉体の少なくも１種類の金属粉体を含んでいてもよい。特に、第３皮膜用溶液は、亜鉛粉体とアルミニウム粉体を含むことが好ましい。亜鉛粉体および金属粉体の形状は、例えば球状でもよいし鱗片状でもよい。粉体の短径は例えば０．０５μｍ～５μｍであり、長径は例えば０．５μｍ～１００μｍである。亜鉛粉体は、例えば亜鉛を９０質量％以上または９９質量％以上含む。亜鉛以外の金属粉体（例えばアルミニウム粉体）は、例えば亜鉛以外の金属元素（例えばアルミニウム）を９０質量％以上または９９質量％以上含む。亜鉛粉体と亜鉛以外の金属粉体（例えばアルミニウム粉体）との合計の粉体質量に対する亜鉛粉体の質量の比は５０質量％以上が好ましく、７０質量％以上がより好ましい。亜鉛粉体と亜鉛以外の金属粉体（例えばアルミニウム粉体）との合計の粉体質量に対する亜鉛以外の金属粉体（例えばアルミニウム）の質量の比は１質量％以上が好ましく、５質量％以上がより好ましい。 In one method of forming the third coating 16, a solvent for the third coating is applied onto the second coating 14 and then heated (baked). The solvent for the third coating contains zinc powder, an organosilicon compound, and a solvent. The solution for the third coating may contain at least one type of metal powder, such as aluminum powder, nickel powder, tin powder, iron powder, and magnesium powder, in addition to zinc powder. In particular, it is preferable that the solution for the third coating contains zinc powder and aluminum powder. The shape of the zinc powder and the metal powder may be, for example, spherical or scaly. The powder has a short diameter of, for example, 0.05 μm to 5 μm, and a long diameter of, for example, 0.5 μm to 100 μm. The zinc powder contains, for example, 90% by mass or more or 99% by mass or more of zinc. The metal powder other than zinc (for example, aluminum powder) contains, for example, 90% by mass or more or 99% by mass or more of a metal element other than zinc (for example, aluminum). The ratio of the mass of zinc powder to the total powder mass of zinc powder and metal powder other than zinc (e.g. aluminum powder) is preferably 50% by mass or more, more preferably 70% by mass or more. The ratio of the mass of metal powder other than zinc (e.g. aluminum) to the total powder mass of zinc powder and metal powder other than zinc (e.g. aluminum powder) is preferably 1% by mass or more, more preferably 5% by mass or more.
　有機ケイ素化合物は例えばアルコキシシランおよびその加水分解物の少なくとも一方を含む。アルコキシシランは、特に炭素数が３個以下のテトラメトキシシラン、テトラエトキシシラン、テトラプロポキシシラン等のテトラアルコキシシランが好ましい。第３皮膜用溶液の溶媒は、例えばアルコール類、エステル類、グリコール類またはエーテル類である。溶媒は、特にメタノール、エタノール、プロパノール、イソプロパノール、ブタノール、ヘキサノール、メトキシブタノール、メトキシメチルブタノール等のアルコール類が好ましい。第３皮膜用溶液内の亜鉛粉体および金属粉体の合計の含有量は例えば２０～６０質量％である。溶液内の有機シリコン化合物の含有量は例えば５～４０質量％である。第３皮膜用溶液内の有機溶剤の含有量は例えば１０～６０質量％である。 The organosilicon compound includes, for example, at least one of an alkoxysilane and a hydrolyzate thereof. The alkoxysilane is preferably a tetraalkoxysilane having 3 or less carbon atoms, such as tetramethoxysilane, tetraethoxysilane, or tetrapropoxysilane. The solvent of the third coating solution is, for example, an alcohol, ester, glycol, or ether. The solvent is preferably an alcohol, such as methanol, ethanol, propanol, isopropanol, butanol, hexanol, methoxybutanol, or methoxymethylbutanol. The total content of the zinc powder and metal powder in the third coating solution is, for example, 20 to 60 mass %. The content of the organosilicon compound in the solution is, for example, 5 to 40 mass %. The content of the organic solvent in the third coating solution is, for example, 10 to 60 mass %.
　第３皮膜用溶液の第２皮膜１４の表面への塗布は、例えば浸漬法、スプレー法またはスピンコート法を用いる。第３皮膜用溶液を塗布した後の加熱処理の温度は例えば１００℃～４００℃である。加熱処理の温度は第３皮膜用溶液内の溶媒が蒸発する温度以上である。加熱処理の時間は例えば１０分～１２０分である。これにより、第２皮膜１４の表面に第３皮膜１６が形成される。第３皮膜１６の膜厚は、例えば１μｍ～２０μｍであり、一例として８μｍである。第３皮膜１６内の亜鉛粉体および亜鉛以外の金属粉体（例えばアルミニウム粉体）の合計の含有量は例えば７０質量％以上かつ９５質量％以下であり、シリコン化合物の含有量は例えば５質量％以上かつ３０質量％以下である。亜鉛粉体と亜鉛以外の金属粉体（例えばアルミニウム粉体）との合計の粉体質量に対する亜鉛粉体の質量の比は５０％以上が好ましく、７０％以上がより好ましい。一例として第３皮膜１６における亜鉛粉体の含有量は７０質量％、アルミニウム粉体の含有量は１５質量％、シリコン化合物の含有量は１５質量％である。 The third coating solution is applied to the surface of the second coating 14 by, for example, dipping, spraying, or spin coating. The temperature of the heat treatment after applying the third coating solution is, for example, 100°C to 400°C. The temperature of the heat treatment is equal to or higher than the temperature at which the solvent in the third coating solution evaporates. The heat treatment time is, for example, 10 minutes to 120 minutes. As a result, the third coating 16 is formed on the surface of the second coating 14. The thickness of the third coating 16 is, for example, 1 μm to 20 μm, and is, for example, 8 μm. The total content of zinc powder and metal powder other than zinc (e.g. aluminum powder) in the third coating 16 is, for example, 70 mass% or more and 95 mass% or less, and the content of silicon compounds is, for example, 5 mass% or more and 30 mass% or less. The ratio of the mass of zinc powder to the total powder mass of zinc powder and metal powder other than zinc (e.g. aluminum powder) is preferably 50% or more, and more preferably 70% or more. As an example, the zinc powder content in the third coating 16 is 70% by mass, the aluminum powder content is 15% by mass, and the silicon compound content is 15% by mass.
［工程５：シリカ皮膜１８の形成］
　次に、図１（ｅ）に示すように、第３皮膜１６上に多孔質シリカ皮膜１８を形成する。多孔質シリカ皮膜１８の形成は、第３皮膜１６上にシリカ皮膜用溶液を塗布し、加熱処理（焼付け処理）することで形成する。シリカ皮膜用溶液は、シリコン化合物および溶媒を含む。シリコン化合物は例えばオルガノシロキサンおよびシランカップリング剤の少なくとも一方である。シリコン化合物は、ケイ酸アルカリ金属を含んでもよい。シリカ皮膜用溶液はチタン化合物を含んでもよい。チタン化合物は例えば有機チタネート化合物である。シリカ皮膜用溶液の溶媒は、例えば水、アルコール類、エステル類、グリコール類またはエーテル類である。シリカ皮膜用溶液内のシリコン化合物の含有量は例えば４０質量％以上かつ９０質量％以下であり、溶媒の含有量は例えば１０質量％以上かつ６０質量％以下である。シリカ皮膜用溶液を第３皮膜１６の表面へ塗布することで、第３皮膜１６の表面に例えばポリオルガノシロキサン薄膜が形成される。 [Step 5: Formation of silica coating 18]
Next, as shown in FIG. 1(e), a porous silica film 18 is formed on the third film 16. The porous silica film 18 is formed by applying a silica film solution onto the third film 16 and performing a heat treatment (baking treatment). The silica film solution contains a silicon compound and a solvent. The silicon compound is, for example, at least one of an organosiloxane and a silane coupling agent. The silicon compound may contain an alkali metal silicate. The silica film solution may contain a titanium compound. The titanium compound is, for example, an organic titanate compound. The solvent of the silica film solution is, for example, water, alcohols, esters, glycols, or ethers. The content of the silicon compound in the silica film solution is, for example, 40% by mass or more and 90% by mass or less, and the content of the solvent is, for example, 10% by mass or more and 60% by mass or less. By applying the silica film solution to the surface of the third film 16, a polyorganosiloxane thin film, for example, is formed on the surface of the third film 16.
　シリカ皮膜用溶液の第３皮膜１６の表面への塗布は、例えば浸漬法、スプレー法またはスピンコート法を用いる。シリカ皮膜用溶液を塗布した後の加熱処理の温度は例えば１００℃～４００℃である。加熱処理の温度はシリカ皮膜用溶液内の溶媒が蒸発する温度以上である。加熱処理の時間は例えば１０分～１２０分である。これにより、第３皮膜１６の表面に多孔質シリカ皮膜１８が形成される。シリカ皮膜１８の膜厚は、例えば０．１μｍ～１０μｍであり、一例として１μｍである。多孔質シリカ皮膜１８がシリコン化合物とチタン化合物を含む場合、シリコン化合物の含有量は例えば５０質量％以上かつ９５質量％以下であり、チタン化合物の含有量は例えば５質量％以上かつ５０質量％以下であり、一例としてシリコン化合物およびチタン化合物の含有量はそれぞれ７５質量％および２５質量％である。 The silica film solution is applied to the surface of the third film 16 by, for example, dipping, spraying, or spin coating. The temperature of the heat treatment after applying the silica film solution is, for example, 100°C to 400°C. The temperature of the heat treatment is equal to or higher than the temperature at which the solvent in the silica film solution evaporates. The heat treatment time is, for example, 10 minutes to 120 minutes. As a result, a porous silica film 18 is formed on the surface of the third film 16. The thickness of the silica film 18 is, for example, 0.1 μm to 10 μm, and is, for example, 1 μm. When the porous silica film 18 contains a silicon compound and a titanium compound, the content of the silicon compound is, for example, 50 mass% or more and 95 mass% or less, and the content of the titanium compound is, for example, 5 mass% or more and 50 mass% or less, and, for example, the content of the silicon compound and the titanium compound are 75 mass% and 25 mass%, respectively.
　特許文献１では、過酷な条件下では亜鉛または亜鉛合金皮膜と混合皮膜とが剥がれが生じることがある。実施形態１では、図２（ａ）から図２（ｃ）のように、下地材１０上に形成された亜鉛または亜鉛合金皮膜である第１皮膜１２の表面に、亜鉛または亜鉛合金を含む複数の粉体２０を衝突させることで、亜鉛または亜鉛合金皮膜であり表面が凹凸状である第２皮膜１４を形成する。図１（ｄ）のように、第２皮膜１４の表面に、亜鉛または亜鉛合金を含む第３皮膜１６を形成する。複数の粉体２０が第１皮膜１２の表面に衝突することで、第１皮膜１２と第２皮膜１４とは強固に接合する。また、第２皮膜１４の表面は凹凸面となるため、第２皮膜１４と第３皮膜１６とが強固に接合する。これにより、第１皮膜１２と第３皮膜１６とのの密着性を向上させることができる。このように形成した第２皮膜１４は、図２（ｃ）のように、亜鉛または亜鉛合金を含む複数の粉体１３が潰れ互いに接合した構造を有する。 In Patent Document 1, peeling may occur between the zinc or zinc alloy coating and the mixed coating under harsh conditions. In the first embodiment, as shown in FIG. 2(a) to FIG. 2(c), a plurality of powders 20 containing zinc or zinc alloy are collided with the surface of the first coating 12, which is a zinc or zinc alloy coating formed on the base material 10, to form the second coating 14, which is a zinc or zinc alloy coating and has an uneven surface. As shown in FIG. 1(d), a third coating 16 containing zinc or zinc alloy is formed on the surface of the second coating 14. The plurality of powders 20 collide with the surface of the first coating 12, so that the first coating 12 and the second coating 14 are firmly bonded to each other. In addition, since the surface of the second coating 14 is an uneven surface, the second coating 14 and the third coating 16 are firmly bonded to each other. This improves the adhesion between the first coating 12 and the third coating 16. The second coating 14 formed in this manner has a structure in which multiple powder particles 13 containing zinc or a zinc alloy are crushed and bonded to each other, as shown in FIG. 2(c).
　図２（ｂ）において、第２皮膜１４を形成するときに、複数の粉体２０は、亜鉛または亜鉛合金より硬い剛体紛（核またはショット球）を含む。剛体紛が第１皮膜１２の表面に付着した亜鉛または亜鉛合金に衝突する。これにより、第１皮膜１２と第２皮膜１４とがより強固に接合し、第２皮膜１４の表面はより凹凸面となり第２皮膜１４と第３皮膜１６とがより強固に接合する。これにより、第１皮膜１２と第３皮膜１６とのの密着性をより向上させることができる。 In FIG. 2(b), when the second coating 14 is formed, the multiple powders 20 include rigid powder (nuclei or shot balls) that are harder than zinc or zinc alloy. The rigid powder collides with the zinc or zinc alloy attached to the surface of the first coating 12. This makes the first coating 12 and the second coating 14 more firmly bonded together, and the surface of the second coating 14 becomes more uneven, so that the second coating 14 and the third coating 16 are more firmly bonded together. This can further improve the adhesion between the first coating 12 and the third coating 16.
　粉体２０は、亜鉛および鉄を含有する合金、または、亜鉛、マグネシウムおよびアルミニウムを含有する合金を含む。これにより、第１皮膜１２と第３皮膜１６とのの密着性をより向上させることができる。 The powder 20 contains an alloy containing zinc and iron, or an alloy containing zinc, magnesium, and aluminum. This can further improve the adhesion between the first coating 12 and the third coating 16.
　図１（ｄ）における第３皮膜１６の形成では、第２皮膜１４の表面に亜鉛粉体および有機ケイ素化合物を含む溶液を塗布し、加熱処理することで第３皮膜１６を形成する。特許文献１のように第１皮膜１２上に第３皮膜１６を形成することにより耐食性を向上できる。しかし、第１皮膜１２上に第３皮膜１６を形成すると第１皮膜１２と第３皮膜１６との密着性が低下する。そこで、第２皮膜１４を形成することが好ましい。 In forming the third coating 16 in FIG. 1(d), a solution containing zinc powder and an organosilicon compound is applied to the surface of the second coating 14, and then heat-treated to form the third coating 16. As in Patent Document 1, forming the third coating 16 on the first coating 12 can improve corrosion resistance. However, forming the third coating 16 on the first coating 12 reduces the adhesion between the first coating 12 and the third coating 16. Therefore, it is preferable to form the second coating 14.
　また、図１（ｄ）における第３皮膜１６の形成では、第２皮膜１４の表面に亜鉛粉体、アルミニウム粉体、並びにアルコキシシランおよびその加水分解物の少なくとも一方を含む溶液を塗布し、加熱処理することで第３皮膜１６を形成する。これにより第１皮膜１２上に第３皮膜１６を形成することにより耐食性を向上できる。しかし、第１皮膜１２上に第３皮膜１６を形成すると第１皮膜１２と第３皮膜１６との密着性が低下する。そこで、第２皮膜１４を形成することが好ましい。このように形成した第３皮膜１６は、亜鉛およびアルミニウムを含む。 In addition, in forming the third coating 16 in FIG. 1(d), a solution containing zinc powder, aluminum powder, and at least one of alkoxysilane and its hydrolysate is applied to the surface of the second coating 14, and then heat-treated to form the third coating 16. By forming the third coating 16 on the first coating 12 in this way, corrosion resistance can be improved. However, forming the third coating 16 on the first coating 12 reduces the adhesion between the first coating 12 and the third coating 16. Therefore, it is preferable to form the second coating 14. The third coating 16 formed in this way contains zinc and aluminum.
　図１（ａ）のように、第１皮膜１２は、亜鉛ニッケル合金皮膜である。また、下地材１０上に、電気めっき法を用い第１皮膜１２を形成する。この場合、第２皮膜１４を設けないと第１皮膜１２と第３皮膜１６との密着性が低下することがある。よって、第２皮膜１４を形成することが好ましい。 As shown in FIG. 1(a), the first coating 12 is a zinc-nickel alloy coating. The first coating 12 is formed on the base material 10 by electroplating. In this case, if the second coating 14 is not provided, the adhesion between the first coating 12 and the third coating 16 may decrease. Therefore, it is preferable to form the second coating 14.
　第２皮膜１４を形成する前に、第１皮膜１２に三価クロムを含む溶液を用いクロメート処理を行う。これにより、第１皮膜１２と第２皮膜１４との密着性がより向上する。 Before forming the second coating 14, the first coating 12 is chromated using a solution containing trivalent chromium. This further improves the adhesion between the first coating 12 and the second coating 14.
　また、図１（ｅ）のように、第３皮膜１６上にシリカ皮膜１８（多孔質シリカ皮膜）を形成してもよい。これにより、耐食性がより向上する。 Also, as shown in FIG. 1(e), a silica film 18 (porous silica film) may be formed on the third film 16. This further improves corrosion resistance.
　実施例および比較例として、以下の実験を行った。実験の工程は以下である。
工程１：下地材１０としてＳＰＣＣ－ＳＤ鋼材のＭ２４六角ボルト、Ｍ２４ナットおよびＭ２４ワッシャーを準備した。 The following experiments were carried out as examples and comparative examples. The steps of the experiments are as follows.
Step 1: An M24 hexagonal bolt, an M24 nut and an M24 washer made of SPCC-SD steel were prepared as the base material 10.
工程２：下地材１０に電気めっきを施し第１皮膜１２として亜鉛ニッケル合金皮膜を形成した。亜鉛とニッケルとの質量比を２０：３とし、水酸化ナトリウム水溶液に溶解させためっき液を用いた。第１皮膜１２を形成後、第１皮膜１２の表面を水洗した。第１皮膜１２の膜厚は約６μｍであり、第１皮膜１２内の亜鉛の含有率は８７～９２質量％、ニッケルの含有量は８～１３質量％である。その後、三価クロムを含む溶液を用いクロメート処理を行った。クロメート処理によりクロメート皮膜の膜厚は約０．２μｍである。 Step 2: The base material 10 was electroplated to form a zinc-nickel alloy coating as the first coating 12. A plating solution was used in which zinc and nickel were dissolved in an aqueous sodium hydroxide solution with a mass ratio of 20:3. After the first coating 12 was formed, the surface of the first coating 12 was washed with water. The thickness of the first coating 12 was approximately 6 μm, and the zinc content in the first coating 12 was 87 to 92 mass %, and the nickel content was 8 to 13 mass %. Then, a chromate treatment was performed using a solution containing trivalent chromium. The thickness of the chromate coating after the chromate treatment was approximately 0.2 μm.
　工程３：第１皮膜１２の表面に第２皮膜１４を形成した。粉体２０を直径が約１００μｍの球形の亜鉛合金粉とした。亜鉛合金粉は、直径が約１００μｍであり、亜鉛、アルミニウムおよびマグネシウムからなる合金であり５０質量％以上の亜鉛を含む。ショット球として直径が約１００μｍの球形のステンレス球を用いた。第２皮膜１４の厚さは０．２μｍ～０．３μｍ程度である。 Step 3: A second coating 14 was formed on the surface of the first coating 12. The powder 20 was a spherical zinc alloy powder with a diameter of approximately 100 μm. The zinc alloy powder was an alloy of zinc, aluminum, and magnesium with a diameter of approximately 100 μm, and contained 50% or more by mass of zinc. Spherical stainless steel balls with a diameter of approximately 100 μm were used as shot balls. The thickness of the second coating 14 was approximately 0.2 μm to 0.3 μm.
　工程４：第２皮膜１４の表面に第３皮膜１６を形成した。第３皮膜用溶液として、ユケン工業株式会社製　メタス　ＹＣ－Ｂ１７Ｊとメタス　ＹＣ－Ｂ３とを体積比２５：３の比率で混合し、第１皮膜１２の表面に塗布した。その後、２５０℃～２９０℃において３０分以上の加熱処理を行った。以上の塗布および加熱処理を２回繰り返した。ＹＣ－Ｂ１７Ｊには、亜鉛粉体、亜鉛以外の金属粉体としてアルミニウム粉体、有機ケイ素化合物としてテトラエトキシシランが含まれている。第３皮膜１６の膜厚は約８μｍであり、第３皮膜１６内の亜鉛、アルミニウムおよびシリコン化合物の含有率はそれぞれ７０質量％、１５質量％および１５質量％である。 Step 4: A third coating 16 was formed on the surface of the second coating 14. As a solution for the third coating, Metas YC-B17J and Metas YC-B3 manufactured by Yuken Kogyo Co., Ltd. were mixed in a volume ratio of 25:3 and applied to the surface of the first coating 12. Then, a heat treatment was performed for 30 minutes or more at 250°C to 290°C. The above application and heat treatment were repeated twice. YC-B17J contains zinc powder, aluminum powder as a metal powder other than zinc, and tetraethoxysilane as an organosilicon compound. The thickness of the third coating 16 is about 8 μm, and the zinc, aluminum, and silicon compound contents in the third coating 16 are 70 mass%, 15 mass%, and 15 mass%, respectively.
　工程５：第３皮膜１６の表面に多孔質シリカ皮膜１８を形成した。シリカ皮膜用溶液として、ユケン工業株式会社製　メタスＹＣ－Ｔ、ルブラスＣ１４またはルブラスＣ２４を用い、第３皮膜１６の表面に塗布した。その後、１１０℃～１６０℃において１０分以上の加熱処理を行った。多孔質シリカ皮膜１８の膜厚は約１μｍであり、シリコン化合物およびチタン化合物の含有量はそれぞれ７５質量％および２５質量％である。 Step 5: A porous silica film 18 was formed on the surface of the third film 16. Metas YC-T, Lubras C14 or Lubras C24 manufactured by Yuken Kogyo Co., Ltd. was used as a silica film solution and applied to the surface of the third film 16. Then, a heat treatment was performed at 110°C to 160°C for 10 minutes or more. The thickness of the porous silica film 18 was about 1 μm, and the content of the silicon compound and the titanium compound was 75% by mass and 25% by mass, respectively.
［比較例］
　比較例１として、工程３を実施しないサンプルを作成した。比較例２として、工程３の代わりにアルカリ粗し処理を行いサンプルを作成した。アルカリ粗し処理は、第１皮膜１２の表面を強アルカリ溶液に曝す処理であり、第１皮膜１２の表面を粗面とすることができる。強アルカリ溶液はＮａＯＨの濃度が１００ｇ／Ｌの水溶液を用いた。処理温度は２０℃～３０℃であり、処理時間は５分～１０分である。 [Comparative Example]
As Comparative Example 1, a sample was prepared without carrying out step 3. As Comparative Example 2, a sample was prepared by carrying out an alkaline roughening treatment instead of step 3. The alkaline roughening treatment is a treatment in which the surface of the first coating 12 is exposed to a strong alkaline solution, and the surface of the first coating 12 can be made rough. The strong alkaline solution used was an aqueous solution of NaOH with a concentration of 100 g/L. The treatment temperature was 20°C to 30°C, and the treatment time was 5 to 10 minutes.
［クロスカット法試験］
　密着性の評価として、ＪＩＳ－Ｋ５６００－５－６（ＩＳＯ２４０９）により規定されているクロスカット法を用い皮膜の付着性を評価した。皮膜に１ｍｍ間隔で格子状の６本×６本の切り込みを入れ、切込みを入れた皮膜上に粘着テープを貼り付けはがす。切込みを入れた領域の皮膜の剥がれの程度により皮膜の密着性を評価した。剥がれの程度はＪＩＳ－Ｋ５６００－５－６の分類とした。分類０では、剥がれがほとんどなく、分類が大きくなると剥がれが大きいことを示している。 [Cross-cut method test]
The adhesion of the film was evaluated using the cross-cut method specified by JIS-K5600-5-6 (ISO2409). A grid of 6 x 6 cuts was made in the film at 1 mm intervals, and an adhesive tape was attached to the film with the cuts and peeled off. The adhesion of the film was evaluated based on the degree of peeling of the film in the cut areas. The degree of peeling was classified according to JIS-K5600-5-6. Classification 0 indicates almost no peeling, and higher classifications indicate greater peeling.
　表１は、比較例１、２および実施例１におけるクロスカット法試験による密着性評価の結果を示す表である。
Figure JPOXMLDOC01-appb-T000001
 Table 1 shows the results of the adhesion evaluation by the cross-cut method test in Comparative Examples 1 and 2 and Example 1.
Figure JPOXMLDOC01-appb-T000001
　表１に示すように、比較例１では、クロスカット法の分類４であり密着性が低い。比較例２および実施例１では、クロスカット法の分類０であり、密着性が高い。比較例１では、耐食性が高いものの第１皮膜１２と第３皮膜１６の密着性が低く、第３皮膜１６が第１皮膜１２から剥がれやすい。比較例２のように、アルカリ粗し処理を行い第１皮膜１２の表面の凹凸を大きくした後、第１皮膜１２上に第３皮膜１６を形成すると、第１皮膜１２と第３皮膜１６との間の密着性が向上する。実施例１のように、第１皮膜１２上に第２皮膜１４を形成し、第２皮膜１４上に第３皮膜１６を形成すると、第１皮膜１２と第３皮膜１６との密着性が向上する。クロスカット法を用いた密着性評価では、比較例２および実施例１はいずれも良好である。 As shown in Table 1, Comparative Example 1 is classified as 4 by the cross-cut method and has low adhesion. Comparative Example 2 and Example 1 are classified as 0 by the cross-cut method and have high adhesion. Comparative Example 1 has high corrosion resistance, but the adhesion between the first film 12 and the third film 16 is low, and the third film 16 is easily peeled off from the first film 12. As in Comparative Example 2, when the third film 16 is formed on the first film 12 after performing an alkaline roughening treatment to increase the unevenness of the surface of the first film 12, the adhesion between the first film 12 and the third film 16 is improved. As in Example 1, when the second film 14 is formed on the first film 12 and the third film 16 is formed on the second film 14, the adhesion between the first film 12 and the third film 16 is improved. In the adhesion evaluation using the cross-cut method, both Comparative Example 2 and Example 1 are good.
［振動試験］
　比較例２および実施例１のボルト、ワッシャーおよびナットを箱詰めし、運搬による振動を与えた後の外観試験を行った。シリカ皮膜１８を形成するときの処理の異なる３種類のサンプルを用いた。各処理毎に、ボルトの個数は９個、ワッシャーの個数は１８個、ナットの個数は９個である。 [Vibration test]
The bolts, washers, and nuts of Comparative Example 2 and Example 1 were packed in boxes and subjected to vibration during transportation, after which an appearance test was carried out. Three types of samples were used, each of which was different in the treatment for forming the silica coating 18. For each treatment, the number of bolts was 9, the number of washers was 18, and the number of nuts was 9.
　図３は、比較例２における振動試験後の処理２のボルトの表面の写真である。図３に示すように、破線丸３０において振動試験により皮膜が剥がれている。このように、ボルト、ワッシャーおよびナットを箱詰めした箱に運搬の振動を加えると、各サンプルは衝突または擦れ皮膜が剥がれることがある。各サンプルについて振動試験後の皮膜の剥がれの有無を評価した。 Figure 3 is a photograph of the surface of the bolt of treatment 2 after the vibration test in Comparative Example 2. As shown in Figure 3, the coating has peeled off due to the vibration test at dashed circle 30. In this way, when a box containing bolts, washers, and nuts is subjected to vibration during transportation, each sample may be hit or rubbed, causing the coating to peel off. Each sample was evaluated for the presence or absence of coating peeling after the vibration test.
　表２は、比較例２、実施例１における振動試験による密着性評価の結果を示す表である。Ａ、ＢおよびＣは、工程５においてシリカ皮膜１８を形成するときに、異なるシリカ皮膜用溶液を用いている。
Figure JPOXMLDOC01-appb-T000002
 Table 2 shows the results of the adhesion evaluation by vibration test in Comparative Example 2 and Example 1. In A, B, and C, different silica coating solutions were used when forming the silica coating 18 in step 5.
Figure JPOXMLDOC01-appb-T000002
　表２に示すように、比較例２では、剥がれの発生が多く観察された。実施例１では剥がれはほとんど観察されない。比較例２のように、第１皮膜１２の表面の凹凸を大きくすることで、第１皮膜１２と第３皮膜１６との密着性が向上する。しかし、振動試験のように、大きな衝撃がサンプルに加わる場合に比較例２の密着性では不十分な場合もある。実施例１では、第２皮膜１４を設けることで、第１皮膜１２と第３皮膜１６との密着性を向上でき、かつ大きな衝撃がサンプルに加わっても第３皮膜１６が第１皮膜１２から剥がれることを抑制できる。 As shown in Table 2, peeling was observed frequently in Comparative Example 2. Peeling was hardly observed in Example 1. By increasing the unevenness of the surface of the first coating 12 as in Comparative Example 2, the adhesion between the first coating 12 and the third coating 16 is improved. However, when a large impact is applied to the sample, such as in a vibration test, the adhesion of Comparative Example 2 may be insufficient. In Example 1, by providing the second coating 14, the adhesion between the first coating 12 and the third coating 16 can be improved, and peeling of the third coating 16 from the first coating 12 can be suppressed even if a large impact is applied to the sample.
　図２（ａ）から図２（ｃ）のように、実施例１では、粉体２０を第１皮膜１２の表面に衝突させることにより、潰れた粉体１３と第１皮膜１２との密着性を向上させている。よって、実施例の結果は、第１皮膜１２が亜鉛または亜鉛合金の場合に一般化できると考えられる。第２皮膜１４の表面の凹凸が大きくなるため、第２皮膜１４と第３皮膜１６との密着が向上する。よって、実施例の結果は、第３皮膜１６が亜鉛または亜鉛合金の場合に一般化できると考えられる。シリカ皮膜１８は、耐食性の向上に寄与するものの、第１皮膜１２と第３皮膜１６との密着性にはあまり寄与しないと考えられる。よって、実施例１の結果はシリカ皮膜１８を用いない場合にも一般化できる。 2(a) to 2(c), in Example 1, the powder 20 is collided with the surface of the first coating 12 to improve the adhesion between the crushed powder 13 and the first coating 12. Therefore, the results of the Example are considered to be generalizable to cases where the first coating 12 is zinc or a zinc alloy. The surface unevenness of the second coating 14 increases, improving the adhesion between the second coating 14 and the third coating 16. Therefore, the results of the Example are considered to be generalizable to cases where the third coating 16 is zinc or a zinc alloy. Although the silica coating 18 contributes to improving corrosion resistance, it is considered not to contribute much to the adhesion between the first coating 12 and the third coating 16. Therefore, the results of Example 1 are also generalizable to cases where the silica coating 18 is not used.
　以上、本発明の実施例について詳述したが、本発明はかかる特定の実施例に限定されるものではなく、特許請求の範囲に記載された本発明の要旨の範囲内において、種々の変形・変更が可能である。 　Although the embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as described in the claims.
　１０　下地材
　１２　第１皮膜
　１４　第２皮膜
　１６　第３皮膜
　１８　シリカ皮膜
　 10 Base material 12 First coating 14 Second coating 16 Third coating 18 Silica coating

Claims (12)

  1. 　下地材上に形成された亜鉛または亜鉛合金皮膜である第１皮膜の表面に、亜鉛または亜鉛合金を含む複数の粉体を衝突させることで、亜鉛または亜鉛合金皮膜であり表面が凹凸状である第２皮膜を形成する工程と、
    　前記第２皮膜の表面に、亜鉛または亜鉛合金を含む第３皮膜を形成する工程と、
    を含む皮膜形成方法。     a step of forming a second coating, which is a zinc or zinc alloy coating and has an uneven surface, by colliding a plurality of powders containing zinc or a zinc alloy onto a surface of a first coating, which is a zinc or zinc alloy coating formed on a base material;
    forming a third coating containing zinc or a zinc alloy on a surface of the second coating;
    A method for forming a coating comprising the steps of:
  2. 　前記複数の粉体は、前記亜鉛または亜鉛合金より硬い剛体紛を含む請求項１に記載の皮膜形成方法。 The coating formation method according to claim 1, wherein the plurality of powders includes a rigid powder harder than the zinc or zinc alloy.
  3. 　前記複数の粉体は、亜鉛および鉄を含有する合金、または、亜鉛、マグネシウムおよびアルミニウムを含有する合金を含む請求項１または２に記載の皮膜形成方法。 The coating formation method according to claim 1 or 2, wherein the plurality of powders include an alloy containing zinc and iron, or an alloy containing zinc, magnesium, and aluminum.
  4. 　前記第３皮膜を形成する工程は、前記第２皮膜の表面に亜鉛粉体および有機ケイ素化合物を含む溶液を塗布し、加熱処理することにより前記第３皮膜を形成する工程を含む請求項１または２に記載の皮膜形成方法。 The method for forming a film according to claim 1 or 2, wherein the step of forming the third film includes a step of applying a solution containing zinc powder and an organosilicon compound to the surface of the second film, and then performing a heat treatment to form the third film.
  5. 　前記第３皮膜を形成する工程は、前記第２皮膜の表面に亜鉛粉体、アルミニウム粉体、並びにアルコキシシランおよびその加水分解物の少なくとも一方を含む溶液を塗布し、加熱処理することにより前記第３皮膜を形成する工程を含む請求項１または２に記載の皮膜形成方法。 The method for forming a film according to claim 1 or 2, wherein the step of forming the third film includes a step of applying a solution containing zinc powder, aluminum powder, and at least one of an alkoxysilane and a hydrolyzate thereof to the surface of the second film, and then performing a heat treatment to form the third film.
  6. 　前記第１皮膜は、亜鉛ニッケル合金皮膜である請求項１または２に記載の皮膜形成方法。 The coating formation method according to claim 1 or 2, wherein the first coating is a zinc-nickel alloy coating.
  7. 　下地材上に、電気めっき法を用い前記第１皮膜を形成する工程を含む請求項１または２に記載の皮膜形成方法。 The method for forming a coating according to claim 1 or 2, which includes a step of forming the first coating on a base material using an electroplating method.
  8. 　前記第２皮膜を形成する工程の前に、前記第１皮膜の表面に三価クロムを含む溶液を用いクロメート処理を行う工程を含む請求項１または２に記載の皮膜形成方法。 The method for forming the coating according to claim 1 or 2, further comprising a step of performing a chromate treatment on the surface of the first coating using a solution containing trivalent chromium before the step of forming the second coating.
  9. 　前記第３皮膜の表面にシリカ皮膜を形成する工程を含む請求項１または２に記載の皮膜形成方法。 The coating method according to claim 1 or 2, which includes a step of forming a silica coating on the surface of the third coating.
  10. 　下地材上に、電気めっき法を用い亜鉛ニッケル合金皮膜である第１皮膜を形成する工程と、
    　前記第１皮膜の表面に、亜鉛または亜鉛合金と前記亜鉛または亜鉛合金より硬い剛体紛とを含む複数の粉体を衝突させることで、亜鉛合金皮膜であり表面が凹凸状である第２皮膜を形成する工程と、
    　前記第２皮膜の表面に、亜鉛粉体、アルミニウム粉体、並びにアルコキシシランおよびその加水分解物の少なくとも一方を含む溶液を塗布し、加熱処理することで混合皮膜を形成する工程と、
    を含む皮膜形成方法。     forming a first coating, which is a zinc-nickel alloy coating, on a base material by electroplating;
    a step of forming a second coating, which is a zinc alloy coating and has an uneven surface, by colliding a plurality of powders, which include zinc or a zinc alloy and a rigid powder harder than the zinc or the zinc alloy, on a surface of the first coating;
    A step of applying a solution containing zinc powder, aluminum powder, and at least one of an alkoxysilane and a hydrolyzate thereof to a surface of the second coating film, and performing a heat treatment to form a mixed coating film;
    A method for forming a coating comprising the steps of:
  11. 　下地材と、
    　前記下地材上に形成された亜鉛または亜鉛合金皮膜である第１皮膜と、
    　前記第１皮膜の表面に設けられ、亜鉛または亜鉛合金を含む複数の粉体が潰れ互いに接合した構造を有する亜鉛または亜鉛合金皮膜であり表面が凹凸状である第２皮膜と、
    　前記第２皮膜の表面に設けられ、亜鉛または亜鉛合金を含む第３皮膜と、
    を備える皮膜。     The base material and
    A first coating which is a zinc or zinc alloy coating formed on the base material;
    A second coating is provided on a surface of the first coating, and is a zinc or zinc alloy coating having a structure in which a plurality of powder particles containing zinc or a zinc alloy are crushed and bonded to each other, and has an uneven surface;
    a third coating provided on a surface of the second coating and containing zinc or a zinc alloy;
    A coating comprising:
  12. 　前記第１皮膜は亜鉛ニッケル合金皮膜であり、
    　前記複数の粉体は、亜鉛および鉄を含有する合金、または、亜鉛、マグネシウムおよびアルミニウムを含有する合金を含み、
    　前記第３皮膜は、亜鉛およびアルミニウムを含む請求項１１に記載の皮膜。
    　     the first coating is a zinc-nickel alloy coating,
    the plurality of powders include an alloy containing zinc and iron, or an alloy containing zinc, magnesium, and aluminum;
    The coating of claim 11 , wherein the third coating comprises zinc and aluminum.
PCT/JP2023/042194 2022-11-25 2023-11-24 Film and film formation method WO2024111661A1 (en)

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5645372A (en) * 1979-09-13 1981-04-25 Dowa Teppun Kogyo Kk Material for blast and surface treatment method by use of said material
JPS63179735A (en) * 1987-01-21 1988-07-23 住友金属工業株式会社 Coated steel material having excellent corrosion resistance after coating
JPH02138482A (en) * 1988-11-16 1990-05-28 Nkk Corp Production of steel plate coated with alloyed zinc by galvanization having excellent workability and paintability
JP2000144446A (en) * 1998-11-08 2000-05-26 Nkk Corp Organic-coated steel sheet excellent in corrosion resistance
JP2004002904A (en) * 2002-04-05 2004-01-08 Yuken Industry Co Ltd Base material provided with two-layered electrochemical formation treatment film and automobile parts
WO2009093318A1 (en) * 2008-01-24 2009-07-30 Yuken Industry Co., Ltd. Member with corrosion-resistant coating film, process for production of the same, and coating composition for the production thereof
JP2021063283A (en) * 2019-10-17 2021-04-22 株式会社鈴木商店 Coating formation method

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5645372A (en) * 1979-09-13 1981-04-25 Dowa Teppun Kogyo Kk Material for blast and surface treatment method by use of said material
JPS63179735A (en) * 1987-01-21 1988-07-23 住友金属工業株式会社 Coated steel material having excellent corrosion resistance after coating
JPH02138482A (en) * 1988-11-16 1990-05-28 Nkk Corp Production of steel plate coated with alloyed zinc by galvanization having excellent workability and paintability
JP2000144446A (en) * 1998-11-08 2000-05-26 Nkk Corp Organic-coated steel sheet excellent in corrosion resistance
JP2004002904A (en) * 2002-04-05 2004-01-08 Yuken Industry Co Ltd Base material provided with two-layered electrochemical formation treatment film and automobile parts
WO2009093318A1 (en) * 2008-01-24 2009-07-30 Yuken Industry Co., Ltd. Member with corrosion-resistant coating film, process for production of the same, and coating composition for the production thereof
JP2021063283A (en) * 2019-10-17 2021-04-22 株式会社鈴木商店 Coating formation method

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