JP4546884B2 - Surface treated galvanized steel sheet with excellent corrosion resistance - Google Patents

Description

  The present invention relates to a plated steel sheet, and more particularly to a plated steel sheet that has excellent processed portion corrosion resistance and can be applied as a steel sheet for various uses such as home appliances, automobiles, and building materials.

  One of the most commonly used plated steel sheets with good corrosion resistance is a zinc-based plated steel sheet. These plated steel sheets are used in various manufacturing industries such as automobiles, home appliances, and building materials.

  In particular, the use of Al-added plating has increased in recent years due to its high corrosion resistance.

  In order to improve the corrosion resistance of such a zinc-based plated steel sheet, the present inventors have proposed a molten Zn—Al—Mg—Si plated steel sheet in Japanese Patent No. 3179446.

  In order to improve the smoothness of the surface, the present inventors have disclosed a plated steel sheet to which an intermetallic compound having a high melting point is added in JP-A No. 2003-293108, and an Al-based intermetallic compound in JP-A No. 2003-328100. We proposed a plated steel sheet to which is added.

  Moreover, in order to give the above-mentioned and other previously disclosed plated steel sheets a higher level of rust prevention function, chromate treatment using hexavalent chromate or the like is widely performed after plating, and further if necessary. In other words, coating with an organic resin has been performed to provide high value-added functions such as designability, contamination resistance, and lubricity.

Japanese Patent No. 3179446 JP 2003-293108 A JP 2003-328100 A

  However, in recent years, there is a movement to refrain from using chromate treatment against the background of increasing environmental problems. Then, this invention is made | formed in view of the said problem, and it aims at providing an advanced rust prevention function simply by only one-layer process of a resin-type film | membrane, without performing a chromate process.

In addition, the zinc-based plated steel sheet with added Mg crystallizes the hard and brittle MgZn ₂ phase during plating, so cracking occurs in the plating when severe processing is performed on the zinc-based plated steel sheet with added Mg. There is a problem that corrosion resistance deterioration after processing is likely to occur due to. Since it is difficult to protect cracks generated in plating by only one-layer treatment of a resin-based film, even if coating is applied to such a hard and brittle MgZn ₂ phase, deterioration of corrosion resistance after processing cannot be improved. Has the problem.
Therefore, the present invention also aims to improve the corrosion resistance of the processed part of the plated steel sheet that has been further subjected to the resin-based coating without performing the chromate treatment.

As a result of intensive research on the development of a plated steel sheet having a small environmental load and excellent corrosion resistance at the processed part, the present inventors have found that [Mg ₂ Si in the base of [ternary eutectic structure of Al / Zn / MgZn ₂ ]. Phase spacing of one of the lattice directions constituting the lattice plane of the Bravey lattice in the [Al phase] of the plating layer in which the [phase], [Al phase] and [MgZn ₂ phase] are mixed is 2.57 mm or more and 3.15 mm. Hereinafter, a new finding that the corrosion resistance of the processed portion is improved by having a plating layer containing an intermetallic compound having a lattice plane with the other plane interval of 3.64 mm or more and 4.46 mm or less, and further, By applying a coating obtained by applying an aqueous composition containing a water-based resin and a metal oxide to the upper layer of the plating layer and drying, a new finding that higher corrosion resistance can be imparted is found, Main departure It came to complete Ming.

  That is, the gist of the present invention is as follows.

(1) On one side or both sides of the steel sheet, Al: 4 to 10% by mass, Mg: 1 to 5% by mass, and one plane interval in the lattice direction constituting the lattice plane of the Bravay lattice is 2.57 mm or more and 3.15 mm or less. And a plating layer of a plated steel sheet having a Zn alloy plating layer that includes an intermetallic compound having a lattice plane with the other surface interval of 3.64 to 4.46 mm, and the balance being composed of Zn and inevitable impurities. [Al / Zn / MgZn ₂ ternary eutectic structure] has a metal structure in which [Al phase] and [MgZn ₂ phase] are mixed, and [Al phase] has a Brabey lattice lattice. It is a plating layer containing an intermetallic compound having a lattice plane in which one plane interval in the lattice direction constituting the surface is 2.57 mm to 3.15 mm and the other plane interval is 3.64 mm to 4.46 mm. In addition, water on top of the plating layer That a coating obtained by applying and drying an aqueous composition containing 5 to 50% by mass of metal oxide particles (B) with respect to 100% by mass of the solid content of the conductive resin (A) is formed. A surface-treated plated steel sheet with excellent corrosion resistance at the machined part.

(2) On one side or both sides of the steel plate, Al: 4 to 22% by mass, Mg: 1 to 5% by mass, Si: 0.5% by mass or less, and one plane spacing in the lattice direction constituting the lattice plane of the Bravay lattice Alloy composition comprising an intermetallic compound having a lattice plane in which the distance between the other planes is not less than 2.57 mm and not more than 3.15 mm and the other plane spacing is not less than 3.64 mm and not more than 4.46 mm, and the balance is composed of Zn and inevitable impurities The plated layer of the plated steel sheet having a layer has a metal structure in which [Mg ₂ Si phase], [Al phase] and [MgZn ₂ phase] are mixed in the [Al / Zn / MgZn ₂ ternary eutectic structure] substrate And the [Al phase] has a lattice spacing of 2.57 mm or more and 3.15 mm or less in the lattice direction constituting the lattice plane of the Bravay lattice and the other surface spacing of 3.64 mm or more and 4.46 mm or less. Containing an intermetallic compound having a lattice plane of An aqueous composition containing 5 to 50% by mass of metal oxide particles (B) with respect to 100% by mass of the solid content of the aqueous resin (A) is further applied to the upper layer of the plating layer, A surface-treated plated steel sheet excellent in processed part corrosion resistance, characterized in that a film obtained by drying is formed.

(3) The crystal system of the intermetallic compound according to any one of (1) to (2) is any one of cubic, tetragonal, orthorhombic, monoclinic, and hexagonal. Surface-treated plated steel sheet excellent in processed part corrosion resistance (4) Surface excellent in processed part corrosion resistance characterized in that the content of the intermetallic compound according to any one of (1) to (3) is 1% by mass or less Treated plated steel sheet.

  (5) Intermetallic compound having a lattice plane in which the lattice spacing of one of the lattice directions constituting the lattice plane of the Bravais lattice is 2.57 mm or more and 3.15 mm or less and the other surface spacing is 3.64 mm or more and 4.46 mm or less. The surface treated galvanized steel sheet having excellent processed portion corrosion resistance according to any one of (1) to (4), characterized in that a primary arm of Al phase dendrite grows in the [110] direction.

  (6) The aqueous resin (A) is at least one selected from the group consisting of an aqueous polyester resin, an aqueous polyurethane resin, an aqueous epoxy resin, an aqueous acrylic resin, and an aqueous polyolefin resin. 5) A surface-treated plated steel sheet having excellent processed portion corrosion resistance.

  (7) The metal oxide particles (B) are made of at least one metal element selected from the group consisting of Si, Ti, Al, and Zr, according to any one of (1) to (6), Surface treated galvanized steel sheet with excellent corrosion resistance.

  (8) The aqueous composition further contains 0.01 to 20% by mass of the phosphoric acid compound (C) with respect to 100% by mass of the solid content of the aqueous resin (A). 7) A surface-treated plated steel sheet having excellent processed portion corrosion resistance.

  (9) The aqueous composition further contains at least one crosslinking agent (D) selected from the group consisting of a silane coupling agent, a crosslinkable zirconium compound, and a crosslinkable titanium compound. The surface-treated plated steel sheet having excellent processed portion corrosion resistance according to any one of (1) to (8), which is contained in an amount of 0.1 to 50% by mass with respect to mass%.

  (10) The aqueous composition further comprises at least one crosslinking agent (E) selected from the group consisting of an amino resin, a polyisocyanate compound, a block body thereof, an epoxy compound, and a carbodiimide compound. The surface-treated plated steel sheet having excellent processed portion corrosion resistance according to any one of (1) to (9), which is contained in an amount of 0.1 to 50% by mass with respect to 100% by mass.

  (11) The aqueous composition further contains at least one rust inhibitor (F) selected from the group consisting of a vanadium compound, a tungsten compound, and a molybdenum compound with respect to 100% by mass of the solid content of the aqueous resin (A). The surface-treated plated steel sheet having excellent processed part corrosion resistance according to any one of (1) to (10), characterized by containing 0.01 to 20% by mass.

  (12) The aqueous composition further comprises 0.1 to 50% by mass of the polyphenol compound (G) with respect to 100% by mass of the solid content of the aqueous resin (A). The surface-treated plated steel sheet having excellent processed portion corrosion resistance.

  (13) The aqueous composition further contains a solid lubricant (H) in an amount of 0.1 to 30% by mass with respect to 100% by mass of the solid content of the aqueous resin (A). 12) A surface-treated plated steel sheet having excellent processed portion corrosion resistance.

  (14) The surface-treated plated steel sheet having excellent processed portion corrosion resistance according to (13), wherein the solid lubricant (H) is a polyolefin wax having a particle size of 0.1 to 5.0 μm.

(15) The film obtained by applying and drying the aqueous composition is formed with an adhesion amount of 0.1 to 5 g / m ^2. Surface treated galvanized steel sheet with excellent corrosion resistance.

According to the present invention, it is possible to produce a surface-treated plated steel sheet having excellent processed portion corrosion resistance in a zinc-based plated steel sheet in which an MgZn ₂ phase is crystallized during plating, and an extremely excellent industrial effect can be achieved.

  The present invention is described in detail below.

  The surface-treated plated steel sheet of the present invention is obtained by sequentially providing a plating layer and a resin-based film layer on a steel sheet.

  As the base steel sheet of the present invention, both hot-rolled steel sheets and cold-rolled steel sheets can be used, and the steel grades are ultra-low carbon steel sheets added with Al killed steel, Ti, Nb, etc., and strengthening elements such as P, Si, Mn, etc. Various types such as added high strength steel and stainless steel can be applied.

In the plating layer of the present invention, Al: 4 to 10% by mass, Mg: 1 to 5% by mass, the interval between one plane in the lattice direction constituting the lattice plane of the Bravay lattice is 2.57 mm or more and 3.15 mm or less, and the other A plating layer containing an intermetallic compound having a lattice plane with a surface spacing of 3.64 mm or more and 4.46 mm or less, the balance being made of Zn and inevitable impurities, the plating layer being made of [Al / Zn / MgZn ₂ [Al phase] and [MgZn ₂ phase] are mixed in the matrix, and [Al phase] has one of the lattice directions constituting the lattice plane of the Bravay lattice. It is a plating layer containing an intermetallic compound having a lattice plane with a face spacing of 2.57 mm to 3.15 mm and the other face spacing of 3.64 mm to 4.46 mm, or Al: 4 to 22 Mass%, Mg: 1-5 mass%, Si: 0.5 quality Between metal having a lattice plane with an interval of 2.57 mm or more and 3.15 mm or less in the lattice direction constituting the lattice plane of the Bravais lattice, and an interval between the other planes of 3.64 mm or more and 4.46 mm or less. A plating layer containing a compound and the balance being Zn and inevitable impurities, and the plating layer is [Mg ₂ Si phase] and [Al phase in a [Al / Zn / MgZn ₂ ternary eutectic structure] substrate ] And [MgZn ₂ phase] are mixed, and the [Al phase] has a lattice spacing of 2.57 mm or more and 3.15 mm or less in one of the lattice directions constituting the lattice plane of the Bravey lattice. It is a plating layer containing an intermetallic compound having a lattice plane in which the other plane interval is 3.64 mm or more and 4.46 mm or less.

  The reason why the Al content in the Zn-Al-Mg based plating layer is limited to 4 to 10% by mass is that when the Al content exceeds 10% by mass, the plating adhesion is lowered, so Si is added. This is because the content of Al in the plating layer that is not necessary needs to be 10% by mass or less. In addition, when the amount is less than 4% by mass, the Al phase does not crystallize as the primary crystal, and thus the effect of improving the corrosion resistance of the processed portion by the Al layer is not observed.

  Therefore, in the plating layer according to the present invention, it is essential to add Si to the plating layer in order to ensure plating adhesion, particularly when the Al concentration is high such that the Al concentration exceeds 10% by mass. .

  On the other hand, in the Zn-Al-Mg-Si plating layer, the reason why the Al content is limited to 4 to 22% by mass is that when less than 4% by mass, the Al phase does not crystallize as the primary crystal. This is because the effect of improving the corrosion resistance is not obtained, and when the content exceeds 22% by mass, the effect of improving the corrosion resistance is saturated.

  The reason for limiting the Si content to 0.5% by mass or less (excluding 0% by mass) is that Si has the effect of improving the adhesion, but if it exceeds 0.5% by mass, the adhesion is improved. This is because the effect to be saturated is saturated. Desirably, it is 0.00001-0.5 mass%, More desirably, it is 0.0001-0.5 mass%.

The addition of Si is essential for plating layers with an Al content of more than 10% by mass. However, even in plating layers with an Al content of 10% or less, the effect of improving plating adhesion is great, so the parts are severely processed. It is effective to add Si when high plating adhesion is required. Moreover, [Mg ₂ Si phase] crystallizes in the solidified structure of the plating layer by addition of Si.

Since this [Mg ₂ Si phase] is effective in improving corrosion resistance, it is more desirable to increase the amount of Si added and to produce a metal structure in which [Mg ₂ Si phase] is mixed in the solidified structure of the plating layer.

The reason why the Mg content is limited to 1 to 5% by mass is that if the content is less than 1% by mass, the effect of improving the corrosion resistance is insufficient, and if it exceeds 5% by mass, the plating layer becomes brittle and the adhesion is reduced. It is because it falls. Since the above-mentioned [Mg ₂ Si phase] is more easily crystallized as the amount of Mg added is larger, the content of Mg is preferably 2 to 5% by mass for the purpose of further improving the corrosion resistance.

This plating layer is composed of [Zn phase], [Al phase], [MgZn ₂ phase], [Mg ₂ Si phase], intermetallic compound in the [Al / Zn / MgZn ₂ ternary eutectic structure] substrate. A metallographic structure comprising one or more is produced.

Here, [Al / Zn / MgZn ₂ ternary eutectic structure] is an ternary eutectic structure of an Al phase, a Zn phase, and an intermetallic compound MgZn ₂ phase. The formed Al phase corresponds to, for example, an "Al" phase "(Al solid solution that dissolves the Zn phase in a solid solution and contains a small amount of Mg) in an Al-Zn-Mg ternary equilibrium diagram. Is. The Al ″ phase at high temperature usually appears separated into a fine Al phase and a fine Zn phase at room temperature. The Zn phase in the ternary eutectic structure dissolves a small amount of Al, and in some cases Is a Zn solid solution in which a small amount of Mg is dissolved, and the MgZn ₂ phase in the ternary eutectic structure is a metal present in the vicinity of Zn: about 84% by weight in the Zn-Mg binary equilibrium diagram. As far as the phase diagram shows, Si and other additive elements are not dissolved in each phase, or even if they are dissolved, the amount is considered to be very small, but the amount is normal analysis. In this specification, the ternary eutectic structure consisting of these three phases is expressed as [Al / Zn / MgZn ₂ ternary eutectic structure].

  In addition, the [Al phase] is a phase that looks like an island with a clear boundary in the ternary eutectic structure, which is, for example, at a high temperature in an Al—Zn—Mg ternary equilibrium diagram. "Al" phase "(Al solid solution in which Zn phase is dissolved, and contains a small amount of Mg). The Al ″ phase at this high temperature differs in the amount of Zn and Mg dissolved depending on the Al and Mg concentrations in the plating bath. The Al ″ phase at this high temperature is usually fine Al phase and fine Zn at room temperature. Although it is separated into phases, it can be seen that the island-like shape seen at room temperature retains the shape of the Al ″ phase at high temperature. As far as the phase diagram shows, this phase contains Si and other additive elements. Although it is considered that it is not solid solution or is in very small amount even if it is in solid solution, it cannot be clearly distinguished by ordinary analysis. In this specification, the phase holding the structure is referred to as [Al phase], which can be clearly distinguished from the Al phase forming the ternary eutectic structure by microscopic observation.

  In addition, the [Zn phase] is a phase that looks like an island with a clear boundary in the ternary eutectic structure, and actually contains a small amount of Al and a small amount of Mg as a solid solution. There is also. As far as the phase diagram is concerned, it is considered that Si and other additive elements are not dissolved in this phase, or even if they are dissolved. This [Zn phase] can be clearly distinguished from the Zn phase forming the ternary eutectic structure by microscopic observation. The plating layer of the present invention may contain [Zn phase] depending on the production conditions, but since the experiment hardly showed any influence on the corrosion resistance improvement of the processed part, the plating layer contained [Zn phase]. There is no particular problem.

[MgZn ₂ phase] is a phase that looks like an island with a clear boundary in the ternary eutectic structure, and a small amount of Al may actually be dissolved. As far as the phase diagram is concerned, it is considered that Si and other additive elements are not dissolved in this phase, or even if they are dissolved. This [MgZn ₂ phase] can be clearly distinguished from the MgZn ₂ phase forming the ternary eutectic structure by microscopic observation.

The [Mg ₂ Si phase] is a phase that looks like an island with a clear boundary in the solidified structure of the plating layer to which Si is added. As far as the phase diagram is concerned, it is considered that Zn, Al, and other additive elements are not dissolved, or even if they are dissolved. This [Mg ₂ Si phase] can be clearly distinguished by microscopic observation during plating.

The surface-treated plated steel sheet of the present invention crystallizes a hard and brittle MgZn ₂ phase during plating. Therefore, when severe processing such as T-bending is performed, cracks occur in the plating, and this causes post-processing. Corrosion resistance is likely to deteriorate.

In order to improve the post-working corrosion resistance, the spacing between one surface in the lattice direction constituting the lattice plane of the Bravay lattice in [Al phase] is 2.57 mm or more and 3.15 mm or less, and the other surface spacing is 3.64 mm. It is effective to add an intermetallic compound having a lattice plane of 4.46 mm or more.
A plating layer is formed of an intermetallic compound having a lattice plane in which one surface interval in the lattice direction constituting the lattice plane of the Bravais lattice is 2.57 mm to 3.15 mm and the other surface interval is 3.64 mm to 4.46 mm. The reason why the corrosion resistance after processing is improved by adding to is considered to be the following two reasons.

1. With the addition of this intermetallic compound, the Al phase crystals become fine and uniform equiaxed crystals, the soft Al phase exists evenly between the ternary eutectic structure and the MgZn ₂ phase, and cracks propagating through the MgZn ₂ phase Since it becomes the end point, the growth of cracks is suppressed.

  2. By adding this intermetallic compound, Al phase crystals become fine and uniform equiaxed crystals, and the dendritic arm of the equiaxed Al phase becomes thicker. As a result, the surface area of the dendrites decreases and corrosion progresses. The area of the interface between the Al phase and the ternary eutectic structure that tends to be reduced decreases, and the corrosion rate decreases.

  In addition, an intermetallic compound having a lattice plane in which the lattice spacing of one of the lattice directions constituting the lattice plane of the Bravais lattice is 2.57 mm to 3.15 mm and the other surface spacing is 3.64 mm to 4.46 mm. The reason why the Al phase crystals become fine and uniform equiaxed crystals when added to the plating layer is thought to be that this lattice plane has good consistency with the {110} plane of Al. Since Al has a crystal structure of FCC, the {110} plane is most likely to grow. By adding an intermetallic compound having a lattice plane that has good consistency with the Al {110} plane, it acts as a nucleation site for the Al {110} plane, which is easy to grow. It is thought that many grow in the [110] direction.

  The reason for limiting the distance between one surface in the lattice direction constituting the lattice surface of the Bravais lattice to 2.57 mm or more and 3.15 mm or less is that it matches the Al {110} plane when less than 2.57 mm or more than 3.15 mm. This is because the corrosion resistance of the machined portion is deteriorated and the corrosion resistance of the processed portion is lowered, and the reason why the distance between the other surfaces is limited to 3.64 mm or more and 4.46 mm or less is less than 3.64 mm, or exceeds 4.46 mm. } This is because the compatibility with the surface is deteriorated and the corrosion resistance of the processed portion is lowered.

  In addition, since the crystal system of Al is cubic, the crystal system of the intermetallic compound may be any one of cubic, tetragonal, orthorhombic, monoclinic, and hexagonal with a right angle to the axis angle. desirable.

  The intermetallic compound is effective when added in a small amount, and when the added amount increases, appearance defects such as a rough appearance after plating occur. Therefore, the upper limit is desirably 1% by mass.

  As a result of the inventors investigating a large number of Al phases in plating, intermetallic compounds having a size of several μm were observed from the center of most Al phase dendrites. Further, when the crystal orientations of the intermetallic compound and the Al phase were identified using the EBSP method, one interplanar spacing in the lattice direction of the intermetallic compound was 2.57 mm or more and 3.15 mm or less, and the other interplanar spacing was 3.64 mm or more. It was confirmed that the lattice plane of 4.46 mm or less and the Al phase {110} plane were parallel, and the Al phase dendrite grew in the [110] direction.

As an example of an intermetallic compound present in the Al phase, TiAl ₃ present in the Al phase in the Al—Zn—Mg—Si based plating is shown in FIG. Although this TiAl ₃ is actually considered to be a solid solution of Si or a part of Al in the compound is considered to be replaced by Si, the crystal structure obtained by electron beam diffraction, Kikuchi pattern, etc. is the same as TiAl ₃ Therefore, it is expressed as TiAl ₃ here. The upper diagram in FIG. 1 is a photomicrograph (magnification 3000 times) of the plated layer of the plated steel material in the present invention, and the lower diagram shows the distribution state of each structure in the photograph. As can be seen from this figure, the Al phase can be clearly identified by the micrograph of the plated layer of the plated steel material in the present invention.

Moreover, the pole figure of FIG. 2 shows the electron beam diffraction result of the intermetallic compound of FIG. 1 and an Al phase. From the pole figure, it can be seen that the Al phase dendrite shown in FIG. 1 has a {110} plane growing in the [110] direction. Further, since the positions of the pole figures in FIG. 2 are in good agreement, it can be understood that the {110} plane of the Al phase has the same orientation as the {110} plane and {102} plane of TiAl ₃ .

As a result of determining the crystal orientation of the Al phase and TiAl ₃ by the EBSP method, it becomes clear that the {110} plane of the Al phase in FIG. 1 is parallel to all of the {110} plane and {102} plane of TiAl _3. It was. This is considered to be the result of the growth of Al phase dendrite using the {110} plane and the {102} plane of TiAl ₃ as nucleation sites for the Al phase.

  By using the EBSP method in this way, it is possible to analyze the consistency between a specific lattice plane of the intermetallic compound and the lattice plane of the Al phase.

  In the present invention, the size of the intermetallic compound is not particularly limited, but what the inventors have observed is a size of 10 μm or less. Moreover, although the abundance ratio of the intermetallic compound in the Al phase is not particularly limited, it is desirable that it exists in the Al phase exceeding the majority.

There are no particular limitations on the method of adding the intermetallic compound, and a method of making the intermetallic compound fine powder turbid in the bath, a method of dissolving the intermetallic compound in the bath, or the like can be applied.
The method for producing a plating layer in the present invention is not particularly limited, and a normal non-oxidizing furnace hot-dip plating method can be applied. Even when Ni pre-plating is applied as the lower layer, a conventional pre-plating method may be applied.

There are no particular restrictions on the amount of plating deposited, but it is preferably 10 g / m ² or more from the viewpoint of corrosion resistance and 350 g / m ² or less from the viewpoint of workability.

  Next, the resin-based film layer of the present invention is applied to an aqueous composition containing 5 to 50% by mass of metal oxide particles (B) with respect to 100% by mass of the solid content of the aqueous resin (A) and dried. It is the film | membrane obtained by this.

  The aqueous resin (A) includes, in addition to a water-soluble resin, a resin (water-dispersible resin) that is inherently insoluble in water but can be finely dispersed in water like an emulsion or a suspension.

  The type of the aqueous resin (A) is not particularly limited, and examples thereof include an aqueous epoxy resin, an aqueous phenol resin, an aqueous polyester resin, an aqueous polyurethane resin, an aqueous acrylic resin, and an aqueous polyolefin resin. The aqueous resin (A) may be used alone or in combination of two or more. One or more aqueous composite resins obtained by modifying at least one other aqueous resin in the presence of at least one aqueous resin may be used.

  The aqueous epoxy resin is not particularly limited. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, resorcin type epoxy resin, hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, resorcin type epoxy resin. In the presence of an epoxy resin such as a novolac-type epoxy resin, which is obtained by reacting with an amine compound such as diethanolamine or N-methylethanolamine and neutralizing with an organic acid or an inorganic acid, or in the presence of the epoxy resin, a high acid value Examples thereof include those obtained by radical polymerization of an acrylic resin, neutralized with ammonia or an amine compound, and dispersed in water.

  The aqueous phenol resin is not particularly limited. For example, a methylolated phenol resin obtained by addition reaction of aromatics such as phenol, resorcin, cresol, bisphenol A, paraxylylene dimethyl ether and formaldehyde in the presence of a reaction catalyst. And the like obtained by reacting the phenol resin with amine compounds such as diethanolamine and N-methylethanolamine and neutralizing with an organic acid or inorganic acid.

  The aqueous polyester resin is not particularly limited. For example, ethylene glycol, propylene glycol, diethylene glycol, 1,6-hexanediol, neopentyl glycol, triethylene glycol, bisphenol hydroxypropyl ether, glycerin, trimethylol ethane, trimethylol propane. Dehydration condensation of polyhydric alcohols such as phthalic anhydride, isophthalic acid, terephthalic acid, succinic anhydride, adipic acid, sebacic acid, maleic anhydride, itaconic acid, fumaric acid, and hymic anhydride And those obtained by neutralizing with ammonia or amine compound and dispersing in water.

  The aqueous urethane resin is not particularly limited. For example, ethylene glycol, propylene glycol, diethylene glycol, 1,6-hexanediol, neopentyl glycol, triethylene glycol, bisphenol hydroxypropyl ether, glycerin, trimethylol ethane, trimethylol propane. And polyhydric alcohols such as hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate and the like, and chain extension with diamine or the like, followed by water dispersion.

  The aqueous acrylic resin is not particularly limited, and examples thereof include unsaturated monomers such as styrene, alkyl (meth) acrylates, (meth) acrylic acid, hydroxyalkyl (meth) acrylates, and alkoxysilane (meth) acrylates. Can be obtained by radical polymerization in an aqueous solution using a polymerization initiator. The polymerization initiator is not particularly limited, and for example, persulfates such as potassium persulfate and ammonium persulfate, and azo compounds such as azobiscyanovaleric acid and azobisisobutyronitrile can be used.

  The aqueous olefin resin is not particularly limited. For example, after radical polymerization of ethylene and an unsaturated carboxylic acid such as methacrylic acid, acrylic acid, maleic acid, fumaric acid, itaconic acid, and crotonic acid under high temperature and pressure, ammonia is used. And a compound obtained by neutralizing with an amine compound, a metal compound such as KOH, NaOH, LiOH or the like, ammonia or an amine compound containing the above metal compound, and dispersing in water.

  The metal oxide particles (B) are blended in order to improve the corrosion resistance of the resin film layer.

  The type of the metal oxide particles (B) is not particularly limited, and examples thereof include those composed of at least one metal element selected from the group consisting of Si, Ti, Al, and Zr. Can include silica particles, titania particles, alumina particles, zirconia particles, and the like. As said metal oxide particle (B), a thing with an average particle diameter of about 1-300 nm is suitable. These may be used alone or in combination of two or more.

The said metal oxide particle (B) contains 5-50 mass% with respect to 100 mass% of solid content of the said aqueous resin (A). When the amount is less than 5% by mass, the effect of improving the corrosion resistance is small. When the amount exceeds 50% by mass, the resin-based film becomes brittle and the corrosion resistance of the processed part is lowered.
The resin film layer of the present invention preferably further contains a phosphoric acid compound (C).
When the phosphoric acid compound (C) is contained, a phosphate layer is formed on the plating surface to passivate and improve the corrosion resistance.

  Examples of the phosphoric acid compound (C) include phosphoric acids such as orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, triphosphoric acid, tetraphosphoric acid, and salts thereof; aminotri (methylenephosphonic acid), 1-hydroxyethylidene-1 Phosphonic acids such as 1-diphosphonic acid, ethylenediaminetetra (methylenephosphonic acid) and diethylenetriaminepenta (methylenephosphonic acid) and salts thereof; organic phosphoric acids such as phytic acid and salts thereof. The salt cation species is not particularly limited, and examples thereof include Cu, Co, Fe, Mn, Sn, V, Mg, Ba, Al, Ca, Sr, Nb, Y, Ni, and Zn. These may be used alone or in combination of two or more.

  The phosphoric acid compound (C) is preferably contained in an amount of 0.01 to 20% by mass with respect to 100% by mass of the solid content of the aqueous resin (A). If the amount is less than 0.01% by mass, the content may be small and the effect of improving the corrosion resistance may not be obtained. If the amount exceeds 20% by mass, the resin-based film becomes brittle and the corrosion resistance of the processed part may be lowered.

  The resin film layer of the present invention preferably further contains at least one crosslinking agent (D) selected from the group consisting of a silane coupling agent, a crosslinkable zirconium compound, and a crosslinkable titanium compound. These may be used alone or in combination of two or more.

  When at least one cross-linking agent (D) selected from the group consisting of the silane coupling agent, cross-linkable zirconium compound and cross-linkable titanium compound is contained, the adhesion between the plating and the resin-based film is further improved. .

  The silane coupling agent is not particularly limited. For example, vinyltrimethoxysilane, vinyltriethoxysilane, γ-aminopropyltrimethoxysilane sold by Shin-Etsu Chemical, Nippon Unicar, Chisso, Toshiba Silicone, etc. γ-aminopropylethoxysilane, N- [2- (vinylbenzylamino) ethyl] -3-aminopropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxy Propylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane, 2- (3 , -Epoxycyclohexyl) ethyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltriethoxysilane, N-β- (aminoethyl)- γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane and the like can be mentioned. The said silane coupling agent may be used independently and may use 2 or more types together.

  The crosslinkable zirconium compound is not particularly limited as long as it is a zirconium-containing compound having a plurality of functional groups capable of reacting with a carboxyl group or a hydroxyl group, but is preferably a compound that is soluble in water or an organic solvent. More preferably, it is a zirconium compound. An example of such a compound is zirconyl ammonium carbonate.

  The crosslinkable titanium compound is not particularly limited as long as it is a titanium-containing compound having a plurality of functional groups capable of reacting with a carboxyl group or a hydroxyl group, but dipropoxy bis (triethanolaminato) titanium, dipropoxy bis (diethanolaminato). ) Titanium, propoxy tris (diethanolaminato) titanium, dibutoxy bis (triethanolaminato) titanium, dibutoxy bis (diethanolaminato) titanium, dipropoxy bis (acetylacetonato) titanium, dibutoxy bis (acetylacetonato) Titanium, dihydroxy bis (lactato) titanium monoammonium salt, dihydroxy bis (lactato) titanium diammonium salt, propanedioxytitanium bis (ethylacetoacetate), oxotitanium bis (monoammo) Um oxalate) include isopropyl tri (N- amidoethyl-aminoethyl) titanate and the like. The said crosslinking agent may be used independently and may use 2 or more types together.

  At least one cross-linking agent (D) selected from the group consisting of the silane coupling agent, cross-linkable zirconium compound, and cross-linkable titanium compound is 0.1 to 0.1% by mass based on 100% by mass of the aqueous resin (A). It is preferable to contain 50 mass%. If the amount is less than 0.1% by mass, the content may be small and the effect of improving the adhesion may not be obtained. If the amount exceeds 50% by mass, the stability of the aqueous composition may be lowered.

  The resin-based film layer of the present invention preferably further contains at least one crosslinking agent (E) selected from the group consisting of an amino resin, a polyisocyanate compound, its block, an epoxy compound, and a carbodiimide compound. . These crosslinking agents may be used alone or in combination of two or more.

  When at least one crosslinking agent (E) selected from the group consisting of the amino resin, polyisocyanate compound, block body thereof, epoxy compound and carbodiimide compound is contained, the crosslinking density increases and the barrier property of the resin-based film Improves the corrosion resistance further.

  It does not specifically limit as said amino resin, For example, a melamine resin, a benzoguanamine resin, a urea resin, a glycoluril resin etc. can be mentioned.

  It does not specifically limit as said polyisocyanate compound, For example, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, tolylene diisocyanate etc. can be mentioned. The blocked product is a blocked product of the polyisocyanate compound.

  The epoxy compound is not particularly limited as long as it has a plurality of oxirane rings. For example, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, terephthalic acid diglycidyl ester, sorbitan polyglycidyl ether, pentaerythritol polyglycidyl ether Glycerin polyglycidyl ether, trimethylpropane polyglycidyl ether, neopentyl glycol polyglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol glycol diglycidyl ether, polypropylene glycol glycol diglycidyl ether, 2, 2-bis -(4'-glycidyloxyphenyl) propane, tris (2,3-epoxypropyl) isocyanurate DOO, bisphenol A diglycidyl ether, and hydrogenated bisphenol A diglycidyl ether and the like.

  As the carbodiimide compound, for example, an isocyanate-terminated polycarbodiimide is synthesized by a condensation reaction involving decarbonization of a diisocyanate compound such as an aromatic diisocyanate, an aliphatic diisocyanate, and an alicyclic diisocyanate, and then further reacted with an isocyanate group. Examples thereof include compounds to which a hydrophilic segment having a functional group is added.

  At least one crosslinking agent (E) selected from the group consisting of the amino resin, the polyisocyanate compound, its block, an epoxy compound, and a carbodiimide compound is 0.001% relative to 100% by mass of the solid content of the aqueous resin (A). It is preferable to contain 1-50 mass%. If the amount is less than 0.1% by mass, the content may be small and the effect of improving the corrosion resistance may not be obtained. If the amount exceeds 50% by mass, the resin film may become brittle and the corrosion resistance of the processed part may be lowered.

  The resin-based film layer of the present invention preferably further contains at least one (F) selected from the group consisting of a vanadium compound, a tungsten compound, and a molybdenum compound. These may be used alone or in combination of two or more.

  By containing at least one (F) selected from the group consisting of the vanadium compound, the tungsten compound and the molybdenum compound, the corrosion resistance of the resin film is improved.

  The vanadium compound is not particularly limited, and a conventionally known vanadium-containing compound can be used. For example, vanadate, ammonium vanadate, vanadate such as sodium vanadate, phosphovanadate, and ammonium phosphovanadate. Examples thereof include phosphovanadate.

  The tungsten compound is not particularly limited, and conventionally known tungsten-containing compounds can be used. For example, tungstic acid and ammonium tungstate, tungstates such as sodium tungstate, phosphotungstic acid and ammonium phosphotungstate, etc. Examples thereof include phosphotungstate.

  It does not specifically limit as said molybdenum compound, A conventionally well-known molybdenum containing compound can be used, For example, a molybdate etc. can be used. The molybdate is not limited in its skeleton and degree of condensation, and examples thereof include orthomolybdate, paramolybdate, and metamolybdate. Moreover, all salts, such as a single salt and a double salt, are included, and a phosphate molybdate etc. can be mentioned as a double salt.

  It is preferable to contain 0.01-20 mass% of at least 1 sort (F) selected from the group which consists of the said vanadium compound, a tungsten compound, and a molybdenum compound with respect to 100 mass% of solid content of an aqueous resin (A). If the amount is less than 0.01% by mass, the content may be small and the effect of improving the corrosion resistance may not be obtained. If the amount exceeds 20% by mass, the resin-based film becomes brittle and the corrosion resistance of the processed part may be lowered.

  The resin-based film layer of the present invention preferably further contains a polyphenol compound (G).

  By containing the polyphenol compound (G), the adhesion property of the post-coating film when used for the corrosion resistance of the resin-based film or the post-coating application is improved.

  The polyphenol compound (G) is a compound having two or more phenolic hydroxyl groups bonded to a benzene ring or a condensate thereof. Examples of the compound having two or more phenolic hydroxyl groups bonded to the benzene ring include gallic acid, pyrogallol, catechol and the like. The condensate of the compound having two or more phenolic hydroxyl groups bonded to the benzene ring is not particularly limited, and examples thereof include polyphenol compounds that are widely distributed in the plant kingdom, usually called tannic acid. Tannic acid is a general term for aromatic compounds having a complex structure having a large number of phenolic hydroxyl groups widely distributed in the plant kingdom. The tannic acid may be hydrolyzable tannic acid or condensed tannic acid. The tannic acid is not particularly limited, and examples thereof include hameli tannin, oyster tannin, chatannin, pentaploid tannin, gallic tannin, milobalan tannin, dibidi tannin, argarovira tannin, valonia tannin, catechin tannin and the like. .

  Examples of the tannic acid include commercially available ones such as “tannic acid extract A”, “B tannic acid”, “N tannic acid”, “industrial tannic acid”, “purified tannic acid”, “Hi tannic acid”, "F tannic acid", "local tannic acid" (all manufactured by Dainippon Pharmaceutical Co., Ltd.), "tannic acid: AL" (manufactured by Fuji Chemical Industry Co., Ltd.) and the like can also be used. The said polyphenol compound may be used independently and may use 2 or more types together.

  It is preferable to contain 0.1-50 mass% of said polyphenol compounds (G) with respect to 100 mass% of solid content of aqueous resin (A). If the amount is less than 0.1% by mass, the content may be small and the effect of improving the corrosion resistance may not be obtained. If the amount exceeds 50% by mass, the stability of the aqueous composition may be lowered.

  The resin-based film layer of the present invention preferably further contains a solid lubricant (H).

  By containing the above-mentioned solid lubricant (H), the lubricity of the resin-based film is improved, workability at the time of press molding is improved, wrinkles are prevented by molds and handling, etc., and abrasion scratches are prevented when transporting molded products and coils. Is effective against.

  The solid lubricant (H) is not particularly limited, and examples thereof include known fluorine-based, hydrocarbon-based, fatty acid amide-based, ester-based, alcohol-based, metal soap-based and inorganic lubricants. As a selection criterion for lubricating additives for improving processability, it is necessary to select a material that exists on the surface of the resin film rather than being dispersed in the resin film on which the added lubricant is formed. This is necessary in order to reduce the friction between the surface of the object and the mold and maximize the lubrication effect. That is, when the lubricant is dispersed in the formed resin film, the surface friction coefficient is high, the resin film is easily broken, and powdery substances are peeled and deposited, resulting in poor appearance and reduced workability called powdering phenomenon. Arise. As the substance that exists on the surface of the resin film, a substance that is incompatible with the resin and has a small surface energy is selected.

  Among them, the use of polyolefin wax is more preferable because the dynamic friction coefficient of the surface is lowered, the workability is greatly improved, and the corrosion resistance after processing is also improved. Examples of the wax include hydrocarbon waxes such as paraffin, microcrystalline, and polyethylene. At the time of processing, since the film temperature rises due to the deformation heat and frictional heat of the material, the melting point of the wax is more preferably 70 to 160 ° C. If it is less than 70 degreeC, it may soften and melt at the time of a process, and the outstanding characteristic as a solid lubricant may not be exhibited. In addition, when the melting point exceeds 160 ° C., hard particles are present on the surface and the friction characteristics are deteriorated, so that high moldability may not be obtained.

  The particle diameter of these waxes is more preferably 0.1 to 5 μm. If it exceeds 5 μm, the distribution of the solidified wax may be non-uniform, or the resin-based film may fall off. Moreover, when it is less than 0.1 μm, the workability may be insufficient.

  It is preferable to contain 0.1-30 mass% of said solid lubricant (H) with respect to 100 mass% of solid content of aqueous resin (A). If it is less than 0.1%, the effect of improving workability is small, and if it exceeds 30%, the corrosion resistance may be lowered.

The resin-based film of the present invention may further contain other additives. For example, a pigment may be blended. Examples of the pigment include titanium oxide (TiO ₂ ), zinc oxide (ZnO), calcium carbonate (CaCO ₃ ), barium sulfate (BaSO ₄ ), alumina (Al ₂ O ₃ ), kaolin clay, carbon black, and iron oxide. Inorganic pigments such as (Fe ₂ O ₃ , Fe ₃ O ₄ ), and various colored pigments such as organic pigments can be used.

The adhesion amount after drying of the resin-based film in the present invention is preferably 0.1 to 5 g / m ² . If it is less than 0.1 g / m ² , the corrosion resistance may be reduced. If it exceeds 5 g / m ² , it may be uneconomical or unsuitable for use in welding applications. More preferably 0.2 to 2 g / m ^2.

  It is preferable that the aqueous composition used for formation of the said resin film is 1-50 mass% in solid content concentration, More preferably, it is 5-30 mass%. When the solid content concentration is less than 1% by mass, the coating workability is lowered, and when it exceeds 50% by mass, the bath stability and the coating workability of the aqueous composition may be lowered.

  In the aqueous composition used for forming the resin-based film, a surfactant may be blended in order to improve uniform paintability and stability. Examples of the surfactant include nonionic surfactants and anionic surfactants.

  A solvent may be used in the aqueous composition used for forming the resin-based film in order to improve the film forming property and form a more uniform and smooth film. The solvent is not particularly limited as long as it is generally used for paints, and examples thereof include alcohol-based, ketone-based, ester-based, and ether-based hydrophilic solvents from the viewpoint of leveling.

  The coating method of the aqueous composition used for the formation of the resin-based film is to form a film by applying the aqueous composition to the surface of the plated steel sheet. The coating method is not particularly limited, and commonly used roll coating, air spray, airless spray, immersion, and the like can be appropriately employed. In order to increase the curability of the film, it is preferable to heat the object to be coated in advance or to heat-dry the object after coating. As the heat drying method, any method such as hot air, induction heating, near infrared, far infrared, etc. may be used, or they may be used in combination. The heating temperature of the article to be coated is 50 to 250 ° C, preferably 70 to 220 ° C. When the heating temperature is less than 50 ° C., the evaporation rate of moisture is slow and sufficient film formability cannot be obtained, so that the corrosion resistance may be lowered. On the other hand, when the temperature exceeds 250 ° C., the resin is thermally decomposed, the corrosion resistance is lowered, and the appearance such as yellowing is deteriorated. The drying time for heat drying after coating is preferably 1 second to 5 minutes. Moreover, as long as resin is hardened | cured with an electron beam or an ultraviolet-ray, hardening by these irradiation may be sufficient, and combined use with heat drying may be sufficient.

  Hereinafter, the present invention will be described specifically by way of examples.

First, a cold-rolled steel sheet having a thickness of 1 mm was prepared, and hot-plated for 3 seconds in a 450 ° C. Zn—Mg—Al plating bath and Zn—Mg—Al—Si plating bath to which various metals or intermetallic compounds were added. The amount of plating adhesion was adjusted to 80 g / m ² on one side by N ₂ wiping. Table 1 shows the plating composition of the obtained plated steel sheet and the intermetallic compounds present in the Al phase. The intermetallic compounds were analyzed for elements and composition using EDX. Table 1 shows the surface index of the surface close to the Al {110} surface of each intermetallic compound, the direction index in the lattice direction constituting the surface, and the surface spacing.

  Although some Al-based intermetallic compounds were dissolved in the plating bath and recrystallized, some of the Al was considered to be replaced by Si, but there were significant changes in crystal orientation and interplanar spacing. In the examples, it was expressed as an Al-based intermetallic compound not substituted with Si.

  The crystal orientation of the Al phase and the intermetallic compound was determined from the polished plated surface using the EBSP method, and the consistency between the {110} plane of the Al phase and each lattice plane of the intermetallic compound was investigated. The results are shown in Table 1. The case where the {110} plane of the Al phase and each lattice plane of the intermetallic compound were parallel. The case where no relationship was found between the {110} plane of the Al phase and each lattice plane of the intermetallic compound was marked with x.

Next, an aqueous composition (solid content) containing 30% by mass of metal oxide particles B1 and 1% by mass of phosphoric acid compound C1 with respect to 100% by mass of aqueous resin A6 shown in Table 2 on the plated steel plate. (Concentration: adjusted to 20% by mass) was applied with a bar coater so that the dry adhesion amount was 1.5 g / m ² , dried at a final plate temperature of 150 ° C. in a hot air drying furnace, and then water-cooled. Obtained. A test plate having a size of 50 × 100 mm was cut out from the test material, and a processed portion corrosion resistance test was performed.

In the processed portion corrosion resistance test, 6 mm extrusion processing was performed with an elixir tester, and then the edge and back surface of the test plate were tape-sealed, and a salt spray test (JIS-Z-2371) test was performed. The occurrence of white rust was observed 120 hours after the test time of the part subjected to Erichsen processing, and was judged by the following rating. A score of 3 or more was accepted.
10: No white rust generation 9: less than 1% 8: 1% or more but less than 3% 7: 3% or more but less than 5% 6: 5% or more but less than 7% 5: 7% or more but less than 10% 4: 10% or more but 15% Less than 3: 15% or more but less than 20% 2: 20% or more but less than 30% 1: 30% or more Test results are shown in Table 1.

  In Nos. 5 and 11, since the interplanar spacing between the lattice planes constituting the surface close to the Al {110} plane of the intermetallic compound is outside the range of the present invention, the corrosion resistance of the processed part was rejected. Nos. 20, 26, 32, 38, 44, and 50 are plated steel sheets to which no intermetallic compound is added for comparison of corrosion resistance. The products of the present invention other than these were surface-treated plated steel sheets with excellent processed portion corrosion resistance.

First, a cold-rolled steel sheet having a thickness of 0.8 mm was prepared, and this was subjected to hot-dip plating for 3 seconds in the plating baths of Nos. 3 and 33 shown in Table 1 of Example 1, and the plating adhesion amount was 80 g on one side by N ₂ wiping. / M ² was adjusted. The intermetallic compound present in the Al phase was TiAl ₃ and Ti (Al _1-X Si _x ) ₃ which was considered to be a part of Al of TiAl ₃ being replaced by Si. In any case, the lattice direction constituting the {110} plane, the plane spacing in the [110] direction and the [002] direction are 2.725Å, 4.29Å, the lattice direction constituting the {102} plane, and the [102] direction, respectively. The surface spacing in the [100] direction was 2.8682 mm and 3.8537 mm, respectively.

The crystal orientation of the Al phase and the intermetallic compounds was determined using the EBSP method from polished plating surface, considered part of Al of TiAl ₃ and TiAl ₃ were replaced with Si Ti (Al _1- It was confirmed that the {110} plane and the {102} plane of _X Si _X ) ₃ are parallel to the {110} plane of the Al phase.

Next, using the chemicals shown in Table 2 on the plated steel plate, the aqueous composition (solid content concentration: adjusted to 20% by mass) shown in Tables 3 to 8 was dried with a bar coater. The coating was applied at 5 g / m ² , dried in a hot air drying furnace at an ultimate plate temperature of 150 ° C., and then cooled with water to obtain a test material. A test plate having a size of 50 × 100 mm was cut out from the test material, and a processed portion corrosion resistance test was performed.

In the processed portion corrosion resistance test, 6 mm extrusion processing was performed with an elixir tester, and then the edge and back surface of the test plate were tape-sealed, and a salt spray test (JIS-Z-2371) test was performed. The occurrence of white rust was observed 120 hours after the test time of the part subjected to Erichsen processing, and was judged by the following rating. A score of 3 or more was accepted.
10: No white rust generation 9: less than 1% 8: 1% or more but less than 3% 7: 3% or more but less than 5% 6: 5% or more but less than 7% 5: 7% or more but less than 10% 4: 10% or more but 15% Less than 3: 15% or more but less than 20% 2: 20% or more but less than 30% 1: 30% or more Test results are shown in Tables 3-8.

  Nos. 209 to 216 failed in the corrosion resistance of the processed part because the content of the metal oxide particles contained in the resin-based film was outside the range of the present invention. No. 217 had no resin-based film and was outside the scope of the present invention, so the processed part corrosion resistance was rejected. The products of the present invention other than these were surface-treated plated steel sheets with excellent processed portion corrosion resistance.

  As described above, according to the present invention, it has become possible to produce a surface-treated plated steel sheet having excellent processed portion corrosion resistance in a Zn-Al-Mg plated steel sheet. By expanding the use of high corrosion-resistant steel sheets to members that could not be used due to a decrease in the corrosion resistance of processed parts so far, it becomes possible to greatly contribute to improving the durability of these processed products.

It is a figure which shows an example of the intermetallic compound which exists in Al phase, (a) is the microscope picture (3000 times) of the plating layer of a plated steel plate, (b) is the figure which showed the distribution state of each structure | tissue in a photograph It is. FIG. 1 is a pole figure of the Al phase and the intermetallic compound in FIG. 1, (a) is the (110) pole figure of the Al phase, (b) is the (110) pole figure of the intermetallic compound, (c) is the ( 102) A pole figure.

Claims (15)

On one side or both sides of the steel sheet, Al: 4 to 10% by mass, Mg: 1 to 5% by mass, and the interval between one plane in the lattice direction constituting the lattice plane of Bravay lattice is 2.57 mm to 3.15 mm and the other A plated layer of a plated steel sheet containing an intermetallic compound having a lattice plane with a face spacing of 3.64 mm or more and 4.46 mm or less, and having a Zn alloy plating layer composed of Zn and unavoidable impurities in the balance is [Al / [Al phase] and [MgZn ₂ phase] have a metallic structure mixed in the Zn / MgZn ₂ ternary eutectic structure, and the lattice plane of Bravay lattice is formed in [Al phase] A plating layer containing an intermetallic compound having a lattice plane in which one surface spacing in the lattice direction is 2.57 mm to 3.15 mm and the other surface spacing is 3.64 mm to 4.46 mm, A water-based resin is formed on the plating layer. A coating obtained by applying and drying an aqueous composition containing 5 to 50% by mass of metal oxide particles (B) with respect to 100% by mass of the solid content of (A) is characterized by being formed. Surface treated galvanized steel sheet with excellent corrosion resistance. On one or both sides of the steel plate, Al: 4 to 22% by mass, Mg: 1 to 5% by mass, Si: 0.5% by mass or less, and one spacing in the lattice direction constituting the lattice plane of the Bravay lattice is 2. A Zn alloy plating layer containing an intermetallic compound having a lattice plane of 57 to 3.15 mm and the other plane spacing of 3.64 to 4.46 mm, the balance being composed of Zn and inevitable impurities The plated layer of the plated steel sheet has a metal structure in which [Mg ₂ Si phase] and [Al phase] and [MgZn ₂ phase] are mixed in the [Al / Zn / MgZn ₂ ternary eutectic structure] substrate, In addition, in [Al phase], the lattice spacing on one side of the lattice direction constituting the lattice plane of the Bravay lattice is 2.57 mm to 3.15 mm and the other surface spacing is 3.64 mm to 4.46 mm. With plating layer containing intermetallic compound with surface Furthermore, an aqueous composition containing 5 to 50% by mass of the metal oxide particles (B) is applied to the upper layer of the plating layer and 100% by mass of the solid content of the aqueous resin (A) and dried. A surface-treated plated steel sheet excellent in processed part corrosion resistance, characterized in that a film obtained by the above process is formed.   The crystal system of the intermetallic compound according to any one of claims 1 and 2 is any one of cubic, tetragonal, orthorhombic, monoclinic, and hexagonal, and has excellent processed portion corrosion resistance. Surface-treated plated steel sheet.   A surface-treated plated steel sheet excellent in processed part corrosion resistance, wherein the content of the intermetallic compound according to any one of claims 1 to 3 is 1% by mass or less.   An intermetallic compound having a lattice plane in which the lattice spacing of one of the lattice directions composing the lattice plane of the Bravais lattice is 2.57 mm to 3.15 mm and the other surface spacing is 3.64 mm to 4.46 mm is crystal nuclei. 5. The surface-treated plated steel sheet having excellent processed portion corrosion resistance according to claim 1, wherein a primary arm of an Al-phase dendrite grows in the [110] direction.   6. The aqueous resin (A) is at least one selected from the group consisting of an aqueous polyester resin, an aqueous polyurethane resin, an aqueous epoxy resin, an aqueous acrylic resin, and an aqueous polyolefin resin. A surface-treated plated steel sheet excellent in the corrosion resistance of the processed part as described in 1.   7. The processed part corrosion resistance according to claim 1, wherein the metal oxide particles (B) comprise at least one metal element selected from the group consisting of Si, Ti, Al, and Zr. Excellent surface-treated plated steel sheet.   The aqueous composition further comprises 0.01 to 20% by mass of the phosphoric acid compound (C) with respect to 100% by mass of the solid content of the aqueous resin (A). A surface-treated plated steel sheet excellent in the corrosion resistance of the processed part as described in 1.   The aqueous composition further contains at least one cross-linking agent (D) selected from the group consisting of a silane coupling agent, a cross-linkable zirconium compound, and a cross-linkable titanium compound to a solid content of 100% by mass of the aqueous resin (A). The surface-treated plated steel sheet having excellent processed portion corrosion resistance according to any one of claims 1 to 8, characterized by containing 0.1 to 50% by mass.   The aqueous composition further contains at least one crosslinking agent (E) selected from the group consisting of an amino resin, a polyisocyanate compound, its block, an epoxy compound, and a carbodiimide compound, and the solid content of the aqueous resin (A) is 100 masses. The surface-treated plated steel sheet having excellent processed portion corrosion resistance according to any one of claims 1 to 9, wherein the surface-treated plated steel plate is 0.1 to 50% by mass relative to%.   The aqueous composition further contains at least one rust inhibitor (F) selected from the group consisting of a vanadium compound, a tungsten compound, and a molybdenum compound in an amount of 0.01% with respect to 100% by mass of the solid content of the aqueous resin (A). The surface-treated plated steel sheet having excellent processed portion corrosion resistance according to any one of claims 1 to 10, wherein the surface-treated plated steel sheet is contained in an amount of ~ 20 mass%.   The aqueous composition further comprises 0.1 to 50% by mass of the polyphenol compound (G) based on 100% by mass of the solid content of the aqueous resin (A). A surface-treated plated steel sheet having excellent corrosion resistance in the processed part.   The aqueous composition further contains 0.1 to 30% by mass of the solid lubricant (H) with respect to 100% by mass of the solid content of the aqueous resin (A). A surface-treated plated steel sheet excellent in the corrosion resistance of the processed part as described in 1.   The surface-treated plated steel sheet having excellent processed portion corrosion resistance according to claim 13, wherein the solid lubricant (H) is a polyolefin wax having a particle size of 0.1 to 5.0 µm. The processed part corrosion resistance according to any one of claims 1 to 14, wherein a film obtained by applying and drying the aqueous composition is formed with an adhesion amount of 0.1 to 5 g / m ^2. Excellent surface-treated plated steel sheet.

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