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CN-118621246-B - Zinc-aluminum-magnesium coating, zinc-aluminum-magnesium coating steel plate and preparation method thereof

CN118621246BCN 118621246 BCN118621246 BCN 118621246BCN-118621246-B

Abstract

The application relates to a zinc-aluminum-magnesium coating, a zinc-aluminum-magnesium coated steel plate and a preparation method thereof, wherein the chemical components of the zinc-aluminum-magnesium coating comprise Mg, al, fe, ni and Zn, the content of Mg is 1.6-3%, the content of Al is 2.5-4%, the content of Fe is 3-8%, and the content of Ni is 0.1-1%, 50-90% of Ni is distributed in a depth range of 3 mu m below the surface of the zinc-aluminum-magnesium coating, and the interior and the surface of the zinc-aluminum-magnesium coating both contain 5-40% of Fe-Zn compounds. The application improves the filiform corrosion resistance of the zinc-aluminum-magnesium plating layer.

Inventors

  • Jiang guangrui
  • WANG SONGTAO
  • WANG HAIQUAN
  • LIU GUANGHUI
  • TENG HUAXIANG
  • HAN BIN
  • ZHOU JIMING
  • ZHENG YANKUN

Assignees

  • 首钢集团有限公司

Dates

Publication Date
20260512
Application Date
20240607

Claims (9)

  1. 1. The zinc-aluminum-magnesium coating is characterized by comprising the following chemical components: mg, al, fe, ni and Zn, wherein, in mass fraction, 1.6-3% Of Mg, 2.5-4% of Al, 3-8% of Fe and 0.1-1% of Ni; Wherein 50% -90% of Ni is distributed in a depth range of 3 mu m below the surface of the zinc-aluminum-magnesium plating layer; the interior and the surface of the zinc-aluminum-magnesium coating contain 5% -40% of Fe-Zn compound; in the zinc-aluminum-magnesium coating, the content of Mg and the content of Al satisfy the following relation: -0.2≤[Mg] 1 -[Al] 1 *0.7≤0.2 wherein [ Mg ] 1 represents the mass fraction of Mg in the coating, and [ Al ] 1 represents the mass fraction of Al in the coating.
  2. 2. Zinc-aluminum-magnesium plating layer according to claim 1, characterized in that in the zinc-aluminum-magnesium plating layer, the Mg content is 2.5% and the Al content is 3.7%.
  3. 3. The zinc-aluminum-magnesium plating according to claim 1, wherein the Fe-Zn compound includes at least one of FeZn 10 δ 1p phase, feZn 7 δ 1k phase, fe 3 Zn 10 Γ 1 phase, fe 11 Zn 40 Γ 1 phase, feZn 13 ζ phase.
  4. 4. A zinc-aluminum-magnesium plated steel sheet characterized by comprising a steel substrate and the zinc-aluminum-magnesium plated layer according to any one of claims 1 to 3 attached to at least a part of the surface of the steel substrate.
  5. 5. A method for producing a zinc-aluminum-magnesium plated steel sheet according to claim 4, comprising: hot dip galvanizing zinc aluminum magnesium on the steel substrate by using a plating solution, and then rolling to obtain a first zinc aluminum magnesium plated steel plate; And depositing Ni on at least part of the surface of the first zinc-aluminum-magnesium plated steel plate, and then performing heat treatment to diffuse the Ni and Fe in the steel matrix into the zinc-aluminum-magnesium plated layer of the first zinc-aluminum-magnesium plated steel plate to obtain the zinc-aluminum-magnesium plated steel plate.
  6. 6. The method according to claim 5, wherein the plating solution contains Mg and Al in an amount of The content of (2) satisfies the following relation: -1.5≤[Mg] 2 -[Al] 2 *0.7≤0 Wherein [ Mg ] 2 represents the mass fraction of Mg in the plating solution and [ Al ] 2 represents the mass fraction of Al in the plating solution.
  7. 7. The method according to claim 5, wherein the plating solution Mg is contained in an amount corresponding to the zinc-aluminum-magnesium The Mg content of the coating satisfies the following relation: 1%≤[Mg] 2 -[Mg] 1 ≤4% the content of the plating solution Al and the content of the zinc-aluminum-magnesium plating layer Al meet the following relational expression: 1%≤[Al] 2 -[Al] 1 ≤4% Wherein [ Mg ] 1 represents the mass fraction of Mg in the plating layer, [ Al ] 1 represents the mass fraction of Al in the plating layer, [ Mg ] 2 represents the mass fraction of Mg in the plating solution, and [ Al ] 2 represents the mass fraction of Al in the plating solution.
  8. 8. The method of claim 5, wherein the deposited Ni has a thickness of 30 nm to 200 nm.
  9. 9. The method of claim 5, wherein the heat treatment comprises a heating section and a cooling section, wherein the cooling section has a cooling rate of not less than 10K/s; The end temperature of the heating section is 200-400 ℃, and the heat preservation time is 20-50 s under the condition of the end temperature; the heating rate of the heating section is not lower than 10K/s.

Description

Zinc-aluminum-magnesium coating, zinc-aluminum-magnesium coating steel plate and preparation method thereof Technical Field The application relates to the technical field of steel preparation, in particular to a zinc-aluminum-magnesium coating, a zinc-aluminum-magnesium coating steel plate and a preparation method thereof. Background The zinc-aluminum-magnesium coated steel plate is a novel high corrosion-resistant alloy coated steel plate. The plating layer is developed on the basis of the traditional pure zinc plating layer, and magnesium element and aluminum element are added into the plating layer, so that the plane corrosion resistance and notch corrosion resistance of the plating layer are obviously improved, and the plating layer can be widely used for manufacturing automobiles, household appliances, building outer wall surfaces and the like. In the fields of automobiles and household appliances, zinc-aluminum-magnesium plated steel plates are generally coated. The coating is to coat a layer of organic film including an electrophoresis film, a primer film, a finish paint and the like on the surface of the steel plate coating. However, the zinc-aluminum-magnesium coating contains the Mg element with stronger electrochemical activity, so that the zinc-aluminum-magnesium coating can generate filiform corrosion under an organic film under certain conditions. The filiform corrosion can form an extended corrosion morphology in a specific direction, and can influence the appearance quality of the organic film and the corrosion resistance of the plating layer in severe cases. Disclosure of Invention The application provides a zinc-aluminum-magnesium coating, a zinc-aluminum-magnesium coating steel plate and a preparation method thereof, which aim to solve the technical problem of how to improve the filiform corrosion resistance of the zinc-aluminum-magnesium coating. In a first aspect, the application provides a zinc-aluminum-magnesium plating layer, which comprises the following chemical components: mg, al, fe, ni and Zn, wherein, in mass fraction, 1.6-3% Of Mg, 2.5-4% of Al, 3-8% of Fe and 0.1-1% of Ni; Wherein 50% -90% of Ni is distributed in a depth range of 3 mu m below the surface of the zinc-aluminum-magnesium plating layer; The interior and the surface of the zinc-aluminum-magnesium coating contain 5% -40% of Fe-Zn compound. Optionally, in the zinc-aluminum-magnesium coating, the content of Mg is 2.5%, and the content of Al is 3.7%. Optionally, in the zinc-aluminum-magnesium coating, the content of Mg and the content of Al satisfy the following relation: -0.2≤[Mg]1-[Al]1*0.7≤0.2 wherein [ Mg ] 1 represents the mass fraction of Mg in the coating, and [ Al ] 1 represents the mass fraction of Al in the coating. Optionally, the Fe-Zn compound comprises at least one of the following phases, namely a delta 1p phase (FeZn), a delta 1k phase (FeZn 7), a gamma 1 phase (Fe 3Zn 10), a gamma 1 phase (Fe 11Zn 40) and a zeta phase (FeZn 13). In a second aspect, the present application provides a zinc-aluminum-magnesium plated steel sheet comprising a steel substrate and a zinc-aluminum-magnesium plated layer according to the first aspect attached to at least part of the surface of the steel substrate. In a third aspect, the present application provides a method for preparing the zinc-aluminum-magnesium plated steel sheet according to the second aspect, the method comprising: hot dip galvanizing zinc aluminum magnesium on the steel substrate by using a plating solution, and then rolling to obtain a first zinc aluminum magnesium plated steel plate; And depositing Ni on at least part of the surface of the first zinc-aluminum-magnesium plated steel plate, and then performing heat treatment to diffuse the Ni and Fe in the steel matrix into the zinc-aluminum-magnesium plated layer of the first zinc-aluminum-magnesium plated steel plate to obtain the zinc-aluminum-magnesium plated steel plate. Optionally, in the plating solution, the content of Mg and the content of Al satisfy the following relational expression: -1.5≤[Mg]2-[Al]2*0.7≤0 Wherein [ Mg ] 2 represents the mass fraction of Mg in the plating solution and [ Al ] 2 represents the mass fraction of Al in the plating solution. Optionally, the content of the plating solution Mg and the content of the zinc-aluminum-magnesium plating layer Mg satisfy the following relation: 1%≤[Mg]2-[Mg]1≤4% the content of the plating solution Al and the content of the zinc-aluminum-magnesium plating layer Al meet the following relational expression: 1%≤[Al]2-[Al]1≤4% Wherein [ Mg ] 1 represents the mass fraction of Mg in the plating layer, [ Al ] 1 represents the mass fraction of Al in the plating layer, [ Mg ] 2 represents the mass fraction of Mg in the plating solution, and [ Al ] 2 represents the mass fraction of Al in the plating solution. Optionally, the thickness of the deposited Ni is 30 nm-200 nm. Optionally, the heat treatment comprises a heating section and a cooling section