# US 2021/0340650 A1 · Highly corrosion-resistant plated steel sheet having excellent plating adhesion and resistance to liquid metal embrittlement > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0340650 A1 - Document ID: US20210340650A1 - Status: Published application - Kind: A1 - Application number: 17/280,509 - Filed: 2019-09-20 - Published: 2021-11-04 - Earliest claimed: 2018-09-27 - Assignees: Posco - Applicants: Posco - Inventors: Il-Jeong PARK; Myung-Soo KIM; Suk-Kyu LEE - Web page: https://patentgrep.com/patent/US20210340650A1 ## CPC - C22C 38/06: containing aluminium - B32B 15/012: {one layer being formed of an iron alloy or steel, another layer being formed of aluminium or an aluminium alloy} - B32B 15/04: comprising metal as the main or only constituent of a layer, {which is} next to another layer of {the same or of} a {different material (next to a bituminous or tarry layer B32B11/08; next to a water-setting substance layer B32B13/06; next to a glass layer B32B17/061; next to a cellulosic plastic layer B32B23/042)} - B32B 15/043: {of metal (B32B15/01 takes precedence)} - B32B 15/18: comprising iron or steel {(B32B15/011, B32B15/012 and B32B15/013 take precedence)} - C21D 9/46: for sheet metals - C22C 21/02: with silicon as the next major constituent - C22C 21/04: Modified aluminium-silicon alloys - C22C 21/06: with magnesium as the next major constituent - C22C 21/18: with zinc - C23C 2/022: {by heating} - C23C 2/04: characterised by the coating material - C23C 2/06: Zinc or cadmium or alloys based thereon - C23C 2/12: Aluminium or alloys based thereon - C23C 2/18: Removing excess of molten coatings from elongated material - C23C 2/29: {Cooling or quenching} - C23C 2/40: Plates; Strips - C23C 28/02: only coatings {only including layers} of metallic material - C23C 28/021: {including at least one metal alloy layer} - C23C 28/023: {only coatings of metal elements only} - C23C 28/321: {with at least one metal alloy layer} - C23C 28/322: {only coatings of metal elements only} - C23C 30/00: Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process (C23C26/00, C23C28/00 take precedence) - C23C 30/005: {on hard metal substrates} - C22C 21/10: with zinc as the next major constituent - Y10T 428/12757: Fe - Y10T 428/12785: Group IIB metal-base component - Y10T 428/12799: Next to Fe-base component [e.g., galvanized] - Y10T 428/12972: Containing 0.01-1.7% carbon [i.e., steel] - Y10T 428/24942: including components having same physical characteristic in differing degree - Y10T 428/2495: Thickness [relative or absolute] - Y10T 428/24967: Absolute thicknesses specified - Y10T 428/26: Web or sheet containing structurally defined element or component, the element or component having a specified physical dimension - Y10T 428/265: 1 mil or less - C22C: ALLOYS (treatment of alloys C21D, C22F) - B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM - C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B) - 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 (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract Provided is a highly corrosion-resistant plated steel sheet having plating adhesion and resistance to liquid metal embrittlement. A highly corrosion-resistant plated steel sheet comprises a base steel sheet and a plated layer, which sequentially comprises an Fe—Al alloy layer and an MgZn2 layer from an interface with the base steel sheet. ## Claims ### Claim 1 A highly corrosion-resistant plated steel sheet comprising: a base steel sheet; and a plating layer comprising an Fe—Al alloy layer and an MgZn2 layer sequentially from an interface with the base steel sheet. ### Claim 2 (depends on 1) The highly corrosion-resistant plated steel sheet of claim 1, wherein the Fe—Al alloy layer has a thickness of 1 μm to 8 μm. ### Claim 3 (depends on 1) The highly corrosion-resistant plated steel sheet of claim 1, wherein the MgZn2 layer has a thickness of 0.5 μm or more. ### Claim 4 (depends on 1) The highly corrosion-resistant plated steel sheet of claim 1, wherein the plating layer further includes an Al alloy layer above the MgZn2 layer. ### Claim 5 (depends on 4) The highly corrosion-resistant plated steel sheet of claim 4, wherein a proportion of the MgZn2 phase directly on an Fe—Al alloy phase in the plating layer is 90% or more, and wherein the proportion is determined as a ratio of an area of the MgZn2 phase to an overall area when a layer, formed to be higher than MgZn2, is removed and observed. ### Claim 6 (depends on 1) The highly corrosion-resistant plated steel sheet of one of claim 1, wherein the plating layer includes an Mg2Si phase with a ratio of 10% or less, wherein the ratio is determined as a ratio of an area of the Mg2Si phase to an overall area of the plating layer when the plated steel sheet is cut and observed. ### Claim 7 (depends on 6) The highly corrosion-resistant plated steel sheet of claim 6, wherein an area ratio of an Mg2Si phase in contact with the base steel sheet is 2% or less, and wherein the area ratio of an Mg2Si phase is determined as a ratio of an area of the Mg2Si phase to an overall area when a layer, formed to be higher than Mg2Si, is removed and observed. ### Claim 8 (depends on 1) The highly corrosion-resistant plated steel sheet of claim 1, wherein the plating layer has a composition including, by weight, 5 to 10% of Si, 5 to 30% of Zn, and 1 to 7% of Mg. ### Claim 9 (depends on 8) The highly corrosion-resistant plated steel sheet of claim 8, wherein the composition of the plating layer further includes, by weight, 0.5% or less of Be and Sr in total. ### Claim 10 A method of manufacturing a highly corrosion-resistant plated steel sheet, the method comprising: preparing a base steel sheet; heating the base steel sheet to a temperature of 700° C. to 1050° C.; dipping the base steel sheet into an aluminum-based plating bath, maintained at a temperature of 530° C. to 750° C., to obtain an aluminum-base plated steel sheet; adjusting a coating weight of the obtained aluminum-base plated steel sheet; cooling the aluminum-base plated steel sheet to a temperature of 350° C. at a cooling rate of 7 to 25° C./sec; and cooling the aluminum-base plated steel sheet from the temperature of 350° C. to a temperature of 80° C. at a cooling rate of 5 to 15° C./sec. ### Claim 11 (depends on 10) The method of claim 10, wherein a temperature, at which the steel sheet enters a plating bath, is a plating bath temperature minus 20° C. to the plating bath temperature plus 50° C. ### Claim 12 (depends on 2) The highly corrosion-resistant plated steel sheet of one of claims 2, wherein the plating layer includes an Mg2Si phase with a ratio of 10% or less, wherein the ratio is determined as a ratio of an area of the Mg2Si phase to an overall area of the plating layer when the plated steel sheet is cut and observed. ### Claim 13 (depends on 3) The highly corrosion-resistant plated steel sheet of one of claims 3, wherein the plating layer includes an Mg2Si phase with a ratio of 10% or less, wherein the ratio is determined as a ratio of an area of the Mg2Si phase to an overall area of the plating layer when the plated steel sheet is cut and observed. ### Claim 14 (depends on 12) The highly corrosion-resistant plated steel sheet of claim 12, wherein an area ratio of an Mg2Si phase in contact with the base steel sheet is 2% or less, wherein the area ratio of an Mg2Si phase is determined as a ratio of an area of the Mg2Si phase to an overall area when a layer, formed to be higher than Mg2Si, is removed and observed. ### Claim 15 (depends on 13) The highly corrosion-resistant plated steel sheet of claim 13, wherein an area ratio of an Mg2Si phase in contact with the base steel sheet is 2% or less, wherein the area ratio of an Mg2Si phase is determined as a ratio of an area of the Mg2Si phase to an overall area when a layer, formed to be higher than Mg2Si, is removed and observed. ### Claim 16 (depends on 4) The highly corrosion-resistant plated steel sheet of claim 4, wherein the plating layer includes an Mg2Si phase with a ratio of 10% or less, wherein the ratio is determined as a ratio of an area of the Mg2Si phase to an overall area of the plating layer when the plated steel sheet is cut and observed, and wherein an area ratio of an Mg2Si phase in contact with the base steel sheet is 2% or less, wherein the area ratio of an Mg2Si phase is determined as a ratio of an area of the Mg2Si phase to an overall area when a layer, formed to be higher than Mg2Si, is removed and observed. ### Claim 17 (depends on 5) The highly corrosion-resistant plated steel sheet of claim 5, wherein the plating layer includes an Mg2Si phase with a ratio of 10% or less, wherein the ratio is determined as a ratio of an area of the Mg2Si phase to an overall area of the plating layer when the plated steel sheet is cut and observed, and wherein an area ratio of an Mg2Si phase in contact with the base steel sheet is 2% or less, wherein the area ratio of an Mg2Si phase is determined as a ratio of an area of the Mg2Si phase to an overall area when a layer, formed to be higher than Mg2Si, is removed and observed. ### Claim 18 (depends on 2) The highly corrosion-resistant plated steel sheet of claim 2, wherein the plating layer has a composition including, by weight, 5 to 10% of Si, 5 to 30% of Zn, and 1 to 7% of Mg. ### Claim 19 (depends on 3) The highly corrosion-resistant plated steel sheet of claim 3, wherein the plating layer has a composition including, by weight, 5 to 10% of Si, 5 to 30% of Zn, and 1 to 7% of Mg. ### Claim 20 (depends on 4) The highly corrosion-resistant plated steel sheet of claim 4, wherein the plating layer has a composition including, by weight, 5 to 10% of Si, 5 to 30% of Zn, and 1 to 7% of Mg.