Provided are a zinc-base plated steel material comprising a base steel and a zinc-based plated layer and a post-treatment film, which are sequentially formed on the base steel. The post-treatment film comprises an oxide or oxide salt of at least one group A element selected from B, Al, V, and Fe and an organic compound, wherein the content of oxygen atoms in the post-treatment film is 50 atom % or more, and wherein when the mole number of oxygen atoms forming a covalent bond with hydrogen in the post-treatment film is a and the mole number of oxygen atoms not forming the covalent bond with hydrogen is b, a/b is 0.3 or greater; and a composition for forming the post-treatment film.

There is provided a hot-stamped body including: a steel base metal; and a metallic layer formed on a surface of the steel base metal, wherein the metallic layer includes: an interface layer that contains, in mass %, Al: 30.0 to 36.0%, has a thickness of 100 nm to 15 μm, and is located in an interface between the metallic layer and the steel base metal; and a principal layer that includes coexisting Zn phases and insular FeAl.sub.2 phases, is located on the interface layer, and has a thickness of 1 μm to 40 μm. This hot-stamped body is excellent in fatigue properties, corrosion resistance, and chipping resistance.

The present invention addresses the problem of providing, for example, a novel metal surface treatment agent which can form a film capable of maintaining antimicrobial performance on or over a surface of a metal material. The problem can be solved by a metal surface treatment agent containing: a prescribed copolymer (A) obtained by polymerizing a compound (a) represented by the following Formula (1) [in Formula (1), R.sup.1 and R.sup.2 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R.sup.3 and R.sup.4 each independently represent an alkyl group having 1 to 5 carbon atoms, and X— represents an ion of a halogen atom, or an acid anion] with a compound (b) represented by the following Formula (2) or (3) [in Formula (2), R.sup.5 represents a hydrogen atom or a methyl group, R.sup.6 and R.sup.7 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a benzyl group, or a hydroxyalkyl group having 2 or 3 carbon atoms; and, in Formula (3), R.sup.8 represents a hydrogen atom or a methyl group]; and a water-soluble or water-dispersible resin (B).

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Provided is a multilayer zinc alloy plated steel material comprising a base steel material and multiple plating layers formed on the base steel material, wherein each of the multiple plating layers includes one of a Zn plating layer, a Mg plating layer, and a Zn—Mg alloy plating layer, and the ratio of the weight of Mg contained in the multiple plating layers to the total weight of the multiple plating layers is from 0.13 to 0.24.

The invention relates to a method for patinating zinc surfaces of a structural element, including the steps of: providing a structural element with a zinc surface in a housing; providing an atmosphere around the zinc surface, wherein said atmosphere comprises carbon based gas and humidity; and heating the zinc surface for at least one hour, to provide a patinated zinc surface. The heating of the zinc surface occurs by heating the atmosphere to a temperature of at least 50° C., the humidity is at least 70%, and the carbon-based gas concentration is at least 5% by volume. The invention also relates to a patinated evaporative condenser in a closed-circuit cooling tower The patinated evaporative condenser in a closed-circuit cooling tower is by the method according to the invention. A system for patinating zinc surfaces according to the invention is also disclosed.

A hot-dip galvanized steel sheet including: a hot-dip galvanizing layer on at least one side of a base steel sheet. The hot-dip galvanizing layer has a Fe content of more than 0% to 3.0% and an Al content of more than 0% to 1.0%. The hot-dip galvanized steel sheet includes a Fe—Al alloy layer provided on an interface between the hot-dip galvanizing layer and the base steel sheet and a fine-grain layer provided in the base steel sheet and directly in contact with the Fe—Al alloy layer. The Fe—Al alloy layer has a thickness of 0.1-2.0 μm. The fine-grain layer has an average thickness of 0.1-5.0 μm, includes a ferrite phase with an average grain diameter of 0.1-3.0 μm, and contains oxides of one or more out of Si and Mn, a maximum diameter of the oxides being 0.01-0.4 μm.

A Zn—Mg alloy plated steel material having excellent adhesion to plating and corrosion resistance comprises base steel and a plating layer formed on the surface of the base steel, wherein the plating layer comprises a Zn single phase, a Mg single phase, an MgZn.sub.2 alloy phase, and an Mg.sub.2Zn.sub.11 alloy phase, the Zn single phase is contained in the plating layer at a proportion of 15 to 19 volume %, and the proportion of the Zn single phase in a lower t/2 area of the plating layer adjacent to the base steel may be greater than the proportion of the Zn single phase in an upper t/2 area of the plating layer on the surface layer side of the plating layer. (Here, t means the thickness (μm) of the plating layer).

There is provided a high-strength hot-dipped steel sheet having excellent coating adhesion and a method for manufacturing the steel sheet. The steel sheet has a chemical composition, and a coating layer is disposed on the steel sheet. The chemical composition includes, by mass %, C: 0.02% or greater and 0.30% or less, Si: 0.01% or greater and 2.0% or less, Mn: 0.2% or greater and 3.0% or less, P: 0.08% or less, S: 0.02% or less, and Al: 0.001% or greater and 0.40% or less, with the balance being Fe and incidental impurities. The coating layer has a coating weight per side of 30 to 90 g/m.sup.2 and contains exfoliated base steel in an amount of 0.3 to 1.5 g/m.sup.2.

A surface-treated steel material having cut edge corrosion resistance that is equal to or more than that of a chromate treatment without use of hexavalent chromium. The surface-treated steel material includes a coating film formed on a surface of a steel material through a plating layer that is obtained by immersing the steel material in a galvalume bath containing Mg. The coating film is formed using a coating composition containing a coating film-forming resin, a cross-linking agent, a predetermined vanadium compound, and trimagnesium phosphate; the vanadium compound is a compound satisfying a predetermined electrical conductivity; the content of the vanadium compound is restricted to a predetermined amount; the vanadium compound satisfies a predetermined pH; and the content of the trimagnesium phosphate is a predetermined amount.

A composition for washing a pickled steel plate and a method for washing a pickled steel plate using the same are provided. The composition for washing a pickled steel plate includes a phosphoric acid ester compound, an amine-based compound, sodium carbonate, ammonium acetate, ethylene diamine tetraacetic acid (EDTA) and a remainder of water, and the method for washing a pickled steel plate is performed using the same.