The invention relates to a wet-chemical pretreatment of zinc surfaces prior to applying a corrosion-protection coating, which deposits a thin inorganic coating of oxide and/or metallic iron. An iron layer structure which is applied according to the invention, hereinafter referred to as ferrization, improves the achievable corrosion protection of wet-chemical conversion coatings on zinc surfaces. Furthermore, the ferrization process causes both a reduction of the contact corrosion of joined metal components which have zinc and iron surfaces as well as a reduction of corrosive coating migration on cut edges of galvanized steel strips with coating layer structures. In particular, the invention relates to an alkaline composition containing an iron ion source, a reducing agent based on oxoacids of nitrogen and phosphorus, and water-soluble organic carboxylic acids with an amino group at the , , or position with respect to the acid group and/or the water-soluble salts thereof.

The present invention relates to a substrate comprising a plurality of integrally formed surface features, said surface features being micro-sized and/or nano-sized, said surface features comprising at least one pointed terminus. As a result of this unique surface, said substrate exhibits a biocidal activity because the terminal ends of said surface feature pierce through cell membrane of any microbial cell that comes into contact with the substrate, thereby causing cell deformation and lysis. The present invention also relates to a method producing said substrate. By a simple treatment of copper or zinc foil with a reagent solution comprising an alkali and an oxidizing agent, Cu(OH)2 nanotube arrays, CuO nano-blades and ZnO nano-needles are prepared. These surfaces are proven to be very effective in killing bacterial (such as E. coli) via a physical interaction.

The object of the invention is to provide a surface-treated steel sheet having a coating having fine adhesiveness to an adhesive on the surface and having excellent corrosion resistance, and a production method thereof. Provided is a surface-treated steel sheet including: a steel sheet; a plated layer containing zinc on the steel sheet; and a coating on the plated layer, wherein the coating contains an acrylic resin, zirconium, vanadium, phosphorus and cobalt, and the acrylic resin has an area ratio of 80 to 100 area % in an area from a surface to a thickness of one-fifth of a film thickness of the coating, and an area ratio of 5 to 50 area % in an area including areas from the film thickness center of the coating to a thickness of one-tenth of the film thickness toward the surface side and toward the plated layer side.

The object of the invention is to provide a surface-treated steel sheet having a coating having fine adhesiveness to an adhesive on the surface and having excellent corrosion resistance, and a production method thereof. Provided is a surface-treated steel sheet including: a steel sheet; a plated layer containing zinc on the steel sheet; and a coating on the plated layer, wherein the coating contains an acrylic resin, zirconium, vanadium, phosphorus and cobalt, and the acrylic resin has an area ratio of 80 to 100 area % in an area from a surface to a thickness of one-fifth of a film thickness of the coating, and an area ratio of 5 to 50 area % in an area including areas from the film thickness center of the coating to a thickness of one-tenth of the film thickness toward the surface side and toward the plated layer side.

A liquid passivation mixture for passivating an outer layer of a substrate comprises a first material selected from group consisting of sulfur or selenium and a base selected from a group consisting of quaternary ammonium compound, sodium hydroxide (NaOH), potassium hydroxide (KOH), and amine.

A surface-treated steel material includes a coating film formed on a surface of a steel material through a plating layer. The plating layer is obtained by immersing the steel material in a galvalume bath containing Mg. In the surface-treated steel material, 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 limited to a specified amount with respect to 100 mass % of the total of the coating film-forming resin solids and the cross-linking agent solids. The vanadium compound has a specified pH, and the content of the trimagnesium phosphate is a specified amount with respect to 100 mass % of the total of the coating film-forming resin solids and the cross-linking agent solids.

A method for depositing zinc on the surfaces of a coolant loop of a nuclear power plant includes: providing within a portion of the coolant loop a treatment solution comprising zinc and optionally one or more noble metals and/or reducing agent(s); allowing the treatment solution to remain in the portion for a treatment period; and removing the treatment solution from the portion. According to various embodiments, an average temperature of the treatment solution over the course of the treatment period is less than 150 C. or 100 C. According to various embodiments, an instantaneous temperature of the treatment solution remains below 150 C. or 100 C. throughout the treatment period. The zinc deposition treatment may be applied (1) before the plant is first put into power-generating operation or (2) during an outage following power-generating operation and optionally following a chemical decontamination to remove any oxides formed on surfaces of a coolant loop during prior power operation period(s).

An additive comprising one or more C.sub.3-C.sub.12 hydroxycarboxylic acids and/or one or more C.sub.3-C.sub.12 hydroxycarboxylic acid salts may be added to an aqueous system having galvanized metallurgy or a carbon steel surface in an effective amount to passivate a galvanized coating on the metallurgy or to decrease white rust formation or other types of corrosion upon the galvanized metallurgy or carbon steel surface in an aqueous system. In a non-limiting embodiment, the C.sub.3-C.sub.12 hydroxycarboxylic acid or the C.sub.3-C.sub.12 hydroxycarboxylic acid salt additive may utilize the zinc in the galvanized coating to achieve passivation. The passivation may occur while the system is shut down or in service. The aqueous system may be or include a cooling tower, a cooling water system, and combinations thereof. The additive may be used with or in the absence of a phosphorous-containing compound.

The aluminum-zinc plated steel sheet according to the present invention includes a plated steel sheet and a covering film that covers the plated steel sheet. The covering film contains a basic compound of transition metal other than cobalt and chromium, and metallic cobalt, or metallic cobalt and a cobalt compound. An amount of the covering film per one side is within a range of 0.01 to 0.8 g/m.sup.2. An amount in terms of mass of transition metal other than cobalt in the covering film per one side of the plated steel sheet is within a range of 4 to 400 mg/m.sup.2. An amount in terms of mass of cobalt in the covering film per one side of the plated steel sheet is within a range of 0.1 to 20 mg/m.sup.2.

The aluminum-zinc plated steel sheet according to the present invention includes a plated steel sheet and a covering film that covers the plated steel sheet. The covering film contains a basic compound of transition metal other than cobalt and chromium, and metallic cobalt, or metallic cobalt and a cobalt compound. An amount of the covering film per one side is within a range of 0.01 to 0.8 g/m.sup.2. An amount in terms of mass of transition metal other than cobalt in the covering film per one side of the plated steel sheet is within a range of 4 to 400 mg/m.sup.2. An amount in terms of mass of cobalt in the covering film per one side of the plated steel sheet is within a range of 0.1 to 20 mg/m.sup.2.