A steel substrate coated on at least one of its faces with a metallic coating based on zinc or its alloys wherein the metallic coating is itself coated with a zincsulphate-based layerincludes at least one of the compounds selected from among zincsulphate monohydrate, zincsulphate tetrahydrate and zincsulphate heptahydrate, wherein the zincsulphate-based layer has neither zinc hydroxysulphate nor free water molecules nor free hydroxyl groups, the surface density of sulphur in the zincsulphate-based layer being greater than or equal to 0.5 mg/m.sup.2. A corresponding treatment method is provided.

The present invention provides an aqueous treatment solution containing sulfate ions SO.sub.4.sup.2 in a concentration greater than or equal to 0.01 mol/l, to treat sheet metal including a steel substrate coated on at least one face with a coating including at least zinc and magnesium to reduce blackening or tarnishing of the sheet metal during storage. The present invention also provides a sheet metal treated with a solution of this type.

The present invention provides an aqueous treatment solution containing sulfate ions SO.sub.4.sup.2 in a concentration greater than or equal to 0.01 mol/l, to treat sheet metal including a steel substrate coated on at least one face with a coating including at least zinc and magnesium to reduce blackening or tarnishing of the sheet metal during storage. The present invention also provides a sheet metal treated with a solution of this type.

The present invention relates to a slowly degraded alloy and a method for producing the same. The slowly degraded alloy comprises a degradable metal and a cladding layer. The degradable metal is completely covered with the cladding layer, such that a degradation rate of the degradable metal is decreased. Furthermore, because the cladding layer is made from polymer materials, the cladding layer does not be broken easily when a stress is applied to the slowly degraded alloy, thereby efficiently covering the degradable metal therein, and lowering the degradation rate of the degradable metal.

A composite can include a substrate and a conversion coating overlying the substrate and comprising at least one of a zirconium oxide, a hafnium oxide, or a combination thereof. The conversion coating can be formed from a zirconia or hafnia-based complex obtained by reacting at least one of a zirconium ion source, a hafnium ion source, or a combination thereof, with a chelating compound in a reaction and another chelating compound in another reaction.

A composite can include a substrate and a conversion coating overlying the substrate and comprising at least one of a zirconium oxide, a hafnium oxide, or a combination thereof. The conversion coating can be formed from a zirconia or hafnia-based complex obtained by reacting at least one of a zirconium ion source, a hafnium ion source, or a combination thereof, with a chelating compound in a reaction and another chelating compound in another reaction.

A composition with corrosion inhibiting properties is provided that includes a first phosphate salt of at least one of trimetaphosphate, hexametaphosphate, or tripolyphosphate. A second phosphate salt of at least one of a disodium phosphate and tetrasodium pyrophosphate is also present with the first phosphate salt present in a weight ratio relative to the second phosphate salt of from 1-4:1. Upon dissolution from 0.1 to 5 total weight percent in a solvent a corrosion inhibiting solution results that is well suited for usage as a water conditioner in cooling systems. A process of protecting an iron containing metal from corrosion is also provided that includes exposing the metal to the solution. The corrosion of the metal over time is monitored to assure the protection of the metal.

A composition with corrosion inhibiting properties is provided that includes a first phosphate salt of at least one of trimetaphosphate, hexametaphosphate, or tripolyphosphate. A second phosphate salt of at least one of a disodium phosphate and tetrasodium pyrophosphate is also present with the first phosphate salt present in a weight ratio relative to the second phosphate salt of from 1-4:1. Upon dissolution from 0.1 to 5 total weight percent in a solvent a corrosion inhibiting solution results that is well suited for usage as a water conditioner in cooling systems. A process of protecting an iron containing metal from corrosion is also provided that includes exposing the metal to the solution. The corrosion of the metal over time is monitored to assure the protection of the metal.

The coating film-forming composition includes an aromatic compound having an amino group and an aromatic ring in one molecule, and thio compound (sulfur oxoacids having a pKa of 1.9 or less and salts thereof are excluded). pH of the coating film-forming composition is 4 to 10. The thio compound is preferably one that ionized to form anions in a solution, and thiosulfate and thiocyanate are especially preferable. By bringing the coating film-forming composition into contact with the surface of a metal member, a coating film is formed on the surface of the metal member, so that a surface-treated metal member can be obtained.

The coating film-forming composition includes an aromatic compound having an amino group and an aromatic ring in one molecule, and thio compound (sulfur oxoacids having a pKa of 1.9 or less and salts thereof are excluded). pH of the coating film-forming composition is 4 to 10. The thio compound is preferably one that ionized to form anions in a solution, and thiosulfate and thiocyanate are especially preferable. By bringing the coating film-forming composition into contact with the surface of a metal member, a coating film is formed on the surface of the metal member, so that a surface-treated metal member can be obtained.