A process of preventing crack formation in chemical conversion coating comprising providing a substrate; introducing a chemical conversion coating material; adding an additive containing a binder to the conversion coating material; and coating the substrate with the chemical conversion coating and the additive.

Disclosed is a system for maintaining a pretreatment bath containing a pretreatment comprising a Group IVB metal. The system comprises an aqueous reducing agent comprising a metal cation and a latent source of sulfate which, upon reaction with a contaminant in the pretreatment bath, forms a metal sulfate. The contaminant comprises a nitrite source. The metal sulfate salt has a pKsp of 4.5 to 11 at a temperature of 25° C. Also disclosed is a method for maintaining a pretreatment bath containing a pretreatment composition comprising a Group IVB metal. The method comprises supplying the reducing agent to the pretreatment bath in an amount sufficient to reduce a pollution ratio of the pretreatment bath to less than 1:1. Also disclosed are substrates with a pretreatment bath maintained according to the system and method.

Disclosed is a system for maintaining a pretreatment bath containing a pretreatment comprising a Group IVB metal. The system comprises an aqueous reducing agent comprising a metal cation and a latent source of sulfate which, upon reaction with a contaminant in the pretreatment bath, forms a metal sulfate. The contaminant comprises a nitrite source. The metal sulfate salt has a pKsp of 4.5 to 11 at a temperature of 25° C. Also disclosed is a method for maintaining a pretreatment bath containing a pretreatment composition comprising a Group IVB metal. The method comprises supplying the reducing agent to the pretreatment bath in an amount sufficient to reduce a pollution ratio of the pretreatment bath to less than 1:1. Also disclosed are substrates with a pretreatment bath maintained according to the system and method.

The present invention provides a surface treatment method that improves antimicrobial activity of copper or a copper alloy and enhances immediate effects of antimicrobial actions on the surface of the copper or the copper alloy. A surface treatment method for copper or a copper alloy according to the present invention comprises preparing a reducing agent solution containing a biological reducing substance, and treating the surface of the copper or the copper alloy with the reducing agent solution. The present invention also provides a surface treatment liquid for sterilizing copper or a copper alloy, in which the surface treatment liquid contains a biological reducing substance. The present invention also provides a sterilization method that comprises bringing copper or a copper alloy treated by the surface treatment method into contact with a surface of an object to sterilize the surface of the object.

The present invention provides a surface treatment method that improves antimicrobial activity of copper or a copper alloy and enhances immediate effects of antimicrobial actions on the surface of the copper or the copper alloy. A surface treatment method for copper or a copper alloy according to the present invention comprises preparing a reducing agent solution containing a biological reducing substance, and treating the surface of the copper or the copper alloy with the reducing agent solution. The present invention also provides a surface treatment liquid for sterilizing copper or a copper alloy, in which the surface treatment liquid contains a biological reducing substance. The present invention also provides a sterilization method that comprises bringing copper or a copper alloy treated by the surface treatment method into contact with a surface of an object to sterilize the surface of the object.

The present invention provides a surface treatment method that improves antimicrobial activity of copper or a copper alloy and enhances immediate effects of antimicrobial actions on the surface of the copper or the copper alloy. A surface treatment method for copper or a copper alloy according to the present invention comprises preparing a reducing agent solution containing a biological reducing substance, and treating the surface of the copper or the copper alloy with the reducing agent solution. The present invention also provides a surface treatment liquid for sterilizing copper or a copper alloy, in which the surface treatment liquid contains a biological reducing substance. The present invention also provides a sterilization method that comprises bringing copper or a copper alloy treated by the surface treatment method into contact with a surface of an object to sterilize the surface of the object.

The present invention provides a surface treatment method that improves antimicrobial activity of copper or a copper alloy and enhances immediate effects of antimicrobial actions on the surface of the copper or the copper alloy. A surface treatment method for copper or a copper alloy according to the present invention comprises preparing a reducing agent solution containing a biological reducing substance, and treating the surface of the copper or the copper alloy with the reducing agent solution. The present invention also provides a surface treatment liquid for sterilizing copper or a copper alloy, in which the surface treatment liquid contains a biological reducing substance. The present invention also provides a sterilization method that comprises bringing copper or a copper alloy treated by the surface treatment method into contact with a surface of an object to sterilize the surface of the object.

The objectives of the present invention are: to provide a novel tetrazole silane compound, a method for synthesizing the same, and a silane coupling agent containing the tetrazole silane compound as a component; and to provide a surface treatment solution using the tetrazole silane compound, a method for surface treatment, and a method for adhering two different materials. The tetrazole silane compound according to the present invention is a compound represented by chemical formula (I). (In formula (I), X, R, and n are respectively the same as defined in the specification.) ##STR00001##

The objectives of the present invention are: to provide a novel tetrazole silane compound, a method for synthesizing the same, and a silane coupling agent containing the tetrazole silane compound as a component; and to provide a surface treatment solution using the tetrazole silane compound, a method for surface treatment, and a method for adhering two different materials. The tetrazole silane compound according to the present invention is a compound represented by chemical formula (I). (In formula (I), X, R, and n are respectively the same as defined in the specification.) ##STR00001##

A Sn-plated steel sheet including a base plated steel sheet having a steel sheet, a Sn-plated layer on at least one surface of the steel sheet, and a film layer containing a zirconium oxide and a tin oxide. An adhesion amount of Sn per surface of the Sn-plated steel sheet is 0.1 g/m.sup.2 or more and 15 g/m.sup.2 or less, an amount of the zirconium oxide in the film layer is in a range of 1 mg/m.sup.2 or more and 30 mg/m.sup.2 or less in terms of an amount of metal Zr, a peak position of a binding energy of Sn3d.sub.5/2 of the tin oxide is 1.4 eV or more and less than 1.6 eV from a peak position of a binding energy of metal Sn, and a quantity of electricity required for reduction of the tin oxide is more than 5.0 mC/cm.sup.2 and 20 mC/cm.sup.2 or less.