Abstract: The present invention provides a chromium-free surface treatment liquid which enables forming, on a metal material surface, a film excellent in corrosion resistance at bent portions of a steel sheet, solvent resistance, coating properties after alkaline degreasing, and sweat resistance. The surface treatment liquid contains a resin compound having a specific bisphenol skeleton, a cationic urethane resin emulsion, a silane coupling agent, an organic titanium chelate compound, a quadrivalent vanadyl compound, a molybdate compound, a fluorine compound, and water at predetermined proportions. The pH of the surface treatment liquid is in the range of 4 to 5.

Abstract: A method to inexpensively and efficiently produce conductive materials on the surface of which a nano-level fine structure is formed includes surface modification including immersing a stable anode electrode and a workpiece as a cathode electrode, the workpiece including a conductive material with a work surface, in an electrolytic solution, then applying a voltage not less than a first voltage and less than a second voltage between the stable anode electrode and the workpiece as the cathode electrode immersed in the electrolytic solution, thereby modifying the work surface, the first voltage being a voltage corresponding to a current value that is ½ of the sum of a first maximum current value appearing first in a positive voltage region and a first minimum current value appearing first in the positive voltage region with respect to voltage-current characteristics of a surface modification treatment system, the second voltage exhibiting a complete-state plasma.

Abstract: There is provided a method for producing a surface-treated metallic material, by use of which a metallic material having a stable and excellent sliding characteristic can be produced with a low environmental load without covering the metallic material surface with an oxide film. The method for producing a surface-treated metallic material includes immersing an anode and a cathode in an electrolyte solution, placing a metallic material used as a material to be treated above the surface of the electrolyte solution, and applying a voltage between the anode and the cathode to treat the metallic material surface, the voltage being equal to or higher than a voltage for causing a complete plasma state.

Abstract: A stainless steel having a low surface contact resistance for fuel cell separators is provided. The stainless steel has a Cr content of 16 to 40 mass % or more. The stainless steel includes a region having a fine textured structure on its surface, and the area percentage of the region is 50% or more, preferably 80% or more. The region having a fine textured structure is a region which has a structure having depressed portions and raised portions at an average interval between depressed portions or raised portions of 20 nm or more and 150 nm or less when observed with a scanning electron microscope.

Abstract: The invention provides a hot dip galvanized steel sheet which has: a hot dip galvanizing layer having a flat part on a surface thereof; and a film formed on the flat part. The film is composed of a compound containing Zn, Fe, and O, having an average film thickness A in a range from 10 to 100 nm determined by an element analysis of the film, and has {[Fe]/([Zn]+[Fe])} in the film in a range from 0.002 to 0.25, where [Zn] and [Fe] designate the content (% by atom) of Zn and Fe in the film, respectively. Since the hot dip galvanized steel sheet of the invention has excellent press-formability, bondability, and phosphatability, it is suitable for automobiles and electrical appliances.

Abstract: Stainless steel for fuel cell separators are provided which exhibit stable contact resistance characteristics and excellent practical utility. The stainless steel contains not less than 16 mass % of Cr. When the surface configuration of the stainless steel is analyzed with a scanning electron microscope at a spatial resolution of not more than 0.1 ?m, the surface modulus is not less than 1.02. Preferably, the chemical composition further includes C: not more than 0.03%, Si: not more than 1.0%, Mn: not more than 1.0%, S: not more than 0.01%, P: not more than 0.05%, Al: not more than 0.20%, N: not more than 0.03%, Cr: 16 to 40%, and one or more of Ni: not more than 20%, Cu: not more than 0.6% and Mo: not more than 2.5%, the balance being Fe and inevitable impurities.

Abstract: An electrical steel sheet with an insulation coating excellent in punchability, coating adhesion property and coating film property after annealing, even without containing any chromium compound in the insulation coating. The insulation coating is formed by applying a surface-treatment agent to at least one side of the electrical steel sheet and drying the surface-treatment agent. The surface-treatment agent contains trialkoxysilane and/or dialkoxysilane (A) in which a substituent bound to Si is constituted only by at least one non-reactive substituent selected from the group consisting of hydrogen, an alkyl group, and a phenyl group; and a silane coupling agent (B), at a mass ratio (A/B) of 0.05 to 1.0.

Abstract: Stainless steel for fuel cell separators contains C: ?0.03%, Si: ?1.0%, Mn: ?1.0%, S: ?0.01%, P: ?0.05%, Al: ?0.20%, N: ?0.03%, Cr: 16 to 40%, and one or more of Ni: ?20%, Cu: ?0.6% and Mo: ?2.5%, the balance being Fe and inevitable impurities. According to X-ray photoelectron spectroscopy, the surface of the stainless steel contains fluorine and provides a 3.0 or higher ratio of the total of atomic concentrations of Cr and Fe in other than the metallic forms calculated from data resulting from the separation of peaks of Cr and Fe into metallic peaks and peaks other than the metallic peaks to the total of atomic concentrations of Cr and Fe in the metallic forms calculated from data resulting from the separation of peaks of Cr and Fe into metallic peaks and peaks other than the metallic peaks.

Abstract: A method to inexpensively and efficiently produce conductive materials on the surface of which a nano-level fine structure is formed includes surface modification including immersing a stable anode electrode and a workpiece as a cathode electrode, the workpiece including a conductive material with a work surface, in an electrolytic solution, then applying a voltage not less than a first voltage and less than a second voltage between the stable anode electrode and the workpiece as the cathode electrode immersed in the electrolytic solution, thereby modifying the work surface, the first voltage being a voltage corresponding to a current value that is ½ of the sum of a first maximum current value appearing first in a positive voltage region and a first minimum current value appearing first in the positive voltage region with respect to voltage-current characteristics of a surface modification treatment system, the second voltage exhibiting a complete-state plasma.

Abstract: This invention provides methods and apparatuses which can manufacture Si-containing cold rolled steel sheets exhibiting excellent chemical conversion properties even if a chemical conversion treatment solution is used at a lower temperature while minimally suppressing the generation of sludge as well as reducing running costs. The method includes steps of cold rolling a steel containing 0.5 to 3.0 mass % Si, continuously annealing the cold rolled steel sheet, pickling the surface of the continuously annealed cold rolled steel sheet, and repickling the surface of the pickled steel sheet with a non-oxidative acid. The repickling is performed such that a repickling solution is sampled continuously or periodically, an acid concentration in the sampled solution is measured, and the acid concentration in the repickling solution is regularly controlled within a prescribed concentration range.

Abstract: A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH)2.ZnSO4.xH2O is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH)2.ZnSO4.3-5H2O.

Abstract: There is provided a method for producing a surface-treated metallic material, by use of which a metallic material having a stable and excellent sliding characteristic can be produced with a low environmental load without covering the metallic material surface with an oxide film. The method for producing a surface-treated metallic material includes immersing an anode and a cathode in an electrolyte solution, placing a metallic material used as a material to be treated above the surface of the electrolyte solution, and applying a voltage between the anode and the cathode to treat the metallic material surface, the voltage being equal to or higher than a voltage for causing a complete plasma state.

Abstract: The present invention provides a chromium-free surface treatment liquid which enables forming, on a metal material surface, a film excellent in corrosion resistance at bent portions of a steel sheet, solvent resistance, coating properties after alkaline degreasing, and sweat resistance. The surface treatment liquid contains a resin compound having a specific bisphenol skeleton, a cationic urethane resin emulsion, a silane coupling agent, an organic titanium chelate compound, a quadrivalent vanadyl compound, a molybdate compound, a fluorine compound, and water at predetermined proportions. The pH of the surface treatment liquid is in the range of 4 to 5.

Abstract: An object of the present invention is to make it possible, without necessitating an alkali pretreatment, to form a zinc oxide layer having excellent sliding properties on a hot dip galvanized steel sheet not subjected to alloying after galvanizing and thus having a relatively low degree of surface activity. Another object of the present invention is to make it possible to manufacture a hot dip galvanized steel sheet having higher area ratio of Zn oxide layer formed on a coating surface and larger thickness of the Zn oxide layer.

Abstract: The present invention provides a chromium-free surface treatment agent, comprising: a resin compound having a specific bisphenol skeleton; cationic urethane resin emulsion; silane coupling agent; an organic titanium chelate compound; a quadrivalent vanadyl compound; a molybdic acid compound; and water, wherein these components are blended at predetermined ratios such that pH value of the surface treatment agent is in the range of 4 to 5. The one-pack type chromium-free surface treatment agent of the present invention exhibits good stability during storage and is capable of forming on a metal material surface a coating film excellent in corrosion resistance at a bending-processed portion of a steel sheet, solvent resistance and paintability after alkali degreasing.

Abstract: A hot dip galvannealed steel sheet, which is a plated steel sheet, the plated sheet including an oxide layer being formed on the surface of the plated steel sheet, having an average thickness of 10 nm or more, and containing Zn and at least one element selected from the group consisting of Zr, Ti and Sn.

Abstract: A method of manufacturing a hot dip galvannealed steel sheet, including the steps of: subjecting a steel sheet to hot dip galvanizing to manufacture a hot dip galvanized steel sheet; heating the hot dip galvanized steel sheet for alloying; subjecting the hot dip galvanized steel sheet to temper rolling; bringing the temper-rolled hot dip galvanized steel sheet into contact with an acid solution containing at least one ion selected from the group consisting of Zr ions, Ti ions, and Sn ions to thereby form an acid solution film on the surface of the steel sheet; after completion of the contact, a state where the acid solution film is formed on the surface of the steel sheet is held for at least 1 second; and washing with water the hot dip galvanized steel sheet after holding, to thereby form a Zn oxide layer having a thickness of 10 nm or more on the surface of the galvanized steel sheet.

Abstract: A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH)2·ZnSO4·xH2O is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH)2·ZnSO4·3-5H2O.

Abstract: A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH)2.ZnSO4. xH2O is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH)2.ZnSO4.3-5H2O.

Abstract: A zinc-based metal plated steel sheet is excellent in tribological properties during press forming. An oxide layer containing crystalline 3Zn(OH)2·ZnSO4·xH2O is formed on a plated surface. The oxide layer has a thickness of 10 nm or more. The crystalline oxide layer is composed of 3Zn(OH)2·ZnSO4·3-5H2O.