Toyo Kohan Co. | Date: 2014-01-31
A surface treated steel sheet for a battery case, which has a diffusion layer of a nickel-phosphorus alloy or a nickel-cobalt-phosphorus alloy formed on the outermost layer of the inside surface of a plated steel sheet for a battery case; a battery case which is produced through forming the surface-treated steel sheet having a diffusion layer of a nickel-phosphorus alloy or a nickel-cobalt-phosphorus alloy by the deep drawing method, the DI forming or the DTR forming: and a battery using the battery case. The battery case can be used for producing a battery excellent in battery characteristics.
Toyo Kohan Co. and Toyo Seikan Group Holdings Ltd. | Date: 2014-01-30
A method of producing a surface-treated steel sheet is provided. The method has a step of performing electrolytic treatment thereby to form a layer including a metal-oxygen compound on a surface of a steel sheet. The electrolytic treatment is performed so that the steel sheet is continuously fed into electrolytic treatment baths each including a treatment liquid and an electrode. The treatment liquid contains metal ions. The method is characterized in that: rolls provided for each of the electrolytic treatment baths (a roll for feeding the steel sheet into the electrolytic treatment bath and a roll for feeding the steel sheet out of the electrolytic treatment bath) comprise an energized roll that is electrically connected to a power source for flowing a direct current through the steel sheet and a non-energized roll that is not connected to a power source; and the energized roll is arranged such that, once the metal-oxygen compound has been formed by electrolytic treatment on a surface of the steel sheet to be in contact with the rolls, the metal-oxygen compound and the energized roll are not in contact with each other so as not to generate an arc spot.
Toyo Kohan Co. | Date: 2014-01-30
A method of producing a surface-treated steel sheet is provided. The surface-treated steel sheet includes a layer that contains a metal oxide. The method is characterized by including: dipping a steel sheet for 0.1 to 10 seconds in a treatment liquid that contains at least fluoride ions and has a pH of 2 to 5; and electrically treating by flowing a direct current between the steel sheet and an electrode in a treatment liquid to form a layer that contains a metal oxide on a surface of the steel sheet. According to the present invention, there can be provided a method of producing a surface-treated steel sheet which can enhance the interfacial adhesion with an organic resin layer when the organic resin layer is formed on the metal oxide layer.
Toyo Kohan Co. | Date: 2014-12-10
Provided are a method for production of a hard disk substrate capable of obtaining a smooth surface of a plating film by electroless NiP plating that is not degraded in corrosion resistance against the acid solution and such a hard disk substrate. According to the present invention, a method for production of a hard disk substrate including an electroless NiP plating film, includes the steps of: a first plating step of immersing a substrate in first electroless NiP plating bath containing an additive having a smoothing effect to form a lower layer of the electroless NiP plating film on a surface of the substrate, the lower layer having average surface roughness smaller than an average surface roughness of the surface; and a second plating step of immersing the substrate on which the lower layer of the electroless NiP plating film is formed in the first plating step in second electroless NiP plating bath to form an upper layer of the electroless NiP plating film, the upper layer having corrosion resistance against the acid solution. Thereby, a plating film having a smooth surface that is not degraded in corrosion resistance against the acid solution can be obtained.
Toyo Kohan Co. | Date: 2015-02-20
There is provided a surface-treated steel sheet for battery containers. The surface-treated sheet is used to form a battery container for a battery. The battery uses a nonaqueous electrolytic solution as an electrolytic solution. The surface-treated steel sheet is characterized by the features as below. The surface-treated steel sheet includes a base material made of steel and an iron-nickel diffusion layer formed by performing thermal diffusion treatment after forming a nickel plating layer at least on a surface of the base material to be located at the inner surface side of the battery container. The iron-nickel diffusion layer has an outermost layer of which a ratio of Ni and Fe is 7.5 or less as a molar ratio of Ni/Fe. The iron-nickel diffusion layer has a thickness of 0.6 m or more.