An apparatus for the implementation of a process for the continuous manufacturing of steel strips for packaging coated with a passivation layer is provided. An apparatus contains a transfer roller; a coating roller contacting the transfer roller, a surface of the coating roller having a plurality of hexagonally shaped cells with a line count being from 50 to 200 lines per centimeter and a volume being from 5.Math.10.sup.−6 to 10.Math.10.sup.−6 m.sup.3 per square meter of the coating roller surface; and a tank containing an aqueous passivation solution, the tank providing the aqueous passivation solution to the coating roller.

A trivalent-chromium chemical conversion coating from which substantially no hexavalent chromium is released. The trivalent-chromium chemical conversion coating is one formed on the surface of a zinc or zinc-alloy deposit. In a brine spray test, the chemical conversion coating has unsusceptibility to corrosion (time required for white-rust formation) of 96 hours or longer. The chemical conversion coating has a hexavalent-chromium concentration less than 0.01 μg/cm.sup.2 in terms of metal atom amount. The amount of hexavalent chromium released after 30-day standing in a thermo-hygrostatic chamber at a temperature of 80° C. and a humidity of 95% (amount of hexavalent chromium released when the coating is immersed in 100° C. water for 10 minutes) is smaller than 0.05 μg/cm.sup.2.

A trivalent-chromium chemical conversion coating from which substantially no hexavalent chromium is released. The trivalent-chromium chemical conversion coating is one formed on the surface of a zinc or zinc-alloy deposit. In a brine spray test, the chemical conversion coating has unsusceptibility to corrosion (time required for white-rust formation) of 96 hours or longer. The chemical conversion coating has a hexavalent-chromium concentration less than 0.01 μg/cm.sup.2 in terms of metal atom amount. The amount of hexavalent chromium released after 30-day standing in a thermo-hygrostatic chamber at a temperature of 80° C. and a humidity of 95% (amount of hexavalent chromium released when the coating is immersed in 100° C. water for 10 minutes) is smaller than 0.05 μg/cm.sup.2.

An object of the present invention is to improve a substrate processing apparatus using the CARE method. The present invention provides a substrate processing apparatus for polishing a processing target region of a substrate by bringing the substrate and a catalyst into contact with each other in the presence of processing liquid. The substrate processing apparatus includes a substrate holding unit configured to hold the substrate, a catalyst holding unit configured to hold the catalyst, and a driving unit configured to move the substrate holding unit and the catalyst holding unit relative to each other with the processing target region of the substrate and the catalyst kept in contact with each other. The catalyst is smaller than the substrate.

A processing system and platform for improving both the microscopic and macroscopic uniformity of materials during etching is disclosed herein. These improvements may be accomplished through the formation and dissolution of thin, self-limiting layers on the material surface by the use of wet atomic layer etching (ALE) techniques. For etching of polycrystalline materials, these self-limiting reactions can be used to prevent this roughening of the surface during etching. Thus, as disclosed herein, a wet ALE process uses sequential, self-limiting reactions to first modify the surface layer of a material and then selectively remove the modified layer.

A processing system and platform for improving both the microscopic and macroscopic uniformity of materials during etching is disclosed herein. These improvements may be accomplished through the formation and dissolution of thin, self-limiting layers on the material surface by the use of wet atomic layer etching (ALE) techniques. For etching of polycrystalline materials, these self-limiting reactions can be used to prevent this roughening of the surface during etching. Thus, as disclosed herein, a wet ALE process uses sequential, self-limiting reactions to first modify the surface layer of a material and then selectively remove the modified layer.

This invention provides a threaded connection for oil country tubular goods that exhibits excellent corrosion resistance and galling resistance, and a method for producing the threaded connection for oil country tubular goods. The method includes a Zn—Ni alloy plating layer formation step of forming a Zn—Ni alloy plating layer, and a chromate coating formation step of forming a chromate coating after the Zn—Ni alloy plating layer formation step. The chromate coating formation step includes a chromate treatment step and a drying step. The chromate coating formation step satisfy one or more conditions selected from the following conditions 1 to 3. Condition 1: stirring speed of the chromating solution in the chromate treatment step: a linear speed of 0.5 m/s or more; Condition 2: chromate treatment time in the chromate treatment step: less than 50 seconds; and Condition 3: drying temperature in the drying step: 60° C. or less.

This invention provides a threaded connection for oil country tubular goods that exhibits excellent corrosion resistance and galling resistance, and a method for producing the threaded connection for oil country tubular goods. The method includes a Zn—Ni alloy plating layer formation step of forming a Zn—Ni alloy plating layer, and a chromate coating formation step of forming a chromate coating after the Zn—Ni alloy plating layer formation step. The chromate coating formation step includes a chromate treatment step and a drying step. The chromate coating formation step satisfy one or more conditions selected from the following conditions 1 to 3. Condition 1: stirring speed of the chromating solution in the chromate treatment step: a linear speed of 0.5 m/s or more; Condition 2: chromate treatment time in the chromate treatment step: less than 50 seconds; and Condition 3: drying temperature in the drying step: 60° C. or less.

The present invention relates to a four-function steel surface treatment liquid and a preparation method thereof, the components of raw materials of the four-function steel surface treatment liquid per liter include: phytic acid of 15 g-18 g, hydroxyethylidene-1, 1-diphosphonic acid of 50 g-65 g, phosphoric acid solution of 280 g-320 g, manganous dihydrogen phosphate of 280 g-360 g, thiourea of 5 g-8 g, surfactant of 3 g-6 g, polyethylene glycol of 1 g-2 g, sodium molybdate of 5 g-8 g, and the remaining of water. The four-function steel surface treatment liquid provided by the present invention has the advantages of a good anti-corrosion property and a safe cleaning process, is simple, high efficiency, environmental protection, no hydrogen embrittlement on a metal substrate, no intergranular corrosion, no harm to human skin, no burning, no explosion, and non-toxic, and can be used repeatedly at a normal temperature.

The present invention relates to a four-function steel surface treatment liquid and a preparation method thereof, the components of raw materials of the four-function steel surface treatment liquid per liter include: phytic acid of 15 g-18 g, hydroxyethylidene-1, 1-diphosphonic acid of 50 g-65 g, phosphoric acid solution of 280 g-320 g, manganous dihydrogen phosphate of 280 g-360 g, thiourea of 5 g-8 g, surfactant of 3 g-6 g, polyethylene glycol of 1 g-2 g, sodium molybdate of 5 g-8 g, and the remaining of water. The four-function steel surface treatment liquid provided by the present invention has the advantages of a good anti-corrosion property and a safe cleaning process, is simple, high efficiency, environmental protection, no hydrogen embrittlement on a metal substrate, no intergranular corrosion, no harm to human skin, no burning, no explosion, and non-toxic, and can be used repeatedly at a normal temperature.