Disclosed is a system for treating a metal substrate comprising a conversion composition comprising trivalent chromium in an amount of 0.001 g/L to 20 g/L and a sealing composition comprising an ammonium-containing compound. Also disclosed is a method for treating a metal substrate that includes contacting at least a portion of a surface of the substrate with the conversion composition and then contacting at least a portion of the surface of the substrate with the sealing composition. Also disclosed is a substrate obtainable by treatment with the system and/or obtainable by the method of treatment.

Disclosed is a system for treating a metal substrate comprising a conversion composition comprising trivalent chromium in an amount of 0.001 g/L to 20 g/L and a sealing composition comprising an ammonium-containing compound. Also disclosed is a method for treating a metal substrate that includes contacting at least a portion of a surface of the substrate with the conversion composition and then contacting at least a portion of the surface of the substrate with the sealing composition. Also disclosed is a substrate obtainable by treatment with the system and/or obtainable by the method of treatment.

A steel sheet has a hot-dip Zn—Al—Mg-based coating film, the coating film containing 1 mass % to 22 mass % of Al and 0.1 mass % to 10 mass % of Mg on a surface of the steel sheet, in which an X-ray diffraction peak intensity ratio of a Mg—Zn compound phase in the coating film, that is, MgZn.sub.2/Mg.sub.2Zn.sub.11, is 0.2 or less.

A steel sheet has a hot-dip Zn—Al—Mg-based coating film, the coating film containing 1 mass % to 22 mass % of Al and 0.1 mass % to 10 mass % of Mg on a surface of the steel sheet, in which an X-ray diffraction peak intensity ratio of a Mg—Zn compound phase in the coating film, that is, MgZn.sub.2/Mg.sub.2Zn.sub.11, is 0.2 or less.

The present invention relates to a method for substantially nickel-free phosphating of a metallic surface, wherein a metallic surface is treated one after the other with the following compositions: i) with an alkaline, aqueous cleaner composition which comprises at least one water-soluble silicate, and ii) with an acidic, aqueous, substantially nickel-free phosphating composition which comprises zinc ions, manganese ions and phosphate ions. The invention also relates to the above cleaner composition itself and also to a metallic surface phosphate-coated by the above method, and to the use of said surface.

The present invention relates to a method for substantially nickel-free phosphating of a metallic surface, wherein a metallic surface is treated one after the other with the following compositions: i) with an alkaline, aqueous cleaner composition which comprises at least one water-soluble silicate, and ii) with an acidic, aqueous, substantially nickel-free phosphating composition which comprises zinc ions, manganese ions and phosphate ions. The invention also relates to the above cleaner composition itself and also to a metallic surface phosphate-coated by the above method, and to the use of said surface.

Provided is an Al-plated hot stamped steel material comprising a steel base material, an Al-plating layer formed on at least one surface of the steel base material, and a chemical conversion coating formed on the Al-plating layer and containing zinc phosphate-based crystals and Ce-based compounds deposited on the surfaces of the zinc phosphate-based crystals, wherein an amount of deposition of the zinc phosphate-based crystals in the chemical conversion coating is, converted to metal Zn, 0.3 to 4.0 g/m.sup.2 and an area ratio of the Ce-based compounds in the chemical conversion coating is 0.5 to 25%.

Provided is an Al-plated hot stamped steel material comprising a steel base material, an Al-plating layer formed on at least one surface of the steel base material, and a chemical conversion coating formed on the Al-plating layer and containing zinc phosphate-based crystals and Ce-based compounds deposited on the surfaces of the zinc phosphate-based crystals, wherein an amount of deposition of the zinc phosphate-based crystals in the chemical conversion coating is, converted to metal Zn, 0.3 to 4.0 g/m.sup.2 and an area ratio of the Ce-based compounds in the chemical conversion coating is 0.5 to 25%.

A novel method of blackening surgical needles is disclosed. Surgical needles having outer surfaces are first placed into a first pretreatment bath having a novel composition. The needles are then placed into a second blackening bath having a novel composition for a sufficient period of time to effectively blacken the surfaces of the needles. The novel methods for blackening the surfaces of a stainless steel alloy surgical needle provide a chromium (VI)-free alternative to current needle manufacturing processes. Another unique feature of this novel method is its short processing time. The blackening processes of the present invention can be utilized for in-line treatment processes which can be easily incorporated into high speed needle manufacturing processes, such as strip mounted processes. In addition, the processes of the present invention are readily adaptable to batch processes. Also disclosed are novel systems for blackening surgical needles and novel blackening baths for surgical needles.

A novel method of blackening surgical needles is disclosed. Surgical needles having outer surfaces are first placed into a first pretreatment bath having a novel composition. The needles are then placed into a second blackening bath having a novel composition for a sufficient period of time to effectively blacken the surfaces of the needles. The novel methods for blackening the surfaces of a stainless steel alloy surgical needle provide a chromium (VI)-free alternative to current needle manufacturing processes. Another unique feature of this novel method is its short processing time. The blackening processes of the present invention can be utilized for in-line treatment processes which can be easily incorporated into high speed needle manufacturing processes, such as strip mounted processes. In addition, the processes of the present invention are readily adaptable to batch processes. Also disclosed are novel systems for blackening surgical needles and novel blackening baths for surgical needles.