Dipsol Chemicals Co., Ltd.

Ryuta Kashio

Manabu Inoue

Tomitaka Yamamoto

Takashi Koike

Inoue Manabu

The purpose of the present invention is to provide a water-soluble finishing agent for a trivalent chromium chemical conversion coating film, which has low insulation, no problems with tightening properties, outstanding gloss and high corrosion resistance, and can obtain a trivalent chromium chemical conversion coating film, especially a black trivalent chromium chemical conversion coating film, having few scratches and flaws. The finishing agent for a trivalent chromium chemical conversion coating film is characterized by containing a trivalent chromium source, a phosphate ion source, a zinc ion source, a chelating agent which can form a complex with trivalent chromium, and a non-ionic water-soluble polymer compound selected from a group comprising poly(vinyl alcohol) and derivatives thereof, poly(vinyl pyrrolidone) and derivatives thereof, poly(alkylene glycol)s and derivatives thereof, and cellulose ethers and derivatives thereof.

Finishing agent for trivalent chromium chemical conversion coating film, and method for finishing black trivalent chromium chemical conversion coating film

Provided is a method for regenerating a nitric acid active treatment solution comprising: adding a zinc ion-aggregating agent to a nitric acid active treatment solution for a surface of a zinc-based material plated metal member, the nitric acid active treatment solution containing zinc ions, to thereby aggregate the zinc ions in the solution as an insoluble salt; and separating and removing the insoluble salt. This regeneration method is employed instead of methods conventionally and widely conducted in zinc-based plating on a steel material such as the exchange of the entire amount of the nitric acid active treatment solution after a lapse of a certain time, and is a method for regenerating a nitric acid active treatment solution, comprising: depositing and removing zinc ions which come to be mixed in the nitric acid active treatment solution during a zinc-based plating process on a steel material, so that the quality of a trivalent chromium chemical conversion treatment can be controlled at a constant level through simplification and cost reduction of a plating control step, and the waste nitric acid can be reduced as much as possible.

Method for regenerating solution for nitric acid activation treatment of zinc-plated metal member surface, and regeneration treatment apparatus using the same

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Funabashi, Japan

Ryuta Kashio