US 11,987,888 B2
Trivalent chromium chemical conversion treatment liquid for zinc or zinc alloy base and chemical conversion treatment method using the same
Ryouji Iwanaga, Chiba (JP); Manabu Inoue, Tokyo (JP); Tomitaka Yamamoto, Tokyo (JP); and Takahiro Fujino, Tokyo (JP)
Assigned to Dipsol Chemicals Co., Ltd., Tokyo (JP)
Filed by DIPSOL CHEMICALS CO., LTD., Tokyo (JP)
Filed on Aug. 16, 2022, as Appl. No. 17/888,926.
Application 17/888,926 is a continuation of application No. 16/126,461, filed on Sep. 10, 2018, abandoned.
Claims priority of application No. 2017-177016 (JP), filed on Sep. 14, 2017.
Prior Publication US 2022/0396884 A1, Dec. 15, 2022
Int. Cl. C23C 22/30 (2006.01); C23C 22/34 (2006.01); C23C 22/53 (2006.01); C23C 22/00 (2006.01)
CPC C23C 22/53 (2013.01) [C23C 22/34 (2013.01); C23C 2222/10 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A chemical conversion treatment method of forming a trivalent chromium chemical conversion coating on zinc or zinc alloy plating, the method comprising brining a hexavalent chromium-free trivalent chromium chemical conversion treatment liquid into contact with a base material plated with an acidic zinc or zinc alloy bath, the treatment liquid comprising trivalent chromium ions, zirconium ions, nitrate ions, and chain colloidal silica, wherein
the chemical conversion treatment liquid is free of hexavalent chromium and consists of
one or more trivalent chromium compounds which provide the trivalent chromium ions,
one or more zirconium compounds which provide the zirconium ions,
one or more nitric acid compounds which provide the nitrate ions, chain colloidal silica,
water,
optionally one or more cobalt compounds which provide cobalt ions,
optionally one or more fluorine-containing compounds which provide fluoride ions,
optionally one or more water-soluble carboxylic acids or salts thereof,
optionally one or more water-soluble metal salts containing a metal selected from the group consisting of Zn, Al, Ti, Mo, V, Ce and W,
optionally one or more phosphorus compounds, and
optionally one or more inorganic acids, one or more organic acids or one or more alkaline agents for adjusting the pH;
the base material is a disc brake caliper;
the pH of the treatment liquid is 2.5 to 5.0; and
a molar ratio of trivalent chromium ions to zirconium ions is 0.1 to 4.