Invention Grant
- Patent Title: Corrosion-resistant trivalent-chromium chemical conversion coating and solution for trivalent-chromium chemical treatment
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Application No.: US15497776Application Date: 2017-04-26
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Publication No.: US11643732B2Publication Date: 2023-05-09
- Inventor: Manabu Inoue , Kimitaka Watanabe , Go Nagata , Motoi Nakatani , Keita Ishizu , Toshiki Inomata
- Applicant: DIPSOL CHEMICALS CO., LTD
- Applicant Address: JP Tokyo
- Assignee: Dipsol Chemicals Co., Ltd.
- Current Assignee: Dipsol Chemicals Co., Ltd.
- Current Assignee Address: JP Tokyo
- Agency: Hoffmann & Baron, LLP
- Priority: JP 2007203284 2007.08.03 JP 2007298411 2007.11.16
- The original application number of the division: US12671786
- Main IPC: C23C22/30
- IPC: C23C22/30 ; C23C22/77 ; C23C22/53 ; C23C22/83 ; C23C22/46 ; C23C22/40 ; C23C22/47 ; C23C28/00 ; C09D5/08 ; C23C22/27 ; C23C22/33

Abstract:
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/cm2 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/cm2.
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