Metal treatment – Process of modifying or maintaining internal physical... – Processes of coating utilizing a reactive composition which...
Reexamination Certificate
2011-03-29
2011-03-29
King, Roy (Department: 1733)
Metal treatment
Process of modifying or maintaining internal physical...
Processes of coating utilizing a reactive composition which...
C148S243000, C148S264000, C148S265000, C148S266000, C148S268000
Reexamination Certificate
active
07914627
ABSTRACT:
A processing solution for forming a hexavalent chromium free, corrosion resistant trivalent chromate conversion film on zinc or zinc alloy plating layers comprises: trivalent chromium and oxalic acid in a molar ratio ranging from 0.5/1 to 1.5/1, wherein the trivalent chromium is present in the form of water-soluble complex with oxalic acid; and cobalt ions, which do not form a hardly soluble metal salt with oxalic acid and are stably present in the processing solution without causing any precipitation; wherein the solution reacts with zinc when bringing it into contact with the zinc or zinc alloy plating to form a hexavalent chromium free, corrosion resistant, trivalent chromate conversion film containing zinc, chromium, cobalt, oxalic acid and silicon on the plating. The film is quite thin, free of any hexavalent chromium, has corrosion resistance identical to or higher than that achieved by the conventional hexavalent chromium-containing film and can be formed using a processing solution having a quite low concentration.
REFERENCES:
patent: 4349392 (1982-09-01), Huvar
patent: 4359345 (1982-11-01), Fonte
patent: 4578122 (1986-03-01), Crotty
patent: 5368655 (1994-11-01), Klos
patent: 5582709 (1996-12-01), Oshima et al.
patent: 5630929 (1997-05-01), Oshima et al.
patent: 5743971 (1998-04-01), Inoue et al.
patent: 5938861 (1999-08-01), Inoue et al.
patent: 6287704 (2001-09-01), Preikschat et al.
patent: 6719852 (2004-04-01), Oshima et al.
patent: 2001/0017293 (2001-08-01), Nasu et al.
patent: 1 032 100 (2000-08-01), None
patent: 1 128 508 (2001-08-01), None
patent: 54-142141 (1979-11-01), None
patent: 57-181379 (1982-11-01), None
patent: 63-15991 (1988-04-01), None
patent: 3-10714 (1991-02-01), None
patent: 11-335865 (1999-12-01), None
patent: 2000-509434 (2000-07-01), None
patent: 2000-234177 (2000-08-01), None
patent: 2000-282255 (2000-10-01), None
patent: WO 97/40208 (1997-10-01), None
The ASM Handbook, vol. 13: Corrosion, “Chromate Conversion Coatings: Technology of Chromating Processes”, pp. 1-3, (1992).
Dictionary of Organic Compounds, sixth edition, volume five, Chapman & Hall, p. 4965 (1996).
Merriam-Webster's Collegiate Dictionary, tenth edition, Merriam-Webster Incorporated, p. 172, (1998).
Inoue Manabu
Oshima Katsuhide
Tanaka Shigemi
Yamamoto Tomitaka
Dipsol Chemicals Co., Ltd.
King Roy
Oblon, Spivak McClelland, Maier & Neustadt, L.L.P.
Zheng Lois
LandOfFree
Processing solution for forming hexavalent chromium free and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Processing solution for forming hexavalent chromium free and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Processing solution for forming hexavalent chromium free and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2635680