Title: Phosphating of metallic substrate with electrolytic reduction of nitrate ions

Abstract: In a method for phosphating the surface of a metallic substrate by treament with a phosphating solution comprising nitrite ions as the accelerator, an improvement wherein the supply of the nitrite ions to the phosphating solution is carried out by electrolytic reduction of nitrate ions present in the phosphating solution, whereby a desired concentration of nitrite ions in the phosphating solution is maintained without accumulation of alkali metal and/or ammonium ions unavailable for the phosphating and a uniform phosphate coating film having satisfactorily good coating properties is formed on said surface.

Do you think this is a good invention? Vote now:

Votes so far: For:(0) Against:(0)
Other info:

Inventors: Oka, Shoji (Nara, JP)
Murakami, Ryoichi (Kyoto, JP)
Sueyoshi, Akiko (Osaka, JP)

Application Number: 791470
Filing Date: 1977-04-27
Publication_date: 1978-09-12
Assignee: Nippon Paint Co., Ltd. (Osaka, JP)
Primary Class(es): 148/241 148/262, 204/DIG13, 427/345
Other Classes:
US Patent Ref:

3510412	May, 1970	Raviv et al.	204/103.
3616304	Oct, 1971	Bedi	204/DIG.
3640805	Feb, 1972	Knight et al.	204/DIG.
3996072	Dec, 1976	Oka et al.	148/6.

Other Refs: 2,351,153

Jun, 1974	DE

Primary Examiner: Kendall, Ralph S.
Assistant Examiner:
Attorney: Wenderoth, Lind & Ponack