Abstract: The invention concerns a process, not using chlorate or nitrite, for the production of nickel and manganese containing zinc phosphate films on steel, zinc, and/or zinc alloys by spraying, spray-dipping, and/or dipping, using an aqueous solution. An organic oxidizing agent is added, primarily to depolarize the nascent hydrogen produced.

Abstract: The development of sludge in phosphating baths is prevented by continuously diverting a partial volume of the baths into a separate device comprising three open chambers: an oxidation chamber where the solution is treated with an O.sub.2 -containing gas to oxidize the iron (II) of the solution of iron (III), which precipitates as phosphate; a conditioning chamber in which the iron (iii) phosphate precipitate formed in the oxidation chamber is agglomerated into a readily sedimented form; and a sedimentation chamber in which the sediment formed in the conditioning chamber is separated from the remaining liquid phosphating solution. This solution is then replenished with phosphate layer-forming components, and the replenished solution is subsequently recycled to the phosphating bath.

Abstract: The present invention relates to a process for phosphating metal surfaces, and more specifically of surfaces of iron, zinc, and aluminum and the alloys thereof as a pretreatment for cold working wherein the surfaces without previous activation are contacted in a temperature range of from 30.degree. C. to 70.degree. C. with an aqueous solution containing(a) from 10 to 40 g/l of Ca.sup.2+ ions,(b) from 10 to 40 g/l of Zn.sup.2+ ions,(c) from 10 to 100 g/l of OP.sub.4.sup.3- ionsand, as accelerator,(d) from 10 to 100 g/l of NO.sub.3.sup.- ions and/or(e) from 0.1 to 2.0 g/l of organic nitro compounds,said solution exhibiting a pH value in the range of from 2.0 to 3.8 and a ratio of free acid to total acid of from 1:4 to 1:100.

Abstract: A composition for the after-passivation of phosphated metal surfaces and a method for its use, the composition containing at least one water soluble salt of tetravalent titanium or divalent manganese, cobalt, nickel or copper.