Foam phosphatizing method and composition

A method for phosphatizing a three-dimensional object having exposed metallic surfaces comprising the steps of:

• a. locating said object so that at least one of the metallic surfaces to be phosphatized is a drainable surface;
• b. blending 0.2 to 5 parts by weight of an organic ammonium phosphate with 0.1-1.5 parts by weight of an organic ammonium fluosilicate;
• 0.01-1.0 parts by weight of a nitrated aromatic accelerator;
• 0.25-5 parts by weight of a high-foaming surfactant having an initial Ross-Miles foam height in excess of 100 mm. determined at 0.1% by weight concentration in water in a column of zero hardness water maintained at 50.degree. C., selected from the group consisting of an alkyl-aryl sulfonate, an alkyl-phenolethylene oxide adduct, an alkyl ether sulfate, and mixtures thereof;
• essentially the balance of the resulting mixture being a liquid carrier selected from the group consisting of water, an aromatic liquid solvent, and mixtures thereof;
• said resulting mixture having a pH ranging from about 3.0 to about 5.5;
• c. generating a foam from said mixture of said step (b) and a greater volume of air, relative to the volume of said mixture;
• and spraying said foam onto a said drainable surface, said volume of air being selected to provide an actual dwell time of foam deposit on said drainable surface, which actual dwell time is at least long enough to provide an adherent phosphate layer on said drainable surface in excess of 10mg/ft.sup.2 but not long enough to create powdery, non-adherent deposits;
• said actual dwell time ranging from about 30 seconds to about 20 minutes;
• and
• d. causing downward draining of the foam deposits, resulting from the spraying according to said step (c), on said drainable surface.

A foamable phosphatizing composition comprising, by weight, 1.3 to 3.9% phosphoric acid;

• 0.3 to 0.95 hydrofluosilic acid;
• 0.8 to 2.4% monoethanolamine;
• 0.05 to 0.15% m-nitrobenzene-sulfonate;
• 0.01 to 0.03% molybdenum trioxide;
• 4.75% aromatic solvent;
• 0.15 to 0.45% xylene sulfonic acid;
• 0.14 to 0.3% n-alkyl benzene sulfonate said sulfonate having an initial Ross-Miles foam height in excess of 100 mm. determined at 0.1% by weight concentration in water in a column of zero hardness water maintained at 50.degree. C.;
• 1.2 to 12% sodium lauryl ether sulfonate;
• 1.2 to 12% sodium lauryl ether sulfate;
• 0.25% nonyl phenolethylene oxide adduct;
• and 74.87 to 95.006% water;
• said composition having a pH in the range of about 3 to about 5.5.

A foam phosphatizing composition comprising:

• air and a liquid, said liquid comprising:
• ______________________________________ Parts by Weight ______________________________________ 0.75-4 Phosphoric acid;
• -0.01-1.5 an accelerator system comprising a compound selected from the group consisting of a molybdenum oxide, a molybdate salt, a nitrated aromatic sulfonic acid, a nitrated aromatic sulfonate, and mixtures thereof;
• 0.25-10 at least one high foaming surfactant having an initial Ross-Miles foam height in excess of 100 mm. determined at 0.1% by weight concentration in water in a column of zero hardness water maintained at 50.degree. C., said surfactant selected from the group consisting of an alkyl sulfonate;
• an alkyl sulfate;
• an alkyl ether sulfonate;
• corresponding acids thereof;
• an alkyl phenoxy polyethoxy ethanol;
• alkyl, ethyl cycloimidinium, 1-hydroxy, 3-ethyl alcoholate, 2-methyl-carboxylate;
• alkyl amine oxide;
• neutralized or non-neutralized polypeptide;
• and fatty acid diethanol amide;
• 0-100 organic liquid solvent having a flash point of excess of 85.degree. F. and an initial boiling point in excess of 180.degree. F.;
• 0-100 water;
• ______________________________________
• said composition further containing about 1-3 equivalents of an amine for each three equivalents of phosphoric acid;
• the pH of said composition being in the range of about 3.0 to about 5.5, said foam having sufficient volume of air per volume of liquid to provide a foam having a controlled degree of stability and capable of adhering to overhead, inclined or vertical metal surface.

A foam phosphatizing composition comprising:

• gaseous fluid and a liquid, said liquid comprising:
• 0.75-4.0% by weight phosphoric or polyphosphoric acid;
• at least about one equivalent of an amine for each 3 equivalents of said acid;
• 0-1.5% by weight of an agent selected from the group consisting of an accelerator, a debronzing agent, and mixtures thereof;
• 0-1.5% by weight of a compound of the formula H.sub.2 MF.sub.6 wherein M is an element of Group IV A or IV B of the Periodic Table;
• at least one high-foaming surfactant having an initial Ross-Miles foam height in excess of 100 mm. determined at 0.1% by weight concentration in water in a column of zero
• hardness water maintained at 50.degree. C;
• and
• substantially the balance of said liquid being a liquid carrier selected from the group consisting of water, a substantially hydrocarbon solvent, and mixtures thereof;
• said gaseous fluid being present in an amount sufficient to provide moderately stiff foam capable of remaining in adherent bonding contact with a vertical metal surface until a phosphate coating weight in excess of 10 mg/ft.sup.2 is obtained, the pH of said composition being in the range of about 3.0 to about 5.5, said foam being sufficiently wet to flow under the influence of gravity once the adherent bond between the foam and metal surface relaxes or is broken by chemical change.