초록 ▼

An aqueous solution of manganese phosphate and phosphoric acid, preferably with little or no content of any material conventionally recognized as an accelerator or of any divalent metal ions other than manganese and iron, forms a good quality paint undercoating phosphate conversion coating on metal

An aqueous solution of manganese phosphate and phosphoric acid, preferably with little or no content of any material conventionally recognized as an accelerator or of any divalent metal ions other than manganese and iron, forms a good quality paint undercoating phosphate conversion coating on metal substrates, particularly on steel and galvanized steel substrates, when contacted by spraying or immersion with the substrates at a temperature of 54.degree.-65.degree. C. for a time of 0.5-5 minutes.

대표청구항 ▼

[ The invention claimed is:] [1.] A process for forming a conversion coating on a metal substrate surface, without the imposition of any external electromotive force on or electric current through the metal substrate, by contacting the metal substrate surface with an acidic aqueous liquid compositio

[ The invention claimed is:] [1.] A process for forming a conversion coating on a metal substrate surface, without the imposition of any external electromotive force on or electric current through the metal substrate, by contacting the metal substrate surface with an acidic aqueous liquid composition comprising water and:(A) a concentration of from about 0.70 to about 3.0 ppt of dissolved divalent manganese cations;(B) a concentration of dissolved phosphate anions, expressed in the same units as said concentration of divalent manganese cations, such that the concentration of divalent manganese cations has a ratio to the concentration of dissolved phosphate anions that is from about 1.0:30 to about 1.0:18.0, said concentration of dissolved phosphate anions being not greater than about 40 ppt; and(C) a concentration of nitric acid, d aqueous liquid composition having a temperature not more than 75.degree. C. during its contact with the metal substrate, a Free Acid points value from about -1.5 to about 1.5, a Total Acid points value from about 4 to about 50, and a concentration of not more than 0.02 percent of each of the following constituents: zinc cations; nickel cations; calcium cations, magnesium cations, cobalt(II) cations; nitrite ions, all halate and perhalate ions; chloride ions; ferrocyanide ions, and ferricyanide ions; and said process resulting in formation of a coating with a mass of at least about 1.2 g/m.sup.2 after a contact time not greater than about 5.0 minutes.