Improved posttreatment cleaning method of phosphate treated metal surface

Abstract

Abstract PURPOSE:To drastically enhance corrosion resistance of coated and uncoated metal surface by a method wherein an aqueous solution containing water-soluble Zr cpd. and myoinositol phosphate in which molar ratio and pH are specified is brought into contact with a metal surface treated with phosphate. CONSTITUTION:An aqueous solution is prepared in which water soluble Zr cpd. (e.g. zirconium fluoride and its NH4 salt) is contained in 0.05g/l as ZrO2 and myoinositol phosphate and/or its water soluble salt is contained in 0.05g/l. In this aqueous solution, the molar ratio of the former to the latter is adjusted to 1-50:1 and pH to 3-7. The aqueous solution is brought into contact with the metal surface of Fe, Cu, Al, etc. or their alloy which has been treated with phosphate (e.g. iron phosphate). The contact temperature is at room temperature to 90 deg.C. Myoinositol phosphate is di--hexa-phosphate of myoinositol and physic acid is useful industrially.

Inventors

• 👤 Tamotsu Boda
• 👤 Minoru Ishida

Bibliographic Details