METHOD OF PREPARING ACTIVATING AGENT FOR MANGANESE-PHOSPHATIZING OF METAL SURFACES Russian patent published in 1999 - IPC

FIELD: chemical treatment of metals. SUBSTANCE: method consists of following steps: preparation of initial Mn(II) salt solution, disodium phosphate solution with density 1.065 g/cu.cm, and buffer solution (dipotassium phosphate) with density 1.21 g/cu.cm and pH 8.4-8.8; precipitation of manganese phosphate by interaction of Mn(II) solution with disodium phosphate solution at pH 4.0-4.4 and elevated temperature; treatment of resulting suspension with buffer solution at pH 8.4-8.8; washing away of anion admixture; pressing and drying of product at 100 C. Use of activating agent in operation with simultaneously degreasing and activating surface of metal objects by precipitation technique made it possible to eliminate expensive and environmentally unsafe emulsion degreasing operation and, after subsequent manganese-phosphatizing operation, to obtain homogeneous fine-crystalline phosphate layer with reduced weight. EFFECT: improved manganese-phosphatizing operation. 5 tbl, 4 ex