Method of and composition for chemically dissolving electroless metal deposits

Claim 1

AN AQUEOUS BATH FOR SELECTIVELY DISSOLVING ELECTROLESS NECKEL DEPOSITS FOR EXPOSED SURFACES OF A BASIS METAL, WHICH BATH COMPRISES A TERNARY SYSTEM CONSISTING ESSENTIALLY IN ADDITION TO WATER OF A MEMBER SELECTED FROM EACH OF THE FOLLOWING GROUPS, (A), (B) AND (C): (A) AT LEAST ONE ALKALI METAL HYDROXIDE PROVIDING IN AQUEOUS SOLUTION A HYDROXYL ION CONCENTRATION OF FROM 0.20 TO 2.0 MOLES PER LITER; (B) AN AROMATIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF NITROBENZENE AND NITRONAPHTHALENE DERIVATIVE HAVING AT LEAST ONE WATER-SOLUBILIZING RADICAL IN ADDITION TO THE NITRO RADICAL ATTACHED TO THE AROMATIC NUCLEUS, AND MIXTURES THEREOF, SUCH COMPOUND BEING PRESENT IN SOLUTION AT CONCENTRATIONS OF FROM ABOUT 0.1 TO 1.0 MOLE PER LITER; (C) AT LEAST ONE ALIPHATIC PRIMARY POLYAMINE WHEREIN THE ALIPHATIC RADICAL CONTAINS FROM TWO TO SIX CARBONS, SAID ALIPHATIC AMINE HAVING STRONG COMPLEXING ABILITY FOR NICKEL IONS AND BEING PRESENT IN AMOUNT OF ABOUT 0.1 TO 3.0 MOLES PER LITER.