Phosphating process
AssigneeImperial Chemical Industries PLC
InventorsMichael Brock, Brian Alfred Cooke
Life of this patent
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Abstract
Low molecular weight water soluble polymers (molecular weight less than 5 .times. 10.sup.5) which comprise monomer moieties selected from acrylic acid, methacrylic acid, acrylamide and methacrylamide, when present in acid metal phosphating solutions modify the physical form of sludge produced. Process efficiency is improved.
Claims5
A process of applying a phosphate coating to a ferrous metal substrate by treating the substrate with an acidic zinc phosphate solution and a depolarizing oxidant in the presence of 1 - 100 parts of a water soluble polymer per million parts of the phosphate solution, wherein the polymer is a polyacrylic acid or a polyacrylamide of molecular weight between 150 and 5.times.10.sup.5.
An acidic zinc phosphate solution containing a depolarizing oxidant and 1-100 parts of water soluble polymer, per million parts of phosphate solution, said polymer being a polyacrylic acid or a polyacrylamide of molecular weight between 150 and 5.times.10.sup.5.
Dependencies are inferred from the claim text.