Near neutral pH pickle on multi-metals
AssigneeMacDermid Enthone Inc.
InventorChalo Aoun
Life of this patent
Estimating the term…
Abstract
A near neutral pH pickling composition for the removal of oxides from metallic surfaces, including heat treated steel. The pickling composition comprises a) a water-soluble organic or inorganic nitro compound, wherein a central N atom has an oxidation state of 3+; b) a polarizing agent for the nitro compound, wherein the polarizing agent comprises at least one of a phosphonate and a carboxylate; c) a pH buffer, and d) at least one metal complexing agent. The composition is preferably maintained at a pH between about 4.5 and about 7.5. The near neutral pH pickle composition can be used on various metallic surfaces as well as composite surfaces comprising metallic and non-metallic portions.
Claims23
A method for pickling a surface to remove metallic oxides thereon, wherein the method comprises the steps of:
- a) contacting the surface with a near neutral pH pickle composition comprising:
- i) a water-soluble, organic or inorganic nitro compound, wherein a central N atom has an oxidation state of +3;
- ii) a polarizing agent for the nitro compound, wherein the polarizing agent comprises at least one of a phosphonate and a carboxylate;
- iii) a pH buffer;
- and
- iv) at least one metal complexing agent;
- and
- b) rinsing the surface to remove metallic oxides from the surface.
Dependencies are inferred from the claim text.