Commonwealth Scientific and Industrial Research Organisation

Karen Joy Hammon Nelson

Anthony Ewart Hughes

Simon Gerard Hardin

Klaus Werner Wittel

Terence W Turney

Lance Wilson

Mark Julian Henderson

Sally Ann Nugent

Russell James Taylor

Bruce Roy William Hinton

An aqueous acidic solution for forming a rare earth element containing conversion coating on the surface of a metal, said solution being chromate-free and including effective quantities of at least one rare earth element (as herein defined) containing species, an oxidant and at least one accelerator, comprising a metal selected from Groups VA and VIA of the Periodic Table.

Process and solution for providing a conversion coating on a metallic surface I

An aqueous acidic solution for forming a conversion coating on the surface of a metallic material, said solution containing at least one rare earth element (as herein defined) containing species, an accelerator additive selected from the group consisting of metals of Group IB, IIB, IVA, VA, VIA and VIII of the Periodic Table, a peroxidic species and at least one acid selected from the group of mineral acids, carboxylic acids, sulphonic acids and phosphonic acids, wherein said solution contains no more than 20 mg/liter each of fluoride and of phosphate, and the solution is essentially free of chromate.

Process and solution for providing a conversion coating on a metallic surface II

A metal surface which has been cleaned using an alkaline based solution is treated with an acidic solution which contains rear earth ions to remove any smut which may have been produced during the alkaline cleaning. A coating is formed on the cleaned surface using a different acidic solution containing rare earth cations which have multiple valence states. When the surface is reacted with coating solution, an increase in the pH at the metal surface indirectly results in precipitation of a rare earth metal such as cerium onto the surface. Alternatively, after the removal of the smut, the surface may be coated using a painting technique.

Metal treatment with acidic, rare earth ion containing cleaning solution

A process and an aqueous, acidic solution for forming a rare earth element containing coating on the surface of a metal, said solution including effective quantities of: (a) one or more rare earth element containing species including at least one rare earth element capable of having more than one higher valence state, as herein defined; and (b) one or more additives selected from the groups including: i) aqueous metal complexes including at least one peroxo ligand; and ii) metal salts or aqueous metal complexes of a conjugate base of an acid in which the metals are selected from Transition Elements and Group IVA elements of the Periodic Table as herein defined.

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Plympton, Australia

Karen Joy Hammon Nelson