Ferrate conversion coatings for metal substrates
AssigneeLynntech Coatings, Ltd.
InventorsZoran Minevski, Jason Maxey, Carl Nelson, Cahit Eylem
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Abstract
A method employing oxide film conversion coatings prepared using ferrate (VI) as the oxidizing agent is disclosed. Metal substrates or surfaces, such as aluminum, aluminum alloys or other metals, are contacted with an aqueous solution comprising ferrate (VI) anions to form a corrosion resistant conversion coating on the surface thereof. The ferrate anion concentration is preferably between about 0.0166% and about 1.66% by weight. The coating process is carried out by dipping, spraying, or painting at temperatures ranging from 25° C. to 100° C. for a period of time ranging from about 1 second to about 5 minutes.
Claims18
An aqueous oxidizing solution of transition metal oxyanion salts, each transition metal oxyanion salt having a transition metal oxyanion concentration of 1-100 mmol/l wherein the transition metal oxyanions comprise ferrate (VI) (FeO42−) and one or more transition metal oxyanions selected from the group consisting of permanganate, molybdate, vanadate, tungstate and combinations thereof, and wherein the solution has a pH greater than 13.5.
An oxidizing solution comprising:
- transition metal oxyanion salts, each transition metal oxyanion salt having a transition metal oxyanion concentration of 1-100 mmol/l, wherein the transition metal oxyanions comprise ferrate (VI) (FeO42−) and one or more transition metal oxyanions selected from the group consisting of permanganate, molybdate, vanadate, tungstate and combinations thereof;
- and one or more additional oxidizing agents selected from the group consisting of peroxide, hypochlorite, ozone and combinations thereof, wherein the solution has a pH greater than 13.5.
An oxidizing solution comprising:
- transition metal oxyanion salts, each transition metal oxyanion salt having a transition metal oxyanion concentration of 1-100 mmol/l, wherein the transition metal oxyanions comprise ferrate (VI) (FeO42−) and one or more transition metal oxyanions selected from the group consisting of permanganate, molybdate, vanadate, tungstate and combinations thereof;
- and ethylenediaminetetraacetic acid, wherein the solution has a pH greater than 13.5.
An aqueous oxidizing solution of transition metal oxyanion salts, each transition metal oxyanion salt having a transition metal oxyanion concentration of 1-100 mmol/l, wherein the transition metal oxyanions comprise ferrate (VI) (FeO42−) and one or more transition metal oxyanions selected from the group consisting of permanganate, molybdate, vanadate, tungstate and combinations thereof, and wherein the solution has a pH greater than 14.
An aqueous oxidizing solution consisting essentially of transition metal oxyanion salts, each transition metal oxyanion salt having a transition metal oxyanion concentration of 1-100 mmol/l, wherein the transition metal oxyanions comprise ferrate (VI) (FeO42−) and one or more transition metal oxyanions selected from the group consisting of permanganate, molybdate, vanadate, tungstate and combinations thereof, and wherein the solution has a pH greater than 13.5.
An oxidizing solution of transition metal oxyanion salts, each transition metal oxyanion salt having a transition metal oxyanion concentration of 5-100 mmol/l, wherein the transition metal oxyanions comprise ferrate (VI) (FeO42−) and one or more transition metal oxyanions selected from the group consisting of permanganate, molybdate, vanadate, tungstate and combinations thereof, and wherein the solution has a pH greater than 13.5.
An oxidizing solution of transition metal oxyanion salts, each transition metal oxyanion salt having a transition metal oxyanion concentration of 1-100 mmol/l, wherein the transition metal oxyanions comprise ferrate (VI) (FeO42−) and one or more transition metal oxyanions selected from the group consisting of permanganate, molybdate, vanadate, tungstate and combinations thereof, wherein the solution has a pH greater than 13.5, and wherein the solution does not contain silicate.
An aqueous oxidizing solution of transition metal oxyanion salts, each transition metal oxyanion salt having a transition metal oxyanion concentration of 1-100 mmol/l, wherein the transition metal oxyanions comprise ferrate (VI) (FeO42−) and one or more transition metal oxyanions selected from the group consisting of permanganate, molybdate, vanadate, tungstate, cerate and combinations thereof, wherein the solution has a pH greater than 13.5, and wherein the solution does not contain silicate.
An oxidizing solution comprising:
- transition metal oxyanion salts, each transition metal oxyanion salt having a transition metal oxyanion concentration of 1-100 mmol/l, wherein the transition metal oxyanions comprise ferrate (VI) (FeO42−) and one or more transition metal oxyanions selected from the group consisting of permanganate, molybdate, vanadate, tungstate, cerate and combinations thereof, and one or more additional oxidizing agents selected from the group consisting of peroxide, hypochlorite, ozone and combinations thereof, wherein the solution has a pH greater than 13.5.
An aqueous oxidizing solution of transition metal oxyanion salts, each transition metal oxyanion salt having a transition metal oxyanion concentration of 5-100 mmol/l, wherein the transition metal oxyanions comprise ferrate (VI) (FeO42−) and one or more transition metal oxyanions selected from the group consisting of permanganate, molybdate, vanadate, tungstate, cerate and combinations thereof, and wherein the solution has a pH greater than 13.5.
Dependencies are inferred from the claim text.