Process for treating aluminum with ferricyanide compound
First Claim
1. A process for forming a corrosion and heat resistant, readily dyeable coating on member selected from the group of aluminum, its alloys, and substrates having an aluminum or aluminum alloy surface, said process comprising the step of formation of said coating using chemical means consisting of contacting the surface of said part with a spray comprising an aqueous alkaline solution of a ferricyanide salt having a pH between about 7.5 and 14.0, said ferricyanide salt being present in an amount of at least 0.01 moles per liter of solution.
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Abstract
The invention is for an improved process for chemically forming a protective, color receptive coating on the surface of aluminum. The aluminum may be aluminum parts or substrates coated with a layer of aluminum. Absent conventional steps such as water rinses and the like, the process comprises cleaning the aluminum surface to the extent necessary, including desmutting, and contacting the part with a spray comprising an aqueous alkaline solution of a ferricyanide compound, with or without added oxygen, for a time sufficient to form the coating. The treatment is believed to be a chemical oxidizing step similar to the formation of an oxide film electrically using a conventional anodizing process.
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Citations
20 Claims
- 1. A process for forming a corrosion and heat resistant, readily dyeable coating on member selected from the group of aluminum, its alloys, and substrates having an aluminum or aluminum alloy surface, said process comprising the step of formation of said coating using chemical means consisting of contacting the surface of said part with a spray comprising an aqueous alkaline solution of a ferricyanide salt having a pH between about 7.5 and 14.0, said ferricyanide salt being present in an amount of at least 0.01 moles per liter of solution.
- 13. A process for forming a corrosion and heat resistant readily dyeable coating on a member selected from the group of aluminum, its alloys, and substrates having an aluminum or aluminum alloy surface, said process comprising the steps of formation of said coating using chemical means consisting of contacting the surface of said part with a spray comprising an aqueous alkaline solution of a ferricyanide salt in an amount of from 0.1 to 5 moles per liter, a carbonate salt in an amount of from 0.1 to 5 moles per liter and a trisodium phosphate salt in an amount sufficient to provide an alkaline pH.
Specification