USA As Represented by Secretary of the Navy

US Government As Represented by the Secretary of the Army

Fred Pearlstein

Vinod S Agarwala

Carroll F Evans

Vinod S Agarawala

Elizabeth L MacNamara

Corrosion resistant seal-coatings are formed on anodized aluminum by immeon in aqueous solutions containing trivalent chromic compounds with an alkali added near or slightly beyond the precipitation of insoluble basic compounds. Trivalent chromium seals formed on the anodized aluminum when tested in 5% NaCl salt spray chamber showed improved corrosion resistance. After a post-treatment in a peroxide or permanganate solution, the corrosion resistance for the anodized aluminum showed even greater improvement in the salt chamber.

Trivalent chromium solutions for sealing anodized aluminum

A lightweight corrosivity sensor is provided which is thin enough to be edded between the layers of a composite structure or placed on a surface beneath a coating. It comprises a thin non-conductive base and two electrically isolated conductive elements fixed to the surface thereof. Each conductive element comprises a bus bar and a plurality of strips extending from the bus bar and interdigitated with the strips of the other conductive element. The corrosivity sensor is connectable to a current measuring means for measuring the current across the two conductive elements as an indicator of the presence of a corrosive environment. A masking method of manufacturing such a sensor is also provided.

Corrosivity sensor

Corrosion resistant coatings are formed on aluminum by immersion in aqueous olutions containing chromic salts, a fluoride ion from compounds such as a fluosilicate with an alkali added near or slightly beyond the precipitation of the insoluble basic compounds. Trivalent chromium films formed on the aluminum surface when tested in 5% NaCl salt spray chamber showed corrosion resistance in excess of 96 hours. After a post-treatment with peroxide or permanganate solutions, the corrosion resistance for the aluminum substrates exceeded 168 hours. Trivalent chromium coated aluminum serves as an effective base for paint primers. Anodized aluminums were also afforded excellent corrosion resistance, after being treated in dilute/basic chromic sulfate solutions and post-treated with peroxide.

Trivalent chromium conversion coatings for aluminum

The invention is an improved apparatus for the removal of sodium carbonate from cyanide plating baths. The method involves the precipitation of sodium carbonate by the effect of cooling the cyanide plating bath liquid. A container is submerged in the solution with the container opening extending above the plating bath solution level. The container is filled with dry ice and water which produces a temperature of approximately zero degrees centigrade inside of the container. The solution adjacent to the exterior of the container is cooled so that excess sodium carbonate is precipitated as a crystalline deposit. After a desired interval, the container is removed with the encrustation of sodium carbonate for disposal.

Method and apparatus for removal of sodium carbonate from cyanide

Method for removal of sodium carbonate from cyanide plating baths

Spray cleaner formulations useful in the surface treatment of metallic amition components and the like and comprising sodium metasilicate, sodium carbonate, and either sodium hydroxide or ethylenediamine tetraacetic acid, the cleaner formulation being completely devoid of phosphates such that the spent cleaning formulation, when discharged into waterways, will not promote algae growth therein or eutrophication thereof.

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Philadelphia, PA, United States of America

Fred Pearlstein