The Boeing Company

University of Virginia Patent Foundation

John H Jones

Kay Youngdahl Blohowiak

Harold E Hager

Matthias P Schriever

Chris J Johnson

S Ray Taylor

Robert L Cook, Jr

Chun M Wong

Luong M Tran

Luong (Louie) M Tran

Ray S Taylor

The invention provides a method for producing a corrosion-resistant article, where the article is conductive and subject to hydrogen uptake during electroplating of a coating. The method comprises electroplating a zinc/nickel coating on the article in an aqueous, basic plating solution containing zinc and nickel ions. The method uses an electrolyte in the form of a soluble hydroxide salt with the weight ratio of zinc ions to nickel ions in the solution being sufficient to provide the coating comprising from about 85% to about 95% by weight zinc, and about 5% to about 15% by weight nickel. The plating solution is substantially free of brightening agents which retard hydrogen bake-out.

Low hydrogen embrittlement zinc/nickel plating for high strength steels

The invention provides chromate-free coating mixtures, and coatings formed from these mixtures, that protect an underlying aluminum or aluminum alloy substrate from corrosion. The coating mixtures include a continuous phase selected from organic polymeric compositions, or sol-gels, and a distributed phase, dispersed or dissolved throughout the continuous phase. The distributed phase includes the corrosion-inhibiting chromate-free salts. In accordance with the invention, the mixture of salts includes (1) a first salt selected from (a) the esters of rare earth metals, such as cerium and lanthanum oxalates and acetates, and (b) the vanadate salts of alkali and alkali earth metals, such as sodium metavanadate and calcium metavanadate; and (2) a second salt that is a borate salt of alkali earth metals, such as barium metaborate. In certain embodiments, the coatings of the invention include both (a), and (b), in conjunction with the borate salt (2). In other embodiments, the chromate free salt is a chloride of a rare earth metal, or mixture of such chlorides, either alone or in combination with the first salt or the second salt, or both the first and second salts. Coatings of the invention provide protection to an underlying substrate, even after subjection to a 3000 hour salt spray test. Moreover, the coatings are resistant to degradation by SKYDROL, and are able to withstand impacts of 50 inch-pounds (forward) and 30 inch-pounds (reverse), so that they are well suited for use as protective coatings for aircraft.

Chromate-free protective coatings

Growing community of inventors

Seattle, WA, United States of America

John H Jones