Preparing an environmentally stable stainless surface for bonding
AssigneeThe Boeing Company
InventorYukimori Moji
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Abstract
A method of preparing a stainless steel surface for bonding by anodically treating the steel in an electrolytic bath, at a temperature of 60.degree. F to 180.degree. F, of an aqueous solution of sulfuric acid or an aqueous solution of sulfuric and chromic acids with an impressed voltage during anodizing of a range to remain within the passive region of the stainless steel.
Claims17
A method of preparing a stainless steel surface to provide an environmentally stable interfacial bond with an adhesive, the steps of preparing the stainless steel surface comprising:
- subjecting the steel to electrolytic action as an anode in an electrolyte consisting of an aqueous sulfuric acid bath containing about 400 to 600 grams per liter of sulfuric acid at about 80.degree. F to 160.degree. F, introducing a voltage for imparting about 0.3 to 6 amperes/foot.sup.2 on the anode, and maintaining current flow for about 5 to 25 minutes.
A method of preparing stainless steel to provide an environmentally stable interfacial bond with an adhesive, the steps of preparing the stainless steel surface comprising:
- connecting a stainless steel article to the anode of a pair of electrodes, imparting a voltage across the electrodes and introducing an electric current of about 0.3 to 6 amperes/foot.sup.2 on the article, and immersing the steel with anodic electrode into an electrolyte for 5 to 30 minutes, said electrolyte maintaining a temperature of about 75.degree. F to 160.degree. F and consisting essentially of an aqueous solution of sulfuric acid or of sulfuric acid and hexavalent chromium ion with the chromium ion concentration ratio about 1/7 to 1/13 of the concentration of the sulfuric acid.
A stainless steel article having an adhesive coated surface, said surface prepared for the adhesive by anodizing in an electrolytic aqueous bath from 75.degree. F to 160.degree. F for 5 to 30 minutes at a voltage potential for imparting about 0.3 to 6 amperesfoot.sup.2, said bath consisting of 400-600 grams per liter of sulfuric acid or 300-400 grams per liter of sulfuric acid and 30-40 grams per liter of CrO.sub.3.
A method of preparing a stainless steel surface to provide an environmentally stable interfacial bond with an adhesive, the steps of preparing the stainless steel surface surface comprising:
- utilizing stainless as an anode in an aqueous bath consisting essentially of sulfuric acid or of sulfuric acid and a hexavalent chromium ion with the hexavalent chromium ion concentration about 1/7.5 to 1/13 the concentration of the sulfuric acid and impressing a voltage potential across the electrodes in the bath to impart an electric current of about 0.3 to 6 amperes per square foot to the anode for about 5 to 30 minutes.
Dependencies are inferred from the claim text.