8078 (ISO International Standard INTERNATIONALORGANIZATION FOR STANDARDIZATIONMEKAYHAPOAHAA OPTAHM3ALMA IO CTAHAAPTW3AUMWORGANISATION INTERNATIONALEDE NORMALISATION Aerospace process - Anodic treatment of aluminium alloys -- Sulfuric acid process, undyed coating Procédés de traitement dans I'industrie aerospatiale -- Traitement anodique des alliages d'aluminium -- Traitement a I'acide sulfurique pour revetement non teinte First edition - 1984-10-15 UDC 669.716.9 : 629.7 Ref. No. 1SO 8078-1984 (E) ISO 8078-1984 (E) Descriptors : aircraft industry, aluminium alloys, anodizing, anodic coating, specifications, quality assurance, tests, packing, sulfuric acid. Price based on 3 pages Copyright InternationalOrganizationfor Standardization d without license from IHS Not for Resale Foreword ISo (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing Internationat Standards is normally carried out through ISo technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with Iso, atso take part in the work. Draft Internationat Standards adopted by the technical committees are circutated to the member bodies for approval before their acceptance as International Standards by the ISO Council. They are approved in accordance with ISO procedures requiring at teast 75 % approval by the member bodies voting. International Standard ISO 8078 was prepared by Technicai Committee ISO/TC 20, Aircraft and space vehicles. International Organization for Standardization, 1984 ? Printed in Switzerland n or networking permited without license from IHS No reproduction Not for Resale ISO 8078-1984 (E) INTERNATIONAL STANDARD Aerospace process - Anodic treatment of aluminium alloys --- Sulfuric acid process, undyed coating Scope and field of application 3.3 Process details 1 This International Standard specifies requirements for pro- 3.3.1 Electrolyte ducing and testing an undyed anodic coating on aluminium alloys. The anodic coating is produced by the sulfuric acid pro- The electrolyte shall be an aqueous solution of sulfuric acid, cess. technical grade (o 1,83) at a nominal concentration of 15 % (m/m) (allowable range : 150 to 200 g H2SO4 per litre). The The anodizing process is applied in the manufacture of maximum dissolved aluminium content in the electrolyte shall aerospace products to improve paint adhesion and resistance not exceed 15 g/l. The chloride content, measured as NaCl to corrosion. shall not exceed 0,2 g NaCl per litre. The temperature of the bath shall be maintained at 21 ± 2 oC. 2 References 3.3.2 Water quality ISo 2064, Metallic and other non-organic coatings - Defi- The quality of the water used shall be such that its initial con- ductivity does not exceed 1,o00 μS/m. Total dissolved solids thickness. should not be greater than 12 ppm (suifates, chlorides, etc.), including a maximum of 4 ppm SiO2: The pH value shall be Is0 2106, Anodizing of aluminium and its alloys -- Determina- held between 5,5 and 6,9. Acetic acid or ammonia may be used tion of mass per unit area (surface densityi of anodic oxide to maintain the required pH level. coatings - Gravimetric method. 3.3.3 Sealer Iso 2360, Non-conductive coatings on non-magnetic basis metals - Measurement of coating thickness - -Eddycurrent Unless otherwise specified, the sealing agent used shall be an method. aqueous solution of sodium dichromate or potassium dichromate at a concentration of 3 to 5 % (m/m) Iso 2859, Sampling procedures and tables for inspection by Na2Cr2072H20 or K2Cr207-2H20. The pH value shall be held attributes. between 5,0 and 6,0. Acetic acid or sodium hydroxide may be used to maintain the required pH level. ISo 3768, Metallic coatings - Neutral salt spray test (NSS test). When acceptable to th