Method for coating metal surfaces in a multi-step method

A process for coating metallic surfaces, in particular surfaces of wheels made from an aluminum alloy, in a multi-stage A process, wherein the metallic surfaces are first brought into contact with an aqueous composition containing a substantial content of silane/silanol/siloxane/polysiloxane and then with an aqueous composition predominantly containing a phosphone compound, at least 80% of all phosphone compounds of this composition being selected from compounds of the type XYZ,

• wherein Y is mutually independently an unbranched alkyl group having 8 to 16 C atoms or an alkyl group having 8 to 16 C atoms, of Which as a statistical mean up to 20% of the C atoms of the alkyl chains exhibit a functional group,
• wherein X is an OH, NH2, NHR′, CH═CH2, CONHOH, COOR′, acrylic acid amide, epoxy, CH2═CR″—COO, COOH, HSO4, (OH)2PO, (OH)2PO2, (OH)(OR′)PO, (OH)(OR)PO2 or Si(OH)3 group,
• wherein Z is an (OH)2PO, (OH)2PO2, (OH)(OR′)PO or (OH)(OR′)PO2 group,
• wherein R′ is an alkyl group having 1 to 4 C atoms,
• wherein R″ is an H atom or an alkyl group having 1 to 4 C atoms,
• wherein groups X and Z are each bound to group Y in their terminal position,
• and wherein a silane coating and then a phosphonate coating are formed in succession before the metallic surfaces are coated with a coat of paint or with a coat of adhesive.