| 主权项 |
1. A process for coating a metallic surface comprising the steps of:
contacting the metallic surface with an aqueous composition containing at least one silicon compound selected from the group consisting of a silane, a silanol, a siloxane and a polysiloxane to form a silane coating on the metallic surface and then contacting the metallic surface having the silane coating formed thereon with an aqueous composition containing a phosphone compound to form a phosphonate coating thereon, wherein at least 80 mole % of all phosphone compounds of the aqueous composition containing the phosphone compound are 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′)PO, 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 its terminal position, wherein the silane coating and the phosphonate coating are formed in succession before the metallic surfaces are coated with a coat of paint or with a coat of adhesive, and wherein the metallic surface comprises an aluminum alloy. |
