| abstract |
The invention relates to a process for coating metallic surfaces with a composition containing silane/silanol/siloxane/polysiloxane, wherein, in addition ton a) at least one compound selected from silanes, silanols, siloxanes and polysiloxanes, b) at least one compound containing titanium, hafnium, zirconium, aluminium and/or boron, and c) at least one type of cation selected from cations of metals of subgroups 1 to 3 and 5 to 8, including lanthanides, and of main group 2 of the periodic table of the elements, and/or at least one corresponding compound,n nthe composition contains at least one substance d) selected from:n d 1 ) silicon-free compounds having at least one amino, urea and/or ureido group in each case, d 2 ) anions of nitrite and/or compounds having at least one nitro group, d 3 ) compounds based on peroxide, and d 4 ) phosphorus-containing compounds, anions of at least one phosphate and/or anions of at least one phosphonate, as well as e) water, and f) optionally also at least one organic solvent. nn The invention further relates to corresponding aqueous compositions. |