摘要 |
Methods comprising: (a) providing a coating composition comprising a fluoroacid compound of the general formula (I): <?in-line-formulae description="In-line Formulae" end="lead"?>XpMqFrOs (I)<?in-line-formulae description="In-line Formulae" end="tail"?> wherein each of q and r independently represents an integer of 1 to 10; each of p and s independently represents an integer from 0 to 10; X represents at least one cation selected from the group consisting of hydrogen, ammonium, alkaline earth metals and alkali metals; and M represents at least one element selected from the group consisting of Ti, Zr, Hf, Si, Sn, Al, Ge, and B; (b) contacting a metal substrate with the coating composition; and (c) adding to the coating composition a component selected from the group consisting of fluorine-free compounds of an element M, Group 2 metal compounds, Group 12 metal compounds, Group 13 compounds, Group 14 compounds, and combination thereof. |