| abstract |
An aqueous, acidic, anti-corrosion conversion coating composition (in particular, an aqueous, acidic Group IV metal-containing anti-corrosion conversion coating composition) for metal substrates comprising as an additive a catechol compound and/or the reaction products of at least one catechol compound and at least one co-reactant compound having one or more functional groups reactive with the at least one catechol compound, desirably the reaction product of a catechol and an polyamine (e.g., a polyethyleneimine), that enhances the anti-corrosion effects of the conversion coating composition; methods of making and applying the conversion coating compositions and coated metal substrates. The catechol-containing conversion coating composition can be applied to metal substrate surfaces at temperatures as low as below 40° C. and with exposure times of 5 minutes or less. The catechol compound or reaction product thereof can become incorporated into the conversion coating formed on the metal substrate. |