METAL PRETREATMENT MODIFICATION FOR IMPROVED THROWPOWER

摘要

A pretreatment composition and a method for pretreating a metal substrate is disclosed. The method comprises: (a) pretreating the metal substrate with a Group IV(b) metal ion, followed by (b) treating the substrate of (a) with a composition comprising: (i) a Group IV(b) metal ion, (ii) a copper ion, (iii) a fluoride ion, and (iv) an organophosphonic acid, followed by (c) electrodepositing a cationic electrodepositable composition on the metal substrate.