PRETREATMENT COMPOSITIONS AND METHODS FOR COATING A METAL SUBSTRATE

摘要

Disclosed are methods for treating metal substrates, including ferrous substrates, such as cold rolled steel and electrogalvanized steel. The methods include contacting the substrate with a pretreatment composition that includes: (a) a group UIB and/or IVB metal an electropositve metal (c) free fluorine; (d) a metal fluoride salt formed from a metal which forms a fluoride salt having a pKsP of at least 11; and (e) water.