TWO-STEP ZINC PHOSPHATING PROCESS

摘要

Described are methods for treating a multi-metal assembly. The assembly has a first portion that includes an aluminum substrate and a second portion that includes a non-aluminum metal substrate. The methods include treating the multi-metal assembly by contacting the assembly with a zinc-phosphate composition and contacting the treated assembly with a composition that includes a Group IIIB and/or IVB metal and free fluoride.