Titanium free composition and process for activating metal surfaces prior to zinc phosphating

摘要

Effective, titanium-free agents for activating metal surfaces prior to phosphating these surfaces with phosphating baths containing zinc ions can be made by reacting alkali metal phosphates with 1,1-diphosphonic acids and their alkali metal salts and/or poly(aldehydocarboxylic acids) and their alkali metal salts.