Patent ID: 8071523

Claim:
A process for treating metal surfaces of aluminum or colored metals and alloys thereof, the process comprising subjecting the metal surfaces to a corrosion inhibitor system consisting of a) an alkyleneoxy-alkyl phosphate di- or triester having the general formula where Z is either â€”O-M or â€”O-(AO) n 2 -Alkyl wherein M is an ammonium, alkali metal or alkaline earth metal cation, Alkyl independent from each other, is a straight or branched, saturated or unsaturated alkyl group having from 5 to 22 carbon atoms or is an alkylaryl group wherein alkyl is as defined above and aryl is a monocyclic or bicyclic aromatic group, AO represents an alkylene oxide having from 2 to 4 carbon atoms which may be substituted by one or more C 1-3 alkyl groups, and n 1 , n 2 and n 3 independent from each other are an integer of from 2 to 10; b) an alkaline agent in amount sufficient to achieve a pH of >7.0 in the global system; c) a chelating agent; d) an alkanolamine; e) a nonionic surfactant; f) water; and g) a hydrotrope; at a temperature from 0 to 80Â° C. for 10 s to 60 min, wherein the alkyleneoxy-alkyl phosphate di- or triester of formula I is selected such that the corrosion inhibitor system reduces the corrosion rate of an aluminum surface subjected to the corrosion inhibitor system at a temperature of 60Â° C. for 60 min by a factor of at least 300 as compared to the aluminum surface subjected to the corrosion inhibitor system without the selected alkyleneoxy-alkyl phosphate di- or triester of formula I under the same conditions.