AN AQUEOUS BASIC ETCHING COMPOSITION FOR THE TREATMENT OF SURFACES OF METAL SUBSTRATES

An aqueous etching composition comprising:(a) functionalized urea, biuret and guanidine derivatives and/or salts thereof selected from compounds having formulae I or II:whereinX and Y are independently selected from oxygen, NRR′ and NR5,R, R′ and R5 are independently selected from R1, hydrogen, polyethylene glycols, aromatic compounds, and C1-C4 alkyl, wherein the aromatic compounds and C1-C4 alkyl optionally comprise at least one substituent selected as OR6,R6 is selected from hydrogen and C1-C4alkyl,X and Y can be identical or different;R1 and R2 are independently selected from hydrogen, alkyl compounds, amines, and nitrogen-comprising heteroaromatic compounds,R1 and R2 can be identical or different, with the proviso that R1 cannot be hydrogen,and with the proviso that in compounds having formula I R1 cannot be hydrogen or alkyl compound if X is oxygen;m is an integer from 1 to 4, andn is an integer from 0 to 8;wherein m and n can be identical or different;(b) an oxidizing agent; andwherein the composition comprises a pH from 7.1 to 14.