POST-TREATMENT COMPOSITION FOR INCREASING CORROSION RESISTANCE OF METAL AND METAL ALLOY SURFACES
The present invention relates to aqueous post-treatment compositions and an immersion and/or electrolytical process using said compositions for corrosion protection of metal and/or metal alloy surfaces. The aqueous post-treatment compositions comprise at least one polysiloxane betaine compound and at least one phosphorus containing compound.
1 . An aqueous post-treatment composition for treating a metal or metal alloy surface comprising
at least one polysiloxane betaine compound represented by formula I:
wherein n for compounds according to formula I ranges from 0 to 200 and m ranges from 1 to 50; and
at least on phosphorus compound or its salt represented by the formulae II to VII:
wherein R1, R2 and R3 can be equal or different and are selected independently from the group consisting of H or the counter ions NH4+, Li+, Na+, K+, C1-C20 alkyl, substituted or unsubstituted, linear or branched, C1-C6 alkaryl, linear or branched, substituted or unsubstituted and aryl, substituted or unsubstituted and wherein for compounds according to formulae II to VII n is an integral number ranging from 1 to 15.
2 . An aqueous post-treatment composition according to claim 1 , wherein for compounds according to formula In ranges from 2 to 100.
3 . An aqueous post-treatment composition according to claim 1 , wherein for compounds according to formula I n ranges from 5 to 50.
4 . An aqueous post-treatment composition according to claim 1 , wherein m ranges from 1 to 25.
5 . An aqueous post-treatment composition according to claim 1 , wherein m ranges from 2 to 10.
6 . An aqueous post-treatment composition according to claim 1 , wherein the at least one polysiloxane betaine compound represented by formula I is used in an amount of 0.05 to 50 g/l.
7 . (canceled)
8 . An aqueous solution for treating a metal surface according to claim 1 , wherein the at least one phosphorus compound or its salt is selected from compounds having the following formula III.:
wherein R1 of the phosphorus compound III. is selected from the group consisting of n-propyl, isopropyl, n-hexyl, isohexyl, n-heptyl, isoheptyl, n-octyl, isooctyl, n-nonyl, isononyl, d-decyl, isodecyl, n-undecyl, isoundecyl, n-dodecyl, isododecyl and wherein R2 and R3 is H.
9 . An aqueous post-treatment composition according to claim 1 , wherein the at least one phosphorous compound is used in an amount of 0.02 to 10 g/l.
10 . A process for increasing corrosion resistance of a substrate having a metal or metal alloy surface by contacting the surface with an aqueous post-treatment composition according to claim 1 .
11 . A substrate having a metal or metal alloy surface treated with the aqueous post-treatment composition according to claim 1 .
12 . A substrate according to claim 11 having at least one layer selected from the group comprising gold, gold alloy, nickel, nickel phosphorus alloy, nickel boron alloy, nickel palladium alloy, ternary nickel alloy, palladium, tin, tin alloy, copper, copper alloy, tin, tin alloy, silver, silver alloy chromium and chromium alloy.
13 . A substrate according to claim 11 , wherein the substrate is a gold or gold alloy plated semi-finished good.
14 . A substrate according to claim 13 wherein the good comprises a gold or gold alloy plate or gold or gold alloy wire or a lead frame, a connector or a printed circuit board.