| abstract |
The present invention provides a conversion coating solution containing polymetalates and/or heteropolymetalates to oxidize the surface of various metal substrates. The polymetalates have the general formula MxOyn-, where M is selected from the group comprising Mo, V and W. The heteropolymetalates have the general formula BM¿xOy?n-, where B is a heteroatom selected from P, Si, Ce, Mn or Co, and M is again selected from Mo, V, W or combinations thereof. The concentration of polymetalates and/or heteropolymetalates anions is preferably between about 1 % and about 5 % by weight. Examples of typical anions used include, but are not limited to, (PMo¿12O40)?3-, (PMo¿10?V2O40)?5-¿, (MnPW¿11O39)?5-, (PW¿12O40)?3-, (SiMo¿12O40)?4-, (SiW¿12?O40)?4-, (Mo¿7O24)6-, (CeMo¿12O42)?8- and mixtures thereof. |