| 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 M x O y n− , where M is selected from the group comprising Mo, V and W. The heteropolymetalates have the general formula BM x O y 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 12 O 40 ) 3− , (PMo 10 V 2 O 40 ) 5− , (MnPW 11 O 39 ) 5− , (PW 12 O 40 ) 3− , (SiMo 12 O 40 ) 4− , (SiW 12 O 40 ) 4− , (Mo 7 O 24 ) 6− , (CeMo 12 O 42 ) 8− and mixtures thereof. |