Corrosion resistant seal coat composition and method of forming

摘要

A seal coat composition comprises a slurry consisting essentially of an aluminum neutralized phosphate bonding solution and iron oxide (Fe2O3) powder. The bonding solution advantageously contains a relatively small but essential amount of vanadium pentoxide and, preferably, magnesium. A process for forming the bonding solution component of the coating slurry includes equilibrating an aqueous phosphate solution with a small but controlled and necessary amount of solute aluminum prior to adding iron oxide powder to form the slurry. The present invention overcomes the problem of bonding solutions which require environmentally disadvantageous chromates or molybdates to neutralize the bonding solution prior to formation of the slurry.