Coating composition and method of forming

摘要

A coating composition for ferrous metal alloy surfaces comprises a slurry consisting essentially of an aluminum neutralized phosphate bonding solution and aluminum powder. 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 aluminum powder to form the slurry. The bonding solution preferably also contains magnesium. 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.