Patent ID: 8802190

Claim:
A method of forming a protective coating on a metallic substrate consisting of: depositing a first coating composition on a surface of the substrate, the first coating composition comprising first reducible metallic particles selected from the group consisting of aluminum-containing compounds, zinc-containing compounds, or a mixture thereof, second reducible metallic particles including iron-containing compounds thereof, and a polymeric binder; depositing a second coating composition on a surface of the first coating composition, the second coating composition comprising first reducible metallic particles selected from the group consisting of aluminum-containing compounds, zinc-containing compounds, or a mixture thereof, second reducible metallic particles including iron-containing compounds, and a polymeric binder; treating the coating compositions under conditions sufficient to remove substantially all of the polymeric binder from the first and second coating compositions to form a residual layer comprising the first and second metallic particles of the first and second coating compositions; treating the residual layer under conditions sufficient to reduce the first and second metallic particles of the first and second coating compositions and form a reduced layer of first metal particles and second metal particles of the first and second coating compositions; and treating the reduced layer of first and second metal particles of the first and second coating compositions under conditions sufficient to form an alloy layer having a thickness on the substrate surface.