Patent ID: 8313570

Claim:
An autodeposition bath composition for use in coating an active metal surface comprising: a. an aqueous solution of an autodeposition accelerator comprising an acid, in an amount such that the composition has a pH of about 1.6 to about 3.8, and at least one oxidizing agent; b. particles of a coating-forming polymeric material uniformly dispersed throughout the composition; c. a component of non-black solid pigment particles, stabilized against said acid, uniformly dispersed throughout the composition; d. an emulsifying component comprising an anionic surfactant; and, optionally, e. black pigment and/or finely divided solids suitable as fillers in the coatings to be formed from the composition; said composition being effective to chemically attack, in the absence of an external electrical potential, an active metal surface immersed therein to dissolve therefrom metal to release ions of said metal and sufficient to cause said polymeric material and said non-black solid pigment particles to deposit on the active metal surface as an initially adherent coating which increases in weight or thickness the longer the time said surface is immersed in said composition; wherein relative hydrophobicity/hydrophilicity of the non-black solid pigment particles and hydrophobicity/hydrophilicity of the particles of a coating-forming polymeric material are selected such that the non-black solid pigment particles remain dispersed in the bath and deposit adherently on the active metal substrate.