Abstract: Method and composition for applying a coating to a metallic surface, the surface being immersed in an acidic aqueous coating composition comprising dispersed solid particles of an organic polymeric resinous coating-forming material and an oxidizing agent, wherein the weight or thickness of the coating formed on the surface is a function of the time the surface is immersed in the composition.

Abstract: A metallic surface is coated with a polymeric resinous coating by immersing the surface in an acidic aqueous coating composition comprising polymeric resinous coating-forming material and an oxidizing agent. The corrosion resistance and/or the surface appearance of the resinous coating is modified by rinsing the coating with an aqueous rinse solution containing hexavalent chromium or an aqueous rinse solution containing hexavalent chromium and reduced forms of chromium.

Abstract: An acidic aqueous coating composition containing an organic coating-forming material forms on a metallic surface immersed therein a coating, the weight or thickness of which is related to the time the surface is immersed in the composition. The coating composition, which tends to become unstable as a result of the build up of metal ions in the composition, is stabilized by removing the metal ions with an ion exchange material. Also, in maintaining stability, anionic and/or nonionic surfactants or dispersing agents, which are present in the composition to disperse the organic-coating forming material, are added to the composition in an amount in excess of that which is added to replenish the organic coating-forming material as it is consumed during use. Also, coating compositions treated with the ion exchange material tend to produce coatings which have a textured or grainy appearance.

Abstract: Acidic aqueous coating compositions containing an organic coating-forming material form coatings on metallic surfaces which are immersed therein. The thickness or weight of the coating formed by the coating composition is a function of the time the metallic surface is immersed in the composition. The resulting coatings have adhesion properties thereby providing an adherent base to which other coatings, for example, paint primers and/or final finish paints can be applied.

Abstract: Method and apparatus for agitating an acidic aqueous coating composition containing dispersed particles of an organic coating-forming material are disclosed. Movable vanes are disposed beneath the surface of a bath of the composition. The vanes have a relatively large surface area and are moved through the bath at low speed so that the shear stress imposed on the dispersed particles is minimized. This prolongs the stability of the composition.

Abstract: Polymeric resinous coatings are formed on metallic surfaces by immersing them in an acidic aqueous coating composition comprising an oxidizing agent and a coating-forming polymeric resin dispersed in said composition by a dispersing agent said resin and dispersing agent being present in a predetermined proportion. The coating composition tends to become unstable as it is used. The stability of the coating composition is maintained by controlling the amounts of metal ions which tend to build-up in the bath and/or the dispersing agent. Specifically, dispersing agent and resin are added to said coating composition in amounts to replenish these ingredients and in a proportion such that the proportion of said added dispersing agent to said added resin is greater than said predetermined proportion and sufficient to maintain the stability of the dispersed resin in the composition thereby prolonging the operability of the coating composition.