Methylene chloride phosphatized coating
AssigneeDiamond Shamrock Corporation
InventorsEdward A. Rowe, Jr., William H. Cawley
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Abstract
A liquid composition, containing methylene chloride, can provide phosphate coatings on metal articles. In addition to the methylene chloride, the composition contains a phosphatizing proportion of phosphoric acid and a solubilizing solvent capable of solubilizing phosphoric acid in methylene chloride. Most critically, the composition contains water in an amount exceeding the proportion of phosphoric acid, yet, the water-containing liquid composition maintains liquid phase homogeneity. Phosphatized coatings of desirable water insolubility and unique characteristics are thereby obtained.
Claims13
A coated ferruginous substrate having an adherent and water-insoluble surface coating that is a complex coating of the iron phosphate type obtained by contacting said ferruginous substrate with a methylene chloride and water-containing liquid phosphatizing composition containing water in an amount up to water saturation of the composition, said surface coating containing, in addition to trace elements, the elements iron, phosphorus and oxygen, plus carbon and nitrogen, and having a coating surface of oxygen atoms to phosphorus atoms of at least about 4:1.
A coated ferruginous substrate having a corrosion-resistant and water-insoluble composite surface coating, the base coating of the composite on the substrate surface being a complex coating of the iron phosphate type obtained by contacting said ferruginous substrate with a methylene chloride and water-containing liquid phosphatizing composition containing water in an amount up to water saturation of the composition, said surface coating containing, in addition to trace elements, the elements iron, phosphorus, and oxygen plus carbon and nitrogen, and having a coating surface ratio of oxygen atoms to phosphorus atoms of at least about 4:1, with the subsequent coating in the composite being an adherent coating from a nonphosphatizing solution for treating metal surfaces.
Dependencies are inferred from the claim text.