Sermatech International Inc.

John E Hughes

Mark F Mosser

Kevin B Eddinger

Ronald E Myers

A heat curable bonding composition for providing a coating to a solid substrate comprises water, phosphate ions, borate ions, and aluminum ions. The bonding composition has a pH in the range from about 1.4 to about 2.2, and is substantially free of chromate ions, molybdate ions, and magnesium ions.

Chromate-free phosphate bonding composition

A heat curable bonding composition of the present invention comprises an aqueous solution containing phosphate ion (PO,) and chromium(III) ion (Cr,, or trivalent chromium) and is substantially free of hexavalent chromium ions. The bonding composition may further contain at least one secondary cationic species. The bonding composition has a pH in the range of about 1 to about 3.5.

Hexavalent chromium-free phosphate-bonded coatings

A bonding composition for a heat curable overlay coating for coating a substrate is provided. The bonding composition comprises phosphate ions, permanganate ions, at least one species of metal cation having a valence greater than +1, and water. The bonding composition has a pH in the range from about 1.5 to about 4.5 and is substantially free of chromate ions and molybdate ions. Preferably, the molar ratio of phosphate ions to permanganate ions in the bonding composition is in the range from about 2:1 to about 580:1 and the nonvolatile content of the bonding composition is in the range from about 10% (wt) to about 35% (wt). Aluminum ions are a preferred species of metal cation in the bonding composition. Overlay coating compositions are also provided containing metallic aluminum particles dispersed in the bonding composition of the invention.

Phosphate bonded aluminum coatings

A heat curable protective coating composition for providing barrier protection to a solid substrate. The coating composition comprises an aqueous solution of phosphate ions and nitrate ions and at least one species of metal ion having a valency greater than +1. The metal ions may be selected from the group consisting of aluminum ions, manganese ions, magnesium ions, cerium ions, cobalt ions, chromium(III) ions, nickel ions, iron ions, copper ions, and zinc ions. The composition has a pH in the range from about 0.5 to about 3.5. The composition is substantially free of chromate ions and molybdate ions. A cured topcoat is substantially clear and has a glossy appearance.

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West Chester, PA, United States of America

John E Hughes