Treatment for Metallic Surfaces U.S. Pafent5,362,334. Nov. 8, I!?94 I! Adams et al., assigws to MacDennid Inc., Waterbury, Conn.

A process for chemically forming a protective layer on a metallic surface, which comprises treating with an aqueous solution comprising a benzimidazole com- pound.

Conversion Coating for Aluminum Alloys U.S. Patent 5,362,335. Nov. 8, 1994 R. Rungta, assignor to Genera/ Motors Corp., Detroit

A process for enhancing the corrosion resistance of an aluminum alloy, compris- ing exposing to a hygroscopic solution so as to form a bohmite film; exposing to an aqueous solution consisting essentially of cerous chloride and water at a temperature of lOO-200°F and for a duration of 10-20 min so as to form cerium oxide on the aluminum alloy, such that the cerium oxide is incorporated in the bohmite film, the aqueous solution of cerous chloride com- prising 8,000-12,000 ppm cerous chloride and having a pH of 3-5; rinsing in water;

and drying at an elevated temperature of 20&320°F and for a duration of 10-30 min, so as to form a mixed barrier layer of the cerium oxide in the bohmite film, which significantly extends the passivity range of the aluminum alloy.

Circuit Board Fabrication Process U.S. fafanf5,362,359. Nov. 8, 1994 E. Horikoshi et al., assignors to Fujitsu Ltd., Kawasaki, Japan

A process for producing a circuit board, comprising forming an electrodeposition- painted coating on a core material selected from a group consisting of magnesium, magnesium alloy, and a magnesium-based composite material; forming a polyimide resin coating on the electrodeposition- painted coating; forming a via hold extend- ing through the polyimide resin coating to the electrodeposition-painted coating; etch- ing and removing the electrodeposition- painted coating in a first region exposed by the via hole, while masking a second region with the polyimide resin coating, to extend the via hole to the core material; forming a metal film on at least a free surface of the

polyimide resin coating and an inner sur- face of the extended via hole; and etching by using a photoresist mask to form a conductor layer having a predetermined pattern.

Polyester Coating Composition U.S. Patent5,362,519. Nov. 8, 1994 J. N. Agyropou/os et a/., assignors to Union Carbide $Theka/s d Plastics Technology Corp., Danbury,

A polyester particularly suitable for use in coating compositions that are sprayed with compressed fluids as viscosity reduc- ing agents.

Base Coat/Clear Coat U.S. fatent5,362,521. Nov. 8, 1994 7: Ozaki et al, assignors to Kansai Paint Co. Ltd, HYW, Japan

A method of forming a coating film by forming in sequence a pigmented base coat and a clear top coat on a substrate followed by finishing with a two-coat one-bake technique, the method being characterized by using as a coating composition for the pigmented base coat, a composition con-

* Precipitates heavy metal ions, forming coarse, easily dewatered, non- leachable floes.

?? Is an environmentally safe product, exhibiting very low toxicity towards aquatic organisms (fish, shrimp), bacteria, and humans.

Degussa e

Corpomtion

Works in acidic, neutral, and alkaline media.

Does not release toxic gases (e.g., hydrogen sul- fide) or flammable, toxic products (e.g., carbon disulfide), even at pH ~1.

Frequently reduces sludge volumes.

For more information, call or write to: Fleimund Pieter Degussa Corporation 65 Challenger Road Ridgefield Park, NJ 07660 Tel: (201) 641-6100 Fax: (201) 641-0385

Circle 042 on reader information card Circle 137 on mader information card

150 METAL FINISHING . JUNE 1995