The J. M. Ney Company

David C Wright

Stephen P Schaffer

Matthew M Guzowski

A tarnish-resistant gold color alloy comprises 30-50 percent by weight gold; 20-50 percent copper; 5-15 percent silver; 2-20 percent zinc; 1.5-15 percent palladium; up to 4.0 percent by weight platinum; and up to 1.0 percent by weight rhenium. The atomic ratio of copper to silver, copper to zinc and copper to palladium are respectively, 6-8:1; 2-12:1; and 5-30:1 and the weight ratios are respectively, 3.5-4.7:1; 3.0-18:1; and 1.95-11.66:1. Dental restorations comprising castings of the alloy have color values on the Hunter scale of L=80-90; a=2.5-3.5; and b=14-18. The dental restorations exhibit tarnish-resistant values of DE.sub.1 less than 13 and DE.sub.10 less than 20.

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Enfield, CT, United States of America

David C Wright