Novel palladium alloy and dental restorations utilizing same

Claim 2

A dental alloy consisting essentially of: a. 50-85 percent by weight palladium; b. 5-40 percent by weight of at least one metal selected from the group of cobalt and copper; c. 1.15 percent by weight gallium; d. up to 5 percent by weight of a modifier selected from the group consisting of nickel, gold, indium, ruthenium, tin and mixtures thereof; e. up to 1 percent by weight boron; and f. up to 0.5 percent by weight of a grain refiner selected from the group consisting of rhenium, iridium, and mixtures thereof, said alloy having a thermal expansion of about 0.66-0.72 percent at 500° C., a solidus temperature of at least 1100° C., a liquidus temperature of not more than 1400° C., Vickers hardness greater than 150, offset yield strength at 0.1 percent of greater than 40,000 p.s.i., and tensile elongation greater than 6 percent.

Claim 3

The dental alloy of claim 1 wherein the boron content is 0.1-0.5 percent.

Claim 4

The dental alloy of claim 1 wherein the palladium content is 7-82 percent, the cobalt and/or copper content is 5-15 percent, the gallium content is 3-12 percent, and the modifier content is 1-3 percent.

Claim 5

The dental alloy of claim 3 wherein the boron content is 0.1-0.5 percent.

Claim 6

The dental alloy of claim 4 wherein the modifying element is gold.

Claim 7

The dental alloy of claim 1 wherein the palladium content is 76-80 percent, the cobalt and/or copper content is provided by copper in the amount of 9-12 percent, the gallium content is 8-11 percent, the modifying element is provided by gold in the amount of 1-3 percent, the boron content is 0.2-0.35 percent; and the grain refiner comprises 0.05-0.15 percent thereof.

Claim 8

A dental restoration comprising: a. a casting of a dental alloy consisting essentially of (i) 50-85 percent by weight palladium, (ii) 5-40 percent by weight of at least one metal selected from the group of cobalt and copper, (iii) 1-15 percent by weight gallium, (iv) up to 5 percent by weight of a modifier selected from the group consisting of nickel, gold, indium, ruthenium, tin and mixtures thereof, (v) up to 1 percent by weight boron, and (vi) up to 0.5 percent by weight of a grain refiner selected from the group consisting of rhenium, iridium, and mixtures thereof, said alloy having a thermal expansion of about 0.66-0.72 percent at 500° C., a solidus temperature of at least 1100° C., a liquidus temperature of not more than 1400° C. Vickers hardness greater than 150, offset yield strength at 0.1 percent of greater than 40,000 p.s.i., and tensile elongation greater than 6 percent; and b. a porcelain coating upon a portion of said casting, said coating being firmly bonded to said casting and being substantially free from discoloration, the bond of said coating to said casting having a minimum value for maximum bending strength of 12,000 p.s.i. and a minimum value for the bending strength ratio of 0.7×10 -3 .

Claim 9

A dental restoration comprising: a. a casting of a dental alloy consisting essentially of (i) 50-85 percent by weight palladium, (ii) 5-40 percent by weight of at least one metal selected from the group of cobalt and copper, (iii) 1-15 percent by weight gallium, (iv) up to 5 percent by weight of a modifier selected from the group consisting of nickel, gold, indium, ruthenium, tin and mixtures thereof, (v) up to 1 percent by weight boron, and (vi) up to 0.5 percent by weight of a grain refiner selected from the group consisting of rhenium, iridium, and mixtures thereof, said alloy having a thermal expansion of about 0.66-0.72 percent at 500° C., a solidus temperature of at least 1100° C., a liquidus temperature of not more than 1400° C. Vickers hardness greater than 150, offset yield strength at 0.1 percent of greater than 40,000 p.s.i., and tensile elongation greater than 6 percent; and b. a porcelain coating upon a portion of said casting, said coating being firmly bonded to said casting and being substantially free from discoloration, the bond of said coating to said casting having a minimum value for maximum bending strength of 12,000 p.s.i. and a minimum value for the bending strength ratio of 0.7×10 -3 .

Claim 10

The dental restoration of claim 7 wherein the boron content of said alloy is 0.1-0.5 percent by weight thereof.

Claim 11

The dental restoration of claim 7 wherein said alloy contains 70-82 percent by weight palladium, 5-15 percent by weight cobalt and/or copper, 3-12 percent by weight gallium, 1-3 percent by weight of the modifier, and 0.05-0.15 percent by weight of the grain refiner.

Claim 12

The dental restoration of claim 9 wherein the boron content of said alloy is 0.1-0.5 percent by weight thereof.

Claim 13

The dental restoration of claim 10 wherein the modifying element is gold.