US2132116A - Alloy - Google Patents

Description

Patented Oct. 4, 1938 ALLOY Henry R. Kiepe, Newark, N. 3., assignmto Baker & Company, Inc., a corporation sey of New Jer- No Drawing. Application January 29, 1938, Serial No. 187,660

4 Claims. (01. 15-172) This invention relates to alloys of which palladium constitutes the major portion, one object of the invention being to provide such an alloy which shall be harder than palladium, which can be highly polished, which can be easily worked into various shapes, which shall have an attractive white color and shall be highly resistant to oxidation, tarnish or other discoloration.

Palladium is known to be a relatively soft metal in both the annealed and the hard-worked state. It is also known that palladium can be hardened by alloying it with ruthenium. However, the structure of alloys of palladium and ruthenium is not good; there is a tendency of the constituents to resist the formation of a uniform crystalline structure, as the result of which the harder or richer ruthenium particles appear as streaks in the alloy, especially when the alloy is polished. Moreover, the palladiumruthenium alloys become practically unworkable if they contain over ten percent (10%) of ruthemum.

I have discovered that these deficiencies of the palladium-ruthenium alloys can be eliminated or diminished by the addition of copper to the palladium and ruthenium. The copper acts as a mutual solvent for the palladium and ruthenium, and thereby makes possible an alloy of uniform structure. These alloys containing substantially palladium, ruthenium and copper also are hard-but not brittle, will take a high polish, resist oxidation and tarnish, and are easily workable. Therefore, they can be made into many different articles of simple or complicated shapes, for example articles of jewelry, pen nibs, electric switch contacts, spinnerets used for manufacture of artificial silk, electrical resistance wires, dental and orthodontic appliances, and so forth.

As above stated, the alloy of the invention is predominantly palladium, the remainder being substantially ruthenium and copper. The proportions of the constituent metals may be widely varied. The amount of palladium,- preferably, is from eighty percent to ninety-eight percent (98%). The ruthenium content may be as low as five-tenths of one percent (0.5%) or as high as fifteen percent (15%), but preferably lies within the range of from one percent (1%) to ten percent (10%). The content of the copper may similarly vary from five-tenths of one percent (0.5%) to fifteen percent preferably the variations lie within the range of from one percent (1%) to ten percent (10%). The particularly preferred alloy comprises sub- (15%). but" stantially about ninety-three and one-half percent (93.5%) of palladium, about three and onehalf percent (3.5%) of ruthenium and about three percent (3%) of copper.

A striking feature of the invention is the discovery that the deficiencies of the known palladium and ruthenium alloys can be overcome or reduced by the addition of copper to the palladium and the ruthenium. This remarkable effect of copper is demonstrated particularly in connection with the hardness of the alloys. Heretofore, alloys of palladium and ruthenium have been considered to be unworkable when more than ten percent (10%) of ruthenium is present. Copper is generally considered to be a hardening agent, and ordinarily the addition of a hardening element to an alloy renders the resultant alloy still more diflicult to work. However, I have discovered that the addition of copper to palladium-ruthenium alloys, makes the resultant alloy more easily workable, even to the extent of making workable such an alloy containing 'as much as fifteen percent (15%) of ruthenium.

The following table illustrates the hardness of various alloys lying within the scope of the invention.

Brinnell hardness (baby Brinnell 2 mm. ball, kg. Pd Ru Cu Percent Percent Percent Annealed Hard 000 0. 15 worked minutes 98 l 1 109 59 95 4 l 158 89 93.5 4.5 2 107 95 2 3 123 74 93.5 3.5 3 163 90 80 l0 10 227 166 70 15 15 237 152. 84.5 0.5 15 178 101 84.5 15 0.5 229 198 is capable of being highly polished, which is re--v sistant to oxidation and tarnish, and which is easily workable into many different articles requiring all or any of the aesthetic, physical, metallurgical and chemical properties hereinbefore described.

half percent (93.5%) palladium, three and one- 10 half percent (3.5%) ruthenium and three percent (3%) copper.

3. An alloy containing-from one percent 1%) to ten percent (10%) ruthenium, andirom one percent (1%) to ten percent (10%) copper, the

remainder being palladium.

4. An alloy of palladium, ruthenium and copper wherein there is from eighty percent (80%) to ninety-eight percent (98%) 01 palladium, the,

remainder consisting of approximately equal amounts of ruthenium and copper.

HENRY R. KIEPE.