US 2303402 A
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Patented Dec. 1, 1942 UNITED STATES PATENT OFFICE ALLOY No Drawing. Application July 9, 1941, Serial No. 401,653
This invention relates to alloys and is concerned in particular with platinum metal alloys.
It is one object of my invention to provide alloys of great corrosion resistance, high melting point and great hardness and strength. It is another object of my invention to provide such alloys of great electrical resistance. It is a further object of my invention to provide such alloys of low specific gravity and low cost.
This application is a continuation in part of my application No. 378,376, filed February 11, 1941.
The alloys according to my invention consist of palladium, rhodium and iridium. In such alloys the palladium content may be as low as about 60% and as high as about 95%, and the content of rhodium and iridium combined may vary from about 5% to about The alloys contain a minimum of 2.5% rhodium and a minimum of 2.5% iridium, with a corresponding maximum content of 37.5% rhodium and 37.5% iridium, subject, however, to the requirement of an upper limit of 40% for the combined rhodium and iridium content. In its best embodiments the alloys consist entirely of palladium, rhodium and iridium in the proportions specified herein, although of course minor quantities of other metals may be present so long as they do not substantially afiect the beneficial properties and characteristics of my alloys. I have found that in my alloys I may replace for instance rhodium and iridium by ruthenium up to a maximum of 10% of the whole alloy so long as in such alloys there is present at least 5% of rhodium and iridium combined.
The alloys according to my invention are capable of being used advantageously in widely different fields. They may be used in the construction of corrosion resistant apparatus and they may be used in the field of jewelry and the decorative arts. They may be used in the electrical industry for instance as electrical resistance wires, a use more particularly described and claimed in my co-pending application Serial No. 378,376, filed February 11, 1941. Such alloys may be used in the form of wire, sheet or other manufactured article and may be given intricate shapes and forms due to their great hardness combined with great ductility.
The alloys according to my invention have a high melting point and possess great hardness and mechanical strength, have great electrical resistance and are of low specific gravity and low cost. All alloys according to my invention are surprisingly ductile notwithstanding their high tensile strength and great hardness. The alloys according to my invention also have excellent corrosion resistance.
Particularly advantageous are such specific embodiments of my invention as alloys containing 80% palladium, 10% rhodium and 10% iridium,
I or containing 90% palladium 5% rhodium and equal amounts of rhodium and iridium, and While I have found that substantially equal amounts of rhodium and iridium, and if desirable, a like amount of ruthenium, are particularly advantageous for many purposes, I wish it to be understood that such particular interrelationship between the contents of rhodium and iridium, with or Without ruthenium, is not necessary. It is, therefore, fully within my invention to produce any alloys containing to 95% palladium and 5% to 40% rhodium and iridium, with or without up to 10% ruthenium, so long as the alloyscontain not more than 40% rhodium and iridium and, if present, ruthenium, and contain at least 5% rhodium and iridium, preferably at least 5% of rhodium and 5% of iridium.
What I claim is:
1. An alloy of approximately eighty percent to ninety per cent palladium, approximately five (5) per cent to ten (10) percent rhodium, and approximately five (5) percent to ten (10) percent iridium.
2. An alloy of sixty (60) per cent to ninetyfive percent palladium and approximately equal amounts of rhodium and iridium in a combined proportion of not less than five (5) percent and not more than forty (40) percent of the total alloy.
3. An alloy of 60% to 95% palladium, 2.5% to 37.5% rhodium, and 2.5% to 37.5% iridium, wherein the combined content of rhodium and iridium does not exceed 40%.
CECIL SPENCER SIVIL.