US2303401A

US2303401A - Resistance or fuse wire

Info

Publication number: US2303401A
Application number: US378376A
Authority: US
Inventors: Sivil Cecil Spencer
Original assignee: Baker and Co Inc
Current assignee: Baker and Co Inc
Priority date: 1941-02-11
Filing date: 1941-02-11
Publication date: 1942-12-01
Anticipated expiration: 1959-12-01

Description

Patented Dec. 1, 1942 EDiSTATES- PATENT RESISTANCE on rose WIRE Cecil Spencer Sivil, Roselle, N. J., asslgnor to Baker & Company, Inc., Newark, N. J., a corpoi-ation of New Jersey N 0 Drawing.

Application February 11, 1941 savanna-378,376

3 Claims. (cram-is) This invention relatesfto wires suitable as electrical resistances particularly in the ignition of explosives, such as resistance wires or bridge wires in blasting caps, detonators and the like.

Heretofore such resistance wires for igniting or setting off explosives usually consisted of an alloy of platinum-iridium containing from to iridium, the alloy of 80% platinum and.

stantially of precious metals only and shall have low specific gravity, high electrical resistance and satisfactory breaking loads or tensile strength to take the place of fuse wire of platinumiridium alloys heretofore in general use in setting off explosives, and which while having char- 5 acteristics similar to those of such platinumiridium wires shall be of considerably lower cost. It is another object of myinvention to produce such wires for such purposes as resistances in Wheatstone bridges, resistance coils and resistance wires for use in igniting explosives, as in blasting caps, detonators or the like. A still further object of my present invention is to provide such resistance wires which shall be cheaper than the resistance wires described in my copending application above referred to and yet of equal quality or even superior quality.

The electrical resistance wire of my present invention consists of an alloy of palladium with rhodium and iridium containing from approximately 60% to 95% palladium and from to 5% rhodium and iridium combined. Such alloys have excellent corrosion resistance and their melting points are in excess of the ignition point of detonating charges. As such alloys have, further, high electrical resistance and great strength they are admirably suited for such purposes as resistance wires or bridge wires in blasting caps, detonators and the like. I have found particularly satisfactory such specific alloys as palladium-rhodium-iridium alloys containing 80% palladium 10% rhodium and 10% iridium,

trical resistance wire' can be obtained per ounce of alloy.

Referring to an electrical resistance wire of 80% palladium 10% rhodium and 10% iridium,

I found, for instance, an electrical resistivity of 218 ohms/mil ft.; thus an electrical resistance wire of such alloy having a diameter of 0.00138" was found to have an electrical resistance of 304 ohms/yd. and a tensile strength of 150,300 lbs.

per square inch. Compared therewith an electrical resistance wire according to my aforesaid copending application of an alloy of 87% palladium 10% platinum and 3% ruthenium has a resistivity of 153 ohms/milft. and a wire having a diameter of 0.00135 was found to havean electrical resistance of 309 ohms/yd. and a tensile strength of 110,000 lbs. per square inch. The

specific gravity of 'the alloy of 80% palladium 10% rhodium and 10% iridium is 12.5 and I may thus produce approximately 8150 feet of 0.00138" electrical resistance wire from 1 ounce .of such alloy. The melting point of the alloy is 1650 C. In the alloys above described'I can replace part or all of the rhodium-iridium content with ruthenium, but I have-found that not more than 10% ruthenium should be present in such alloys. Thus I have made experiments with for instance an electrical resistance wire of an alloy of 95% palladium and 5% ruthenium, and an alloy of 90% palladium 5% rhodium and 5% ruthenium and found satisfactory results as to electrical resistance and tensile strength. The specific gravity of the alloy of 95% palladium and 5% ruthenium is 12.1 and I may thus PTO-y duce approximately 7500 feet of 0.0015" electrical resistance wire from 1 ounce of such alloy.

The melting point of the alloy is 1600 C. The

particular feature of the electrical resistance wires according to the present invention is that is low and consequently a large footage of electhey are completely satisfactory without the presence of any platinum, whereby it is possible to take full advantage of the extremely low price and the low specific gravity of palladium. I-

may, however,- replace palladium in the alloys with up to one-half thereof by platinum.

What I claim is:

1. An electrical resistance wire consisting of an alloy of palladium, rhodium and iridium containing palladium from sixty percent to ninety-five percent, and rhodium plus iridium from five (5) percent to forty (40) percent.

"2. An electrical resistance wire consisting of an alloy of palladium, rhodium and iridium containing from sixty (60) percent'to ninety-five alloy.

3. electrical resistance wire for setting of! explosives consisting or an alloy composed of approximately eighty (80) percent to ninety (90) percent palladium, approximately flve (5) percent to ten (10) percent rhodium and approximately ilve (5) percent to ten (10) percent CECIL SPENCER SIVIL.

5 iridium.