US1010866A - Process of making composite conductors. - Google Patents

Description

winner: :0.

ELECTRIC COMPANY, A .COR POB ATIO N OF NEW YORK.

coonrnen, or SCHENECTADY, Nnwronx; n'ssmuon Tournamrnocnss or nnxme .comrosrrn connucrona To all whom it may concern: I

Be it known that I, WILLIAM D. Coonncn, a citizen 'of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Processes of Mak-" ingGomposite Conductors, of which the following is a specification.

My present invention has for its object'- the production of refractory conductors suitable for use in incandescent electric lamps, electric furnaces, and other appara tus where electrical energy is transformed into heator light-'- Myimproved conductorlconsists in part of refractory metal',such as tungsten, and

possesses some of thequalities of a pure tungsten conductor. It has the advantage,

however, of a high specific resistance; so high. in fact that incandescent lamps can be built for commercial voltages with but a single filament loo The filament is of such composition that it is strong and comparativelyrigid even at the exceedingly high:

temperatures incident to efficient operation inalama 1 The d dtails of'my improved refractory conductor and of the procedure by which it may be made and used, are set forth in detail in the accompanying description,

which should ,be taken in conjunction with I the accompanying drawing. In'this descrip .t1on, I have disclosed my invention with .specialreference to its application to the ductors for other purposes as .for use in eleca tric making of filamentary conductors for incandescent lamps; but the steps disclosed are equally app icable to the making of confurnaces'. As a basis orcore for my improved composi'te conductor, I utilize a threadof thoria or similar refractory oxid. Such threads can be made by mixing pureand' finely di- H been produced on the copperlated thorla 10.0

videdthoria with water and then squirting under pressure'throughadie. If desired, a small quantity of carbonaceous binder 'may be mixed with the thoria 'rior to the squirting operation, though if and leave behind nothingbut pure thoria.

I Specification of-Letters ratent. 7 Application and September 23', 1903; smelled-154,449.

1s is'used I prefer" to heat the squirted threads with' an openfiame'toburn out the carbon of the binder this hightempe panying drawing. In the drawing shown an apparatus whereby the thoria threads Patented Dec. '5, 19 11.

may be'spattered with copper by virtue of I the disintegrating action of an electrical dis: charge passed through a poor vacuum.

The apparatus consists of an envelop 1. connected permanently to'a vacuum pump.

and exhaustedtoa pressure amountingto I that of about 1 mm. of mercury after having been washed out with hydrogen to removeoxidizing gases. At theto of the envelop issu ported a copper bloc 2 provided with e ectrical connections to render it serviceable as cathode for an electrical discharge. The corresponding anode 3 is passed through-the side of the envelop or otherwise suitably arranged. When currentis passedfrom anode to cathode, copper is disintegrated from block 2 and is spate tered or deposited on any object placed underneath. This henomenon is well understood and there ore needs no further exlanation. "After the thoria threads have een coated with copper as above described, they will conduct current through the copper coating. a

According to the next step in my process,

the copper coated thoriathreads are mountedin an envelop andthere given a coating 7 I of tungsten or molybdenum. This coating can be conveniently efie'cted according to' the method disclosed by. DeLodyguine in United States Patent No. 575,668, issued January 19, 1897. According to the process there disclosed, the conductors-to be coated are heated with current in an atmosphere consisting. of a mixture of hydrogen and a volatile compound of a refractory metal,

such as the oxychlorid of tungsten. The

heated conductor serves to decompose the oxychlorid with depositions of metallic tungsten on the conductor- After a ooherent shell-of tungsten or similar metal has threads, the conductor can be eated in hydrogen or in a mixture of hydrogen and nitrogen or in a vacuum to vaporize and distil the copper from the conductor. The coppears to come out without alloying i0 consolidation of the tungsten rior to the liberation of all the copper. A er the copper has beenremoved, the temperature of treatment can be raised by increasing the current and can be continued until the tungsten layer on the thoria thread has been sintered and shrunk into a dense and homogeneous shell.

The composite filament above described has a high-specific resistance and, owing to the rigidity of the thoria at high temperatures, is strong and not liable to distortion when used in a lamp. Single loop lamps having commercial voltages are altogether feasible though my invention is not llmited in its application to lamps of any particular type or size.

What I claim as new and desire to secure by Letters Patent of the United States, is:

l. The method which consistsdn reducing a thread of refractory oxid, coatmg said oxid with a conductor, treating the body so formed to cover it with refractory metal, and subsequently heating to a higher tem perature to drive out with which the oxid was initially coated.

2'. The method which consists in shaping threads of refractoryqmaterial, coating said threads. to produce a conductive body, depositing thereon a coating of tungsten and temperature to drive out the conductive layer then driving out of said conductor all components except tungsten and the original refractory material. 3. Themethod threads ofthoria, coating with a metal, coating again with a more refractory metal, and then heating the conductor so produced to a temperature sufficient to drive out the less refractory metal and leave a composite filament of thoria inclosed in a shell of'inore refractory meta i. The method which consists in shapinga thread of thoria, coating said thread with copper, depositing on said copper a layer of tungsten, and then removing said "copper.

which consists in shaping to leave a composite filament of thoria in- I closed in a shell of tungsten.

5 The process which consists in producin a thread ofrefractory material, coating said thread with conductive material, treatin the resulting body to cover it with highly re ractory material, and heating to a high said conductive material.

In witness whereof, I have hereunto set my hand this 21st damf September, 1908.

.WILLI Witnesses:

BENJAMIN B. HULL, MARGARET E. Woommr.

n. ooomnen. 4

Images