US1601982A - Process for the production of a compound metal - Google Patents

Description

Patented Oct. 5, 192 6.

Y for producing compound metal articles and EMILIO 'ROMANELLI, or BL LAMP COMPANY, A co :enoons's FOR THE PRODUCTION or .& comrouun METAL.

No Drawing. Application filed January 4,

This invention relates to a new process especially leading-1n wires for .incandescent electric lamps. An object of this invention is a process of producing a compound metal. which will have exactly a predetermined coeflicient of expansion.

A special obje ct of the invention is a .methodof producing a clad metal having no air spaces between the layers of the-metals comprising the compound. '.Such a compound metal article is valuable for many purposes but for incandescent lamps. lows the use of 'any'kind of glass for the bulb of the lamp without lead-in wire nite co-eiiicient of particularly so as a It albeing limited to a defiexpansion, because, by this process, a wire can be produced which will meet allthe requirements of a good lead-in wire, including a co-eflicient of expansion close enough to that of the' glass selected to .maintain an air-tight seal between it and the glass throughout to which an incan the range of temperature descent lamp is subject.

I Platinum has been displacedas a lead-in wire for incandescent electric lamps by composite metals of which an example is a copper-coated nickel steel wire. Obviously the contact between the copper and the. nickel steel core must be close enough to prevent air from passing between them when the wire is sealed into a lamp. manufacturing such quently produce it tween the layers at ence of this air gives Present processes of with pockets of air besome parts. The presthe wire a different coefficient of expansion where a pocket exists.

Defective wire of lamp, permits air I therefore, causes life.

A good leadin this sort, when used in a to leak into the bulb and, the lamp to have a short -in wire should be free from pockets and have a coeiiicient of expansion substantially equal to that of the glass into which it is sealed. With a nickel steel alloy of a given com- 1 position, the. coefiicient of expansion of the 'copper-coated-nickel steel wire depends on the relative thickness of the metals composing it. The coefficient of expansion of such wire may be largely controlled by regulating the amount the core.

of copper deposited upon Other defects of present practice in maka composite wire fre- 1,601,982 {PATENT OFFICE.

OOMFIELD, NEW JERSEY, ASSIGNOR TO WESTINGHOUSE RPQRATION OF PENNSYLVANIA.

1921, sum in. 435,027. Renewed February 25, 1926.

ing composite wire of the nature described are the great difliculty in regulating the th ckness of the coppercoating and the nonumform thickness of copper around the perimeter of the wire.

The method of practicing my invention by which I have overcome the defects of prevlous processes, is as follows A. rod of nickel steel about 400 mil in diameter and 5 ft. long is cleaned in an alkali, followed by a cleaning in an acid to remove metallic oxides and scales. The rod is then electroplated with copper about 1 mil in thickness in a preliminary bath of the following composition:

. Grams. Sodium sulphite (Na SO 20 Sodium carbonate (Na CO -1OH O) 20 Sodium bisulphite (NaHSO 20 Gupric acetate (Cu(O H O -11 0) 20 Potassium cyanide (100%KCN) Water,"1 liter.

The current density used is from three tenths (0.3) to one (-1) ampere per square decimeter. The copper-plated rod is then electroplated" with copper to the desired thickness in another bath of the following composition Copper sulphate, 480 gms; sulphuric five (5) to'ten (10) am- If desired, a coating of zinc, or other I metal which has a melting point lower than copper and which will alloy with both the nickel steel and the copper, may be put on the core before depositing the copper, in order to'make the copper coating more adherent. However, it is not necessary to use a metal between the nickel steel core and the copper.

From the foregoing it will be apparent that my invention provides a quick audaccurate method formanufacturing a composite wire which shall have exactly the coefiicient of expansion desired, inasmuch as the thickness of the copper plating may be exactly controlled by measuring the amountof currentpassed through the plating circuit and the time during which it is passed, both of which quantities may be accurately measured. This method also results in a uniform thickness of copper over the whole surface of the wire. I 7

It will be understood that, while I have described the process for the production of a copper-clad nickel steel wire, my invention is applicable to other suitable metals.

What is claimed is:

1. A step in the process of producing a composite metallic body which consists in electroplating on a metallic core another metal of such thickness as to give to the composite body a predetermined coefficient of expansion.

2. The process of producing a composite metallic body which consists in electroplating on a metallic core another metal of such thickness as to give to the composite body a redetermined coefficient ofexpansion, and heating the deposited metal to incipient fusion.

3. The process of producing a composite metallic body which consists in electroplating a core of nickel steel With copper and heating the said copper to incipient fusion.

4. A method for accurately controlling the coefficient of expansion of a composite wire which consists in electrolytically depositing on a metallic core a predetermined amount of another metal.

5. The method of producing a composite t-roplating a thin coating of copper from a cyanide bath and depositing on the said coating :1 second coating from a sulphate bath and thereafter heating said body to cause incipient fusion of the coatings thereon.

.6. As an article of manufacture, a composite wire free from pockets between the layers thereof.

7. As an article of manufacture, a com posite wire composed of constituent layers having their adjoining surfaces in intimate contact, whereby pockets between said layers are obviated.

8. As an article of manufacture a composite wire free from pockets between the layers thereof and having a predetermined coefficient of expansion.

9. As an article of manufacture a composite wire free from pockets between the layers thereof, comprising a core of nickel steel and a sheath of electrolytically deposited copper.

10. As an article ofmanufacture a com posite wire free from pockets between the layers thereof and having exactly a predetermined coefficient of expansion, comprising a core of nickel steel and a sheath of electrolytically deposited copper.

In testimony whereof, I have hereunto subscribed my name this third day of J anuary 1921.

EMILIO ROMANELL'I.