US645198A - Process of producing incandescent materials suitable for electric lighting. - Google Patents

Description

basis the common unnoble metals.

NITED STATES'PATENT Errol.

GEORG ALEFELD, OF DARMSTADT, GERMANY, ASSIGNOR TO THE PHARMA- ZEUTISCHES INSTITUT LUDWIG WILI-IELM GANS, OF FRANKFORT-O N- THE-MAIN, GERMANY.

PROCESS OF PRODUCING IIICANDESCENT MATERIALS SUITABLE FOR ELECTRIC LIGHTING.

SPECIFICATION forming part of Letters Patent No. 645,198, dated March 13, Application filed February 21, 1899. Serial No. 706,362. (No specimensi) To all whom it may concern.-

Be it known that I, GEORG ALEFELD, a citizen of Germany, andaresident of Darmstadt, in the Empire of Germany, have invented a 5 new and useful Improvement in the Produc tion of Incandescent Materials Suitable for Electric Lighting, of which the following is a specification.

Incandescent materials consisting of an into ner conductor having an outer covering of metallic oxids are known. Their manufacture, however, is attended with great difficulties. Neither galvanic nor mechanical coatings give satisfactory results, since all attempts to produce an even but sufficientlythin coating have been unsuccessful. The

' object of my invention is to overcome these difficulties.

In my process the so-called lusters or lustrous preparations of the metals are used which'have heretofore been sold and used for the decoration of porcelain, glass, 850. These lusters are organic compounds of metals (resin, acid compounds, or sulfureted resin 2 5 compounds, or products of the decomposition of metallic chlorids produced by heating them with lavender-oil) which are. mixed in their application with an ethereal oil, such as lavender-oil. Such lusters of many of the metals are well known, but there is a very remarkable difierence between those which have for their basis the so-called noble metals-that is, gold, silver, and all the metals of the platinum group-and those which have for their The first named when applied upon porcelain, glass, or metal and then heated to a high temperature leave behind a thin skin of metal, while the lusters of the unnoble met- 0 als when treated in the samemanner form a skin of metallic oxid.

My completed incandescent consists of a core or interior of one of the highly-infusible metals of the platinum group-such as 0s- 5 mium, rhodium, ruthenium, 850., or alloys of the same-covered by an adhesive coherent coating of one of the luminous earthy metals, such as thorium, didymium, cerium, erbium, zirconium, and the like. A mixture of ninetynine per cent. of thorium and one per cent.

of cerium seems best adapted for this pur-' pose as far as I am at present informed;

1 will now describe the two phases of my process, first, the production of the core, and, 5 secondly, the application of the coating to the core. I, P

1. Production of the c0re.Upon small rods,- tubes, or disks of glass or porcelain is spread a solution of a ceramic luster of a highly-in fusible metal of the platinum group, such as ruthenium, rhodium, osmium, and the like. Lustrous preparations of these metals may be prepared in an analogous manner to those of gold, silver, and platinum. The small rods, tubes, or disks and the like are coated in straight or' curved lines or in any other form with the preparations and then burned in. Mixtures also of these different metals are suitable and form alloys, which are pro duced in the manner above described. When necessary, the skin of metal thus formed can be strengthened by electrodeposition.

Though known inthe art, it may not be amiss to mention that while the lusters of the non-oxidizable noble metals may be burned in without precaution against oxidation the lusters of the oxidizable metals, such as osmium, should be burned in in a reductionfiame, or, better still, in a closed muffle in the presence of a reducing or neutral gas, such as illuminating-gas, hydrogen, or carbonic acid.

The next step is to detach the skin of the noble metal. In order to do that, the glass or the porcelain must be removed, which is done very easily by treating it with hydrofluoric acid or even with hydrochloric acid, provided a special kind of glass soluble in this acid has been used. In so doing it is not at all necessary that the whole of the glass, porcelain, &c., be dissolved before one is able to detach the metal-skin; but generally after a brief treatment with the hydrofluoric acid the metal-skin can bev removed as easily as, for instance, a postage-stamp stuck on paper can be removed from the latter by dipping into 5 water; but these skins of the 'noble metal, particularly if very thin, are easily torn. To avoid such accidents,it is advisable to brush over the skin ofnoble metal with some form of tough varnish, such as collodion or a gutta- I00 able.

This hereinbefore described method of making the core or interior of my incandescent materials being not very convenient for several reasons, a second method has been d.e-

vised by me which is much better adapted to the purpose. This new process in question has not only been found adapted for producing the core of my incandescents, but serves also for the manufacture of metal foil or leaf, which hitherto could only be obtained by hammering. In an application of even date herewithfSerial No. 706,361, I have explicitly described this method of producing metal foil or leaf. Therefore here I will only repeat the principal point-s of the process.

A solution of a ceramic luster elf-an unnoble metal-for example, the resin-acid compound mixed with an ethereal oil-isspread upon the surface of porcelain, glass, metal, or any other material which is acid-resistant and capable of enduring unimpaired the tem perature necessary to burn in the ceramic luster employed. The luster may be substituted'by fluxes easily soluble in acid, such as borosilicates or phosphates of soda, &c. Then the luster or' its substitute is burned in. Upon this bed, as it may be called, a lustrous preparation of the desired noble metal is laid and burned in in the usual manner. This may be repeated until the desired thickness is attained, or it may be thickened by electrolytic deposition of the metal. Thenthe skin of the noblemetal is detached by immersing the plate in a solvent (usually inorganic and strong organic acids) of the bed, which is thus dissolved away, leaving the skin of. the noble metal free. Before putting the plate into the solvent the skin may be covered with tough varnish, such as collodion or a gutta-percha solution, as hereinbefore described. The foil or leaf, still covered with the protecting-varnish, it such varnish is used, is formed into a thin rod or thread by rolling it upon itself or into a tube by rolling it around a thread or string or in any other suitable manner. The said rod or thread or tube isthen formed into the desired shape, and the collodion or varnish and the thread or string core, if any, is burned or dissolved away. As shown in my said application of even date herewith, Serial No.

706,361, metal foil or leaf may by its method be produced in the form of a sheet or in the form of any pattern, so the core of my in candescent bodycan in accordance with that inventionbegiven any desired form-for example, that of a network--by laying the luste'r upon its bed in areticulated pattern, burning it in, and then forming it into a mantle like those usedv in gas incandescent lighting, or such a reticulated mantle, or, indeed, almost any form, can be produced by giving the desired form to the porcelain or its substitute, to which the lusters are applied before the first firing.

2. Applying the coating to the core-This core, produced as described, may be used in this form as an-incandescent body. In order to strengthen its illuminating power, it may be coated with luminous earthy metal. This second step of my invention is carried out as follows: Upon the core, formed, as hereinbefore described, of one of the highly-infusible metals of the platinum group, is applied a coating of a ceramic resin luster of the desired luminous earthy metal, such as a mixture of ninety-nine per cent. thorium and one per cent. cerium, by dusting iton. in the form of'a powder or by painting it onor dipping intoor otherwise applying a solution or mixture of said resin ceramic luster with an ethereal oil, such as lavender-oil. It is then fired in the usual manner, and. the result is an incandescent adapted to incandescent electric lighting, which. consists of acore-of one of the highly-infusible metals of. the platinum group covered with an adherent glasslike coating of a luminous earthy metal. A great practical diiterence is found in the behavior of these resin compounds of. the luminous earthy metals and that of their usual soluble saltsnitrates, acetates, &c.since with the latter, when fired, the oxid is left behind as a raw powder which has little adhesion, while with the resin compounds avery adherent glass-like coating isproduced. My incandescent can then be introducedinto an electric circuit in the usual manner and may be used. as asubstitute for the ordinary carbon filament, in a bulb, which in case the core contains one of those-metals of the platinum group which are oxidizable in the air, such as osmium, can be evacuated or filled with a reducing or neutral gas, such as illuminatingrgas, hydrogen, or carbonic acid; The core is heated, by the electric current and heats, in its turn, the exterior coating of the luminous earthy metal to incandescence.

The temperature to which the electric incandescent bodies are heated by the current being far higher than that reached by Auers incandescentlight,even those kinds of earthfor example, lime, magnesia, &o.can be em ployed of which thep'ower of light emission is still trifling at the temperature of Auer light, but increases considerably at a higher temperature.

Having thus described my invention, What I claim as new,,and desire to patent, is-- 1. The withinfdescribed process of producing bodies suitable for incandescent electric lighting, which consists: first, in wholly or partially coveringa suitable bed'with a-lustrons preparation of one or more of the highlyinfusible metals of the platinum group and burning the same in; second, detaching the resultant metallic film from the bed by the action of solvents which will attack the bed and not the film; and third, forming the said metallic film into the desired shape.

2. The within-described process of producing bodies suitable for incandescent electric lighting, which consists: first, in wholly, or partially covering a suitable bed with a lustrous preparation of one or more of the highlyinfusible metals of the platinum group and burning the same in; second, covering the metallic film so produced with a tough protective varnish; third, detaching the resultant metallic film from the bed by the action of solvents which will attack the bed and not the film; and fourth, forming the said metallic film into the desired shape.

, 3. The within-described process of producing bodies suitable for incandescent electric lighting which consists: first, in wholly or partially covering an acid and heat resisting plate or matrix with a ceramic lustrous preparation of one or more of the unnoble metals and burning the same in; second, laying upon this coating of unnoble metallic oxid a lustrous preparation of one or more of the highly-infusible metals of the platinum group and burning it in; third, detaching the resultant film of the said highly-infusible metal by the action of a solvent which will attack the unnoble metallic oxid but not the highly-infusi ble metal film, and lastly forming the detached film of the highly-infusible metal into the desired shape.

4. The within-described process of producing bodies suitable for incandescent electric lighting which consists: first, in wholly or partially covering an acid and heat resisting plate or matrix with a ceramic lustrous-preparation of one or more of the unnoble metals and burning the same in; second, laying upon this coating of unnoble metallic oxid a lustrous preparation of one or more of the highly-infusible metals of the platinum group and burningitin; third, covering the metallic film so produced with a tough protective varnish; fourth, detaching the resultant film of the said highly-infusible metal by the action of a solvent which will attack the unnoble metallic oxid but not the highly-infusible metal film, and lastly forming the detached film of the highly-infusible metal into the desired shape. v v

5. The within-described process of producing bodies suitable for incandescent electric lighting,which consists: first, in wholly or partially covering a suitable bed with a lustrous preparation of one or more of the highly-infusible metals of the platinum group and burning the same in; second, detaching the resultant metallic film from the bed by the action of solvents which will attack the bed and not the film; third, forming the said metallic film into the desired shape; and fourth, coating said so-formed metallic film with ceramic resin luster of one or more of the luminous earthy metals and burning the same in.

6. The within-described process of producing bodies suitable for incandescent electric lighting,which consists: first, in wholly or partially covering an acid and heat resisting plate or matrix with a ceramic lustrous preparation of one or more of the unnoble metals and burning the same in; second, laying upon this coating of unnoble metallic-oxid a lustrous preparation of one or more of the highly-infusible metals of the platinum group and burning it in; third, detaching the resultant film of the said highly-infusible metal by the action of a solvent which will attack the unnoble metallic oxid but not the highly-infusible metal film; fourth',forming the ,detached film of the highly-infusible metal into the desired shape; and lastly, coating said so-formed metallic film with ceramic resin luster of one or more of the luminous earthy metals and burning the same in.

7. The within-described process of producing bodies suitable for incandescent electric lighting, which consists: first, in wholly or partially covering a suitable bed with a lustrous preparation of one or more of the highly-infusible metals of the platinum group and burning the same in; second, covering the metallic film so produced with a tough protective varnish; third, detaching the resultant film from the bed by the action of solvents which will attack the bed and not the film; fourth, forming the said metallic film into the desired shape; fifth, removing the tough protective varnish from the metallic film by means of a solvent or by burning, using either fire or the electric current, and sixth, coat= ing the metallic film with ceramic resin luster of one or more of the luminous earthy metals and burning the same in.

8. The within-described process of producing bodies suitable for incandescent electric lighting,which consists; first, in wholly or partially covering an acid and heat resisting plate or matrix with a ceramic lustrous preparation of one or more of the unnoble metals and burning the same in; second, laying upon this coating of unnoble metallic oxid a lustrous preparation of one or more of the highly-infusible metals of the platinum group and burning it in; third, covering the metallic film so produced with a tough protective varnish; fourth, detaching the resultant film of the said highly-infusible metal by the action of a solvent which will attack the unnoble metallic oxid but not the highly-infusible metal film; fifth, forming the said metallic film into the desired shape; sixth, removing the tough protective varnish from the metallic film by means of a solvent or by burning, using either fire or the electric current; and seventh, coating the metallic film with ceramic resin luster of one or more of the luminous earthy metals and burning the same in.

4 mam 9. As a next article of manufacture an in- Signed atFrankfort-on-the-Main,in the Emcandescent body adapted to incandescent pire of Germany, this 27th day of January,-1o electric lighting, consisting of a core of one A. D. 1899.

or more of the hi hiy-infusible metals of the 5 platinum group, brovided with a glass-like GEORG ALEFELD coherent and adherent exterior coating of in- Witnesses: minous earthy metal as produced by burning RICHARD GUENTHER,

in a ceramic resin luster 0f the same. JEAN GRUND.