US1592459A - Preparation of rare metallic oxides - Google Patents

Description

5 the like.

Patented July 13, 1926.

UNITED STATES norm ALLEN nanny, or new HAVEN, comvnc'rrcv'r.

PREPARATION OF RARE METALLIC OXIDES.

No Drawing.

In electrical appliances and particularly in incandescent lamps there are many uses for highly refractory materials, such as the rare metallic oxides, thoria, zirconia, and These oxides have uses in various electrical appliances particularly as asso-' eiate'd with refractory conductors for heating or resistance uses. When usedin a vacuum or inert gas container, preferably in molded form, as in incandescent lamps, Iv

have found that'such metallicoxides, prepared for use in obvious ways, are porous and full of occluded gases detrimental to my purpose, particularly the oxygen content.

When' the metallic oxide is associated with the heating element in a lamp bulb, for example, the gases suchas oxygen in the pores of the oxide expand and escape. The oxygen content of the gases thus liberated has, at the temperature of operation, a greater atfinity for the metal of the resistor than it has for the elements with which it is combined, and a chemical reaction takes place whereby the oxygen of the gases frees itself and combines with the metal of the resistor to form an oxide of that metal. This reaction decreases the cross-section of the metal, increases its resistance, decreases the temperature andgenerally operates to defeat the purpose of the desired structure in use.

The use of the rare metallic oxides for lamps is advantageous as resistor illuminants because of their non-conductivity and any local action in the lamps which tends.

to break-down the oxide and hence decrease the resistance of the same is deleterious to the lamp operation and efiiciency.

The purpose of this invention is to provide a new and useful method of preparing the rare metallic oxides for use in electrical appliances, such as incandescent lamps, a new and useful method of conditioning the oxides in' the lamp or similar appliance for the desired use, and a new and useful product.

The invention will be described as applicable to an incandescentlamp structure as one of its important uses. In this use chemically pure zirconia, thoria, or other rare metallic oxide, may be used as an illuminant base. The resistor is associated with the base in the bulb or container to act- Ap'plication filed November 14, 1918. Serial No, 262,616.

ing element for the base. The latter, when sufficiently heated as it is by the resistor or heating element, becomes an illuminant. However, the resistor and base, working together in the desired purpose for illumina-.

tion, may act one on the other, due to detrimental gases in the base, to defeat such purpose. This is true-no matter to what possible degree the lamp is evacuated in its manufacture, because the porous base will not give up its occluded gases under such treatment.

The solution ofthe problem, then, begins with the treatment or preparation of the base before it goes in the lamp. I start with powdered zirconia, which I will use as an example, subject it to an intense heat to dehydrate it, then mix the dehydrated powder with a temporary binder, as water, mold it to the shape of the desired base, subject the molded base to heat suflicient to completely drive off the temporary binder, and

then sinter it under intense heat. So far, the treatment given the base is particularly important if such base is to be used in an evacuated. or inert gas filled lamp or like appliance.

The base so prepared is now put in a bath the temperature of which is preferably the boiling point of the substance composing the bath. Such substance should be something in the nature of parafline or solid hydrocarbon. The heat causes the expansion and free exit of all occluded gases, which will then thoroughly be driven out of the base, due to the entrance of the'parafline of higher specific gravity into all the pores, assisted by capillary attraction. The base may now be cooled, preferably with a sufficient coating to insure it against the entrance of any air due to the contraction of the paraffine in the pores.

The lamp is now structurally made up in the desired manner with the resistor and base associated for their functional purpose. One efl ective way, but not necessary to an understanding of this invention, is shown in my copending application Serial No. 271,352, filed January 16, 1919. The lamp is connected to the vacuum. pump and evacuated. Then a current is passed through the resistor sufficient to volatilize and drive off the parafiine from the base. The paraffine is evacuated in volatile form by the vacuum pump, During the latter operation the bulb is preferably kept warm to avoid the deposition of the parafiine on the interior of the bulb.

If the lamp is to be operated with inert gas, the container "is -filled with such gas' after the paraiiine passes off; otherwise, the lamp or container is sealed tightly in the usual manner.

The base illuminant of rare metallic oxide is now in the desired condition for useful operation in the inert gas or vacuum. It is in pure condition and has had treatment to insure it against chemical reactions between it and the resistor with which it is associated.

Thus, I have provided a base to be used as a luminant in my improved lamp which has the advantageous characteristics of being free of any action in the lamps'operation other than intended. The rare metallic oxides, when used in the manner stated, greatly increase the efiiciency of lamps in the art of electric lighting.

I claim as my invention:

1. The method of preparing a porous body of highly refractory material for use in electrical appliances, which consists in subjecting the body to heat in the presence of a molten substance solid at normal temperatures, until the ases in the pores have been replaced by sai molten substance, allowing the body to cool and said substance to solidify in the pores thereof, incorporating the same in a container, volatilizing the substance fillin the pores, and simultaneously evacuating t e container.

2. The method of preparing a porous body. of hi hly refractory material for use in electrica appliances which consists in removing the occluded gases therefrom, filling the pores with a material solid at ordinary temperatures but capable of being volatilized, incorporating the same in the appliance and then removing the material filling the pores.

3. The method of preparing a substance containing a rare metallic oxide for use in electrical appliances which consists in removing the occluded gases therefrom, sealing the pores with a liquefied solid, incorporating the same in the electrical appliance and then removin the seal from the pores.

4. The met 0d of preparing a substance containing a rare metallic oxide for use in electrical appliances which consists in replacing the occluded gases therein with a solid hydrocarbon, incorporating the same in the electrical appliance and removing the hydrocarbon.

5. The method of preparing a substance containing a rare metallic oxide for use in electrical appliances, whichconsists in replacing the occluded gases therein with .a

.solid hydrocarbon, incorporating the same in the electrical appliance and removing the hydrocarbon while the body is in a vacuum.

- aeeaaee .mersing the body in a bath of a solid hydrocarbon at the temperature of boiling of the same until the occluded gases have been replaced by the liquid, allowing the liquid' to become solid, incorporating the re ared body in the electrical appliance, vo ati izing the hydrocarbon and removing the vapors by exhaustion.

8. The method of forming a light source for incandescent electric lamps including a luminant composed of rare metallic oxides having associated therewith a heating element, which consists in immersin the luminant in a bath of boiling para e until the occluded gases have been replaced by the parafline, allowing the parafline to solidify, associating the heating element withthe luminant, incorporating the light source in the bulb of. a lamp, exhausting the bulb, volatilizing the parafiine and removing the vapors from the bulb.

9.- The method of forming a light source for incandescent electric lamps including a luminant of rare metallic oxides having as- I sociated therewith a heating element, which consists in immersing the luminant in a bath of boiling parafline until the occluded gases have been replaced by the parafiine, allowing the parafline to solidify, associating the heating element with the luminant, incorporating the light source in the. bulb of a lamp, exhausting the bulb, volatilizin the parafline and removing the vapors rom the bulb while the bulb is kept at a temperature su'flicient to prevent deposition of the parafiine thereon.

10. The method of preparing a body of rare metallic oxide for use in electrical appliances which consists in introducing a material capable of being volatilized into the pores of the body, inserting the body in the appliance and heating the electric appliance to remove the material.

11. The process of removing occluded solid and displace the 000 uded gases therein, 5

removing the body to a closed chamber, heating the chamber-until the material in the body is volatilized, and removing the volatilized gases.

12. A method of removing oxygen fro a fi body for use in electric lamps which consists in replacing the oxygen withva solid and vaporizing the solid in a vacuum.

13. A method of preparing a solid freed of occluded oxidizing gases which consists in ap 1y heat to a solid to remove the gases, an rep acing the gases with an inert vaporizagle soggdsupstance. 1 d t ed' f met 0 re arin asoi re 0 ocdl iided p P g oxidizing gases for use in electric.

apparatus which consists in removingthe' occluded gases in a solid by the application of heat, replacing the gases with an inert vaporizable solid substance and heating the solid-in a vacuum toremove the inert substance.

15. A method of removing occluded gases from solids which com rises immersing the solid in a heated liquid bath of a vaporizable substance solid at normal room temperatures,

permitting the substance to permeate the solid and displace the occluded gases allow-' ing the solid to cool and the substance to solidify, placing the body in a chamber subject to the evacuating action of a suction pump, and subjecting the body to heat while under evacuation whereby the coating substance is vaporized and removed.

16. The method of preparing refractory oxides containing occluded gases for use under high tem erature conditions which consists in pow ering the oxide, heating the oxide, to brin about dehydration, moulding the dehydrated oxide to the desired form, sintermg the oxide by the application of relatively high temperatures, heating the oxide in a liquid bath until the occluded gases are removed, permitting the liquid to permeate the oxide and displace the occluded gases therein, chilling vthe oxide to cause solidification of the liquid, placing the oxide in an evacuated chamber, heating the oxide within said chamber to volatilize the solidified liquid, and removing the volatilized vapors by suction apparatus.

JOHN ALLEN HEANY.