US1958967A - Electron discharge tube and method of making same - Google Patents

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l5, 193. i- KNlEPEN 1,958,967

ELECTRON DISCHARGE TUBE AND METHOD oF MAKING SAME Filed 00T.. 21. 1932 INVENTOR y r ATTORNEY Patented May l5, 1934 PA'rEr ELECTRON DISCHARGE TUBE AND METHOD OF MAKING SAlVIE Peter Kniepen, Berlin-Finkenkrug, Germany, as-

sgnor to Allgemeine Elektritatz Gesellschaft, Berlin, Germany, a corporation of Germany Application October 21,1932, Serial No. 638,896 In Germany October 22, 1931 6 Claims. (Cl. Z50-27.5)

radiation than bare polished metals and also that pose of out-gassing discharge vessels or tubes, their radiation powers are not appreciably altered in the course of relativelyrlong periods of metals are disposed in the interior thereof of a kind capable of absorbing gases. More particuoperating time. According to the invention larly, a, method has been disclosed in which, with powders of the said sort, say, zirconium powder, 6. the said end in view, difticultly meltable metals are prepared in paste form as above described such as zirconium are employed in the shape and are applied to the anode by spraying or of sheets, ribbons and the like or else in the pulpainting. The result is that the load-carrying Verulent state. capacity of the tube can be greatly increased, 10 Now, the basic idea of the invention consists with the consequence that far smaller dimenin using compounds, more especially hydrides of sions may be chosen for the anode and thus for such metals rather than the pulverulent metals. the whole tube conjointly with a chance of using These are decomposed in outgassing during the metals that had heretofore been unserviceable pumping process while incidentally resulting in for the present purpose, under like -load conditions, such as nickel. It has been discovered that 75 highly reactive metallic powder in a state of extremely ne division. Compounds of the kind in the case of a nickel anode coated as above it here concerned moreover oier this further adis able to carry a specific load of from 6 to 8 vantage that they are stable in air. watts per sq. cm. and over, as contrasted with Their use in practice is very simple. The pow- 2-3 watts per sq. cm. in the case of uncoated der is elutriated in a liquid that is inert in nature nickel anodes, and 4-5 watts per sq. cm. for tan- 80 and readily evaporable, whereupon such parts as talum anodes. The load capacity is further inare to be coated, e. g., the anode, are dipped in creasable if instead of nickel, molybdenum, tungthe said elutriation or paste, or else the latter is sten or tantalum is used as the supporting or applied by spraying or painting. It is particusubstratum material. larly the hydride form of compound that has What is claimed is: 85

1. In the art of gettering an evacuated enproved especially suitable seeing that the hydrogen which is evolved during outgassing process, velope, the method which consists in introducing as is well known in the art, promotes andexpethe solid hydride of a gettering material into the dites to a, large degree the completion of the envelope before evacuation, heating the material, outgassing operation, cleaning of electrodes, etc. and evacuating the envelope to remove the 90 Particularly useful was found to be, for instance, evolved hydrogen whereby said material is a paste prepared withv zirconium hydride and changed into a porous mass capable of absorbing readily volatilizable hydrocarbons such as xylene large quantities of deleterious gases. with an addition or admixture of a, substance 2. In the art of gettering an evacuated enwith a high boiling point such as paraiiln. velope containing a support member, the method 95 It may also be advantageous to use as the supwhich consists in coating the member with the port for the porous layer a sort of metal such as hydride of a gettering material, heating said nickel which is capable of alloyng itself with the member to remove the hydrogen from the rna ensuing porous metal such as zirconium, because terial and to obtain a porous metal coating capable this promotes the adhesiveness upon the subof absorbing large quantities of deleterious gases. 100

stratum. 3. In the art of gettering an evacuated en- It may furthermore be of advantage to use velope containing electrodes, the method which y mixtures of compounds of such metals, such as consists in depositing zirconium hydride on one tantalum or zirconium, as Will in practical use of the electrodes, heating the coated electrode and fail to form mixed crystals, in order to preclude removing the evolved hydrogen to obtain a residue 105 in spite ofhigh loads the sinteringv of the porous layer in finely divided form capable of absorbing layer with an incidental loss of its porous proplarge quantities of deleterious gases. erties and gas absorptiveness. 4. The method of improving the heat radiating Occasionally it may be advantageous, with aA qualities of anode electrodes in electron discharge view to promote the adhesiveness of the active tubes, which comprises coating the anode with metal upon the substratum, to roughen the latzirconium hydride. ter or to provide it with a porous coat consisting 5. An electron discharge tube having a meof the same metal or some other metal,- such as tallic anode, and a hydride compound coated on nickel. For the identical. reason it is advanta-` said anode and capable of alloying therewith.

geous to priorly anneal (thoroughly heat) the 6. An electron discharge tube having an anode 115 metal parts to be treated in an atmosphere of of nickel, and a zirconium hydride compound capable of alloying with said nickel anode coated pure hydrogen.

PETER KNIEPEN.

It is known in the prior art that, for the pur- It has also been discovered that gas-absorbent thereon. metallic powders such as zirconium, titanium, o0 vanadium and niobium, possess a'hlgher heat

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