US2472760A - Electrode for electron discharge devices - Google Patents
Electrode for electron discharge devices Download PDFInfo
- Publication number
- US2472760A US2472760A US516251A US51625143A US2472760A US 2472760 A US2472760 A US 2472760A US 516251 A US516251 A US 516251A US 51625143 A US51625143 A US 51625143A US 2472760 A US2472760 A US 2472760A
- Authority
- US
- United States
- Prior art keywords
- platinum
- electrode
- grid
- tube
- alloy
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 62
- 229910052697 platinum Inorganic materials 0.000 description 30
- 239000000463 material Substances 0.000 description 13
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 10
- 229910045601 alloy Inorganic materials 0.000 description 8
- 239000000956 alloy Substances 0.000 description 8
- 229910052721 tungsten Inorganic materials 0.000 description 8
- 239000010937 tungsten Substances 0.000 description 8
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 229910001260 Pt alloy Inorganic materials 0.000 description 2
- 238000005275 alloying Methods 0.000 description 2
- 230000007812 deficiency Effects 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 239000004922 lacquer Substances 0.000 description 2
- PXXKQOPKNFECSZ-UHFFFAOYSA-N platinum rhodium Chemical compound [Rh].[Pt] PXXKQOPKNFECSZ-UHFFFAOYSA-N 0.000 description 2
- DKPFZGUDAPQIHT-UHFFFAOYSA-N Butyl acetate Natural products CCCCOC(C)=O DKPFZGUDAPQIHT-UHFFFAOYSA-N 0.000 description 1
- 101100102624 Drosophila melanogaster Vinc gene Proteins 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 239000000020 Nitrocellulose Substances 0.000 description 1
- 229910000629 Rh alloy Inorganic materials 0.000 description 1
- FJWGYAHXMCUOOM-QHOUIDNNSA-N [(2s,3r,4s,5r,6r)-2-[(2r,3r,4s,5r,6s)-4,5-dinitrooxy-2-(nitrooxymethyl)-6-[(2r,3r,4s,5r,6s)-4,5,6-trinitrooxy-2-(nitrooxymethyl)oxan-3-yl]oxyoxan-3-yl]oxy-3,5-dinitrooxy-6-(nitrooxymethyl)oxan-4-yl] nitrate Chemical compound O([C@@H]1O[C@@H]([C@H]([C@H](O[N+]([O-])=O)[C@H]1O[N+]([O-])=O)O[C@H]1[C@@H]([C@@H](O[N+]([O-])=O)[C@H](O[N+]([O-])=O)[C@@H](CO[N+]([O-])=O)O1)O[N+]([O-])=O)CO[N+](=O)[O-])[C@@H]1[C@@H](CO[N+]([O-])=O)O[C@@H](O[N+]([O-])=O)[C@H](O[N+]([O-])=O)[C@H]1O[N+]([O-])=O FJWGYAHXMCUOOM-QHOUIDNNSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- WYACBZDAHNBPPB-UHFFFAOYSA-N diethyl oxalate Chemical compound CCOC(=O)C(=O)OCC WYACBZDAHNBPPB-UHFFFAOYSA-N 0.000 description 1
- -1 e. g. Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- FUZZWVXGSFPDMH-UHFFFAOYSA-N hexanoic acid Chemical compound CCCCCC(O)=O FUZZWVXGSFPDMH-UHFFFAOYSA-N 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229920001220 nitrocellulos Polymers 0.000 description 1
- 229940079938 nitrocellulose Drugs 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000004848 polyfunctional curative Substances 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 239000007779 soft material Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J19/00—Details of vacuum tubes of the types covered by group H01J21/00
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J19/00—Details of vacuum tubes of the types covered by group H01J21/00
- H01J19/28—Non-electron-emitting electrodes; Screens
- H01J19/38—Control electrodes, e.g. grid
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2893/00—Discharge tubes and lamps
- H01J2893/0001—Electrodes and electrode systems suitable for discharge tubes or lamps
- H01J2893/0012—Constructional arrangements
- H01J2893/0015—Non-sealed electrodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2893/00—Discharge tubes and lamps
- H01J2893/0001—Electrodes and electrode systems suitable for discharge tubes or lamps
- H01J2893/0012—Constructional arrangements
- H01J2893/0019—Chemical composition and manufacture
- H01J2893/0022—Manufacture
Definitions
- This invention relates to electron discharge devices and moreparticularly to the electrodes used in discharge tubes operated at high temperatures.
- the material of the grid electrodes must have a high melting point and must have high mechanical strength at high temperatures. These conditions are fulfilled for certain materials, e. g., tungsten, molybdenum, and tantalum. These materials do, howevenhave the undesirable feature that they have a tendency toward secondary and primary electron emission, and collect some of the emitter material evaporating from the thermionic cathode. Platinum, on the other hand, is very desirable as a material from the viewpoint of low secondary and primary electron emission.
- One object of the invention relates to means for increasing the mechanical stiffness of a grid made of platinum.
- means are provided to alloy the surface of a platinum grid structure so as to increase its mechanical stiffness and to preserve the low electron emission properties of platinum.
- Another principal object of the invention relates to the use of a platinum alloy as material for making grids for thermionic tubes operated at high temperatures, which incorporates the desirable low electron-emitting features of platinum combined with a mechanical stiffness considerably higher than that of platinum.
- a feature of the invention relates to means for making grids which cannot be contaminated by the emitter material evaporating from the thermionic cathode during processing and life of the tube.
- the invention is based on the fact, that some of the physical properties of a metal are usually changed, while others remain constant when a pure metal is alloyed with one or several other metals. Recognizing the superior qualities of platinum as a grid material, with respect to its low electron-emitting properties, but recognizing also the deficiency of this material in mechanical stiffness, in particular at high temperatures, the present invention provides the possibility of alloy-' ing platinum with an appropriate "hardener, resulting in an alloy which will preserve the desirable low electron emission properties of platinum, but having the desirable increased mechanical stiffness.
- an appropriate platinum alloy grid made from a grid made of pure platinum wire.
- the ready or preformed platinum grid is sprayed with a lacquer suspension. of fine tungsten powder immediately preceding the mounting of the electrode assembly within the tube.
- the heat applied to the grid in the ordinary processing of the tube during exhaust running as high as 1600 0. results in the formation of a stifier alloy, which however still preserves the low electron-emitting features of platinum.
- the grid emission of the tubes having platinum grids treated in this manner was substantially as low as that of tubes made with. pure platinum grids.
- the stiffness of the grids treated in this way was found to be considerably higher than that of the grids made of plain platinum wire, as demonstrated by comparative tests made with grids of both kinds, namely plain platinum grids and grids treated as described.
- the invention is not limited'toth'e particular method of alloying thetungsten andiplatinum described.
- the platinum and tungsten r may 'be alloyed in any well-known commercialmanner'and then drawn down to the wire 'size "required for .grid structures.
- one alloy that was found suitable for the purpose above described -contained approximately 2-6% tungsten and the balance platinum.
- the tungsten should be 4% and the platinum 96%.
- a platinum rhodium alloy' may be alloyed with the tungsten provided the platinum isthe major part of the platinum rhodium portion of the. alloy.
- a wire grid electrode ' for use within an electron tube and subjected to electron bombardment during the normal operation of the tube.
- said electrode comprising an alloy of approximately 96% platinum and 4% tungsten to increase the stififness of the electrode while preserving the low electron-emissive properties of platinum.
- a gridrelectrode for' use in an eleotron tube of the type which employs a thermionic cathode "I0 i'tending to deposit emissive material on the grid during .operationoi .the tube, said grid electrode :comprising a platinum base alloy consisting mainly of platinum with from 2% to 6% tung- :sten for:inhibiting:primary emission from the grid when such emissive material is deposited *thereon and-for the purpose of increasing the stifiness of the electrode while preserving the low emissive properties of platinum.
Landscapes
- Solid Thermionic Cathode (AREA)
Description
June 7, 1949. H. L. RATCHFORD 2,472,760
ELECTRODE FOR ELECTRON DISCHARGE DEVICES Filed Dec. 30, 1945 /D7'-M/ ALLOY JURFACE PLATINUM AND TU/VGS TEN Mme L AA Til/FORD [NV ENTO R ATTORN EY Patented June 7, 1949 ELECTRODE FOR. ELECTRON DISCHARGE DEVICES Harry L. Ratchford, Williamsport, Pa., assignor to Sylvania Electric Products vInc, Emporium, Pa... a corporation of Massachusetts Application December 30, 1943, Serial No. 516,251
2 Claims.
This invention relates to electron discharge devices and moreparticularly to the electrodes used in discharge tubes operated at high temperatures.
One of the difficulties encountered in the operation of thermionic tubes operated or processed at high temperatures, as power and transmitting tubes, is the occurrence of uncontrolled electron emission from the control grid or any of the other cold discharge electrodes. It is in general desirable that the only source of electron emission be the thermionic cathode (the hot electrode), as primary and secondary electron emission from any of the cold tube electrodes influence the electrical tube characteristics in an undesirable manner.
In tubes designed for operation at high temperatures, the material of the grid electrodes must havea high melting point and must have high mechanical strength at high temperatures. These conditions are fulfilled for certain materials, e. g., tungsten, molybdenum, and tantalum. These materials do, howevenhave the undesirable feature that they have a tendency toward secondary and primary electron emission, and collect some of the emitter material evaporating from the thermionic cathode. Platinum, on the other hand, is very desirable as a material from the viewpoint of low secondary and primary electron emission. Unfortunately, the mechanical strength of platinum is comparatively low, in particular at high temperatures, and what is gained by the use of platinum as a grid material for high temperature operated tubes, considering its desirable low electron emission properties is lost again in View of the deficiency of this material in mechanical stiffness. The characteristics of tubes incorporating platinum grids vary widely from tube to tube, due to changes in the shapes of the grids made of this soft material during the processing or the life of the tube.
It is, therefore, a principal object of the invention to produce electron discharge tubes which can be processed and operated at high temperatures, and whose characteristics do not change from tube to tube of the same standard design as a result of the softness of their cold electrodes, and do not exhibit the undesirable effect typical of primary or secondary electron emission from these electrodes.
One object of the invention relates to means for increasing the mechanical stiffness of a grid made of platinum.
According to another object of the invention, means are provided to alloy the surface of a platinum grid structure so as to increase its mechanical stiffness and to preserve the low electron emission properties of platinum.
Another principal object of the invention relates to the use of a platinum alloy as material for making grids for thermionic tubes operated at high temperatures, which incorporates the desirable low electron-emitting features of platinum combined with a mechanical stiffness considerably higher than that of platinum.
A feature of the invention relates to means for making grids which cannot be contaminated by the emitter material evaporating from the thermionic cathode during processing and life of the tube.
In the drawing there is shown in diagrammatic form a grid electrode embodying the invention.
The invention is based on the fact, that some of the physical properties of a metal are usually changed, while others remain constant when a pure metal is alloyed with one or several other metals. Recognizing the superior qualities of platinum as a grid material, with respect to its low electron-emitting properties, but recognizing also the deficiency of this material in mechanical stiffness, in particular at high temperatures, the present invention provides the possibility of alloy-' ing platinum with an appropriate "hardener, resulting in an alloy which will preserve the desirable low electron emission properties of platinum, but having the desirable increased mechanical stiffness.
According to one embodiment, there is provided an appropriate platinum alloy grid made from a grid made of pure platinum wire. For this purpose, the ready or preformed platinum grid is sprayed with a lacquer suspension. of fine tungsten powder immediately preceding the mounting of the electrode assembly within the tube. The heat applied to the grid in the ordinary processing of the tube during exhaust running as high as 1600 0., results in the formation of a stifier alloy, which however still preserves the low electron-emitting features of platinum. It was found that the grid emission of the tubes having platinum grids treated in this manner was substantially as low as that of tubes made with. pure platinum grids. At the same time, the stiffness of the grids treated in this way was found to be considerably higher than that of the grids made of plain platinum wire, as demonstrated by comparative tests made with grids of both kinds, namely plain platinum grids and grids treated as described.
According to the above-described embodiment Parts Medium viscosity nitro cellulose (approximately 20 seconds) '1 Diethyl oxalate :10 Butyl acetate "30 i Tungsten powder to 10 parts of above lacquer (by weight) 1 mounted into a tube, which is then exhausted. During exhaust, the gridlis heated to a'temperature of 1500 to 1600 C.,'for five to ten minutes,
wherebyihedesired alloying of-the tungsten with the'platinum takes :place, "resulting in increased stiffness of the grid'struotureand in substantial preservation of the low electron-emitting properties of pure platinum.
It will be understood 'that the invention is not limited'toth'e particular method of alloying thetungsten andiplatinum described. Thus the platinum and tungsten rmay 'be alloyed in any well-known commercialmanner'and then drawn down to the wire 'size "required for .grid structures. Thus one alloy that was found suitable for the purpose above described -contained approximately 2-6% tungsten and the balance platinum. Preferably, the tungsten should be 4% and the platinum 96%. Instead of using pure "platinum with the tungsten a platinum rhodium alloy'may be alloyed with the tungsten provided the platinum isthe major part of the platinum rhodium portion of the. alloy.
"What is claimed is:
'1. A wire grid electrode 'for use within an electron tube and subjected to electron bombardment during the normal operation of the tube.
said electrode comprising an alloy of approximately 96% platinum and 4% tungsten to increase the stififness of the electrode while preserving the low electron-emissive properties of platinum.
2. A gridrelectrode for' use in an=eleotron tube of the type which employs a thermionic cathode "I0 i'tending to deposit emissive material on the grid during .operationoi .the tube, said grid electrode :comprising a platinum base alloy consisting mainly of platinum with from 2% to 6% tung- :sten for:inhibiting:primary emission from the grid when such emissive material is deposited *thereon and-for the purpose of increasing the stifiness of the electrode while preserving the low emissive properties of platinum.
HARRY L. RATCI-IFORD.
REFERENCES CITED The following referenlces are of "record in 'the file of this patent:
.UNITED STATES PATENTS Number Name Date 803,684 Fleming Nov. 7, 1905 1,096,655 Weintraub May1'2, 1914 1,236,383 'Fahrenwal'd Aug.'7,-1917 1,342,801 Gebauer June 8, 1-920 1,346,192 Gebauer July 13, 1920 407,525 Fry =Feb.' 21, 1922 1,566,534 Haagan Dec. '22, 1925 1,655,269 Howe Jan. 3, 1928 1,719,774 Metcalf July 2, 1929 2,032,694 Gertler Mar. '3, 1936 2,183,635 Barker Dec. 19, 1939 2,395,313 {Becker Feb. 19, I946 FOREIGN PATENTS Number Country Date 407,658 GreatiBritain June 14, 1932
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US516251A US2472760A (en) | 1943-12-30 | 1943-12-30 | Electrode for electron discharge devices |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US516251A US2472760A (en) | 1943-12-30 | 1943-12-30 | Electrode for electron discharge devices |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2472760A true US2472760A (en) | 1949-06-07 |
Family
ID=24054764
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US516251A Expired - Lifetime US2472760A (en) | 1943-12-30 | 1943-12-30 | Electrode for electron discharge devices |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US2472760A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2549551A (en) * | 1948-01-15 | 1951-04-17 | Bell Telephone Labor Inc | Grid electrode structure and manufacturing method therefor |
| US2691116A (en) * | 1953-03-31 | 1954-10-05 | Rca Corp | Color-kinescopes, etc. |
| US2729763A (en) * | 1952-03-19 | 1956-01-03 | Cohn Eugene | Electron tube grids |
| US3465400A (en) * | 1967-02-01 | 1969-09-09 | Varian Associates | Method of making cylindrical mesh electrode for electron tubes |
Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US803684A (en) * | 1905-11-07 | Marconi Wireless Telegraph Co America | Instrument for converting alternating electric currents into continuous currents. | |
| US1096655A (en) * | 1914-03-05 | 1914-05-12 | Gen Electric | Platinum alloy. |
| US1236383A (en) * | 1916-05-31 | 1917-08-07 | Frank A Fahrenwald | Process of coating tungsten or molybdenum with noble metals. |
| US1342801A (en) * | 1917-05-17 | 1920-06-08 | Charles L Gebauer | Process of producing metal bodies |
| US1346192A (en) * | 1916-04-12 | 1920-07-13 | Charles L Gebauer | Composition of matter |
| US1407525A (en) * | 1920-04-02 | 1922-02-21 | Wilson H A Co | Platinum alloy |
| US1566534A (en) * | 1925-12-22 | Tioh of w | ||
| US1655269A (en) * | 1928-01-03 | Goodwin h | ||
| US1719774A (en) * | 1929-07-02 | metcalf | ||
| GB407658A (en) * | 1932-06-14 | 1934-03-22 | Siebert G M B H G | Improvements in and relating to thermocouples |
| US2032694A (en) * | 1933-06-20 | 1936-03-03 | Harry I Stein | Method for hardening metals |
| US2183635A (en) * | 1937-03-10 | 1939-12-19 | Western Electric Co | Method of and apparatus for making articles |
| US2395313A (en) * | 1943-08-09 | 1946-02-19 | Eitel Mccullough Inc | Electron tube and electrode for the same |
-
1943
- 1943-12-30 US US516251A patent/US2472760A/en not_active Expired - Lifetime
Patent Citations (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1655269A (en) * | 1928-01-03 | Goodwin h | ||
| US803684A (en) * | 1905-11-07 | Marconi Wireless Telegraph Co America | Instrument for converting alternating electric currents into continuous currents. | |
| US1719774A (en) * | 1929-07-02 | metcalf | ||
| US1566534A (en) * | 1925-12-22 | Tioh of w | ||
| US1096655A (en) * | 1914-03-05 | 1914-05-12 | Gen Electric | Platinum alloy. |
| US1346192A (en) * | 1916-04-12 | 1920-07-13 | Charles L Gebauer | Composition of matter |
| US1236383A (en) * | 1916-05-31 | 1917-08-07 | Frank A Fahrenwald | Process of coating tungsten or molybdenum with noble metals. |
| US1342801A (en) * | 1917-05-17 | 1920-06-08 | Charles L Gebauer | Process of producing metal bodies |
| US1407525A (en) * | 1920-04-02 | 1922-02-21 | Wilson H A Co | Platinum alloy |
| GB407658A (en) * | 1932-06-14 | 1934-03-22 | Siebert G M B H G | Improvements in and relating to thermocouples |
| US2032694A (en) * | 1933-06-20 | 1936-03-03 | Harry I Stein | Method for hardening metals |
| US2183635A (en) * | 1937-03-10 | 1939-12-19 | Western Electric Co | Method of and apparatus for making articles |
| US2395313A (en) * | 1943-08-09 | 1946-02-19 | Eitel Mccullough Inc | Electron tube and electrode for the same |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2549551A (en) * | 1948-01-15 | 1951-04-17 | Bell Telephone Labor Inc | Grid electrode structure and manufacturing method therefor |
| US2729763A (en) * | 1952-03-19 | 1956-01-03 | Cohn Eugene | Electron tube grids |
| US2691116A (en) * | 1953-03-31 | 1954-10-05 | Rca Corp | Color-kinescopes, etc. |
| US3465400A (en) * | 1967-02-01 | 1969-09-09 | Varian Associates | Method of making cylindrical mesh electrode for electron tubes |
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