US2233917A - Black coating for electron discharge devices - Google Patents

Black coating for electron discharge devices Download PDF

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Publication number
US2233917A
US2233917A US246284A US24628438A US2233917A US 2233917 A US2233917 A US 2233917A US 246284 A US246284 A US 246284A US 24628438 A US24628438 A US 24628438A US 2233917 A US2233917 A US 2233917A
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Prior art keywords
coating
black
electron discharge
discharge devices
oxide
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Expired - Lifetime
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US246284A
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Boer Jan Hendrik De
Scheerman Leonardus Theodorus
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RCA Corp
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RCA Corp
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    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J19/00Details of vacuum tubes of the types covered by group H01J21/00
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01JELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2893/00Discharge tubes and lamps
    • H01J2893/0001Electrodes and electrode systems suitable for discharge tubes or lamps
    • H01J2893/0012Constructional arrangements
    • H01J2893/0019Chemical composition and manufacture
    • H01J2893/0022Manufacture
    • H01J2893/0023Manufacture carbonising and other surface treatments

Description

March 4, 1941. J. H. DE BOER ETAL 2,233, 7
BLACK COATING FOR ELECTRON DISCHARGE DEVICES Filed D80. 17, 1938 JAN HENDRIK DE BOER,
HAJO BRUINING AND LEONARDUS THEODORUSSCHEER N 0 INVENTO ATTORNEY. v
BLACK TITAN/UM 0x105 METAL coRE.
ated Mar. 4, 1941 UNITED STATES:
BLACK COATING FOR ELECTRON DISCHARGE DEVICES Jan Hendrik de Boer, Halo Bruining, and Leonardus Theodorus Scheerman,
Eindhoven.
Netherlands, assignors, by mesne assignments, to Radio Corporation of America, New York, N. Y., a corporation of Delaware Application December 17, 1938, Serial No. 246,284 In Germany March 25, 1938 Claims.
The invention relates to electron discharge devices and to methods of manufacturing them.
Different materials have been proposed to reduce secondary emission during operation of 6 tubes and to improve the radiation of heat from the electrodes and envelope walls. It is known to provide the electrodes of discharge tubes, such as grids and anodes, with cooling members and also to blacken these electrodes, either entirely 10 or partly, with a coating material such as carbon or chromium oxide, or with a coating material which has low secondary emission such as chromium oxide, silver oxide, zirconium or zirconium oxide. A coating which has good black body characteristics and low secondary emission,
however, is usually difflcult toapply to the electrodes in a smooth adherent layer.
According to the present invention, a coating material is used which reduces secondary emission, improves the radiation of heat and adheres well to the electrodes. According to the invention one or more electrodes or other parts are tion, and Figure 2 is a detailed sectional view of aportion of an electrode coated with black titanium oxide according to the invention.
40 A conventional electron discharge device with an envelope I enclosing a cathode 2, grid 3 and anode 4 may be constructed in the usual manner with the cold or non-emitting electrodes coated with a layer of black titanium oxide. The metal 45 core 5 of an electrode such as the grid or plate,
is coated with a layer B of titanium dioxide which when reduced to black titanium oxide leaves the surface of the core velvety black. The coating is adherent, is not electron emissive and because of 0 its good heat radiating properties keeps the coated electrodes relatively cool.
According to one particular embodiment of the invention, an electron discharge tube comprises a grid, the operative portion of the wires of which 5 are coated with black titanium oxide.
According to a further embodiment, an anode is coated, at least on part or its surface, with black titanium oxide. it may be desirable in this case to provide this material both on that side oi the anode which is directed towards the 5 cathode, in order to reduce the secondary emission, and on the outside of the anode, in order to improve the thermal radiation.
An advantage of the above described material is that it can be applied very easily to a support. 10 Titanium dioxide may be first coated on the electrodes and then partially reduced. Titanium dioxide is of advantage compared to zirconium oxide since titanium dioxidecan be reduced more easily.
The core or base to which the improved coating material is applied should be a metal which favors the reduction of the titanium dioxide. For this purpose use is preferably made of a metal such as tungsten. or molybdenum or ferrous metals such as iron or nickel. If these metals are used for the core the titanium dioxide coating is easily reduced by heating in vacuum to a temperature of about 1500 C. The use of further reducing agents may not be necessary in this case. If other metals are used for the core or support, the titanium dioxide is reduced by heating, for example, in the presence of hydrogen or of mixtures of hydrogen and nitrogen.
The titanium dioxide may be applied to the support in diiierent ways. Very satisfactory results are obtained by cataphoretically depositing the dioxide. Alternatively, powdered titanium dioxide may be suspended in a nitrocellulose lacquer and sprayed or painted on the cores and then heated in a reducing atmosphere such as hydrogen to reduce the coating to black titanium oxide. When applied to nickel and fired at 1350 C. the white titanium dioxide may readily be reduced to a black adherent coating that can not be rubbed off in handling. Apparently the particles of the coating move into intimate contact with the core as the higher oxide is heated an reduced to the monoxide. i
Rutile, TlOz, is less expensive in manufactureand insures good adhesion of the titanium dioxide when wet and of the black titanium oxide when subsequently produced.
We claim:
1. An electron discharge device comprising an envelope, a non-emitting electrode in said envelope, said electrode being coated with black titanium oxide, and a cathode within said envelope.
2. An electrode for an electron discharge dee 5. A method of manufacturing an electrode ior vice said electrode being oi. a metal included in an electron discharge tube comprising applying the group consisting or iron and nickel; and a a coating or titanium dioxide to said electrode black titanium oxide coating on said electrodes. and then reducingsaid titanium dioxide to an 5 3.-An anode comprising a metal core and a adherent black coating ot an oxide oi titanium; l
coating consisting of a substantially black'oxide V of titanium. j JAN HENDRIK n: BOER.
. 4. An electrode for an electron discharge de- HAJO BRUINING. v vice comprising a metal core, a non-emitting ad- I LEONARDUS THEODORUS'SCHEERMAN. l0 herent coating of a black compound 01 titanium and oxygen on said core. i
US246284A 1938-03-25 1938-12-17 Black coating for electron discharge devices Expired - Lifetime US2233917A (en)

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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2417730A (en) * 1942-11-30 1947-03-18 Eitel Mccullough Inc Electron tube and method of making same
US2454031A (en) * 1944-07-29 1948-11-16 Gen Electric Electric discharge device of the magnetron type
US2512769A (en) * 1945-10-30 1950-06-27 Texas Co Neutron detection
US2530167A (en) * 1944-12-14 1950-11-14 Hartford Nat Bank & Trust Co Discharge tube
US2769112A (en) * 1953-06-11 1956-10-30 Westinghouse Electric Corp Discharge lamp, mount therefor, and method
US2846609A (en) * 1954-02-08 1958-08-05 Philips Corp Non-emissive electrode for electron discharge device
US2885587A (en) * 1956-06-13 1959-05-05 Westinghouse Electric Corp Low pressure discharge lamp and method
US2955229A (en) * 1956-11-14 1960-10-04 Gen Electric Secondary emission suppression in electron beam tubes
US3133224A (en) * 1960-11-25 1964-05-12 Gen Electric Electric discharge device
US3309302A (en) * 1963-10-07 1967-03-14 Varian Associates Method of preparing an electron tube including sputtering a suboxide of titanium on dielectric components thereof
US20160240328A1 (en) * 2013-09-29 2016-08-18 Shanghai Institute Of Ceramics, Chinese Academy Of Sciences Titanium oxide-based supercapacitor electrode material and method of manufacturing same

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2417730A (en) * 1942-11-30 1947-03-18 Eitel Mccullough Inc Electron tube and method of making same
US2454031A (en) * 1944-07-29 1948-11-16 Gen Electric Electric discharge device of the magnetron type
US2530167A (en) * 1944-12-14 1950-11-14 Hartford Nat Bank & Trust Co Discharge tube
US2512769A (en) * 1945-10-30 1950-06-27 Texas Co Neutron detection
US2769112A (en) * 1953-06-11 1956-10-30 Westinghouse Electric Corp Discharge lamp, mount therefor, and method
US2846609A (en) * 1954-02-08 1958-08-05 Philips Corp Non-emissive electrode for electron discharge device
US2885587A (en) * 1956-06-13 1959-05-05 Westinghouse Electric Corp Low pressure discharge lamp and method
US2955229A (en) * 1956-11-14 1960-10-04 Gen Electric Secondary emission suppression in electron beam tubes
US3133224A (en) * 1960-11-25 1964-05-12 Gen Electric Electric discharge device
US3309302A (en) * 1963-10-07 1967-03-14 Varian Associates Method of preparing an electron tube including sputtering a suboxide of titanium on dielectric components thereof
US20160240328A1 (en) * 2013-09-29 2016-08-18 Shanghai Institute Of Ceramics, Chinese Academy Of Sciences Titanium oxide-based supercapacitor electrode material and method of manufacturing same
US10192690B2 (en) * 2013-09-29 2019-01-29 Shanghai Institute Of Ceramics, Chinese Academy Of Sciences Titanium oxide-based supercapacitor electrode material and method of manufacturing same

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