GB2226573A - Dispenser cathode - Google Patents
Dispenser cathode Download PDFInfo
- Publication number
- GB2226573A GB2226573A GB8924407A GB8924407A GB2226573A GB 2226573 A GB2226573 A GB 2226573A GB 8924407 A GB8924407 A GB 8924407A GB 8924407 A GB8924407 A GB 8924407A GB 2226573 A GB2226573 A GB 2226573A
- Authority
- GB
- United Kingdom
- Prior art keywords
- pellet
- powder
- mixture
- dispenser cathode
- powder mixture
- 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.)
- Granted
Links
- 239000008188 pellet Substances 0.000 claims abstract description 36
- 239000000843 powder Substances 0.000 claims abstract description 25
- 239000000203 mixture Substances 0.000 claims abstract description 23
- 229910052751 metal Inorganic materials 0.000 claims abstract description 17
- 239000002184 metal Substances 0.000 claims abstract description 17
- 238000000034 method Methods 0.000 claims abstract description 14
- 238000004519 manufacturing process Methods 0.000 claims abstract description 13
- 150000004649 carbonic acid derivatives Chemical class 0.000 claims abstract description 12
- 229910052721 tungsten Inorganic materials 0.000 claims abstract description 10
- 239000007864 aqueous solution Substances 0.000 claims abstract description 9
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 8
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 8
- 229910052715 tantalum Inorganic materials 0.000 claims abstract description 8
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 7
- 239000000243 solution Substances 0.000 claims abstract description 7
- 239000000956 alloy Substances 0.000 claims abstract description 3
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 3
- 239000004615 ingredient Substances 0.000 claims abstract description 3
- 150000002739 metals Chemical class 0.000 claims abstract 2
- 238000005470 impregnation Methods 0.000 claims description 3
- 230000015572 biosynthetic process Effects 0.000 claims 4
- 150000001399 aluminium compounds Chemical class 0.000 claims 2
- 239000000470 constituent Substances 0.000 claims 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims 1
- 239000004411 aluminium Substances 0.000 claims 1
- 238000010438 heat treatment Methods 0.000 abstract description 7
- -1 aluminum compound Chemical class 0.000 abstract description 5
- 206010067484 Adverse reaction Diseases 0.000 abstract description 3
- 230000006838 adverse reaction Effects 0.000 abstract description 3
- 238000007796 conventional method Methods 0.000 abstract description 3
- 239000010406 cathode material Substances 0.000 description 6
- 239000011575 calcium Substances 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 3
- 239000010937 tungsten Substances 0.000 description 3
- FQNGWRSKYZLJDK-UHFFFAOYSA-N [Ca].[Ba] Chemical compound [Ca].[Ba] FQNGWRSKYZLJDK-UHFFFAOYSA-N 0.000 description 2
- AYJRCSIUFZENHW-UHFFFAOYSA-L barium carbonate Chemical compound [Ba+2].[O-]C([O-])=O AYJRCSIUFZENHW-UHFFFAOYSA-L 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 239000011363 dried mixture Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 125000004430 oxygen atom Chemical group O* 0.000 description 1
- 239000011369 resultant mixture Substances 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/04—Making non-ferrous alloys by powder metallurgy
- C22C1/045—Alloys based on refractory metals
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
- H01J9/02—Manufacture of electrodes or electrode systems
- H01J9/04—Manufacture of electrodes or electrode systems of thermionic cathodes
- H01J9/042—Manufacture, activation of the emissive part
- H01J9/047—Cathodes having impregnated bodies
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Solid Thermionic Cathode (AREA)
- Powder Metallurgy (AREA)
Abstract
A manufacturing method for a dispenser cathode is disclosed which comprises a step of immersing, in an aqueous solution containing an aluminum compound, a powder mixture made by mixing metal powder selected from among Mo, Ta and W or powder of alloys of at least two or more metals selected from among the carbonates of Sr, Ba and Ca; or immersing in said solution a pellet formed into a required shape from the former metal powder mixture whereby the aluminum ingredient in said aqueous solution is impregnated into said powder mixture or the pellet. According to the present method, a heat treatment at a temperature of over 1700 DEG C is not required unlike the case of conventional methods, and therefore, the decrease of the electron releasing efficiency due to the adverse reactions generated at the high temperature heat treatment can be avoided.
Description
MANUFACTURING METHOD FOR DISPENSER CATHODE
Field of the Invention
The present invention relates to a manufacturing method for a dispenser cathode, and particularly to a manufacturing method for a dispenser cathode in which the decrease of the electron releasing efficiency due to a high temperature heat treatment can be restrained.
Background of the Invention
The general dispenser cathode as shown in Figure 1 comprises a porous pellet 3 containing barium-calcium aluminate as the cathode material, a cup 2 for storing the pellet 3, and a sleeve 1 for storing a heater 4. Among these components, the pellet 3 which is an important component is manufactured by sintering a high melting point metal powder such as tungsten(W), and has to undergo a high temperature heat treatment because the material itself is a high melting point heat resistant metal. There are many different methods for manufacturing the pellet, and one of them is carried out in such a manner that a mixture of
BaCO3 , CaC03 , and A12 CO3 as the cathode material, or barium-calcium aluminate obtained by baking the above.
mixture is impregnated into a porous pellet made of a heat resistant metal such as tungsten. Another method is carried out such that a mixture prepared by mixing a heat resistant metal powder such as tungsten, molybdenum, or tantalum with a cathode material in a proper ratio is fabricated through compression into the required shape, and is sintered.(Refer to U.S.Pat. No. 4,737,679; 4,400,648)
In such conventional methods, a baking process has to be carried out at a temperature of over 1700C , but according to these methods, the electron releasing efficiency is greatly lowered due to the adverse reaCtion generated by the high temperature treatment.The reason is that Al2 03 , e.g., alumina which is very high in its own melting point and the reaction temperature related to other materials is used as the cathode material, and as long as
A12 03 is used as the cathode material, the high temperature baking process causing the thermal adverse effect can not be excluded.
Summarv of the Invention
Therefore, it is the object of the present invention to provide a manufacturing method for a dispenser cathode in which the decrease of the electron releasing efficiency in the cathode material accruable due to a high temperature heat treatment can be restrained.
To accomplish the above object, the manufacturing method for a dispenser cathode according to the present invention comprises:
a step of immersing, in a aqueous solution containing an aluminum compound, powder mixture made by mixing metal powder selected from among Mo, Ta and W or powder of alloys of at least two or more metal selected from among the carbonates of Sr, Ba and Ca; or immersing in said solution the pellet formed into required shape with the former metal powder mixture so as for the aluminum ingredient in said aqueous solution to be impregnated into said powder mixture or the pellet.
Brief DescriDtion of the Drawings
The above object and other advantages of the present invention will become more apparent by describing the preferred embodiment of the present invention with reference to the attached drawing in which:
Figure 1 is a sectional view of the general dispenser cathode.
Description of the Dreferred embodiments Examole 1 NaCO 3 is dissolved in a solution containing a mixture of SrNO3 , BaNO3 and CaNO3 so tht Sr, Ba and Ca are let to be commonly deposited in the form of carbonates. Then the deposited carbonates are recovered and dried to mix them with the metal powders of Mo, Ta and W, and the above mixture is press-formed into a pellet having the required shape. Meanwhile, an aluminum compound is dissolved in a proper medium, and the pellet is immersed in the solution to conduct a impregnation. Thereafter, the pellet is baked at a temperature of 1200 - 130or to remove CO2 , thereby completing the manufacturing of the pellet.
ExamDle 2 NaCo3 is dissolved in a solution containing SrNO3
BaNO 3 and CaNO, so tht Sr, Ba and Ca are let to be commonly deposited in the form of carbonates through chemical reactions. Then the deposited carbonates are recovered and dried, and then the dried carbonates are mixed with the metal powders of Mo, Ta and W. And the mixture is press-formed into a pellet having the required shape.
Thereafter, the pellet is baked at a temperature of 1200 13000C to remove C0z , the pellet is immersed into an aqueous solution containing an dissolved aluminum compound to conduct a impregnation, and the pellet is taken out and dried. As the following process, the pellet is subjected to a reduction treatment under a hydrogen atmosphere at a temperature of slightly over 1200 - 1300C -in order to remove the residue oxygen atoms.
Example 3
NaNO 3 is dissolved in a solution containing SrNO, BaND3 and CaNO3 so that Sr, Ba and Ca are let to be commonly deposited in the form of carbonates through chemical reactions, then the deposited carbonates are recovered and dried, the dried carbonates are mixed with the metal powders of Mo, Ta and W, the resultant mixture is put into an aqueous solution containing an aluminum compound in order to impregnate the mixture, and the impregnated mixture is recovered and dried. The dried mixture is put into a pellet having the required shape, and the fabricated pellet is subjected to baking and reducing processes, thereby completing the manufacturing of the pellet.
The pellet 3 manufactured based on the above described processes is inserted into a cup 2 which is secured at the portion of the leading end of a sleeve 1 as shown in Figure 1, and the pellet 3 is fixea by a resistance welding or a laser welding.
According to the manufacturing method of the present invention as described above, a heat treatment at a temperature of over 1700"C is not required unlike in the case of the conventional methods, but all the required baking and reducing processes can be conducted at a temperature of no more than 1200-1300'C . Accordingly, the decrease of the electron releasing efficiency due to the adverse reactions generated at the high temperature heat treatment can be avoided, thereby improving the electron releasing efficiency, and making it possible to produce a high performance cathode.
Claims (9)
1. A manufacturing method for a dispenser cathode comprising a step of immersing, in an aqueous solution containing an aluminium compound, powder mixture made by mixing metal powder selected from among Mo, Ta and W or powder of alloys of at least two or more metals selected from among the carbonates of
Sr, Ba and Ca; or immersing in said solution the pellet formed into required shape with the former metal powder mixture so as for the aluminium ingredient in said aqueous solution to be impregnated into said powder mixture or the pellet.
2. A method of manufacturing a porous pellet for a dispenser cathode, comprising making a powder mixture containing a first powder carbonate constituent selected from the carbonates of Sr, Ba and Ca, and a second powder metal constituent selected from Mo, Ta and W, and forming a pellet from the powder mixture, wherein the powder mixture is impregnated with an aqueous solution of an aluminium compound either before or after said formation thereof into said pellet.
3. A method according to claim 2 wherein the mixture is impregnated after formation into said pellet, and said pellet is baked after impregnation to remove C02.
4. A method according to claim 2 wherein the mixture is impregnated after formation into said pellet and after baking of the pellet to remove CO2.
5. A method according tq claim 2 wherein the mixture is impregnated before formation into said pellet.
6. A method of making a porous pellet for a dispenser cathode substantially as hereinbefore described with reference to examples 1, 2 or 3 described herein.
7. A porous pellet for a dispenser cathode, made by a method according to any preceding claim.
8. A dispenser cathode including a porous pellet according to claim 7.
9. A dispenser cathode according to claim 8 and substantially as hereinbefore described with reference to the accompanying Fig. 1.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR8815259A KR910003699B1 (en) | 1988-11-19 | 1988-11-19 | Manufacturing method of dispenser cathode |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8924407D0 GB8924407D0 (en) | 1989-12-20 |
| GB2226573A true GB2226573A (en) | 1990-07-04 |
| GB2226573B GB2226573B (en) | 1992-12-02 |
Family
ID=19279420
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8924407A Expired - Lifetime GB2226573B (en) | 1988-11-19 | 1989-10-30 | Method of manufacturing a porous pellet for a dispenser cathode |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPH02244536A (en) |
| KR (1) | KR910003699B1 (en) |
| GB (1) | GB2226573B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2333565C1 (en) * | 2007-05-17 | 2008-09-10 | Федеральное государственное унитарное предприятие "Научно-производственное предприятие "Исток" (ФГУП "НПП "Исток") | Method of making dispenser cathode |
| RU2724980C1 (en) * | 2019-10-15 | 2020-06-29 | Акционерное общество "Научно-производственное предприятие "Алмаз" (АО "НПП "Алмаз") | Two-layer dispensed cathode and method of its manufacturing |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2338291C1 (en) * | 2007-05-14 | 2008-11-10 | Федеральное государственное унитарное предприятие "Научно-производственное предприятие "Исток" (ФГУП "НПП "Исток") | Method of dispenser cathode manufacture |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1052791A (en) * | 1962-08-24 | |||
| US1465473A (en) * | 1922-07-12 | 1923-08-21 | Thomas C Hansen | Means for molding backings for artificial teeth |
| US2813807A (en) * | 1954-07-19 | 1957-11-19 | Philips Corp | Method of making a dispenser cathode |
| GB924595A (en) * | 1961-02-07 | 1963-04-24 | Csf | Method of manufacturing cathodes |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS551029A (en) * | 1978-06-19 | 1980-01-07 | New Japan Radio Co Ltd | Manufacture of impregnated cathode |
-
1988
- 1988-11-19 KR KR8815259A patent/KR910003699B1/en not_active Expired
-
1989
- 1989-10-30 GB GB8924407A patent/GB2226573B/en not_active Expired - Lifetime
- 1989-11-13 JP JP29476289A patent/JPH02244536A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1465473A (en) * | 1922-07-12 | 1923-08-21 | Thomas C Hansen | Means for molding backings for artificial teeth |
| US2813807A (en) * | 1954-07-19 | 1957-11-19 | Philips Corp | Method of making a dispenser cathode |
| GB924595A (en) * | 1961-02-07 | 1963-04-24 | Csf | Method of manufacturing cathodes |
| GB1052791A (en) * | 1962-08-24 |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2333565C1 (en) * | 2007-05-17 | 2008-09-10 | Федеральное государственное унитарное предприятие "Научно-производственное предприятие "Исток" (ФГУП "НПП "Исток") | Method of making dispenser cathode |
| RU2724980C1 (en) * | 2019-10-15 | 2020-06-29 | Акционерное общество "Научно-производственное предприятие "Алмаз" (АО "НПП "Алмаз") | Two-layer dispensed cathode and method of its manufacturing |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02244536A (en) | 1990-09-28 |
| GB8924407D0 (en) | 1989-12-20 |
| KR910003699B1 (en) | 1991-06-08 |
| GB2226573B (en) | 1992-12-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20011030 |