JP2910426B2 - Manufacturing method of tungsten powder sintered body for impregnated cathode - Google Patents
Manufacturing method of tungsten powder sintered body for impregnated cathodeInfo
- Publication number
- JP2910426B2 JP2910426B2 JP4190070A JP19007092A JP2910426B2 JP 2910426 B2 JP2910426 B2 JP 2910426B2 JP 4190070 A JP4190070 A JP 4190070A JP 19007092 A JP19007092 A JP 19007092A JP 2910426 B2 JP2910426 B2 JP 2910426B2
- Authority
- JP
- Japan
- Prior art keywords
- tungsten powder
- tungsten
- sintered body
- impregnated cathode
- powder
- 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
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 title claims description 40
- 238000004519 manufacturing process Methods 0.000 title claims description 10
- 229910052721 tungsten Inorganic materials 0.000 claims description 14
- 239000010937 tungsten Substances 0.000 claims description 14
- 239000002245 particle Substances 0.000 claims description 13
- 238000005245 sintering Methods 0.000 claims description 7
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 claims description 5
- 239000000843 powder Substances 0.000 claims description 5
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 4
- 239000001257 hydrogen Substances 0.000 claims description 4
- 229910052739 hydrogen Inorganic materials 0.000 claims description 4
- 238000003825 pressing Methods 0.000 claims description 3
- 239000013078 crystal Substances 0.000 description 17
- 229910052788 barium Inorganic materials 0.000 description 6
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 6
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 5
- 239000011148 porous material Substances 0.000 description 5
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 239000011521 glass Substances 0.000 description 4
- 238000007796 conventional method Methods 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 229910052786 argon Inorganic materials 0.000 description 2
- QVQLCTNNEUAWMS-UHFFFAOYSA-N barium oxide Chemical compound [Ba]=O QVQLCTNNEUAWMS-UHFFFAOYSA-N 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 229910052741 iridium Inorganic materials 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 238000001953 recrystallisation Methods 0.000 description 2
- 239000011800 void material Substances 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 1
- 239000000292 calcium oxide Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
Landscapes
- Powder Metallurgy (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、含浸型陰極用タングス
テン粉末焼結体の製造方法に関し、特に高電流密度用の
含浸型陰極用タングステン粉末焼結体の製造方法に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a sintered tungsten powder for an impregnated cathode, and more particularly to a method for producing a sintered tungsten powder for an impregnated cathode for high current density.
【０００２】[0002]
【従来の技術】従来の含浸型陰極タングステン粉末焼結
体（以下、ポーラスＷ棒という）は、平均粒径が４〜５
μｍのタングステン粉末を１ｔｏｎ／平方ｃｍの圧力で
プレス成形した後、水素雰囲気中、又は真空雰囲気中に
おいて約２０００℃で加熱、焼結させ製作されている。2. Description of the Related Art A conventional impregnated cathode tungsten powder sintered body (hereinafter referred to as a porous W rod) has an average particle size of 4 to 5 mm.
It is manufactured by press-molding a μm tungsten powder under a pressure of 1 ton / square cm, and then heating and sintering at about 2000 ° C. in a hydrogen atmosphere or a vacuum atmosphere.
【０００３】このポーラスＷ棒を用いて製作される含浸
型陰極は、マトリックス状のタングステン焼結体の中に
酸化バリウム、酸化カルシウム、及び酸化アルミニウム
が含浸された構造であるため、その基体金属であるポー
ラス棒も空孔率が約２０％のマトリックス状にする必要
がある。上記方法によって製作されたポーラスＷ棒はタ
ングステン粒の大きさが４〜８μｍ、空孔径が３〜６μ
ｍのマトリックスを形成する。[0003] The impregnated cathode manufactured using this porous W rod has a structure in which barium oxide, calcium oxide and aluminum oxide are impregnated in a matrix-like tungsten sintered body. Some porous rods also need to be in a matrix with a porosity of about 20%. The porous W rod manufactured by the above method has a tungsten particle size of 4 to 8 μm and a pore diameter of 3 to 6 μm.
Form a matrix of m.
【０００４】[0004]
【発明が解決しようとする課題】上述したように従来の
ポーラスＷ棒は、タングステン粉末の粒径が４〜８μ
ｍ、空孔径が３〜６μｍとなるため、次のような問題点
があった。すなわち、As described above, the conventional porous W rod has a tungsten powder having a particle size of 4 to 8 μm.
m, and the pore diameter is 3 to 6 μm, which causes the following problems. That is,
【０００５】含浸型陰極は、空孔に含浸されたバリウ
ムの表面拡散により仕事関数を低下させ電子を取り出し
ている。このため、空孔からしみだしたバリウムが陰極
全体に均一に拡散すれば最も仕事関数の低い良好な含浸
型陰極が得られる。In the impregnated cathode, the work function is lowered due to the surface diffusion of barium impregnated in the pores, and electrons are taken out. For this reason, if barium exuding from the pores diffuses uniformly throughout the cathode, a good impregnated cathode having the lowest work function can be obtained.
【０００６】しかし、タングステン粉末の平均粒径が４
〜５μｍと大きいと、バリウムが陰極表面全体に拡散す
る前に蒸発してしまい、バリウムの拡散していないタン
グステン表面の領域が発生し、含浸型陰極表面の仕事関
数を増加させてしまう。又、タングステン粉末同士が２
次焼結し、タングステン粒が６〜８μｍになった場合
は、バリウムの拡散面積がさらに減少し、仕事関数の低
下が顕著となる。However, the average particle size of the tungsten powder is 4
If it is as large as ~ 5 [mu] m, barium evaporates before diffusing over the entire cathode surface, and a region of the tungsten surface where barium is not diffused is generated, thereby increasing the work function of the impregnated cathode surface. In addition, two tungsten powders
In the case where the tungsten particles become 6 to 8 μm after the subsequent sintering, the diffusion area of barium is further reduced, and the work function is significantly reduced.
【０００７】このように空孔からのバリウムの拡散が含
浸型陰極表面上で不均一となると、含浸型陰極からの電
子放出分布が不均一となるため、進行波管などではヘリ
ックス電流の増加など異常電流が発生する。[0007] If the diffusion of barium from the pores becomes non-uniform on the surface of the impregnated cathode, the electron emission distribution from the impregnated cathode becomes non-uniform. Abnormal current occurs.
【０００８】従来の方法で上記問題点を解決するため
にタングステン粉末の粒径を１〜４μｍに小さくする
と、タングステン粒子が密に詰まるため、空孔率が１７
％以下になってしまい、上記同様仕事関数が増加し、含
浸型陰極として使用することができない。If the particle size of the tungsten powder is reduced to 1 to 4 μm in order to solve the above-mentioned problems by the conventional method, the tungsten particles are densely packed, so that the porosity is 17
%, The work function increases as in the above case, and it cannot be used as an impregnated cathode.
【０００９】本発明の目的は、含浸型陰極の仕事関数を
低下させ、電子放出特性を向上させる含浸型陰極用タン
グステン粉末焼結体の製造方法を提供することにある。An object of the present invention is to provide a method of manufacturing a tungsten powder sintered body for an impregnated cathode, which lowers the work function of the impregnated cathode and improves electron emission characteristics.
【００１０】[0010]
【課題を解決するための手段】前記目的を達成するた
め、本発明に係る含浸型陰極用タングステン粉末焼結体
の製造方法は、平均粒径１〜４μｍのタングステン粉末
を円柱形状にプレス加工した後、高温等方圧プレスでプ
レスおよび焼結させ、 その後、水素雰囲気中または真空
雰囲気中にて１６００℃以上で再焼結して焼結体の空孔
率を約２０％とするものである。 In order to achieve the above-mentioned object, a method for producing a tungsten powder sintered body for an impregnated cathode according to the present invention comprises a tungsten powder having an average particle diameter of 1 to 4 μm.
After pressing into a cylindrical shape, press
And sintered, then in a hydrogen atmosphere or vacuum
Void of sintered body after re-sintering at 1600 ° C or more in atmosphere
The rate is about 20%.
【００１１】また、前記再焼結前の高温等方圧プレスの
プレス温度は９００〜１２００℃であり、プレス圧は１
０００〜１５００気圧である。The pressing temperature of the high-temperature isostatic press before the resintering is 900 to 1200 ° C.
000 to 1500 atm.
【００１２】また、前記平均粒径１〜４μｍのタングス
テン粉末に代えて、１〜３μｍのタングステン粉末と
０．１〜２μｍのイリジウム粉末とを４：１の割合で混
合した粉末を使用するものである。 Further, the tangs having an average particle size of 1 to 4 μm.
Instead of Ten powder, 1-3 μm tungsten powder
0.1 to 2 μm iridium powder mixed at a ratio of 4: 1
The combined powder is used.
【００１３】[0013]
【作用】本発明の含浸型陰極用タングステン粉末焼結体
は、ＨＩＰによりプレスと焼結とを同時に行い、その後
１６００℃以上で再焼結させることにより、空孔率を約
２０％に制御することが可能であり、従来のような空孔
率の低下を防止する。The sintered tungsten powder for impregnated cathode of the present invention is simultaneously pressed and sintered by HIP and then re-sintered at 1600 ° C. or more to control the porosity to about 20%. It is possible to prevent the porosity from decreasing as in the related art.
【００１４】[0014]
【実施例】次に、本発明の実施例について図面を用いて
説明する。図１は、本発明の製造方法を実施するＨＩＰ
装置の縦断面図、図２は、本発明によるポーラスＷ棒の
断面図である。Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a HIP for implementing the manufacturing method of the present invention.
FIG. 2 is a longitudinal sectional view of the apparatus, and FIG. 2 is a sectional view of a porous W bar according to the present invention.
【００１５】まず、平均粒径１〜４μｍのタングステン
粉末を約１〜３ｔｏｎ／平方ｃｍの水圧プレスにより１
次プレスし、所定の円柱形状に成形する。次に、図１に
示すように成形したタングステン粉末成形体１をガラス
管２に挿入し、酸化アルミニウム３中に埋め込む。次に
埋め込んだガラス管２を１×１０-6の真空度まで排気
し、気密封止する。First, tungsten powder having an average particle size of 1 to 4 μm is pressed by a hydraulic press of about 1 to 3 ton / square cm.
Next, it is pressed and formed into a predetermined cylindrical shape. Next, the tungsten powder compact 1 molded as shown in FIG. 1 is inserted into a glass tube 2 and embedded in aluminum oxide 3. Next, the embedded glass tube 2 is evacuated to a degree of vacuum of 1 × 10 −6 and hermetically sealed.
【００１６】ガラス管２中に真空気密したタングステン
粉末成形体１と酸化アルミニウム３をプレス容器４中の
酸化アルミニウム５に埋め込む。これをＨＩＰの圧力室
６に配置し、周囲の加熱ヒータ７により約１０００℃に
加熱しながらアルゴンガス８により１５００気圧の圧力
を９０分間かけ、プレス加工と焼結とを同時に行う。A vacuum-tight airtight tungsten powder compact 1 and aluminum oxide 3 are buried in a glass tube 2 in an aluminum oxide 5 in a press vessel 4. This is placed in a HIP pressure chamber 6, and a pressure of 1500 atm is applied by an argon gas 8 for 90 minutes while being heated to about 1000 ° C. by a surrounding heater 7 to simultaneously perform press working and sintering.
【００１７】さらに空孔率を２０％にあわせるため、水
素雰囲気中で１６００℃、１０分の再焼結を行う。Further, resintering is performed at 1600 ° C. for 10 minutes in a hydrogen atmosphere to adjust the porosity to 20%.
【００１８】このように製作されたポーラスＷの断面は
図２に示すように４〜８μｍに結晶成長したタングステ
ン２次結晶９の中に１〜３μｍの１次結晶１０により形
成された空孔１１があり、さらにタングステン２次結晶
により形成された３〜４μｍの空孔１２が空孔１１の周
囲に形成されている。As shown in FIG. 2, the cross section of the porous W manufactured as described above is a hole 11 formed by a primary crystal 10 of 1 to 3 μm in a tungsten secondary crystal 9 having a crystal growth of 4 to 8 μm. In addition, a hole 12 of 3 to 4 μm formed by a tungsten secondary crystal is formed around the hole 11.
【００１９】従来の方法によるポーラスＷの断面図を図
４に示す。このように４〜５μｍのタングステン粉末で
はタングステン粒径が大きいため、結晶全体で結晶成長
が起こりにくいため、２次結晶が均一に形成されない。
このために１次結晶粒界１９により形成された３〜４μ
ｍの空孔２０しか形成されない。FIG. 4 is a sectional view of a porous W formed by a conventional method. As described above, since the tungsten powder having a diameter of 4 to 5 μm has a large tungsten particle size, crystal growth hardly occurs in the entire crystal, so that a secondary crystal is not formed uniformly.
For this purpose, 3-4 μm formed by primary crystal grain boundaries 19
Only m holes 20 are formed.
【００２０】図３は本発明の別の実施例に係るポーラス
Ｗ棒を示す縦断面図である。１〜３μｍのタングステン
粉末と０．１〜２μｍのイリジウム粉末を４：１の割合
で良く混合した後、前記実施例と同様にＨＩＰ、再結晶
を行いポーラスＷを作製すると、図３に示す通り、タン
グステン１３とイリジウム１４との１次結晶粒界１５に
０．５〜３μｍの空孔１６が形成され、さらに２次結晶
粒界１７に３〜４μｍの空孔１８が形成される。FIG. 3 is a longitudinal sectional view showing a porous W bar according to another embodiment of the present invention. After thoroughly mixing tungsten powder of 1 to 3 μm and iridium powder of 0.1 to 2 μm in a ratio of 4: 1, HIP and recrystallization are performed in the same manner as in the above embodiment to produce a porous W. As shown in FIG. A hole 16 of 0.5 to 3 μm is formed in a primary crystal grain boundary 15 between tungsten 13 and iridium 14, and a hole 18 of 3 to 4 μm is formed in a secondary crystal grain boundary 17.
【００２１】以上説明したようにＨＩＰによりプレス加
工と焼結とを同時に行なうことにより、１次結晶粒界に
空孔を形成した後、再結晶により結晶成長を起こさせ、
２次結晶粒界による空孔を形成するため、含浸型陰極表
面全体に均一で、小さい空孔を形成することが可能とな
った。As described above, by simultaneously performing press working and sintering by HIP, a hole is formed at the primary crystal grain boundary, and then crystal growth is caused by recrystallization.
Since holes are formed by secondary crystal grain boundaries, uniform and small holes can be formed on the entire surface of the impregnated cathode.
【００２２】さらに本発明による含浸型陰極用タングス
テン粉末焼結体により含浸型陰極を製作した場合、含浸
工程が同一でも図５に示すように仕事関数が０．０２〜
０．０５ｅＶ小さくなるという結果を得た。Further, when an impregnated cathode is manufactured from the tungsten powder sintered body for an impregnated cathode according to the present invention, the work function is 0.02 to 0.02 as shown in FIG.
The result was that it became 0.05 eV smaller.
【００２３】[0023]
【発明の効果】以上説明したように本発明は、１〜４μ
ｍのタングステン粉末を使用し、ＨＩＰ、再焼結するこ
とによって空孔率を２０％に制御し、小さい空孔を陰極
表面全体に均一に形成することによって、含浸型陰極の
仕事関数を図５のように０．０２〜０．０５ｅＶ低下さ
せ、電子放出特性を向上させることができるという効果
がある。As described above, according to the present invention, 1 to 4 μm
The work function of the impregnated cathode is shown in FIG. 5 by controlling the porosity to 20% by HIP and re-sintering using tungsten powder of m. As described above, there is an effect that the electron emission characteristics can be improved by lowering by 0.02 to 0.05 eV.
【図１】本発明の製造方法を実施するＨＩＰ装置を示す
縦断面図である。FIG. 1 is a longitudinal sectional view showing a HIP device for implementing a manufacturing method of the present invention.
【図２】本発明によるポーラスＷ棒を示す断面図であ
る。FIG. 2 is a sectional view showing a porous W bar according to the present invention.
【図３】本発明の別の実施例に係るポーラスＷ棒を示す
断面図である。FIG. 3 is a cross-sectional view showing a porous W bar according to another embodiment of the present invention.
【図４】従来の方法によるポーラスＷ棒を示す断面図で
ある。FIG. 4 is a sectional view showing a porous W bar according to a conventional method.
【図５】本発明と従来例との特性を示す図である。FIG. 5 is a diagram showing characteristics of the present invention and a conventional example.
１ タングステン粉末成形体 ２ ガラス管 ３，５ 酸化アルミニウム ４ プレス容器 ６ ＨＩＰ圧力室 ７ 加熱ヒータ ８ アルゴンガス ９ タングステン２次結晶 １０，１９ タングステン１次結晶 １１，１２，１６，１８，２０ 空孔 １３ タングステン １４ イリジウム １５ １次結晶粒界 １７ ２次結晶粒界 DESCRIPTION OF SYMBOLS 1 Tungsten powder compact 2 Glass tube 3,5 Aluminum oxide 4 Press vessel 6 HIP pressure chamber 7 Heater 8 Argon gas 9 Tungsten secondary crystal 10,19 Tungsten primary crystal 11,12,16,18,20 Void 13 Tungsten 14 Iridium 15 Primary crystal grain boundary 17 Secondary crystal grain boundary
Claims (3)
を円柱形状にプレス加工した後、高温等方圧プレスでプ
レスおよび焼結させ、 その後、水素雰囲気中または真空雰囲気中にて１６００
℃以上で再焼結して焼結体の空孔率を約２０％とする こ
とを特徴とする含浸型陰極用タングステン粉末焼結体の
製造方法。 1. A tungsten powder having an average particle size of 1 to 4 μm.
After pressing into a cylindrical shape, press
And sintering, and then 1600 in a hydrogen atmosphere or a vacuum atmosphere.
A method for producing a sintered tungsten powder sintered body for an impregnated cathode, wherein the sintered body is re-sintered at a temperature of not less than ° C to reduce the porosity of the sintered body to about 20% .
ス温度は９００〜１２００℃であり、 プレス圧は１０００〜１５００気圧であることを特徴と
する請求項１に記載の含浸型陰極用タングステン粉末焼
結体の製造方法。2. The impregnated cathode according to claim 1, wherein a press temperature of the high-temperature isostatic press before the resintering is 900 to 1200 ° C., and a press pressure is 1000 to 1500 atm. Of manufacturing tungsten powder sintered body for use.
粉末に代えて、１〜３μｍのタングステン粉末と０．１
〜２μｍのイリジウム粉末とを４：１の割合で混合した
粉末を使用することを特徴とする請求項１又は２に記載
の含浸型陰極用タングステン粉末焼結体の製造方法。3. Tungsten having an average particle size of 1 to 4 μm.
Instead of powder, 1-3 μm tungsten powder and 0.1
２2 μm iridium powder was mixed in a ratio of 4: 1
The method for producing a tungsten powder sintered body for an impregnated cathode according to claim 1 or 2, wherein a powder is used .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4190070A JP2910426B2 (en) | 1992-06-24 | 1992-06-24 | Manufacturing method of tungsten powder sintered body for impregnated cathode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4190070A JP2910426B2 (en) | 1992-06-24 | 1992-06-24 | Manufacturing method of tungsten powder sintered body for impregnated cathode |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0612978A JPH0612978A (en) | 1994-01-21 |
| JP2910426B2 true JP2910426B2 (en) | 1999-06-23 |
Family
ID=16251862
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4190070A Expired - Lifetime JP2910426B2 (en) | 1992-06-24 | 1992-06-24 | Manufacturing method of tungsten powder sintered body for impregnated cathode |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2910426B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5176275B2 (en) * | 2006-01-18 | 2013-04-03 | パナソニック株式会社 | Cathode material for flash discharge tube and flash discharge tube provided with the cathode material |
-
1992
- 1992-06-24 JP JP4190070A patent/JP2910426B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0612978A (en) | 1994-01-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3584253A (en) | Getter structure for electrical discharge and method of making the same | |
| JPS58154131A (en) | Impregnation type cathode | |
| JPH0558207B2 (en) | ||
| US4146497A (en) | Supported getter | |
| US5096450A (en) | Method for fabricating an impregnated type cathode | |
| JP2910426B2 (en) | Manufacturing method of tungsten powder sintered body for impregnated cathode | |
| US2945150A (en) | Thermionic cathodes and methods of making | |
| EP0390269B1 (en) | Scandate cathode | |
| US5306189A (en) | Cathode impregnated by an electron emissive substance comprising (PBAO.QCAO).NBAA1204, where P>1, Q>0, N>1 | |
| US4117367A (en) | High-pressure discharge lamp | |
| US5294399A (en) | Preparation of cathode structures for impregnated cathodes | |
| US4310781A (en) | Controllable hydrogen source with gettering effect for electronic tubes | |
| US4900285A (en) | Method of manufacturing a dispenser cathode; dispenser cathode manufactured according to the method, and device incorporating such a cathode | |
| US3269804A (en) | Dispenser cathode and method for the production thereof | |
| KR950002566B1 (en) | Dispenser cathode and its manufacturing method | |
| US3688150A (en) | Degassing arrangement for electron beam tube including an mk dispenser cathode | |
| JP2710700B2 (en) | Method for producing impregnated cathode and cathode obtained by this method | |
| JP2001006521A (en) | Cathode body structure and color picture tube | |
| JPH01163941A (en) | Manufacture of scandium system cathode | |
| US2995674A (en) | Impregnated cathodes | |
| JP3271056B2 (en) | Tungsten electrode and method of manufacturing the same | |
| JPS59203343A (en) | Impregnated cathode | |
| US4246682A (en) | Method of making cathode support nickel strip | |
| JPS612226A (en) | Impregnated cathode | |
| JPH08241663A (en) | Thermoelectron emitting cathode and its manufacture |