JPH0777115B2 - Impregnated cathode - Google Patents
Impregnated cathodeInfo
- Publication number
- JPH0777115B2 JPH0777115B2 JP10584085A JP10584085A JPH0777115B2 JP H0777115 B2 JPH0777115 B2 JP H0777115B2 JP 10584085 A JP10584085 A JP 10584085A JP 10584085 A JP10584085 A JP 10584085A JP H0777115 B2 JPH0777115 B2 JP H0777115B2
- Authority
- JP
- Japan
- Prior art keywords
- cathode
- tungsten
- barium
- rhenium
- impregnated
- 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 - Fee Related
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
- H01J1/02—Main electrodes
- H01J1/13—Solid thermionic cathodes
- H01J1/20—Cathodes heated indirectly by an electric current; Cathodes heated by electron or ion bombardment
- H01J1/28—Dispenser-type cathodes, e.g. L-cathode
Landscapes
- Solid Thermionic Cathode (AREA)
Description
【発明の詳細な説明】 〔発明の利用分野〕 本発明は、電子放出物質中のバリウムの電子管内への蒸
発を抑制し、しかも電子放出特性を劣化させないように
した含浸形陰極に関する。Description: FIELD OF THE INVENTION The present invention relates to an impregnated cathode that suppresses the evaporation of barium in an electron emitting material into an electron tube and does not deteriorate the electron emitting characteristics.
高電子流密度陰極として使用される含浸形陰極は、通
常、タングステン、モリブデンなどの高融点金属の多孔
質焼結基体にバリウム・カルシウム・アルミネートなど
の電子放出物質を含浸させたものである。しかし、この
種の含浸形陰極は、電子管に実装して動作中に、陰極の
表面から多量のバリウムが蒸発し、これが電子管内の陰
極周囲のグリッドなどの電極に付着して、いわゆるグリ
ッド・エミッションを引き起こすという問題があった。The impregnated cathode used as a high electron flow density cathode is usually a porous sintered substrate of a refractory metal such as tungsten or molybdenum impregnated with an electron emitting substance such as barium, calcium, aluminate. However, this type of impregnated cathode is mounted on an electron tube, and during operation, a large amount of barium evaporates from the surface of the cathode, which adheres to electrodes such as the grid around the cathode in the electron tube, resulting in so-called grid emission. There was a problem of causing.
このような現象の対策として、陰極表面に、基体より空
孔率の小さい層（特開昭56-52835号公報）、あるいはタ
ングステン層を形成させて、バリウムの蒸発を抑制する
ようにした含浸形陰極が提案されている。しかし、これ
らの陰極は、いずれもバリウムの蒸発を抑制できる反
面、同時に電子放出特性をも劣化させてしまうという問
題を持っていた。As a countermeasure against such a phenomenon, a layer having a lower porosity than that of the substrate (Japanese Patent Laid-Open No. 56-52835) or a tungsten layer is formed on the cathode surface so as to suppress the evaporation of barium. A cathode has been proposed. However, all of these cathodes have a problem that they can suppress the evaporation of barium, but at the same time, they also deteriorate the electron emission characteristics.
さらに、このような問題の対策として、陰極表面に、基
体とは別の多孔質タングステン層を設けた含浸形陰極が
提案されている（IEE Proc.,Vol.128,Pt.1,No.1,Februa
ry 1981）。しかし、このような構成の含浸形陰極を実
際に製作して実験してみると、表面の多孔質タングステ
ン層によってバリウムの蒸発を抑制することは出来る
が、実用上十分な電子放出特性が得られなかった。Furthermore, as a measure against such a problem, an impregnated cathode in which a porous tungsten layer different from the substrate is provided on the cathode surface has been proposed (IEE Proc., Vol.128, Pt.1, No.1). , Februa
ry 1981). However, when an impregnated cathode having such a structure was actually manufactured and tested, barium evaporation could be suppressed by the surface porous tungsten layer, but sufficient electron emission characteristics were obtained for practical use. There wasn't.
このように含浸形陰極の表面に多孔質タングステン層を
設けることによって、十分な電子放出特性が得られなく
なる理由については、必ずしも明瞭ではないが、一応次
ぎのように考えられる。すなわち、多孔質タングステン
層をバリウムや酸素が通過する際に、BaWO4が生成さ
れ、このBaWO4が電子放出を妨げる有害な作用をするも
のと考えられる。The reason why sufficient electron emission characteristics cannot be obtained by providing the porous tungsten layer on the surface of the impregnated cathode in this way is not necessarily clear, but is considered to be the following. That is, it is considered that BaWO 4 is generated when barium or oxygen passes through the porous tungsten layer, and this BaWO 4 has a harmful effect of hindering electron emission.
本発明の目的は、上記従来の含浸形陰極のような問題点
を解消した、すなわち、バリウムの蒸発を適度に抑制
し、かつ実用上十分な電子放出特性が得られる含浸形陰
極を提供することにある。An object of the present invention is to provide an impregnated cathode that solves the problems of the conventional impregnated cathode described above, that is, that the evaporation of barium is appropriately suppressed and that practically sufficient electron emission characteristics are obtained. It is in.
上記目的を達成するために本発明においては、含浸形陰
極の電子放出を行う側の表面に、タングステンとレニウ
ムの合金からなる被膜を付着させることとした。In order to achieve the above object, in the present invention, a film made of an alloy of tungsten and rhenium is attached to the surface of the impregnated cathode on the electron emission side.
この場合、タングステン・レニウム合金の被膜は、バリ
ウムの蒸発を抑制するのに十分な程度の、すなわち500
Å以上の厚さを有し、しかも、陰極表面へ、良好な電子
放出特性を維持するのに不足しない程度のバリウムを供
給できる、すなわち２μｍ以下の厚さであることが必要
である。また、タングステン・レニウム合金中のレニウ
ム含有量は、良好な電子放出特性を安定に維持するため
には、0.2〜10重量％であることが必要で、さらに望ま
しくは１〜５重量％が好適であることが実験により判明
した。このタングステン・レニウム合金被膜の上には、
さらにオスミウム膜を形成する。In this case, the tungsten-rhenium alloy coating is sufficient to suppress barium evaporation, i.e., 500
It is necessary that the barium has a thickness of Å or more and that barium can be supplied to the cathode surface in an amount sufficient for maintaining good electron emission characteristics, that is, a thickness of 2 μm or less. Further, the content of rhenium in the tungsten-rhenium alloy must be 0.2 to 10% by weight, and more preferably 1 to 5% by weight, in order to stably maintain good electron emission characteristics. It turned out by experiment. On this tungsten-rhenium alloy coating,
Further, an osmium film is formed.
第１図は本発明一実施例の模式的断面図である。１は電
子放出物質を含浸させた陰極基体すなわちペレットであ
って、このペレット１は空孔率20〜25％の多孔質タング
ステン焼結体２と空孔３とから形成されており、この空
孔３の中には、バリウム・カルシウム・アルミネートが
含浸されている。このペレット１はタンタル・カップ４
に装着され、さらにタンタル・カップ４はタンタル・ス
リーブ５の端部にレーザ熔接により固着されている。ま
た、ペレット１の上には約３重量％のレニウムを含む厚
さ約5000Å程度のタングステン・レニウム合金膜６と、
厚さ約5000Å程度のオスミウム膜７とが順次積層されて
付着されている。なお、オスミウム膜は、従来から含浸
形陰極の表面を被覆させると、仕事関数を低下させて電
子放出特性を向上させるものとして公知である。ペレッ
ト１は、タングステン芯線８をアルミナ被膜９で被覆し
て絶縁したヒータ10によって加熱される。FIG. 1 is a schematic sectional view of an embodiment of the present invention. Reference numeral 1 is a cathode substrate or pellet impregnated with an electron-emitting substance, and the pellet 1 is composed of a porous tungsten sintered body 2 and pores 3 having a porosity of 20 to 25%. 3 is impregnated with barium calcium aluminate. This pellet 1 is a tantalum cup 4
The tantalum cup 4 is fixed to the end of the tantalum sleeve 5 by laser welding. Further, on the pellet 1, a tungsten-rhenium alloy film 6 containing about 3% by weight of rhenium and having a thickness of about 5000 Å,
An osmium film 7 having a thickness of about 5000Å is sequentially laminated and attached. Incidentally, the osmium film is conventionally known to reduce the work function and improve the electron emission characteristics when the surface of the impregnated cathode is coated. The pellet 1 is heated by a heater 10 in which a tungsten core wire 8 is covered with an alumina coating 9 for insulation.
このような構造の含浸形陰極を陰、陽２極を有する電子
管に封入、実装して、陽極にパルス幅約５μｓの高圧パ
ルスを100Hzで繰り返し印加して飽和電流密度を測定し
た。その結果、本発明による含浸形陰極の電子放出特性
は、タングステン・レニウム合金膜を付着させなかった
標準含浸形陰極（ただしオスミウム膜付着）とほぼ同等
であった。また、これと並行して、陽極に高電圧パルス
を印加しない状態で、陽極に付着したバリウム量をオー
ジェ（Auger）電子分光分析法によって調べたところ、
本発明含浸形陰極からのバリウム蒸発量は、タングステ
ン・レニウム合金被膜を付着させてない従来の標準含浸
形陰極からのバリウム蒸発量の約1/3以下であった。さ
らに、比較のため、タングステン・レニウム合金膜の代
わりに、純タングステンの薄膜を付着させた含浸形陰極
について、上記と同一の条件で電子放出特性を測定した
結果、本発明による陰極に比べて、約1/2となり、更に
其の電子放出特性が短時間で減衰、低下する傾向が見ら
れた。The impregnated cathode having such a structure was sealed and mounted in an electron tube having a negative and a positive two poles, and a high voltage pulse having a pulse width of about 5 μs was repeatedly applied to the anode at 100 Hz to measure the saturation current density. As a result, the electron emission characteristics of the impregnated type cathode according to the present invention were almost the same as those of the standard impregnated type cathode in which the tungsten / rhenium alloy film was not deposited (however, the osmium film was deposited). In parallel with this, when the high voltage pulse was not applied to the anode, the amount of barium adhering to the anode was examined by Auger electron spectroscopy.
The amount of barium evaporated from the impregnated cathode of the present invention was about 1/3 or less of the amount of barium evaporated from the conventional standard impregnated cathode having no tungsten-rhenium alloy coating deposited thereon. Further, for comparison, instead of the tungsten-rhenium alloy film, for the impregnated cathode having a thin film of pure tungsten attached, the result of measuring the electron emission characteristics under the same conditions as above, as compared with the cathode according to the present invention, It was about 1/2, and there was a tendency that the electron emission characteristics were attenuated and deteriorated in a short time.
以上説明したように本発明によれば、純タングステン薄
膜などを付着させた場合に比較してバリウムの蒸発を抑
制する効果は劣らず、しかも電子放出特性はバリウム蒸
発抑制用の膜を付着させてない標準陰極とほぼ同等の電
子放出特性が得られた。As described above, according to the present invention, the effect of suppressing the evaporation of barium is not inferior as compared with the case where a pure tungsten thin film or the like is adhered, and the electron emission characteristic is that the film for suppressing barium evaporation is adhered. The electron emission characteristics almost equal to those of the standard cathode were obtained.
第１図は本発明一実施例の模式的断面図である。 １……ペレット、２……多孔質タングステン焼結体、３
……空孔、４……タンタル・カップ、５……タンタル・
スリーブ、６……本発明に係るタングステン・レニウム
合金膜、７……オスミウム膜、10……ヒータ。FIG. 1 is a schematic sectional view of an embodiment of the present invention. 1 ... Pellet, 2 ... Porous tungsten sintered body, 3
... holes, 4 tantalum cups, 5 tantalum
Sleeve, 6 ... Tungsten-rhenium alloy film according to the present invention, 7 ... Osmium film, 10 ... Heater.
Claims (1)
質を含浸させた含浸形陰極において、陰極の電子放出す
る側の表面に、タングステンとレニウムの合金の被膜を
付着させ、前記タングステン・レニウム合金中のレニウ
ム含有量を１〜５重量％とし、かつ前記表面に付着させ
たタングステン・レニウム合金被膜の厚さを0.05〜２μ
ｍとし、さらに前記タングステン・レニウム合金被膜の
上に約0.5μ厚のオスミウム膜を形成したことを特徴と
する含浸形陰極。1. An impregnated cathode obtained by impregnating a porous sintered substrate of a refractory metal with an electron-emitting substance, wherein a film of an alloy of tungsten and rhenium is adhered to the surface of the cathode on the electron-emitting side.・ The rhenium content in the rhenium alloy is 1 to 5% by weight, and the thickness of the tungsten-rhenium alloy coating deposited on the surface is 0.05 to 2 µ.
and an osmium film having a thickness of about 0.5 μm is formed on the tungsten-rhenium alloy film.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10584085A JPH0777115B2 (en) | 1985-05-20 | 1985-05-20 | Impregnated cathode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10584085A JPH0777115B2 (en) | 1985-05-20 | 1985-05-20 | Impregnated cathode |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61264625A JPS61264625A (en) | 1986-11-22 |
| JPH0777115B2 true JPH0777115B2 (en) | 1995-08-16 |
Family
ID=14418217
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10584085A Expired - Fee Related JPH0777115B2 (en) | 1985-05-20 | 1985-05-20 | Impregnated cathode |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0777115B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102637566B (en) * | 2012-03-30 | 2014-11-19 | 安徽华东光电技术研究所 | Barium-tungsten cathode with high current density and preparation method thereof |
| CN113936981B (en) * | 2021-09-29 | 2023-06-23 | 北京工业大学 | Preparation method of an impregnated tungsten-rhenium-osmium ternary mixed matrix diffusion cathode |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6068527A (en) * | 1983-09-26 | 1985-04-19 | Toshiba Corp | Impregnated cathode |
-
1985
- 1985-05-20 JP JP10584085A patent/JPH0777115B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61264625A (en) | 1986-11-22 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |