JPH0556604B2 - - Google Patents
Info
- Publication number
- JPH0556604B2 JPH0556604B2 JP20810484A JP20810484A JPH0556604B2 JP H0556604 B2 JPH0556604 B2 JP H0556604B2 JP 20810484 A JP20810484 A JP 20810484A JP 20810484 A JP20810484 A JP 20810484A JP H0556604 B2 JPH0556604 B2 JP H0556604B2
- Authority
- JP
- Japan
- Prior art keywords
- cathode
- alumina
- impregnated
- tungsten
- coating
- 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
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 14
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 13
- 229910052721 tungsten Inorganic materials 0.000 claims description 13
- 239000010937 tungsten Substances 0.000 claims description 13
- 239000011248 coating agent Substances 0.000 claims description 9
- 238000000576 coating method Methods 0.000 claims description 9
- 230000008018 melting Effects 0.000 claims description 5
- 238000002844 melting Methods 0.000 claims description 5
- 229910052751 metal Inorganic materials 0.000 claims description 5
- 239000002184 metal Substances 0.000 claims description 5
- 239000000758 substrate Substances 0.000 claims description 4
- 239000000956 alloy Substances 0.000 claims description 3
- 229910045601 alloy Inorganic materials 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 2
- 230000008020 evaporation Effects 0.000 description 7
- 238000001704 evaporation Methods 0.000 description 7
- 239000010408 film Substances 0.000 description 6
- 239000008188 pellet Substances 0.000 description 6
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 239000010406 cathode material Substances 0.000 description 3
- 150000004645 aluminates Chemical class 0.000 description 2
- 229910052788 barium Inorganic materials 0.000 description 2
- 101150038956 cup-4 gene Proteins 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000002542 deteriorative effect Effects 0.000 description 2
- 229910052762 osmium Inorganic materials 0.000 description 2
- SYQBFIAQOQZEGI-UHFFFAOYSA-N osmium atom Chemical compound [Os] SYQBFIAQOQZEGI-UHFFFAOYSA-N 0.000 description 2
- 229910052715 tantalum Inorganic materials 0.000 description 2
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012528 membrane Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000000682 scanning probe acoustic microscopy Methods 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
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
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明は高電流密度カソードとして用いられる
含浸形カソードに係わり、特にカソード表面にタ
ングステンとアルミナの混合物からなる層を付着
させ電子放出特性を向上させた含浸形カソードに
関するものである。[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an impregnated cathode used as a high current density cathode, and in particular, a layer made of a mixture of tungsten and alumina is deposited on the surface of the cathode to improve electron emission characteristics. The present invention relates to an impregnated cathode.
高電流密度カソードとして使用される含浸形カ
ソードは、タングステン（Ｗ）、モリブデン
（Mo）等の高融点金属の多孔質基体にBa−Caア
ルミネート等の電子放出物質を含浸させて構成さ
れる。
An impregnated cathode used as a high current density cathode is constructed by impregnating a porous substrate of a high melting point metal such as tungsten (W) or molybdenum (Mo) with an electron emitting substance such as Ba-Ca aluminate.
しかしながら、この種の含浸形カソードは、動
作中にカソード表面から多量のバリウム（Ba）
が蒸発し、これが周囲の電極に付着していわゆる
グリツドエミツシヨンを引起すという問題があつ
た。 However, this type of impregnated cathode releases a large amount of barium (Ba) from the cathode surface during operation.
There was a problem in that the evaporated evaporated and this evaporated onto the surrounding electrodes, causing so-called grid emission.
このような問題を改善したものとしては、カソ
ードの表面に空孔率の小さい層（特開昭56−
52835号公報）あるいはＷ層を形成してBaの蒸発
を抑制したカソードが提案されている。 To improve this problem, a layer with low porosity (Japanese Unexamined Patent Application Publication No. 1983-1999) is added to the surface of the cathode.
52835) or a cathode in which a W layer is formed to suppress Ba evaporation has been proposed.
しかしながら、これらのカソードは、いずれも
Baの蒸発を抑制できる反面、同時にエミツシヨ
ン特性も劣化させてしまうという問題があつた。 However, both of these cathodes
Although Ba evaporation can be suppressed, there is a problem in that the emission characteristics are also deteriorated at the same time.
さらにこのような問題を改善したものとして
は、カソード表面に多孔質のＷを設けた含浸形カ
ソードが提案されている（IEE PROC.、
Vol.128、Pt.I、No.1、FEBRUARY1981.）。 In order to further improve this problem, an impregnated cathode in which porous W is provided on the surface of the cathode has been proposed (IEE PROC.
Vol.128, Pt.I, No.1, FEBRUARY1981.)
しかしながら、このような構成による含浸形カ
ソードを実際に製作して実験してみると、表面の
多孔質ＷによつてBaの蒸発を抑制することがで
きるが、実用上十分なエミツシヨン特性が得られ
なかつた。 However, when an impregnated cathode with such a configuration was actually fabricated and tested, it was found that although Ba evaporation can be suppressed by the porous W on the surface, emission characteristics sufficient for practical use cannot be obtained. Nakatsuta.
このようにカソードの表面に多孔質Ｗを設ける
ことによつて、十分なエミツシンヨン特性が得ら
れないメカニズムについては必ずしも明瞭ではな
いが、一応次のように考えられる。すなわち、多
孔質Ｗの内部をBa、Ｏが通過すると、有害な
BaWO4が生成し、このBaWO4はエミツシヨンを
防げる作用をする。また、Ｗの結晶粒が時間の経
過とともに大きくなつて通路が少なくなるものと
考えられる。 The mechanism by which sufficient emission characteristics cannot be obtained by providing the porous W on the surface of the cathode is not necessarily clear, but it is thought to be as follows. In other words, when Ba and O pass through the porous W, harmful
BaWO 4 is generated, and this BaWO 4 acts to prevent emission. It is also believed that the W crystal grains become larger over time and the number of passages decreases.
したがつて本発明は、前述した従来の問題に鑑
みてなされたものであり、その目的とするところ
は、Baの蒸発を適度に抑制しかつ実用上十分な
エミツシヨン特性が得られる含浸形カソードを提
供することにある。
Therefore, the present invention was made in view of the above-mentioned conventional problems, and its purpose is to provide an impregnated cathode that can moderately suppress Ba evaporation and provide practically sufficient emission characteristics. It is about providing.
このような目的を達成するために本発明は、カ
ソードの表面に、
(a) タングステンもしくはタングステンを主体と
する高融点金属からなる合金と、
(b) アルミナもしくはアルミナを主体とする酸化
物、
との混合からなる被膜を付着させたものである。
In order to achieve such an object, the present invention provides the following features on the surface of the cathode: (a) tungsten or an alloy consisting of a high melting point metal mainly composed of tungsten; (b) alumina or an oxide mainly composed of alumina; A coating consisting of a mixture of these is attached.
すなわち、カソード材料の表面に、アルミナを
重量比で0.1％以上20％以下の範囲で含んだ厚さ
500Å〜2μｍの範囲のダンクステン・アルミナ混
合物からなる被膜を付着させたものである。 In other words, the surface of the cathode material has a thickness that contains alumina in a range of 0.1% to 20% by weight.
A coating of danxten-alumina mixture ranging from 500 Å to 2 μm was deposited.
このような構成によれば、Baの蒸発の抑制に
伴ない、エミツシヨン特性が劣化すのを阻止する
ことができる。この場合、タングステン・アルミ
ナ混合物被膜の厚さは、Ba蒸発を抑制するのに
十分なほど厚く（500Å以上）、かつカソード表面
へのBa供給が不足にならないほど厚くはない
（2μｍ以下）ことが必要である。また、アルミナ
の含有量は良好なエミツシヨン特性を得るのに十
分な量（0.1重量％以上）であり、かつ導電性を
失なわないほど多くはない（20重量％以下）こと
が必要である。 According to such a configuration, it is possible to prevent the emission characteristics from deteriorating due to the suppression of Ba evaporation. In this case, the thickness of the tungsten-alumina mixture coating should be thick enough (500 Å or more) to suppress Ba evaporation, but not so thick (2 μm or less) that Ba supply to the cathode surface is insufficient. is necessary. Further, the content of alumina needs to be sufficient (0.1% by weight or more) to obtain good emission characteristics, but not so large as to cause loss of conductivity (20% by weight or less).
次に図面を用いて本発明の実施例を詳細に説明
する。
Next, embodiments of the present invention will be described in detail using the drawings.
図は本発明による含浸形カソードの一例を模式
的に示した断面図である。同図において、１はカ
ソード材料としてのペレツトであり、このペレツ
ト１は空孔率20〜25％の多孔質Ｗ基体２と空孔３
とから形成されており、この空孔３中にはBa−
Caアルミネートが含浸されている。そして、こ
のペレツト１はタンタル（Ta）カツプ４に装着
され、さらにこのTaカツプ４はTaスリーブ５に
レーザ溶接して固定配置されている。また、カソ
ードペレツト１上には、約４重量％のAl2O3を含
む厚さ約5000Å程度のスパツタリングＷ−Al2O3
膜６と、厚さ約5000Å程度のオスミウム（Os）
膜７とが順次積層されて付着されている。そし
て、ペレツトの加熱はタングステン（Ｗ）芯線８
をアルミナ被膜９で被覆したヒータ１０を用いて
行なう。 The figure is a sectional view schematically showing an example of an impregnated cathode according to the present invention. In the figure, 1 is a pellet as a cathode material, and this pellet 1 has a porous W substrate 2 with a porosity of 20 to 25% and pores 3.
Ba− is formed in this hole 3.
Impregnated with Ca aluminate. The pellet 1 is attached to a tantalum (Ta) cup 4, and the Ta cup 4 is laser welded to a Ta sleeve 5 and fixed thereto. Further, on the cathode pellet 1, there is sputtered W-Al 2 O 3 with a thickness of about 5000 Å containing about 4% by weight of Al 2 O 3 .
Membrane 6 and osmium (Os) with a thickness of about 5000 Å
The films 7 are deposited in a sequentially laminated manner. The pellets are heated using a tungsten (W) core wire 8.
This is carried out using a heater 10 coated with an alumina film 9.
このように構成されるカソードを用いてカソー
ド・アノード２極管方式で、アノードに幅約5μs
の繰り返し100Hzの高圧パルスを印加して飽和電
流密度を測定した。その結果、本発明によるカソ
ードのエミツシヨン特性は、Ｗ−Al2O3膜６を付
着させなかつた標準カソードのエミツシヨン特性
とほぼ同等であつた。また、これと並行してアノ
ードに高電圧パルスを印加しない状態でアノード
に付着するBa量をオージエ電子分光分析法によ
つて調べたところ、前者からのBa蒸発量は後者
からのそれの約1/3以下であつた。さらに比較と
してＷ−Al2O3膜６の代りにＷのみの薄膜を付着
させたカソードについて前述と同一条件でエミツ
シヨン特性を測定した結果、本発明のものに比べ
て約1/2となり、さらにそれが短時間で低下する
傾向が見られた。 Using a cathode configured in this way, a cathode-anode diode system is used, and a width of about 5 μs is applied to the anode.
The saturation current density was measured by repeatedly applying high voltage pulses of 100 Hz. As a result, the emission characteristics of the cathode according to the present invention were almost the same as those of a standard cathode to which the W--Al 2 O 3 film 6 was not attached. In addition, in parallel with this, the amount of Ba adhering to the anode was investigated using Auger electron spectroscopy without applying a high voltage pulse to the anode, and the amount of Ba evaporated from the former was approximately 1 of that from the latter. It was less than /3. Furthermore, as a comparison, the emission characteristics of a cathode with a thin film of only W attached instead of the W-Al 2 O 3 film 6 were measured under the same conditions as described above, and the emission characteristics were approximately 1/2 that of those of the present invention. There was a tendency for it to decrease in a short period of time.
以上説明したように本発明による含浸形カソー
ドは、カソード材料の表面に、
(a) タングステンもしくはタングステンを主体と
する高融点金属からなる合金と、
(b) アルミナもしくはアルミナを主体とする酸化
物、
との混合からなる被膜を付着させたことによつ
て、タングステンのみの被膜を付着させた場合に
比較してエミツシヨン特性を劣化させることな
く、Baの蒸発を抑制することができるという極
めて優れた効果が見られる。
As explained above, the impregnated cathode according to the present invention includes, on the surface of the cathode material, (a) tungsten or an alloy consisting of a high melting point metal mainly composed of tungsten, (b) alumina or an oxide mainly composed of alumina, By depositing a coating consisting of a mixture of tungsten and tungsten, the evaporation of Ba can be suppressed without deteriorating the emission characteristics, compared to the case where a coating consisting only of tungsten is deposited. can be seen.
図は本発明による含浸形カソードの一例を模式
的に示した断面図である。
１……ペレツト、２……多孔質Ｗ基体、３……
空孔、４……タンタル（Ta）カツプ、５……Ta
スリーブ、６……Ｗ−Al2O3膜、７……オスミウ
ム（Os）膜、８……タングステン（Ｗ）芯線、
９……アルミナ被膜、１０……ヒータ。
The figure is a sectional view schematically showing an example of an impregnated cathode according to the present invention. 1... Pellet, 2... Porous W substrate, 3...
Vacancy, 4...Tantalum (Ta) cup, 5...Ta
Sleeve, 6...W-Al 2 O 3 film, 7... Osmium (Os) film, 8... Tungsten (W) core wire,
9...Alumina coating, 10...Heater.
Claims (1)
浸させた含浸形カソードにおいて、カソード材料
の表面に、 (a) タングステンもしくはタングステンを主体と
する高融点金属からなる合金と、 (b) アルミナもしくはアルミナを主体とする酸化
物、 との混合物からなる被膜を付着させたことを特徴
とする含浸形カソード。 ２ 前記被膜のアルミナ含有量を0.1〜20wt％の
範囲としたことを特徴とする特許請求の範囲第１
項記載の含浸形おソード。 ３ 前記被膜の厚さを0.05〜2μｍの範囲としたこ
とを特徴とする特許請求の範囲第１項記載の含浸
形カソード。[Claims] 1. In an impregnated cathode in which a porous substrate made of a high melting point metal is impregnated with an electron emitting substance, (a) tungsten or an alloy consisting of a high melting point metal mainly composed of tungsten and , (b) an impregnated cathode characterized in that a coating consisting of alumina or an oxide mainly composed of alumina is attached. 2. Claim 1, characterized in that the alumina content of the coating is in the range of 0.1 to 20 wt%.
Impregnated sword as described in section. 3. The impregnated cathode according to claim 1, wherein the thickness of the coating is in the range of 0.05 to 2 μm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59208104A JPS6188421A (en) | 1984-10-05 | 1984-10-05 | Impregnated cathode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59208104A JPS6188421A (en) | 1984-10-05 | 1984-10-05 | Impregnated cathode |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6188421A JPS6188421A (en) | 1986-05-06 |
| JPH0556604B2 true JPH0556604B2 (en) | 1993-08-20 |
Family
ID=16550699
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59208104A Granted JPS6188421A (en) | 1984-10-05 | 1984-10-05 | Impregnated cathode |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6188421A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63236239A (en) * | 1987-03-10 | 1988-10-03 | シーメンス、アクチエンゲゼルシヤフト | Dispenser cathode for discharge tube and making thereof |
-
1984
- 1984-10-05 JP JP59208104A patent/JPS6188421A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6188421A (en) | 1986-05-06 |
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