JPS62287544A - Manufacture of impregnated cathode - Google Patents
Manufacture of impregnated cathodeInfo
- Publication number
- JPS62287544A JPS62287544A JP13022486A JP13022486A JPS62287544A JP S62287544 A JPS62287544 A JP S62287544A JP 13022486 A JP13022486 A JP 13022486A JP 13022486 A JP13022486 A JP 13022486A JP S62287544 A JPS62287544 A JP S62287544A
- Authority
- JP
- Japan
- Prior art keywords
- iridium
- phase
- porous substrate
- layer
- tungsten
- 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
- 238000004519 manufacturing process Methods 0.000 title claims description 8
- 238000010438 heat treatment Methods 0.000 claims abstract description 34
- 239000000758 substrate Substances 0.000 claims abstract description 27
- 229910001080 W alloy Inorganic materials 0.000 claims abstract description 11
- 229910000287 alkaline earth metal oxide Inorganic materials 0.000 claims abstract description 4
- GKOZUEZYRPOHIO-UHFFFAOYSA-N iridium atom Chemical compound [Ir] GKOZUEZYRPOHIO-UHFFFAOYSA-N 0.000 claims description 40
- 229910052741 iridium Inorganic materials 0.000 claims description 38
- 229910045601 alloy Inorganic materials 0.000 claims description 26
- 239000000956 alloy Substances 0.000 claims description 26
- 238000000034 method Methods 0.000 claims description 24
- 229910052721 tungsten Inorganic materials 0.000 claims description 18
- 239000010937 tungsten Substances 0.000 claims description 17
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 16
- 150000002736 metal compounds Chemical class 0.000 claims description 3
- 229910000575 Ir alloy Inorganic materials 0.000 claims description 2
- 239000010410 layer Substances 0.000 abstract description 35
- 239000002344 surface layer Substances 0.000 abstract description 3
- 230000000977 initiatory effect Effects 0.000 abstract 2
- 230000032683 aging Effects 0.000 description 13
- 239000011247 coating layer Substances 0.000 description 13
- IGUHATROZYFXKR-UHFFFAOYSA-N [W].[Ir] Chemical compound [W].[Ir] IGUHATROZYFXKR-UHFFFAOYSA-N 0.000 description 9
- 239000013078 crystal Substances 0.000 description 8
- 238000002441 X-ray diffraction Methods 0.000 description 7
- 238000005275 alloying Methods 0.000 description 5
- 239000011521 glass Substances 0.000 description 5
- 239000002345 surface coating layer Substances 0.000 description 5
- 230000007774 longterm Effects 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- QVQLCTNNEUAWMS-UHFFFAOYSA-N barium oxide Chemical compound [Ba]=O QVQLCTNNEUAWMS-UHFFFAOYSA-N 0.000 description 3
- 238000004544 sputter deposition Methods 0.000 description 3
- 229910052715 tantalum Inorganic materials 0.000 description 3
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 3
- -1 argon ions Chemical class 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 206010017740 Gas poisoning Diseases 0.000 description 1
- 229910001182 Mo alloy Inorganic materials 0.000 description 1
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- RZJQYRCNDBMIAG-UHFFFAOYSA-N [Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Zn].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn] Chemical class [Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Cu].[Zn].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Ag].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn].[Sn] RZJQYRCNDBMIAG-UHFFFAOYSA-N 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 230000003679 aging effect Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- XKRFYHLGVUSROY-UHFFFAOYSA-N argon Substances [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- 239000010953 base metal Substances 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
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 238000000151 deposition Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 238000001483 high-temperature X-ray diffraction Methods 0.000 description 1
- 238000011065 in-situ storage Methods 0.000 description 1
- 229910000765 intermetallic Inorganic materials 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910052762 osmium Inorganic materials 0.000 description 1
- SYQBFIAQOQZEGI-UHFFFAOYSA-N osmium atom Chemical compound [Os] SYQBFIAQOQZEGI-UHFFFAOYSA-N 0.000 description 1
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical group [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 1
- 229910052702 rhenium Inorganic materials 0.000 description 1
- WUAPFZMCVAUBPE-UHFFFAOYSA-N rhenium atom Chemical compound [Re] WUAPFZMCVAUBPE-UHFFFAOYSA-N 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Abstract
Description
【発明の詳細な説明】
３、発明の詳細な説明
［発明の目的コ
（産業上の利用分野）
この発明は、電子管等に使用する含浸形陰極の製造方法
に係わり、とくにその電子放出表面に安定な結晶構造を
もつ合金層を形成する製造方法に関する。[Detailed Description of the Invention] 3. Detailed Description of the Invention [Purpose of the Invention (Industrial Application Field) This invention relates to a method of manufacturing an impregnated cathode used in an electron tube, etc. The present invention relates to a manufacturing method for forming an alloy layer having a stable crystal structure.
（従来の技術）
含浸形陰極構体は、周知のようにタングステン（Ｗ＞の
ような高融点金属の粉末を焼結してつくった多孔質基体
の空孔部に、酸化バリウム（ＢａＯ）、Ｍ化物ルシウム
（Ｃａｂ） 、および酸化アルミニウム （１２０３＞
のようなアルカリ土類金属酸化物からなる電子放射物質
を溶融含浸させたものである。この陰極は、酸化物陰極
に比べ動作温度が高いが、高電流密度が得られ、またガ
ス被毒に強いという特質を有する。このため、例えば衛
星搭載用進行波管や、核融合プラズマ加熱用の大電力ク
ライストロンなどに実用されている。(Prior Art) As is well known, the impregnated cathode structure is made by adding barium oxide (BaO), M compound lucium (Cab), and aluminum oxide (1203>
It is melted and impregnated with an electron-emitting material made of an alkaline earth metal oxide such as This cathode has a higher operating temperature than an oxide cathode, but has the characteristics of being able to obtain a high current density and being resistant to gas poisoning. For this reason, it is put into practical use, for example, in traveling wave tubes mounted on satellites and high-power klystrons for heating fusion plasma.
このような分野では、さらに長寿命、安定動作などの高
信頼性および高電′？＃、密度が要求されている。In such fields, high reliability such as long life, stable operation, and high voltage are required. #, density is required.
信頼性を高める１つの方策として、陰極表面にイリジウ
ム（Ｉｒ）、オスミウム（Ｏ５）、ルテニウム（Ｒｕ）
のような白金族金属、あるいはその合金からなる被覆層
を設（プで陰極表面部の仕事関数を下げ、動作温度の低
減を図ることが知られている。このような被１ｆｆｌを
設けることにより、被覆層がない場合と同じ電流密度を
得るのに、数十℃乃至百数十℃も動作温度を下げること
ができる。One measure to increase reliability is to add iridium (Ir), osmium (O5), and ruthenium (Ru) to the cathode surface.
It is known to lower the work function of the cathode surface by providing a coating layer made of a platinum group metal or its alloy, such as 1ffl, to lower the operating temperature. , the operating temperature can be lowered by tens of degrees Celsius to hundreds of degrees Celsius while obtaining the same current density as without the coating layer.
〈発明が解決しようとする問題点）
しかしながら、このような含浸形陰極構体は表面部に被
覆層がない場合に比べて動作温度を低下させることがで
きるとはいえ、その動作温度がおよそ９００〜１０００
℃であり、やはり動作に伴って多孔質基体を形成するＷ
が表面被覆層中に拡散して表面被覆層金属とＷとの合金
層を徐々に生成することが避けられない。この表面被覆
層の合金化進行過程は、それに伴って電子放射特性を変
化させ、早期の安定動作、長寿命特性など信頼性向上へ
の１つの隘路となっている。そして従来から行なわれて
いる多孔質基体の表面部に前記金属と基体金属であるタ
ングステンとの合金層を被覆することは有効であるが、
しかし動作初期から結晶構造が変化せず電子放射特性の
安定な合金層を得ることは実際問題として困難であった
。(Problems to be Solved by the Invention) However, although such an impregnated cathode structure can lower the operating temperature compared to a case where there is no coating layer on the surface, the operating temperature is approximately 900 - 900℃. 1000
℃, and W also forms a porous substrate with operation.
It is inevitable that the metal diffuses into the surface coating layer and gradually forms an alloy layer of the surface coating layer metal and W. This process of alloying of the surface coating layer changes the electron emission characteristics accordingly, and is one of the bottlenecks in improving reliability such as early stable operation and long life characteristics. Although it is effective to coat the surface of a porous substrate with an alloy layer of the metal and tungsten as the base metal, which has been conventionally done,
However, it has been difficult in practice to obtain an alloy layer whose crystal structure does not change from the initial stage of operation and whose electron emission characteristics are stable.
この発明は、以上の事情に鑑みてなされたもので、動作
初期から安定な電子放射特性を有する表面合金層を再現
性よく、容易に（ｑることができる含浸形陰極の製造方
法を提供することを目的とする。The present invention has been made in view of the above circumstances, and provides a method for manufacturing an impregnated cathode that can easily and reproducibly form a surface alloy layer that has stable electron emission characteristics from the initial stage of operation. The purpose is to
［発明の構成］
（問題を解決するための手段）
この発明は、内部にアルカリ土類金属酸化物を含浸した
多孔質基体の表面に、イリジウム、またはイリジウムお
よびタングステン合金の層を被着し、その後この多孔質
基体を真空中または不活性雰囲気中おいて、表面部にイ
リジウムおよびタングステンの金属化合物のεＩＩ相か
らなる合金層を生成するように約１１００″Ｃ乃至１２
６０℃の範囲の温度で所定時間加熱処理する含浸形陰極
の製造方法である。[Structure of the Invention] (Means for Solving the Problem) The present invention provides a method of depositing a layer of iridium or an iridium and tungsten alloy on the surface of a porous substrate whose interior is impregnated with an alkaline earth metal oxide, Thereafter, this porous substrate is placed in a vacuum or an inert atmosphere to form an alloy layer consisting of an εII phase of a metal compound of iridium and tungsten on the surface at a temperature of about 1,100″C to 12°C.
This is a method for manufacturing an impregnated cathode in which heat treatment is performed at a temperature in the range of 60° C. for a predetermined period of time.
（作用）
この発明によれば、多孔質基体の表面部に生成されたイ
リジウム−タングステン合金層は、その結晶構造が動作
初期からきわめて安定なものが得られる。したがって、
表面被覆層のイリジウムおよびタングステン濃度組成が
ほぼ一定化しており、それにより仕事関数が比較的低い
値で一定に保たれる。こうしてこの発明によれば動作初
期から長期間にわたってきわめて安定な電子放射特性を
もつ含浸形陰惨を再現性よく得ることができる。(Function) According to the present invention, the iridium-tungsten alloy layer formed on the surface of the porous substrate has an extremely stable crystal structure from the initial stage of operation. therefore,
The iridium and tungsten concentration composition of the surface coating layer is approximately constant, thereby keeping the work function constant at a relatively low value. Thus, according to the present invention, it is possible to obtain an impregnated gruesome shape with extremely stable electron emission characteristics over a long period of time from the initial stage of operation with good reproducibility.
（実施例）
以下図面を参照してその実施例を説明する。なお同一部
分は同一符号であられす。(Example) An example will be described below with reference to the drawings. Identical parts are designated by the same reference numerals.
この発明により得る含浸形陰極構体の構造例を第１図に
示す。直径１．’５ｍ、厚さ０．４．、の空孔率的２０
％の多孔質タングステンに、酸化バリウム、酸化カルシ
ウム及び酸化アルミニウムの混合酸化物（モル比で約４
：１：１＞を溶融含浸させ、その後表面を洗浄し、過剰
な３ａを除去した後、多孔質基体１１を作製した。次い
で、この多孔質基体１１は厚さ２５μｍのタンタル製の
カップ１２に、しニウムｔ７Ｑ１３を介して抵抗溶接さ
れた。次いで、タンタル製カップ１２は、タンタル製の
支持スリーブ１４の一端開口部の内側にレーザ溶接され
た。なお、支持スリーブ１４は、図示しないレニウム−
モリブデン合金からなる３本の支持用ストラップを介し
て外側支持円筒に固定された。このようにして製作され
た陰極構体の多孔質基体１１の表面に、スパッタリング
により５０人乃至１０，０００人の範囲の厚さ、例えば
３，５００人の厚さにイリジウムを被覆した。An example of the structure of an impregnated cathode structure obtained according to the present invention is shown in FIG. Diameter 1. '5m, thickness 0.4. , the porosity of 20
% of porous tungsten, mixed oxide of barium oxide, calcium oxide and aluminum oxide (about 4% in molar ratio)
:1:1> was melted and impregnated, and then the surface was washed to remove excess 3a, and then the porous substrate 11 was prepared. Next, this porous substrate 11 was resistance welded to a tantalum cup 12 having a thickness of 25 μm via t7Q13. The tantalum cup 12 was then laser welded inside the opening at one end of the tantalum support sleeve 14. Note that the support sleeve 14 is made of rhenium (not shown).
It was fixed to the outer support cylinder via three support straps made of molybdenum alloy. The surface of the porous substrate 11 of the cathode structure thus produced was coated with iridium by sputtering to a thickness ranging from 50 to 10,000, for example, 3,500.
次にこの陰極構体を、真空又は不活性雰囲気、例えば１
Ｏ−７Ｔｏｒｒ以下に排気された真空排気ペルジャー内
に入れ、図示しない陰極構体内部の加熱ヒータに通電し
て所定ｇ度で所定時間加熱処理した。This cathode structure is then placed in a vacuum or an inert atmosphere, e.g.
The sample was placed in an evacuated Pelger that was evacuated to 0-7 Torr or less, and a heater (not shown) inside the cathode structure was energized to heat it at a predetermined g degree for a predetermined time.
この加熱処理工程の例を第２図に示す。すなわち、脱ガ
スを主目的として徐々に陰極温度を上昇させるライティ
ンク工程（■、■、■、ＩＶ、Ｖ、ＶＩ）、および輝度
温度が約１１８０℃で所定時間等温加熱するエージング
工程（■、■、■）を経る。なお温度は、陰極表面を６
５０ｎｍでフィルタされた輝度温度で示されている。An example of this heat treatment step is shown in FIG. Specifically, there is a lighting process (■, ■, ■, IV, V, VI) in which the cathode temperature is gradually increased with the main purpose of degassing, and an aging process (■, , ■). Note that the temperature is 6
Brightness temperature is shown filtered at 50 nm.
こうして、電子放出表面部に格子定数ａの範囲が、２．
７６人乃至２８７８人、格子定数Ｃの範囲が４．４４人
乃至４．４６人のｈｃｐ構造を示すε相を主体とする結
晶構造をもつイリジウム−タングステンの表面合金層１
５を形成した。そしてこのような含浸形陰極構体を、例
えば衛星搭載用の進行波管内に組込み、動作させた。In this way, the range of the lattice constant a in the electron emitting surface region is 2.
Surface alloy layer 1 of iridium-tungsten having a crystal structure mainly composed of ε phase showing an hcp structure with a lattice constant C ranging from 76 to 2878 people and a range of 4.44 to 4.46 people.
5 was formed. Then, such an impregnated cathode structure was installed, for example, in a traveling wave tube for use in a satellite, and was operated.
このような含浸形陰極構体は、動作初期から長時間の動
作において安定度のきわめてすぐれた電子放飼特性を示
した。以下、その理由を説明する。Such an impregnated cathode structure exhibited extremely stable electron emission characteristics from the initial stage of operation to long-term operation. The reason for this will be explained below.
まず、表面部の合金化プロセスを解明するために真空高
温Ｘ線回折装置を用い、前記の約３，５００人の厚さに
イリジウムを被覆した陰極構体の、多孔質基体表面層の
結晶構造変化をその場観察的にＸ線回折により測定した
。第２図に示した陰極加熱スケジュールに沿い、Ｘ線回
折パターンの変化をみると第３図に示すように変化する
ことが確認された。なお第３図の右の縦軸に加熱工程を
示した。First, in order to elucidate the alloying process on the surface, we used a vacuum high-temperature X-ray diffraction device to investigate changes in the crystal structure of the surface layer of the porous substrate of the cathode structure coated with iridium to a thickness of approximately 3,500 mm. was measured in situ by X-ray diffraction. According to the cathode heating schedule shown in FIG. 2, changes in the X-ray diffraction pattern were observed as shown in FIG. 3. Note that the heating process is shown on the right vertical axis of FIG.
同図から理解されるように、ライティング工程中の変化
として、イリジウム相の減少及びイリジウムとダンゲス
テンとの金属間化合物ε相の出現が、主としてライティ
ング工程（１ｖ）以降に認められた。ε相はｈｃｐ構造
を示す。エージング工程では、このε相が示す一連のそ
れぞれの回折ピークの低角度側に対をなして同じ結晶系
を示す一連の回折ピークが出現した。その後、エージン
グ工程が進むにつれ、初めの一連のピークは消滅し後の
回折パターンに置き代わった。初期に形成されたε相を
ε■相、後にＸ線回折の低角度側に現れた相をεＩＩ相
と称することにする。ε１相からεＩＩ相への不連続な
回折パターンの変化は、格子定数の不連続な変化に対応
する。すなわちε■相の格子定数はそれぞれ、ａ＝ ２
．７３５乃至２．７４５人、Ｃ＝ ４．３８５乃至４．
３９５人である。またεＩＩ相では、ａ＝ ２．７６０
乃至２．７８０人、ｃ＝ Ｌ４４０乃至４．４６０人の
範囲を示した。なお、これら格子定数の値と、イリジウ
ム−タングステン合金中のタングステン濃度との関係は
既に報告されており、第４図に実線で示すような関係で
ある。そして本発明者らの実益で得られたε１相および
εＩＩ相の格子定数の値を、第４図中に点線の斜線で示
した。これらの対応するタングステン濃度は、ε１相で
約２０乃至２５原子％、εＩＩ相で約４０乃至５０原子
％となる。ε１相からεＩＩ相への移行により、表面層
組成の変動もきわめて不連続に生じていることがわかる
。As can be understood from the figure, as changes during the writing process, a decrease in the iridium phase and the appearance of an ε phase, an intermetallic compound of iridium and dungesten, were mainly observed after the writing process (1v). The ε phase shows an hcp structure. In the aging process, a series of diffraction peaks indicating the same crystal system appeared in pairs on the low angle side of each of the series of diffraction peaks exhibited by the ε phase. Then, as the aging process progressed, the initial series of peaks disappeared and were replaced by later diffraction patterns. The initially formed ε phase will be referred to as the ε■ phase, and the phase that later appears on the low angle side of X-ray diffraction will be referred to as the εII phase. The discontinuous change in the diffraction pattern from the ε1 phase to the εII phase corresponds to a discontinuous change in the lattice constant. In other words, the lattice constants of the ε■ phase are a= 2
．． 735 to 2.745 people, C = 4.385 to 4.
There are 395 people. In addition, in the εII phase, a= 2.760
The range was from 2.780 people to 2.780 people, c=L440 to 4.460 people. Incidentally, the relationship between the values of these lattice constants and the tungsten concentration in the iridium-tungsten alloy has already been reported, and is the relationship shown by the solid line in FIG. 4. The values of the lattice constants of the ε1 phase and εII phase obtained by the present inventors are indicated by dotted diagonal lines in FIG. Their corresponding tungsten concentrations are approximately 20 to 25 atomic % for the ε1 phase and approximately 40 to 50 atomic % for the εII phase. It can be seen that due to the transition from the ε1 phase to the εII phase, the surface layer composition changes extremely discontinuously.
そしてεＩＩ相はきわめて安定な結晶構造を示し、その
俄の熱処理ではほとんど格子定数の変化を生じることが
なかった。すなわ５１１８０℃でのエージング工程での
約５５分間の加熱で、ε１相からεＩＩ相に完全に移行
した。The εII phase exhibited an extremely stable crystal structure, and the heat treatment during that time hardly caused any change in the lattice constant. That is, by heating at 51,180° C. for about 55 minutes in the aging process, the ε1 phase completely transitioned to the εII phase.
また、ライティング工程終了後、およびエージング工程
終了後の表面合金層について、オージェ電子分光装置に
より、アルゴンイオンを用いたスパッタリング方式を用
いて表面から深さ方向の組成分析を試み、第５図（ａ）
、 （ｂ）の結果を得た。In addition, we attempted to analyze the composition of the surface alloy layer after the writing process and after the aging process in the depth direction from the surface using an Auger electron spectrometer using a sputtering method using argon ions. )
, the result of (b) was obtained.
同図（ａ）はライティング終了後、同図（ｂ）はエージ
ング工程１２０分後の相対濃度分布で市る。そして曲線
５１および５３は相対イリジウム濃度、同５２、および
５４は相対タングステン濃度を示している。The figure (a) shows the relative concentration distribution after the writing is completed, and the figure (b) shows the relative concentration distribution after 120 minutes of the aging process. Curves 51 and 53 show relative iridium concentrations, and curves 52 and 54 show relative tungsten concentrations.
この結果から、ライティング工程終了時点のものでは、
表面中のタングステン濃度に勾配が少なく、タングステ
ンのイリジウムへの速い拡散が推察される。またエージ
ング工程（ＩＩＩ＞終了段階のものでは、表面および合
金層中のタングステン濃度が４０乃至５０ ＋ｔｘ了％
となっていることが判明した。これらの事実は、第４図
に示した格子定数の変化から推察される表面被覆層の組
成変動に一致した結果になっている。From this result, at the end of the writing process,
There is little gradient in the tungsten concentration on the surface, suggesting rapid diffusion of tungsten into iridium. In addition, in the aging process (III> completion stage), the tungsten concentration on the surface and in the alloy layer is 40 to 50 +tx completion%.
It turned out that it was. These facts are consistent with the compositional variation of the surface coating layer inferred from the change in lattice constant shown in FIG.
以上のように、多孔￥１基体の表面にイリジウムを被覆
し、これを所定温度で所定時間加熱処理することにより
、表面部に安定なεＩＩ相からなるイリジウム−タング
ステン合金層を確実に形成することができる。As described above, by coating iridium on the surface of a porous substrate and heat-treating it at a predetermined temperature for a predetermined time, an iridium-tungsten alloy layer consisting of a stable εII phase can be reliably formed on the surface. Can be done.
次に、多孔質基体表面に被覆するイリジウム層の厚さと
、加熱処理すなわちエージング条件との関係について検
討した。イリジウム被覆層が、約１ｏｏｏ人、約２００
０人、約３５００人、約５０００人の厚さのものを用意
し、いずれも１１８０℃で所定時間加熱した。その結果
得られたＸ線回折の結果を第６図に示す。同図において
、縦軸のＸ線回折強度比は、ε１相、εＩＩ相およびイ
リジウムの主回折ピーク強度のそれぞれの和に対するε
ＩＩ相の回折ピーク強度の比率をあられしている。この
結果から、ε■相からεＩＩ相へと移行するのに要する
加熱処理時間は、イリジウム被覆層の厚さに依存し、イ
リジウム層が厚いほどεＩＩ相の形成に多くの加熱処理
時間を要することがわかった。なお同図において曲線６
１はイリジウム被覆層厚が約１０００人のものの場合、
同６２は約２０００人、同６３は約３５００人、同６４
は約５ｏｏｏ人のものの場合をそれぞれあられしている
。また、エージング時間を一定とした場合は、イリジウ
ム被覆層の厚さが厚いほど、表面までのεＩＩ相の完全
生成のためにはより一層高温での加熱処理を要する結果
が得られた。Next, the relationship between the thickness of the iridium layer coated on the surface of the porous substrate and the heat treatment, ie, aging conditions, was investigated. The iridium coating layer is about 100, about 200
Thicknesses with a thickness of 0, about 3,500, and about 5,000 were prepared, and all were heated at 1180° C. for a predetermined period of time. The resulting X-ray diffraction results are shown in FIG. In the figure, the X-ray diffraction intensity ratio on the vertical axis is ε to the sum of the main diffraction peak intensities of ε1 phase, εII phase, and iridium.
The ratio of diffraction peak intensities of phase II is shown. From this result, the heat treatment time required to transition from the ε■ phase to the εII phase depends on the thickness of the iridium coating layer, and the thicker the iridium layer, the longer the heat treatment time required to form the εII phase. I understand. Note that in the same figure, curve 6
1 is when the iridium coating layer thickness is about 1000 people,
62 had about 2000 people, 63 had about 3500 people, 64
The cases of about 500 people are each hailed. Furthermore, when the aging time was constant, the thicker the iridium coating layer, the higher the need for heat treatment at a higher temperature to completely generate the εII phase up to the surface.
また第７図にイリジウム被覆層厚、エージング加熱処理
時間に対する空間電荷制限領域における最大エミッショ
ン値すなわちＭＩＳＣの変化を示した。この空間電荷制
限領域における最大エミッション値ＭＩＳＣは、陽極電
圧を２秒間印加したときの印加開始１秒後の値で表現し
ており、この値は陽極電圧印加方式として通常用いられ
るパルス的な場合と、直流的な場合とのほぼ中間的な特
性を示す。同図において曲線７１はイリジウム被覆層厚
が約１０００人のものの場合、同７２は約２０００人、
同７３は約３５００人、同７４は約５０００人のものの
場合をそれぞれあられしている。Further, FIG. 7 shows changes in the maximum emission value, ie, MISC, in the space charge limited region with respect to the iridium coating layer thickness and the aging heat treatment time. The maximum emission value MISC in this space charge limited region is expressed as the value 1 second after the start of application when the anode voltage is applied for 2 seconds, and this value is different from the pulsed case normally used as the anode voltage application method. , exhibits characteristics that are almost intermediate to those of the DC case. In the figure, curve 71 is for a case where the iridium coating layer thickness is about 1,000 people, curve 72 is for about 2,000 people,
73 and 74 are cases of approximately 3,500 and 5,000 people, respectively.
このような結果から、イリジウム被覆層厚が厚いほどＭ
ＩＳＣ値の増加傾向が緩やかであり、エミッション的活
性化にも長時間を要することが確認された。このように
電子放射特性がεＩＩ相の形成率と強い相関があり、ε
ＩＩ相が基体表面まで完全に生成されている場合が最も
大きな電子放射特性を得られ、且つ安定であることが明
らかとなった。そして、十分に活性化された陰極基体の
表面合金層はＸ線回折的にはほぼεＩＩ相だ【ブからな
ることが対応づけられた。From these results, the thicker the iridium coating layer, the more M
It was confirmed that the increasing trend of the ISC value was gradual and that emission activation also required a long time. In this way, the electron emission characteristics have a strong correlation with the formation rate of εII phase, and ε
It has become clear that when the II phase is completely formed up to the substrate surface, the greatest electron emission characteristics can be obtained and stability is achieved. The surface alloy layer of the sufficiently activated cathode substrate was found to consist of approximately εII phase by X-ray diffraction.
ざらにまた、合金化終了後の陰極断面を走査形電子顕微
鏡によりＩ察し、イリジウム被覆層厚に対する生成合金
層厚の関係をみた。その結果を第８図に示す。その結果
、形成される合金層の厚さは、はじめ被着するイリジウ
ム層の厚さのおよそ２倍になることが確認された。In addition, the cross section of the cathode after alloying was inspected using a scanning electron microscope to examine the relationship between the thickness of the formed alloy layer and the thickness of the iridium coating layer. The results are shown in FIG. As a result, it was confirmed that the thickness of the formed alloy layer was approximately twice the thickness of the initially deposited iridium layer.
以上に述べた諸結果を考慮し、次に電子放射特性との関
連を考察した。以下にその概要を述べる。Considering the results described above, we next considered the relationship with electron emission characteristics. The outline is described below.
多孔質基体表面にスパッタリングにより約５０人から約
１０，０００の入範囲の任意適当な厚さでイリジウムを
被覆した試料を用意し、所定の熱処理を施した。この熱
処理による表面合金化処理は、管内加熱すなわち電子管
内に組込んだ状態で陰極構体内の加熱ヒータに通電して
加熱することにより合金化する方式、および単体加熱す
なわち真空排気されるガラスペルジャー内に陰極構体を
配置し加熱する方式で実施した。それら各方式は、前者
すなわち管内加熱は比較的低電圧電子管などに適するこ
とを考慮し、また後者すなわち単体加熱方式は大形又は
高電圧動作用の電子管などに適することを考慮している
。そして電子放射特性は、平行平板形２極管のガラスダ
ミー管を作製して評価した。A sample was prepared in which the surface of a porous substrate was coated with iridium by sputtering to an arbitrary thickness ranging from about 50 to about 10,000, and was subjected to a predetermined heat treatment. This surface alloying treatment by heat treatment is carried out by in-tube heating, which is a method in which alloying is performed by energizing a heater inside the cathode assembly while it is incorporated in the electron tube, and by single-unit heating, which is a glass Pelger that is evacuated. The method was carried out by placing a cathode structure inside and heating it. Each of these methods takes into consideration that the former, ie, tube heating, is suitable for relatively low-voltage electron tubes, and the latter, ie, the unit heating method, is suitable for large-sized or high-voltage operation electron tubes. The electron emission characteristics were evaluated by fabricating a parallel plate diode glass dummy tube.
管内加熱方式の場合は、ライティング工程をガラスダミ
ー管の排気中に実施し、その１卦排気管を封止切りして
から所定の等温度でエージング加熱処理した。エージン
グ工程中の電子放射特性の変化を測定した。また単体加
熱方式では、ガラスペルジャー内で所定のライティング
、エージング工程を実施し、その後得られた陰極構体を
平行平板形２極管のガラスダミー管内に組込んで、管内
加熱方式の場合と同様な方法で電子放射特性を測定した
。なお測定中のエージング効果を防ぐため、電子放射特
性はいずれもカソード温度を１０ＱＯ℃に下げて測定し
た。In the case of the in-tube heating method, the lighting process was performed while the glass dummy tube was being evacuated, and after the one-liter exhaust tube was sealed and cut, aging heat treatment was performed at a predetermined constant temperature. Changes in electron emission properties during the aging process were measured. In addition, in the single heating method, prescribed lighting and aging processes are carried out in a glass Pel jar, and then the obtained cathode structure is assembled into a glass dummy tube of a parallel plate diode, similar to the case of the in-tube heating method. The electron emission characteristics were measured using a unique method. In order to prevent aging effects during measurements, all electron emission characteristics were measured with the cathode temperature lowered to 10QO<0>C.
それらの比較結果を表１に示す。同表において、実施例
とはその後の分析により裏面部合金層のほぼ全体にεＩ
Ｉ相の形成が確認されたこの発明の実施例のもの、また
比較例とは表面合金層にε１相とεＩＩ相の両方が観察
されたものの場合である。Table 1 shows the comparison results. In the same table, Examples indicate that almost the entire back surface alloy layer has εI as determined by subsequent analysis.
Examples of the present invention in which the formation of phase I was confirmed, and comparative examples refer to cases in which both ε1 phase and εII phase were observed in the surface alloy layer.
（以下余白）
表１
（続き）
＊印は（℃１分）
表１の結果から、はじめに被覆されたイリジウム層の厚
さに応じて所定の熱９Ｂ理を施してほぼεＩＩ相のみか
らなる合金化層を形成させることにより、初期および長
時間にわたる動作でも安定で良好な電子放射特性を得る
ことができることが確認された。そして前述のようにイ
リジウム層の厚さに応じて適宜の加熱処理条件を設定す
ることにより、εＩＩ相からなるイリジウム−タングス
テン合金化層を再現性よく、確実に（与ることができる
。(Margins below) Table 1 (Continued) *marks indicate (°C 1 minute) From the results in Table 1, alloys consisting almost only of the εII phase are obtained by applying a predetermined thermal 9B process depending on the thickness of the iridium layer initially coated. It was confirmed that by forming a chemical layer, stable and good electron emission characteristics could be obtained even during initial and long-term operation. As described above, by setting appropriate heat treatment conditions depending on the thickness of the iridium layer, an iridium-tungsten alloyed layer consisting of the εII phase can be reliably formed with good reproducibility.
なお、はじめに多孔質基体表面に被着形成する層は、イ
リジウムのみに限らず、イリジウムおよびタングステン
を主体とする合金を被覆してもよい。そしてそれを、前
述のように真空中または不活性雰囲気中において表面部
にイリジウムおよびタングステンの金属化合物のεＩＩ
相からなる合金層を生成するように約１１００℃乃至１
２６０℃の範囲の温度で所定時間加熱処理すればよい。Note that the layer that is first formed on the surface of the porous substrate is not limited to only iridium, but may also be coated with an alloy mainly consisting of iridium and tungsten. Then, as mentioned above, in vacuum or in an inert atmosphere, the surface part is coated with εII of a metal compound of iridium and tungsten.
at about 1100°C to 1°C to form an alloy layer consisting of
Heat treatment may be performed at a temperature in the range of 260° C. for a predetermined period of time.
このＪ：うに、表面にイリジウムを含む合金層を形成す
る含浸形陰極の製造方法において、多孔質基体表面にイ
リジウム、またはイリジウム−タングステン合金を被着
し、それを真空中または不活性雰囲気中において表面部
にイリジウムおよびタングステンの金属化合物のεＩＩ
相からなる合金層を生成するように約１１００℃乃至１
２６０℃の範囲の温度で所定時間加熱処理することにり
、動作初期からきわめて安定で、しかも良好な電子放射
特性を有する含浸形陰極を再現性よく￥！造することが
できる。すなわち表面部に生成されるεＩＩ相からなる
合金層は極めて安定で、長時間動作に対しても変化がき
わめて小さいという特質を有する。In this method for manufacturing an impregnated cathode that forms an alloy layer containing iridium on the surface, iridium or an iridium-tungsten alloy is deposited on the surface of a porous substrate, and the iridium-tungsten alloy is deposited in a vacuum or in an inert atmosphere. εII of iridium and tungsten metal compounds on the surface
at about 1100°C to 1°C to form an alloy layer consisting of
By heat-treating at a temperature in the range of 260°C for a predetermined period of time, we can produce an impregnated cathode that is extremely stable from the beginning of operation and has good electron emission characteristics with good reproducibility! can be built. That is, the alloy layer made of the εII phase formed on the surface is extremely stable, and has the characteristic that it undergoes extremely little change even during long-term operation.
また得られるεＩＩ相は、格子定数ａの範囲が２．７６
乃至２，７８人、格子定数Ｃが４．４４乃至４．４６人
の範囲のｈｃｐ構造を示し、これは換言すればタングス
テンが飽和固溶したイリジウム−タングステン合金のε
相からなることを特徴としている。こうして表面部のイ
リジウム及びタングステン濃度組成が一定化しており、
それにより仕事関数が比較的低い値で一定に保たれる。Furthermore, the obtained εII phase has a lattice constant a in the range of 2.76.
It shows an hcp structure with a lattice constant C ranging from 4.44 to 4.46, which means that the ε of an iridium-tungsten alloy in which tungsten is a saturated solid solution is
It is characterized by consisting of phases. In this way, the iridium and tungsten concentration composition at the surface is kept constant,
This keeps the work function constant at a relatively low value.
したがって動作初期から野命明間中、きわめて安定な電
子放射ＩＳ性を得ることができる。Therefore, extremely stable electron emission IS characteristics can be obtained from the initial stage of operation to the entire period of operation.
なお、熱処理時間の実用的な管理の容易さから、多孔質
基体表面へのイリジウム被覆層の厚さは、５０人乃至１
０．０００人の範囲が適当である。それによりεＩＩ相
からなる合金被覆層の厚さは、およそ２倍の約１００人
乃至２０，０００人の範囲が好ましい厚さである。そし
てその場合の熱処理条件としては、およそ１１００℃乃
至１２６０℃の範囲で、加熱処理時間はおよそ１分乃至
３６０分程度の範囲内で前述のようなイリジウム厚さに
応じて適宜の処理を実施すればよい。In addition, for ease of practical management of heat treatment time, the thickness of the iridium coating layer on the surface of the porous substrate is 50 to 1.
A range of 0.000 people is appropriate. Accordingly, the thickness of the alloy coating layer consisting of the εII phase is preferably approximately twice the thickness, in the range of about 100 to 20,000. In that case, the heat treatment conditions are in the range of approximately 1100°C to 1260°C, and the heat treatment time is in the range of approximately 1 minute to 360 minutes, and appropriate treatment should be performed depending on the iridium thickness as described above. Bye.
なお、加熱処理温度が１２６０℃よりも高いと、基体中
のバリウムの蒸発■が多くなり過ぎ、むしろ所期の電子
放射特性を損うおそれがある。また、１１００℃以下で
はεＩＩ相の合金化にきわめて長時間を要し、実用性に
乏しい。またεＩＩ相合金層の厚さが、１００人より薄
いと寿命が短くなり、一方、２０、０００人を超すと高
い動作温度が要求されるなどの短所が顕著となってしま
う。If the heat treatment temperature is higher than 1260° C., too much barium evaporates in the substrate, which may actually impair the desired electron emission characteristics. Further, at temperatures below 1100°C, it takes a very long time to alloy the εII phase, which is impractical. Furthermore, if the thickness of the εII phase alloy layer is less than 100 people, the service life will be shortened, while if it exceeds 20,000 people, disadvantages such as a high operating temperature will become noticeable.
［発明の効果コ
以上説明したようにこの発明の”ｊＡ？ｊ方法によれば
、多孔質基体の表面部に結晶構造のきわめて安定なεＩ
Ｉ相からなるイリジウム−タングステン合金層を、再現
性よく確実に形成できる。[Effects of the Invention] As explained above, according to the method of the present invention, εI with an extremely stable crystal structure is formed on the surface of the porous substrate.
An iridium-tungsten alloy layer consisting of I phase can be reliably formed with good reproducibility.
したがって、動作初期から長時間動作にわたってきわめ
て安定で良好な電子放射特性をもつ含浸形陰極を、確実
、容易にｊＪることができる。Therefore, it is possible to reliably and easily produce an impregnated cathode that has extremely stable and good electron emission characteristics from the initial stage of operation to long-term operation.
第１図はこの発明により得られる含浸形陰極の一部断面
を示す斜視図、第２図はこの発明の実施例における陰極
加熱処理工程を示す図、第３図はその加熱処理工程にお
ける表面部のＸ線回折パターン図、第４図、第５図（ａ
） 、（ｂ）、第６図、第７図、および第８図はそれぞ
れ各工程における特性図である。
１１・・・多孔質基体、１５・・・表面合金層。FIG. 1 is a perspective view showing a partial cross section of an impregnated cathode obtained according to the present invention, FIG. 2 is a view showing a cathode heat treatment step in an embodiment of the present invention, and FIG. 3 is a surface portion in the heat treatment step. X-ray diffraction pattern diagrams, Figures 4 and 5 (a
), (b), FIG. 6, FIG. 7, and FIG. 8 are characteristic diagrams in each step, respectively. 11... Porous substrate, 15... Surface alloy layer.
Claims (1)
グステンの合金層を形成する工程を備える含浸形陰極の
製造方法において、 前記多孔質基体の表面に、イリジウム、またはイリジウ
ムおよびタングステン合金の層を被着し、 その後この多孔質基体を真空中または不活性雰囲気中に
おいて、表面部にイリジウムおよびタングステンの金属
化合物のε＿II相からなる合金層を生成するように約１
１００℃乃至１２６０℃の範囲の温度で所定時間加熱処
理することを特徴とする含浸形陰極の製造方法。[Scope of Claims] A method for producing an impregnated cathode comprising the steps of impregnating a porous substrate with an alkaline earth metal oxide and forming an alloy layer of iridium and tungsten on the surface of the porous substrate, comprising: A layer of iridium or an iridium and tungsten alloy is deposited on the surface of a porous substrate, and then this porous substrate is placed in a vacuum or an inert atmosphere to form an alloy consisting of an ε_II phase of a metal compound of iridium and tungsten on the surface. Approximately 1 to produce a layer
A method for manufacturing an impregnated cathode, which comprises performing a heat treatment at a temperature in the range of 100°C to 1260°C for a predetermined period of time.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61130224A JPH0795422B2 (en) | 1986-06-06 | 1986-06-06 | Method for manufacturing impregnated cathode |
| EP87108036A EP0248417B1 (en) | 1986-06-06 | 1987-06-03 | Impregnated cathode |
| DE8787108036T DE3782543T2 (en) | 1986-06-06 | 1987-06-03 | IMPREGNATED CATHODE. |
| US07/273,157 US4928034A (en) | 1986-06-06 | 1988-11-18 | Impregnated cathode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61130224A JPH0795422B2 (en) | 1986-06-06 | 1986-06-06 | Method for manufacturing impregnated cathode |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62287544A true JPS62287544A (en) | 1987-12-14 |
| JPH0795422B2 JPH0795422B2 (en) | 1995-10-11 |
Family
ID=15029056
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61130224A Expired - Lifetime JPH0795422B2 (en) | 1986-06-06 | 1986-06-06 | Method for manufacturing impregnated cathode |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0795422B2 (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54133871A (en) * | 1978-03-23 | 1979-10-17 | Emi Varian Ltd | Thermion cathode and method of producing same |
| JPS57210538A (en) * | 1981-06-22 | 1982-12-24 | Nec Corp | Impregnation type cathode and its manufacturing process |
-
1986
- 1986-06-06 JP JP61130224A patent/JPH0795422B2/en not_active Expired - Lifetime
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54133871A (en) * | 1978-03-23 | 1979-10-17 | Emi Varian Ltd | Thermion cathode and method of producing same |
| JPS57210538A (en) * | 1981-06-22 | 1982-12-24 | Nec Corp | Impregnation type cathode and its manufacturing process |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0795422B2 (en) | 1995-10-11 |
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| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |