JPH0719532B2 - Method for manufacturing impregnated cathode - Google Patents
Method for manufacturing impregnated cathodeInfo
- Publication number
- JPH0719532B2 JPH0719532B2 JP25499487A JP25499487A JPH0719532B2 JP H0719532 B2 JPH0719532 B2 JP H0719532B2 JP 25499487 A JP25499487 A JP 25499487A JP 25499487 A JP25499487 A JP 25499487A JP H0719532 B2 JPH0719532 B2 JP H0719532B2
- Authority
- JP
- Japan
- Prior art keywords
- cathode
- scandium
- impregnated
- carbonate
- alkaline earth
- 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
Description
【発明の詳細な説明】 ［発明の目的］ （産業上の利用分野） この発明は、含浸型陰極の製造方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a method for producing an impregnated cathode.
（従来の技術） 一般に、含浸型陰極は第１図に示すように構成され、陰
極支持筒１と、この陰極支持筒１内に配設され埋込材２
により固定されたヒータ３と、陰極支持筒１の一端に埋
込材２に接してろう材４により接合され電子放射物質が
含浸された陰極基体５とからなっている。(Prior Art) In general, an impregnated cathode is constructed as shown in FIG. 1, and includes a cathode support cylinder 1 and an embedding material 2 arranged in the cathode support cylinder 1.
And a cathode base 5 impregnated with an electron emitting substance, which is in contact with the embedding material 2 at one end of the cathode support cylinder 1 and is joined by a brazing material 4.
このような含浸型陰極の製造に当たっては、タングステ
ン、モリブデン等の高融点金属の単体又は混合粉末を高
温真空中或いは水素中で焼結した多孔質体に、切削加工
をよくするために、銅又はプラスチックを含浸し、その
状況で所望の形状に切削加工する。更に、所定の操作で
切削前に含浸した銅又はプラスチックを除去した後、所
望モル比に混合した電子放射物質を多孔質の陰極基体５
上に高周波水素炉中で溶解含浸したものが良く知られて
いる。In producing such an impregnated cathode, tungsten, a porous body obtained by sintering a single or mixed powder of a refractory metal such as molybdenum in a high temperature vacuum or in hydrogen, in order to improve the cutting process, copper or It is impregnated with plastic and then cut into the desired shape. Further, the impregnated copper or plastic is removed by a predetermined operation before cutting, and then the electron-emitting substance mixed in a desired molar ratio is mixed with the porous cathode substrate 5.
It is well known that the above is melt impregnated in a high frequency hydrogen furnace.
又、最近では、動作温度を下げ、更に高電流密度で長時
間良好な電子放射を得るために、電子放射物質に酸化ス
カンジウムを含有せしめた陰極が開発されている（特開
昭58−154131号公報）。Recently, in order to lower the operating temperature and obtain good electron emission at high current density for a long time, a cathode containing scandium oxide as an electron emitting substance has been developed (Japanese Patent Laid-Open No. 154131/1983). Gazette).
この含浸型陰極は、タングステン粉末と酸化スカンジウ
ムとの混合体をプレス加工した後、1700℃程度の温度で
焼結し、所要の形状に切削加工を行ない、この陰極基体
にBaO、CaO、Al2O3等の電子放射物質を含浸せしめるこ
とにより得られる。This impregnated cathode was formed by pressing a mixture of tungsten powder and scandium oxide, sintering it at a temperature of about 1700 ° C., and cutting it into the required shape. BaO, CaO, Al 2 It is obtained by impregnating an electron emitting substance such as O 3 .
（発明が解決しようとする問題点） ところが、上記の含浸型陰極は、酸化スカンジウムを含
有しないものに比較して、電子放射特性は向上するが、
次のような欠点を有している。(Problems to be Solved by the Invention) However, the above-mentioned impregnated cathode has improved electron emission characteristics as compared with those containing no scandium oxide,
It has the following drawbacks.
スカンジウム及びその化合物は非常に高価であり、陰
極基体を焼結した後の切削加工により失われるスカンジ
ウムは、経済的に不利である。Scandium and its compounds are very expensive, and scandium lost by cutting after sintering the cathode substrate is economically disadvantageous.
酸化スカンジウムは粉砕しにくいため、均一な粒度分
布にならず、焼結体内部の酸化スカンジウム濃度にムラ
が生じる。この結果、長時間に亘り安定な動作をさせる
ことが困難である。Since scandium oxide is difficult to pulverize, it does not have a uniform particle size distribution, resulting in uneven scandium oxide concentration inside the sintered body. As a result, it is difficult to perform stable operation for a long time.
この発明は、以上のような従来のスカンジウムを含有す
る含浸型陰極の持つ不都合を解消し、特に高電流密度で
長時間動作をさせても、電子放射特性の安定した低価格
の含浸型陰極が得られる含浸型陰極の製造方法を提供す
ることを目的とする。The present invention eliminates the disadvantages of the conventional impregnated cathode containing scandium as described above, and provides a low-priced impregnated cathode having stable electron emission characteristics even when operated for a long time at a high current density. It is an object of the present invention to provide a method for manufacturing the obtained impregnated cathode.
［発明の構成］ （問題点を解決するための手段） この発明は、アルカリ土類金属炭酸塩にスカンジウムを
共沈により含有せしめ、このスカンジウム入りアルカリ
土類金属炭酸塩を、多孔質高融点金属からなる陰極基体
に溶融含浸することを特徴とする含浸型陰極の製造方法
であり、上記アルカリ土類金属炭酸塩は、バリウム単塩
又はそれらの複塩である。[Structure of the Invention] (Means for Solving the Problems) The present invention is that alkaline earth metal carbonate is made to contain scandium by coprecipitation, and the alkaline earth metal carbonate containing scandium is added to a porous refractory metal. 1. A method for producing an impregnated-type cathode, which comprises melting and impregnating a cathode substrate made of (1), wherein the alkaline earth metal carbonate is a barium single salt or a double salt thereof.
（作用） この発明によれば、陰極基体に含有されるスカンジウム
の分布がが非常に均一となり、長時間・高電流密度で安
定な動作特性を有する含浸型陰極の製造方法を得ること
が出来る。(Operation) According to the present invention, it is possible to obtain a method for producing an impregnated cathode having a uniform distribution of scandium contained in the cathode substrate and having stable operation characteristics at a high current density for a long time.
（実施例） 以下、図面を参照して、この発明の一実施例を詳細に説
明する。Embodiment An embodiment of the present invention will be described in detail below with reference to the drawings.
この発明の製造方法により得られる含浸型陰極は、第１
図に示したものと同様に構成されているが、製造に当た
っては、先ずタングステン粉末をプレス成型し、水素雰
囲気中で加熱焼結した多孔質タングステン体に、銅を含
浸した後、所定の陰極形状に切削し、しかる後、酸に浸
漬し、更に加熱して完全に銅を除去して陰極基体を作
る。これは、周知の一般的な方法である。The impregnated cathode obtained by the manufacturing method of the present invention is
Although the structure is similar to that shown in the figure, in manufacturing, first, tungsten powder is press-molded, and the porous tungsten body heat-sintered in a hydrogen atmosphere is impregnated with copper, and then, a predetermined cathode shape It is cut into pieces, then dipped in an acid, and further heated to completely remove copper to form a cathode substrate. This is a well-known general method.
次に、上記陰極基体に含浸する電子放射物質の製造方法
について説明する。Next, a method of manufacturing the electron emitting material with which the cathode substrate is impregnated will be described.
先ず、アルカリ土類金属硝酸塩例えば高純度の硝酸バリ
ウムを96.6重量％純水に溶解する。この溶解液に硝酸ス
カンジウムを3.4重量％撹拌しながら溶解し、液温を95
℃以上に保つ。First, an alkaline earth metal nitrate such as high-purity barium nitrate is dissolved in 96.6% by weight of pure water. Scandium nitrate was dissolved in this solution with stirring at 3.4% by weight, and the solution temperature was adjusted to 95%.
Keep above ℃.
次に、高純度の炭酸アンモニウムを所定量純水に溶解
し、撹拌しながら65〜70℃に保持する。この炭酸アンモ
ニウム溶液を、上記硝酸バリウムと硝酸スカンジウムの
硝酸塩液に一定の添加速度で加え、反応させる。生成す
る結晶形状は、反応速度、液濃縮度等で自由にコントロ
ールできるが、この発明では針状結晶を得る反応条件と
した。Next, a predetermined amount of high-purity ammonium carbonate is dissolved in pure water, and the temperature is maintained at 65 to 70 ° C while stirring. This ammonium carbonate solution is added to the nitrate solution of barium nitrate and scandium nitrate at a constant addition rate to cause a reaction. The crystal shape to be formed can be freely controlled by the reaction rate, the degree of liquid concentration, etc., but in the present invention, the reaction condition for obtaining needle-like crystals was used.
炭酸アンモニウム添加終了後も、生成した結晶を熟成さ
せるために、約30分間撹拌を継続する。生成した炭酸バ
リウムと炭酸スカンジウムの共沈炭酸塩を静置し、上澄
液を排出し、不純物が除去されるまで温水による洗浄を
繰返し、遠心脱水等の方法により脱水し、乾燥させて白
色の共沈炭酸塩を得る。このようにして得られる炭酸塩
は、バリウム98重量％、スカンジウム2.0重量％の構成
になる。After the addition of ammonium carbonate is completed, stirring is continued for about 30 minutes in order to age the formed crystals. The barium carbonate and scandium carbonate co-precipitated carbonate thus formed is allowed to stand still, the supernatant liquid is discharged, and washing with warm water is repeated until impurities are removed. Coprecipitated carbonate is obtained. The carbonate thus obtained is composed of 98% by weight of barium and 2.0% by weight of scandium.
次に、上記のようにして得た電子放射質を、陰極基体に
含浸する。Next, the cathode substrate is impregnated with the electron emission material obtained as described above.
先ず、上記で得たスカンジウムを含有する炭酸バリウム
と炭酸カルシウムと酸化アルミニウムとを4:1:1のモル
比で混合し、前処理の加熱後、陰極基体に還元性雰囲気
で加熱しながら含浸し、余剰物の除去を行なうと含浸型
陰極基体が完成する。First, the scanium-containing barium carbonate, calcium carbonate, and aluminum oxide obtained above were mixed at a molar ratio of 4: 1: 1, and after the pretreatment was heated, the cathode substrate was impregnated while heating in a reducing atmosphere. After the surplus is removed, the impregnated cathode substrate is completed.
その後、表面にIrを被覆し、熱処理してIr-W合金層を形
成する。After that, Ir is coated on the surface and heat treatment is performed to form an Ir—W alloy layer.
以上の陰極基体を用い、周知の方法で陰極構体を作り、
２極管を完成させた。この２極管について長時間動作に
伴なう電子放射特性を測定した。第２図は、電流密度1.
6A/cm2で長時間動作させた場合の各時間毎のパルスエミ
ッション比（％）を示すものである。同図中に示す実線
Ｘはこの発明を用いた場合、点線Ｙは従来の陰極（タン
グステン粉末に５重量％酸化スカンジウムを混合し、プ
レス後、焼結したもの）の場合である。Using the above cathode substrate, a cathode structure is made by a known method,
Completed the dipole. The electron emission characteristics of this diode with long-term operation were measured. Figure 2 shows the current density 1.
It shows the pulse emission ratio (%) for each time when operating for a long time at 6 A / cm 2 . A solid line X shown in the figure shows the case of using the present invention, and a dotted line Y shows the case of a conventional cathode (a mixture of tungsten powder with 5 wt% scandium oxide, followed by pressing and sintering).
この特性曲線図が示す通り、この発明の含浸型陰極は、
高電流密度での長時間動作による電子放射特性の劣化
が、非常に少ないことが明らかである。パルスエミッシ
ョンの劣化が非常に少ないことは、高い安定した電子放
射能力を長時間維持出来ることを意味している。As this characteristic curve diagram shows, the impregnated cathode of the present invention is
It is apparent that the deterioration of the electron emission characteristics due to long-time operation at high current density is very small. The very small deterioration of pulse emission means that high stable electron emission capability can be maintained for a long time.
尚、上記実施例では、炭酸バリウムに炭酸スカンジウム
を2.0重量％含有せしめたものについて説明したが、発
明者の実験によれば、含有量0.1〜5.0重量％の範囲で同
様の効果が得られる。It should be noted that, in the above-mentioned Examples, the barium carbonate containing 2.0% by weight of scandium carbonate was explained, but according to the experiments by the inventor, the same effect can be obtained in the content range of 0.1 to 5.0% by weight.
含有スカンジウム量が５重量％以上になると、初期の電
子放射特性を安定させるまでに長時間を要し、量産性に
問題があり、スカンジウムの使用量も増えて経済的にも
不都合が生じ、実用範囲ではなかった。又、0.1重量％
以下になると、長時間動作での安定性に問題が生じた。When the amount of scandium contained is 5% by weight or more, it takes a long time to stabilize the initial electron emission characteristics, there is a problem in mass productivity, and the amount of scandium used also increases, which causes economic inconvenience. It wasn't in range. Also, 0.1% by weight
In the following cases, there was a problem in stability during long-term operation.
又、この発明は、上記のようにアルカリ土類金属炭酸塩
にスカンジウムを共沈により含有せしめ、このスカンジ
ウム入りアルカリ土類金属炭酸塩を、多孔質高融点金属
からなる陰極基体に溶融含浸する点以外は、周知の製造
方法を採用しているので、詳細な説明は省略する。Further, according to the present invention, as described above, alkaline earth metal carbonate is made to contain scandium by coprecipitation, and the alkaline earth metal carbonate containing scandium is melt-impregnated into a cathode substrate made of a porous refractory metal. Other than the above, a well-known manufacturing method is adopted, and detailed description thereof will be omitted.
（変形例） 上記実施例では、炭酸バリウムと炭酸スカンジウムの共
沈電子放射物質について説明したが、炭酸カルシウムと
炭酸スカンジウムのの共沈、又は炭酸バリウム、炭酸カ
ルシウム、炭酸スカンジウムの３共沈を用いても、上記
実施例と同様の効果を示すことは説明するまでもない。(Modification) In the above embodiment, the co-precipitation electron-emitting substance of barium carbonate and scandium carbonate was described, but the co-precipitation of calcium carbonate and scandium carbonate or the co-precipitation of barium carbonate, calcium carbonate and scandium carbonate was used. However, it is needless to say that the same effect as that of the above-mentioned embodiment is exhibited.
［発明の効果］ この発明によれば、スカンジウム硝酸塩とアルカリ土類
金属硝酸塩との混合液を炭酸アルカリ例えば炭酸アンモ
ニウム、炭酸ナトリウム溶液と反応させ、スカンジウム
を電子放射物質である少なくともバリウムを含むアルカ
リ土類金属炭酸塩の結晶内部に含有させ、その後で陰極
基体に含浸させている。[Effects of the Invention] According to the present invention, a mixed solution of scandium nitrate and an alkaline earth metal nitrate is reacted with an alkali carbonate such as ammonium carbonate or sodium carbonate solution, and scandium is an alkaline earth containing at least barium which is an electron emitting substance. It is contained in the crystal of a metal carbonate, and then the cathode substrate is impregnated.
このため、電子放射特性に有効なバリウムスカンデート
の生成が、確実・容易であり、陰極基体内で均一且つ有
効に行なわれ、高電流密度での長時間動作でも、電子放
射特性の劣化が少ない。Therefore, the generation of barium scandate effective for the electron emission characteristic is reliable and easy, is uniformly and effectively performed in the cathode substrate, and there is little deterioration of the electron emission characteristic even during long-time operation at high current density. .
又、従来のスカンジウム含有型陰極は、酸化スカンジウ
ム粉体を用いているため、その粒度により陰極基体内の
スカンジウム濃度分布が左右されていたが、この発明は
電子放射物質結晶内に予め含有させているため、スカン
ジウムの濃度分布にムラがなく、非常に均一である。In addition, since the conventional scandium-containing cathode uses scandium oxide powder, the particle size of the scandium concentration distribution influenced the scandium concentration distribution in the cathode substrate. As a result, the scandium concentration distribution is uniform and very uniform.
第１図は一般的な含浸型陰極を示す断面図、第２図は含
浸型陰極における動作時間と電子放射特性の関係を示す
特性曲線図である。 １……陰極支持筒、２……埋込材、３……ヒータ、４…
…ろう材、５……陰極基体。FIG. 1 is a cross-sectional view showing a general impregnated cathode, and FIG. 2 is a characteristic curve diagram showing the relationship between operating time and electron emission characteristics in the impregnated cathode. 1 ... Cathode support tube, 2 ... Embedding material, 3 ... Heater, 4 ...
... brazing material, 5 ... cathode body.
Claims (2)
共沈により含有せしめ、このスカンジウム入りアルカリ
土類金属炭酸塩を、多孔質高融点金属からなる陰極基体
に溶融含浸することを特徴とする含浸型陰極の製造方
法。1. An impregnation method wherein scandium is contained in an alkaline earth metal carbonate by coprecipitation, and the alkaline earth metal carbonate containing scandium is melt-impregnated into a cathode substrate made of a porous refractory metal. Method of manufacturing mold cathode.
酸塩は、バリウム単塩又はそれらの複塩である特許請求
の範囲第１項記載の含浸型陰極の製造方法。2. The method for producing an impregnated cathode according to claim 1, wherein the alkaline earth metal carbonate containing scandium is a barium single salt or a double salt thereof.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25499487A JPH0719532B2 (en) | 1987-10-09 | 1987-10-09 | Method for manufacturing impregnated cathode |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25499487A JPH0719532B2 (en) | 1987-10-09 | 1987-10-09 | Method for manufacturing impregnated cathode |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0197343A JPH0197343A (en) | 1989-04-14 |
| JPH0719532B2 true JPH0719532B2 (en) | 1995-03-06 |
Family
ID=17272733
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP25499487A Expired - Lifetime JPH0719532B2 (en) | 1987-10-09 | 1987-10-09 | Method for manufacturing impregnated cathode |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0719532B2 (en) |
-
1987
- 1987-10-09 JP JP25499487A patent/JPH0719532B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0197343A (en) | 1989-04-14 |
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