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 |
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