JPH0562414B2 - - Google Patents
Info
- Publication number
- JPH0562414B2 JPH0562414B2 JP20252684A JP20252684A JPH0562414B2 JP H0562414 B2 JPH0562414 B2 JP H0562414B2 JP 20252684 A JP20252684 A JP 20252684A JP 20252684 A JP20252684 A JP 20252684A JP H0562414 B2 JPH0562414 B2 JP H0562414B2
- Authority
- JP
- Japan
- Prior art keywords
- pressure
- container
- molded body
- compression molded
- torr
- 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
- 230000006835 compression Effects 0.000 claims description 11
- 238000007906 compression Methods 0.000 claims description 11
- 239000000941 radioactive substance Substances 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims description 5
- 238000000034 method Methods 0.000 claims description 4
- 239000000843 powder Substances 0.000 claims description 4
- 150000001342 alkaline earth metals Chemical class 0.000 claims description 3
- 229910052751 metal Inorganic materials 0.000 claims description 3
- 239000002184 metal Substances 0.000 claims description 3
- 239000011812 mixed powder Substances 0.000 claims description 3
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 claims description 2
- 238000005245 sintering Methods 0.000 description 9
- 239000007789 gas Substances 0.000 description 8
- 238000009792 diffusion process Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 2
- -1 alkaline earth metal carbonate Chemical class 0.000 description 2
- 239000010953 base metal Substances 0.000 description 2
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 239000011733 molybdenum Substances 0.000 description 2
- 238000000748 compression moulding Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 239000007772 electrode material Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000005764 inhibitory process Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 239000012857 radioactive material Substances 0.000 description 1
- 230000004580 weight loss Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
- H01J9/02—Manufacture of electrodes or electrode systems
- H01J9/04—Manufacture of electrodes or electrode systems of thermionic cathodes
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Powder Metallurgy (AREA)
- Discharge Lamp (AREA)
Description
産業上の利用分野
本発明は放電ランプ用焼結電極の製造方法に関
するものである。
従来例の構成とその問題点
従来、放電ランプ用焼結電極の製造方法は、電
極材料として適当な金属粉末と電子放射性物質と
の混合粉末の圧縮成形体を焼結する際に、１気圧
の還元ガス雰囲気中、または真空中で圧縮成形体
を加熱し焼結する方法がとられている。
しかしながら、前者の場合には、多孔質の圧縮
成型体の内部にまで還元ガスが十分にいきわたら
ず、残留ガスや焼結の際に発生する不純ガスによ
つて、圧縮成形体内部が酸化するという問題があ
つた。とくに、電子放射性物質としてアルカリ土
類金属等の炭酸塩を用いた圧縮成形体の焼結のと
きには、この電子放射性物質が基本金属の存在下
で還元ガスと反応して圧縮成形体から除去されて
しまうという問題があつた。
一方、後者の場合には、前者の場合における問
題は生じないが、とくに電子放射性物質としてア
ルカリ土類金属の炭酸塩を用いるときには、この
炭酸塩の分解により酸化性ガスが発生して圧縮成
形体が酸化され、これを電極に用いた放電ランプ
は良好な特性を有しないので、これを防止するた
めに、焼結時の１回分の圧縮成形体の量を制限す
るとか、焼結時の昇温速度を遅くするとかいつた
生産性阻害の問題があつた。
発明の目的
本発明は良好な特性を有し、かつ量産性に適し
た放電ランプ用焼結電極の製造方法を提供するも
のである。
発明の構成
本発明は容器内に、金属粉末と、アルカリ土類
金属の炭酸塩からなる電子放射性物質との混合粉
末の圧縮成形体を入れ、前記容器内を１×10-3
Torr以下の圧力で真空に排気した後、前記排気
を続けながら、前記容器内に１×10-4〜300Torr
の圧力の還元ガスを導入し、この圧力を維持しな
がら、前記排気を続けて、前記圧縮成形体を焼結
する放電ランプ用焼結電極の製造方法を特徴とす
るものである。
実施例の説明
以下、本発明の実施例について図面を用いて説
明する。
図に示すように、試料として、モリブデン
（Mo）を基体金属とし、これに10重量％のアル
カリ土類金属炭酸塩からなる電子放射性物質を含
有する粉末の圧縮成形体１を、内部にヒータ２を
有する真空排気装置の容器３内に100個入れ、１
×10-5Torr以下の圧力になるまで真空ポンプで
排気を行う。圧縮成形体１の重量は500mg／個で
ある。モリブデンと電子放射性物質とほぼ均一に
混合されている。かかる場合、１×10-3Torrを
越える圧力の排気であれば、圧縮成形体の内部に
残留したガスにより焼結の際に圧縮成形体内部が
酸化されてしまうので、圧力を１×10-3Torr以
下にする必要がある。ついで、容器３内の排気を
続けながら、バリアブル・リークバルブ４を開け
て下表に示した圧力になるまで水素ボンベ５内の
水素ガスを容器３内に導入し、この圧力を維持し
ながら排気を続け、圧縮成形体１をヒータ２で加
熱して焼結を行う。真空ポンプとしては拡散ポン
プ６と油回転ポンプ７とを使用した。排気速度は
いずれも300l／ｓである。圧力が１×10-2Torr以
下の場合には拡散ポンプ６および油回転ポンプ７
の両方を、１×10-2Torrを越える場合には油回
転ポンプ７のみを稼動させた。なお、拡散ポンプ
６および油回転ポンプ７を稼働させる際には主に
バルブ８および荒引用バルブ９の両方をあけ、ま
た油回転ポンプ７のみを稼動させ際には荒引用バ
ルブ９のみをあける。ヒータ２の昇温速度は10
℃／分とした。室温から昇温し、焼結温度（最高
温度）を1000℃とした。
上記実験結果を下表に示す。
INDUSTRIAL APPLICATION FIELD The present invention relates to a method of manufacturing a sintered electrode for a discharge lamp. Conventional structure and its problems Conventionally, in the manufacturing method of sintered electrodes for discharge lamps, a compressed body of a mixed powder of a metal powder and an electron radioactive substance suitable as an electrode material is sintered using a pressure of 1 atm. A method of heating and sintering a compression molded body in a reducing gas atmosphere or in a vacuum is used. However, in the former case, the reducing gas does not sufficiently reach the inside of the porous compression molded body, and the interior of the compression molded body is oxidized by residual gas and impurity gas generated during sintering. There was a problem. In particular, when sintering a compacted compact using a carbonate such as an alkaline earth metal as an electron radioactive substance, this electron radioactive substance reacts with reducing gas in the presence of the base metal and is removed from the compacted compact. I had a problem with putting it away. On the other hand, in the latter case, the problems in the former case do not occur, but especially when carbonates of alkaline earth metals are used as the electron radioactive substance, oxidizing gas is generated due to the decomposition of the carbonates, resulting in the compression molding. is oxidized, and a discharge lamp using this as an electrode does not have good characteristics. To prevent this, the amount of compression molded material for one sintering process may be limited, or the There was a problem with productivity inhibition, such as slowing down the heating rate. OBJECTS OF THE INVENTION The present invention provides a method for manufacturing a sintered electrode for a discharge lamp that has good characteristics and is suitable for mass production. Structure of the Invention The present invention places a compression-molded body of a mixed powder of a metal powder and an electron radioactive substance made of an alkaline earth metal carbonate in a container, and the inside of the container is heated to 1×10 −3
After evacuation to a pressure below Torr, while continuing the evacuation, 1×10 -4 to 300Torr is added to the container.
The present invention is characterized by a method for producing a sintered electrode for a discharge lamp, in which reducing gas is introduced at a pressure of 100 ml, and the compressed compact is sintered by continuing the evacuation while maintaining this pressure. DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in the figure, as a sample, a compression molded body 1 of powder containing molybdenum (Mo) as a base metal and an electron radioactive substance made of 10% by weight of an alkaline earth metal carbonate is placed inside. Place 100 pieces in container 3 of a vacuum evacuation device with 1
Evacuate with a vacuum pump until the pressure is below ×10 -5 Torr. The weight of the compression molded product 1 is 500 mg/piece. It is almost uniformly mixed with molybdenum and electron radioactive material. In such a case, if the exhaust pressure exceeds 1×10 -3 Torr, the gas remaining inside the compression molded body will oxidize the inside of the compression molded body during sintering, so the pressure should be reduced to 1×10 -3 Torr. Must be below 3 Torr. Next, while continuing to exhaust the inside of the container 3, open the variable leak valve 4 and introduce the hydrogen gas in the hydrogen cylinder 5 into the container 3 until the pressure shown in the table below is reached, and continue to exhaust while maintaining this pressure. Then, the compression molded body 1 is heated with the heater 2 to perform sintering. A diffusion pump 6 and an oil rotary pump 7 were used as vacuum pumps. The pumping speed was 300 l/s in both cases. If the pressure is below 1×10 -2 Torr, use diffusion pump 6 and oil rotary pump 7.
When the pressure exceeds 1×10 -2 Torr, only the oil rotary pump 7 is operated. Note that when operating the diffusion pump 6 and the oil rotary pump 7, both the valve 8 and the rough intake valve 9 are mainly opened, and when only the oil rotary pump 7 is operated, only the rough intake valve 9 is opened. The heating rate of heater 2 is 10
°C/min. The temperature was raised from room temperature to a sintering temperature (maximum temperature) of 1000°C. The above experimental results are shown in the table below.
【表】【table】
【表】
焼結前重量−焼結後重量
※1 減量率＝[Table] Weight before sintering - Weight after sintering *1 Weight loss rate =
Claims (1)
炭酸塩からなる電子放射性物質との混合粉末の圧
縮成形体を入れ、前記容器内を１×10-3Torr以
下の圧力で真空に排気した後、前記排気を続けな
がら、前記容器内に１×10-4〜300Torrの圧力の
還元ガスを導入し、この圧力を維持しながら、前
記排気を続けて、前記圧縮成形体を焼結すること
を特徴とする放電ランプ用焼結電極の製造方法。1 A compression molded body of a mixed powder of metal powder and an electron radioactive substance made of carbonate of an alkaline earth metal was placed in a container, and the inside of the container was evacuated to a pressure of 1×10 -3 Torr or less. After that, while continuing the evacuation, a reducing gas at a pressure of 1×10 -4 to 300 Torr is introduced into the container, and while maintaining this pressure, the evacuation is continued to sinter the compression molded body. A method for manufacturing a sintered electrode for a discharge lamp, characterized by:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20252684A JPS6180726A (en) | 1984-09-27 | 1984-09-27 | Manufacture of sintering electrode for discharge lamp |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20252684A JPS6180726A (en) | 1984-09-27 | 1984-09-27 | Manufacture of sintering electrode for discharge lamp |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6180726A JPS6180726A (en) | 1986-04-24 |
| JPH0562414B2 true JPH0562414B2 (en) | 1993-09-08 |
Family
ID=16458950
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20252684A Granted JPS6180726A (en) | 1984-09-27 | 1984-09-27 | Manufacture of sintering electrode for discharge lamp |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6180726A (en) |
-
1984
- 1984-09-27 JP JP20252684A patent/JPS6180726A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6180726A (en) | 1986-04-24 |
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