JPH0686359B2 - Rare earth boride single crystal and its growth method - Google Patents
Rare earth boride single crystal and its growth methodInfo
- Publication number
- JPH0686359B2 JPH0686359B2 JP29135390A JP29135390A JPH0686359B2 JP H0686359 B2 JPH0686359 B2 JP H0686359B2 JP 29135390 A JP29135390 A JP 29135390A JP 29135390 A JP29135390 A JP 29135390A JP H0686359 B2 JPH0686359 B2 JP H0686359B2
- Authority
- JP
- Japan
- Prior art keywords
- single crystal
- rare earth
- boride
- earth boride
- raw material
- 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
- 239000013078 crystal Substances 0.000 title claims description 39
- 238000000034 method Methods 0.000 title claims description 38
- 229910052761 rare earth metal Inorganic materials 0.000 title claims description 25
- 150000002910 rare earth metals Chemical class 0.000 title claims description 25
- 239000002994 raw material Substances 0.000 claims description 17
- 229910052746 lanthanum Inorganic materials 0.000 claims description 12
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 claims description 12
- 239000000155 melt Substances 0.000 claims description 12
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 4
- 229910052688 Gadolinium Inorganic materials 0.000 claims description 3
- 229910052772 Samarium Inorganic materials 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 2
- 229910052796 boron Inorganic materials 0.000 claims description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 claims description 2
- 239000000843 powder Substances 0.000 description 6
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 230000007547 defect Effects 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 239000000428 dust Substances 0.000 description 3
- 230000008020 evaporation Effects 0.000 description 3
- 238000001704 evaporation Methods 0.000 description 3
- DSSYKIVIOFKYAU-XCBNKYQSSA-N (R)-camphor Chemical compound C1C[C@@]2(C)C(=O)C[C@@H]1C2(C)C DSSYKIVIOFKYAU-XCBNKYQSSA-N 0.000 description 2
- 241000723346 Cinnamomum camphora Species 0.000 description 2
- 229910052779 Neodymium Inorganic materials 0.000 description 2
- 229910052777 Praseodymium Inorganic materials 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 229960000846 camphor Drugs 0.000 description 2
- 229930008380 camphor Natural products 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- NJPPVKZQTLUDBO-UHFFFAOYSA-N novaluron Chemical compound C1=C(Cl)C(OC(F)(F)C(OC(F)(F)F)F)=CC=C1NC(=O)NC(=O)C1=C(F)C=CC=C1F NJPPVKZQTLUDBO-UHFFFAOYSA-N 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 239000012808 vapor phase Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Crystals, And After-Treatments Of Crystals (AREA)
- Solid Thermionic Cathode (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は六硼化希土類系単結晶とこれを融液法により育
成する方法に関する。TECHNICAL FIELD The present invention relates to a rare earth hexaboride single crystal and a method for growing the same by a melt method.
（従来の技術及び解決しようとする課題） 六硼化希土類単結晶は、現在、寿命の長い高輝度電子放
射材料として、有望視されている。(Prior Art and Problems to be Solved) Rare earth hexaboride single crystals are currently regarded as promising as a high-brightness electron emitting material having a long life.
硼化希土類単結晶の育成法としては、溶液法、気相法、
融液法などが知られているが、高純度な単結晶を育成す
るには、育成温度が高い融液法が適している。As a method for growing a rare earth boride single crystal, a solution method, a vapor phase method,
Although the melt method and the like are known, the melt method with a high growth temperature is suitable for growing a high-purity single crystal.
融液法としては、アークベルヌーイ法、フローティング
・ゾーン法、ペデェスタル法があるが、高品質単結晶を
育成するフローティング・ゾーン法が適している。As the melt method, there are the Arc Bernoulli method, the floating zone method, and the pedestal method, but the floating zone method for growing a high-quality single crystal is suitable.
従来、融液法による硼化希土類単結晶の育成法において
は、単結晶の純度を高くするために、高純度の硼化希土
類原料が用いられてきた。しかし、この方法により育成
された単結晶中には多くの欠陥（例えば、粒界密度で10
3cm/cm2）が存在するという欠点があった。このため、
高品質な部分を選び、電子放射材として使用せざるを得
ないのが実情である。Conventionally, in the method for growing a rare earth boride single crystal by the melt method, a high-purity rare earth boride raw material has been used in order to increase the purity of the single crystal. However, many defects (for example, 10 at grain boundary density) exist in single crystals grown by this method.
3 cm / cm 2 ) was present. For this reason,
The reality is that high quality parts must be selected and used as electron emitting materials.
本発明は、上記従来技術の欠点を解消して、欠陥のない
良質な硼化希土類系単結晶を提供することを目的とする
ものである。An object of the present invention is to solve the above-mentioned drawbacks of the prior art and to provide a high-quality rare earth boride single crystal free of defects.
（課題を解決するための手段） 前記課題を解決するため、本発明者らは、従来の融液法
において高純度の硼化希土類原料を用いても単結晶中に
多くの欠陥が存在することに鑑みて、原料として、硼化
ランタンを含有させることについて試みた。その結果、
硼化希土類に劣らない電子放射特性を示す硼化ランタン
を含有させた原料を使用したところ、硼希希土類の電子
放射特性を劣化することなく、良質の硼化希土類系単結
晶が育成できることを見い出した。特に、直径1cmの単
結晶を育成する場合、30モル％以上の硼化ランタンを含
有させると、全く粒界を含まない完全性の高い単結晶を
育成できることを知見し、ここに本発明をなしたもので
ある。(Means for Solving the Problems) In order to solve the above problems, the present inventors have found that many defects exist in a single crystal even when a high-purity rare earth boride raw material is used in a conventional melt method. In view of the above, an attempt was made to incorporate lanthanum boride as a raw material. as a result,
By using a raw material containing lanthanum boride showing electron emission characteristics comparable to those of rare earth boride, it has been found that a good quality rare earth boride single crystal can be grown without degrading the electron emission characteristics of rare earth boride. It was In particular, in the case of growing a single crystal having a diameter of 1 cm, it was found that, by containing 30 mol% or more of lanthanum boride, it is possible to grow a highly complete single crystal containing no grain boundary, and the present invention is here It was done.
すなわち、本発明は、化学式（M1-XLaX）B6（但し、Ｍ
はPr、Nd、Sm、Gdで、0.01≦ｘ≦0.50）を有することを
特徴とする硼化希土類系単結晶を要旨とするのである。That is, the present invention provides the chemical formula (M 1-X La X ) B 6 (provided that M
Is a rare-earth boride single crystal characterized by having Pr, Nd, Sm, and Gd of 0.01 ≦ x ≦ 0.50).
また、その育成法は、硼化希土類系単結晶を融液法によ
って育成するに際し、原料として、１モル％以上50モル
％未満の硼化ランタンを含有する硼化希土類を使用する
ことを特徴とするものである。Further, the growing method is characterized in that rare earth boride containing 1 mol% or more and less than 50 mol% lanthanum boride is used as a raw material when growing a rare earth boride single crystal by a melt method. To do.
以下に本発明を更に詳述する。The present invention will be described in more detail below.
（作用） 本発明において用いられる単結晶育成法は融液法であ
り、前述の如く種々の方法が可能であるが、フローティ
ング・ゾーン法（以下、「FZ法」という）は、大型で高
品位の単結晶が育成し易いので、好ましい。(Operation) The single crystal growing method used in the present invention is a melt method, and various methods are possible as described above, but the floating zone method (hereinafter, referred to as “FZ method”) is a large-scale and high-quality method. Is preferable because it easily grows.
第１図はFZ法育成炉の概念図であり、１は上軸、１′は
下軸、２、２′はホルダー、３は焼結棒（原料）、３′
は初期融帯保持用焼結棒又は種結晶、４は育成した単結
晶、５は融帯、６は高周波ワークコイルである。Fig. 1 is a conceptual diagram of the FZ growth reactor, where 1 is an upper shaft, 1'is a lower shaft, 2'is a holder, 3 is a sintered rod (raw material), 3 '.
Is a sintered rod or seed crystal for holding the initial melt zone, 4 is a grown single crystal, 5 is a melt zone, and 6 is a high-frequency work coil.
原料としては、硼化希土類粉末に硼化ランタン粉末を１
モル％以上50モル％未満混合し、これに結合剤として少
量の樟脳を加えて、ラバープレス（2000kg/cm2）により
圧粉棒を作製する。この圧粉棒を真空中又は不活性ガス
雰囲気中で千数百℃に加熱して、原料焼結棒を作製す
る。Lanthanum boride powder was added to rare earth boride powder as raw material.
Mix at least mol% but less than 50 mol%, add a small amount of camphor as a binder, and make a dust bar by a rubber press (2000 kg / cm 2 ). This powder compact rod is heated to a few thousand and several hundred degrees Celsius in a vacuum or in an inert gas atmosphere to prepare a raw material sintered rod.
なお、原料焼結棒としては、上記の如く硼化ランタン粉
末を使用する以外に、ランタンの酸化物、水酸化物、塩
化物などと硼素を、硼化ランタン換算で上記所定量を含
有させることも可能である。As the raw material sintered rod, in addition to using the lanthanum boride powder as described above, lanthanum oxide, hydroxide, chloride, etc. and boron should be contained in the above predetermined amounts in terms of lanthanum boride. Is also possible.
得られた原料焼結棒３を上軸１にホルダー２を介してセ
ットし、下軸１′には、初期融帯保持用の焼結棒又は種
結晶３′をホルダー２′を介してセットする。次に原料
焼結棒３の下端を高周波ワークコイル６からの誘導加熱
により溶融させ、融帯５を形成させ、上軸１と下軸１′
をゆっくり下方に移動させて単結晶４を育成する。The obtained raw material sintered rod 3 is set on the upper shaft 1 via the holder 2, and the lower rod 1'is set on the lower shaft 1'with the sintered rod or seed crystal 3'for holding the initial zone through the holder 2 '. To do. Next, the lower end of the raw material sintering rod 3 is melted by induction heating from the high frequency work coil 6 to form a fusion zone 5, and the upper shaft 1 and the lower shaft 1 '
Is slowly moved downward to grow the single crystal 4.
その時の育成速度は0.2〜5cm/h、好ましくは0.5〜2cm/h
である。雰囲気は数気圧のアルゴン又はヘリウムなどの
不活性ガスが用いられる。これは、蒸発の抑制と高周波
ワークコイル部分で発生する放電を防止するためであ
る。The growth rate at that time is 0.2-5 cm / h, preferably 0.5-2 cm / h
Is. As the atmosphere, an inert gas such as argon or helium having a pressure of several atmospheres is used. This is to suppress evaporation and to prevent discharge generated in the high frequency work coil portion.
かくして育成される単結晶は、化学式（M1-XLaX）B
6（但し、ＭはPr、Nd、Sm、Gdで、0.01≦ｘ≦0.50）を
有する硼化希土類系単結晶である。ここで、ｘが0.01未
満では硼化ランタンを添加した効果が殆ど見られない。
すなわち、単結晶中の粒界密度の減少が実験誤差の中に
含まれてしまう程度である。また、0.50以上では単結晶
中に気泡が含有することがあり、実用上好ましくない。The single crystal thus grown has the chemical formula (M 1-X La X ) B
6 (where M is Pr, Nd, Sm, and Gd, 0.01 ≦ x ≦ 0.50), and is a rare earth boride single crystal. Here, when x is less than 0.01, the effect of adding lanthanum boride is hardly seen.
That is, the decrease in the grain boundary density in the single crystal is included in the experimental error. Further, if it is 0.50 or more, bubbles may be contained in the single crystal, which is not preferable in practical use.
融液法による育成法としては、上述の高周波加熱による
FZ法に限らず、赤外線集中加熱によるFZ法も可能であ
り、更には、FZ法以外に、融液より引き上げる引き上げ
法、アーク・ベルヌイ法、ペヂェスタル法も可能であ
り。それぞれの方法に適した原料調整を行う。As the growth method by the melt method, the above-mentioned high frequency heating is used.
The FZ method is not limited to the FZ method, and the FZ method by infrared concentrated heating is also possible. Further, in addition to the FZ method, the pulling method of pulling up from the melt, the arc-Bernui method, and the pedestal method are also possible. Adjust the raw materials suitable for each method.
次に本発明の実施例を示す。Next, examples of the present invention will be described.
（実施例） 硼化希土類粉末に所定比（ｘ＝0.02、0.1、0.2、0.3、
0.4）の硼化ランタン粉末を添加し混合した後、結合剤
として樟脳を少量加えて再び混合した。この混合物を直
径12mmのゴム袋に詰て円柱状にし、これを2000kg/cm2の
ラバープレスして圧粉棒を得た。この圧粉棒を真空中、
1800℃で加熱して焼結棒を得た。(Example) A rare earth boride powder with a predetermined ratio (x = 0.02, 0.1, 0.2, 0.3,
After the lanthanum boride powder of 0.4) was added and mixed, a small amount of camphor as a binder was added and mixed again. The mixture was packed in a rubber bag having a diameter of 12 mm to form a columnar shape, which was rubber-pressed at 2000 kg / cm 2 to obtain a dust bar. This dust bar in vacuum,
A sintered rod was obtained by heating at 1800 ° C.
この焼結棒を第１図に示すFZ育成炉の上軸にホルダーを
介して固定し、下軸には（M1-XLaX）B6単結晶を固定し
た。育成炉に７気圧のアルゴンを充填した後、高周波コ
イルにより原料焼結棒を下端を溶かして初期融帯を形成
し、1cm/hで下方に移動させて、＜100＞方位に単結晶を
育成した。The sintered rod was fixed to the upper shaft of the FZ growth furnace shown in FIG. 1 via a holder, and the (M 1-X La X ) B 6 single crystal was fixed to the lower shaft. After filling the growth furnace with argon at 7 atm, the high-frequency coil melts the lower end of the raw material sintering rod to form an initial melt zone, and moves it downward at 1 cm / h to grow a single crystal in the <100> orientation. did.
得られた単結晶は、直径1cm、長さ7cmであった。育成時
の蒸発による組成変化を、原料焼結棒と焼結棒終端部の
分析から調べたところ、希土類の原子番号が大きい程、
蒸発による損失が大きく、添加したLaB6成分が増加し
た。例えば、40モル％添加した場合、PrB6では１モル
％、NdB6では２モル％、SmB6では４モル％、GdB6では５
モル％、それぞれLaB6成分が増加した。The obtained single crystal had a diameter of 1 cm and a length of 7 cm. When the composition change due to evaporation during growth was examined from the analysis of the raw material sintered rod and the end portion of the sintered rod, the larger the atomic number of the rare earth,
The loss due to evaporation was large, and the added LaB 6 component increased. For example, when added 40 mol%, in PrB 6 1 mol%, in NdB 6 2 mol%, the SmB 6 4 mol%, in GdB 6 5
The mole percentage of LaB 6 was increased.
育成した単結晶の粒界密度は、結晶終端部の（100）面
を切り出し、鏡面研磨した後、エッチング（硝酸：水＝
1:3の液で２〜３分）して測定した結果、第２図に示す
ように、硼化希土類に硼化ランタンを添加してゆくと粒
界密度が減少し、30モル％以上添加するとすべての場合
で粒界が観察できなくなった。単結晶中に粒界が存在し
ない領域は、育成する結晶の直径に依存し、細くなる
程、広くなった。The grain boundary density of the grown single crystal was determined by cutting out the (100) plane at the crystal end, mirror-polishing, and then etching (nitric acid: water =
As a result of measurement with a solution of 1: 3) for 2 to 3 minutes, as shown in FIG. 2, when lanthanum boride is added to rare earth boride, the grain boundary density decreases, and 30 mol% or more is added. Then, the grain boundaries could not be observed in all cases. The region where grain boundaries do not exist in the single crystal depends on the diameter of the grown crystal and becomes wider as it becomes thinner.
（発明の効果） 以上詳述したとおり、本発明によれば、欠陥のない良質
な硼化希土類単結晶を提供することができ、敢えて高純
度硼化希土類原料を使用しなくともよいので経済的であ
る。(Effects of the Invention) As described in detail above, according to the present invention, it is possible to provide a high-quality rare earth boride single crystal free from defects, and it is economical because a high-purity rare earth boride raw material need not be used. Is.
第１図はFZ育成炉の一例を説明する図、 第２図は実施例で得られた単結晶の粒界密度とLaB6添加
量の関係を示す図である。 １……上軸、１′……下軸、２、２′……ホルダー、３
……焼結棒（原料）、３′……初期融帯保持用焼結棒又
は種結晶、４……育成した単結晶、５……融帯、６……
高周波ワークコイル。FIG. 1 is a diagram for explaining an example of an FZ growth furnace, and FIG. 2 is a diagram showing the relationship between the grain boundary density of the single crystal obtained in the example and the amount of LaB 6 added. 1 ... Upper shaft, 1 '... Lower shaft, 2, 2' ... Holder, 3
...... Sintered rod (raw material), 3 '... Sintered rod or seed crystal for holding the initial zone, 4 ... Grown single crystal, 5 ... Zone, 6 ...
High frequency work coil.
Claims (3)
d、Sm、Gdで、0.01≦ｘ≦0.50）を有することを特徴と
する硼化希土類系単結晶。1. A chemical formula (M 1-X La X ) B 6 (where M is Pr, N
A rare-earth boride single crystal having d, Sm, and Gd of 0.01 ≦ x ≦ 0.50).
するに際し、原料として、１モル％以上50モル％未満の
硼化ランタンを含有する硼化希土類を使用することを特
徴とする硼化希土類系単結晶の育成法。2. A rare earth boride containing 1 mol% or more and less than 50 mol% lanthanum boride is used as a raw material when growing a rare earth boride single crystal by a melt method. Method for growing rare earth single crystals.
物、水酸化物又は塩化物と硼素を所定比に混合したもの
を用いる請求項２に記載の方法。3. The method according to claim 2, wherein a mixture of lanthanum oxide, hydroxide or chloride and boron in a predetermined ratio is used instead of lanthanum boride.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29135390A JPH0686359B2 (en) | 1990-10-29 | 1990-10-29 | Rare earth boride single crystal and its growth method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29135390A JPH0686359B2 (en) | 1990-10-29 | 1990-10-29 | Rare earth boride single crystal and its growth method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH04164896A JPH04164896A (en) | 1992-06-10 |
| JPH0686359B2 true JPH0686359B2 (en) | 1994-11-02 |
Family
ID=17767834
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29135390A Expired - Lifetime JPH0686359B2 (en) | 1990-10-29 | 1990-10-29 | Rare earth boride single crystal and its growth method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0686359B2 (en) |
-
1990
- 1990-10-29 JP JP29135390A patent/JPH0686359B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04164896A (en) | 1992-06-10 |
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