JPS60228603A - Production of metallic powder - Google Patents

Abstract

PURPOSE:To produce a substantially fine metallic powder product at a high yield by bringing once the formed metallic melt into collision against an object moving at a high speed to scatter said melt then bringing the melt further into collision against the succeeding object moving at a high speed. CONSTITUTION:The inside of a vacuum vessel 1 is replaced with gaseous Ar. The gaseous Ar is supplied to a plasma gun 4 and the inside of the vessel 1 is maintained under prescribed pressure. An electric power source 8 is operated to generate plasma and the top end of a raw material metal 7 is heated to melt. The melt thereof is dropped in the form of molten drops on the surface of a roll 10 under high-speed rotation and is scattered in the rotating direction. The fine grains among the scattering molten drops have the high speed component in the direction perpendicular to the surface movement of the roll 10 and scatter mainly in a direction 12. The coarse molten drops accelerated by the roll 10 scatter mainly in a direction 13 so as to collide again against the surface of the 2nd roll 11, by which the drops are effectively pulverized. The solidified pulverous powder collides against the inside wall and is recovered through a chute part 1' into a powder container 12.

Description

【発明の詳細な説明】 本発明は、金属又は合金（本発明では金属と記す）の粉
末の機械的アトマイズ法に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for mechanical atomization of powders of metals or alloys (herein referred to as metals).

金属粉末の大量生産方法として、（イ）固体原料を機械
的に粉砕する。（ロ）溶融金属をガス又は液体を媒体と
し【噴霧する。（ハ）溶融金属を高速運動する物体の表
面に衝突させ、微細融滴化、凝固させる（以下機械的ア
トマイズ法と記す）及びに）その他に大別できる。As a method for mass production of metal powder, (a) solid raw materials are mechanically pulverized; (b) Spraying molten metal using gas or liquid as a medium. (c) Making molten metal collide with the surface of an object moving at high speed to turn it into fine melt droplets and solidify it (hereinafter referred to as mechanical atomization method);

上記（ハ）の機械的アトマイズ法は、高速運動する物体
をロール又は円板状部材の表面部とすることにより、設
備を簡易化できる利点を有する。The above mechanical atomization method (c) has the advantage that the equipment can be simplified by using the surface of the roll or disk-shaped member as the object moving at high speed.

本発明でいう真空または低圧とは０．１　ｔｏｒｒ以下
の圧力をいい、このような低圧力下ではロール等の高速
回転に依るキャビテーヨン発生は期待出来ずしたがって
、従来の方法では、供給された溶湯な微細に分断する効
果が十分でなく、ノズルから流出＋る連続した溶湯流に
適用する場合はもちろん、ノズルによる溶湯の汚染を防
止する等のため、固体原料を高エネルギ密度の熱源で加
熱して溶融し、小融滴として直接供給する場合にも、十
分微細な製品粉末を高収率で得ることができなかった。Vacuum or low pressure in the present invention refers to a pressure of 0.1 torr or less. Under such low pressure, cavitation due to high-speed rotation of rolls, etc. cannot be expected to occur, and therefore, in the conventional method, In cases where the effect of dividing the molten metal into fine pieces is insufficient and the application is applied to a continuous flow of molten metal flowing out from the nozzle, solid raw materials are heated with a high energy density heat source in order to prevent contamination of the molten metal by the nozzle. Even when the powder is melted and directly supplied as small melt droplets, it has not been possible to obtain a sufficiently fine product powder with a high yield.

本発明は、従来の機械的アトマイズ法を改良し、十分微
細な金属粉末製品な高収率で生産する方法を提供するこ
とを目的とする。The present invention aims to improve the conventional mechanical atomization method and provide a method for producing sufficiently fine metal powder products with high yield.

本発明は、供給された溶融金属を一旦高速運動物体に衝
突させて飛散させた後この一部又は全部をさらに後続の
高速運動物体に衝突させて微粒化することを特徴とする
金属粉末の製造方法である。The present invention is a method of producing metal powder, which is characterized in that the supplied molten metal is once collided with a high-speed moving object to be scattered, and then a part or all of the supplied molten metal is further collided with a subsequent high-speed moving object to be atomized. It's a method.

従来の機械的アトマイズ法は、高速運動物体が唯−箇で
あり、かつこの高速運動物体に対する供給溶湯の近寄り
速度が小さいため、この溶湯に対する分断又は破砕効果
が低く粗大融滴が多量に発生して、高収率で微細金属粉
末を得ることができなかった。このため従来高速運動物
体の表面を凹凸状とする例もあるが、十分満足する効果
とはなっていない。In the conventional mechanical atomization method, the only object is a high-speed moving object, and the approaching speed of the supplied molten metal to this high-speed moving object is low, so the effect of dividing or crushing the molten metal is low and a large amount of coarse molten droplets are generated. Therefore, it was not possible to obtain fine metal powder in high yield. For this reason, there have conventionally been cases in which the surface of a high-speed moving object is made uneven, but this has not produced a sufficiently satisfactory effect.

本発明によると、一旦高速運動物体に衝突して飛散する
融滴のうち、十分微細な融滴は強い表面張力の作用によ
り次段の高速運動物体と衝突しても、さらに微小化され
る作用は少ないが、粗大な融滴は前段の高速運動物体で
加速されたものであり、次段の高速運動物体に大きい近
寄り速度で衝突し、その内部に発生する高い圧力で、そ
の表面張力に打勝って被装し微細化される。また高速運
動物体と衝突後の融滴の飛散方向は、その粒径に依存性
を有することが判明した。すなわち微細融滴は粗大融滴
に比し、高速運動物体の運動方向の速度成分に対するそ
れに直角方向の速度成分が大きいものが多い。したがっ
て、後続の高速運動物体を粗大融滴の飛散方向に配置す
ることにより、この粗大融滴な選択的に微粒化すること
が可能となる。According to the present invention, among the molten droplets that are scattered once they collide with a high-speed moving object, sufficiently fine molten droplets are made even smaller even if they collide with the next high-speed moving object due to the action of strong surface tension. Although the droplet is small, it is accelerated by the high-speed moving object in the previous stage, and collides with the high-speed moving object in the next stage at a high approaching speed, and the high pressure generated inside the droplet overcomes its surface tension. It is then coated and refined. Furthermore, it was found that the scattering direction of the molten droplets after collision with a high-speed moving object was dependent on the particle size. That is, compared to coarse melt droplets, fine melt droplets often have a larger velocity component in the direction perpendicular to the velocity component in the direction of motion of the high-speed moving object. Therefore, by placing a subsequent high-speed moving object in the scattering direction of the coarse molten droplets, it becomes possible to selectively atomize the coarse molten droplets.

次に、実施例の図面に基づいて本発明を説明する。第１
図は固体原料を真空プラズマで局部加熱して融滴とし、
この融滴に高速運動物体としてロールを使用した本発明
の実施例の装置図である。Next, the present invention will be explained based on drawings of embodiments. 1st
The figure shows solid raw materials being locally heated with vacuum plasma to form molten droplets.
It is a diagram of an apparatus of an embodiment of the present invention in which a roll is used as a high-speed moving object for the melt droplets.

高速運動物体としてロールを使用することの長所、　６
　。Advantages of using rolls as high-speed moving objects, 6
.

は、大量連続生産に必要な高速運動物体の冷却が内壁側
から水冷することで容易であり、また円板に比し、飛散
融滴の飛散方向を収束させ易（、特に本発明において溶
融金属は複数回衝突させるのに有利である。もちろん収
束性をさらに向上するためロールな鼓腸状としてそのの
ど内部に溶融金属を衝突させること、又は分断性向上の
ためロール表面に凹凸状にすることもある程度効果があ
る。It is easy to cool the high-speed moving object required for mass continuous production by water cooling from the inner wall side, and it is also easier to converge the flying direction of the scattered molten droplets compared to a disk (in particular, in the present invention, the molten metal It is advantageous to collide multiple times.Of course, to further improve convergence, it is also possible to collide the molten metal into the throat of the roll as a flattened roll, or to make the surface of the roll uneven to improve breakability. It is effective to some extent.

真空槽１の上部に駆動装置２で上下、左右方向及び回転
が可能とされた支持装置３が設けられ、この下端に真空
プラズマ銃４が取付けられている。A support device 3 is provided at the top of the vacuum chamber 1 and can be rotated vertically, horizontally, and rotated by a drive device 2, and a vacuum plasma gun 4 is attached to the lower end of the support device 3.

また、このプラズマ銃２と軸線が互いに直交するごとく
、駆動装置５で軸線方向に可動とされた原料支持装置６
が設けられ、この先端に原料金属７が固定されている。Further, a raw material support device 6 is movable in the axial direction by a drive device 5 so that the plasma gun 2 and the axis are perpendicular to each other.
is provided, and the raw metal 7 is fixed to the tip thereof.

プラズマ銃４と原料金属７間には電源装［８が接続され
ている。真空槽１は排気口９を経て図示しない排気系に
接続され、所定真空度とすることができる。真空槽１内
には内周側を水冷され、矢印の方向に高速回転駆動され
た二部のローラ１０，１１が、一方ははｙ原料金属７の
・　４　・ 直下に、他方はこれより左やや下方にそれぞれ設けられ
ている。真空槽１の下方にはシュート部１′が設けられ
その下方に粉末容器１２が着脱可能に設けられている。A power supply device [8 is connected between the plasma gun 4 and the raw metal 7. The vacuum chamber 1 is connected to an exhaust system (not shown) through an exhaust port 9, so that a predetermined degree of vacuum can be achieved. Inside the vacuum chamber 1, there are two rollers 10 and 11 whose inner periphery is water-cooled and driven to rotate at high speed in the direction of the arrow. They are located slightly below each other. A chute portion 1' is provided below the vacuum chamber 1, and a powder container 12 is removably provided below the chute portion 1'.

次に上記実施例の作動を説明する。真空槽１内を一旦高
真空にしてＡｒガスで置換した後、プラズマ銃４にＡｒ
ガスを供給するとともに排気系を作動し【真空槽１内を
所定圧力に保持しつつ、電源８を作動させてプラズマを
発生させ、これによって原料金属７の先端部を加熱する
。この加熱で原料金属７の先端は溶融し、この溶融物は
融滴となって高速回転しているロール１００表面に落下
して衝突し、その回転方向に飛散する。飛散融滴のうち
微粒のものはロール１００表面の運動方向に対し直角方
向の速度成分が大きく、したがって１３の方向に主に飛
散し、また粗大融滴はこのロール１０で加速されるとと
もに、主に１４の方向に飛散して第２のロール１１０表
面に再度衝突して効果的に微細化される。か（して微細
化された融滴は、飛散飛行中に輻射及び雰囲気ガスで冷
却され、凝固した後真空槽１の内壁に衝突し、シュート
部１′を経て粉末容器１２に回収される。従来の機械的
アトマイズ法では粗大融滴が多量に生成され、微粉末の
収率な低下することはもちろん、これが十分凝固しない
まま真空槽１の内壁に衝突して付着し、この付着物が生
長し易いため、真空槽１を非常に大型化する必要があり
、また操業を中断する場合もあったが、本発明はこれら
をも回避できる。Next, the operation of the above embodiment will be explained. After the vacuum chamber 1 is once made to a high vacuum and replaced with Ar gas, the plasma gun 4 is injected with Ar gas.
While supplying gas, the exhaust system is operated, and while maintaining the vacuum chamber 1 at a predetermined pressure, the power supply 8 is operated to generate plasma, thereby heating the tip of the raw metal 7. This heating melts the tip of the raw material metal 7, and this molten material falls as molten droplets onto the surface of the roll 100 rotating at high speed, collides with it, and scatters in the direction of rotation. Among the scattered melt droplets, fine particles have a large velocity component in the direction perpendicular to the direction of movement of the surface of the roll 100, and therefore are mainly scattered in the direction 13, while coarse melt droplets are accelerated by the roll 10 and are Then, the particles scatter in the direction 14 and collide again with the surface of the second roll 110, where they are effectively atomized. The molten droplets thus made fine are cooled by radiation and atmospheric gas during the scattering flight, and after solidifying, collide with the inner wall of the vacuum chamber 1, and are collected into the powder container 12 through the chute section 1'. In the conventional mechanical atomization method, a large amount of coarse molten droplets are generated, which not only reduces the yield of fine powder, but also causes the droplets to collide and adhere to the inner wall of the vacuum chamber 1 without solidifying sufficiently, resulting in the growth of these deposits. However, the present invention can also avoid these problems.

次に上記実施例の装置を用いて行った例を説明する。Next, an example using the apparatus of the above embodiment will be explained.

実施例１．　原料金属７はＩｎｃｏ　７１８の直径４０
叫×１０００　ｔｍ長さとし、プラズマ出力５０ＫＷ、
真空槽内は圧力１０　”　Ｔｏｒｒのアルゴン雰囲気、
ロール１０は銅製水冷の直径４００■×４００助長さで
１５０ＯＲＰＭで回転し、融滴落下衝突位置をロールの
軸心に対し５０ｍだけ飛散方向にずらして設定した。ロ
ール１１は銅製水冷、直径３００ｗ＋Ｘ４００ｍ長さと
し、ロール１０に対しその飛散方向に５００ｍ＋下方に
１３０ｍに設け１ｏｏｏＲＰＭで回転した。この条件で
得られた金属粉末は、はｙ球状で粒径１００μｍ以下の
収率は約８０％であったピ次にロール１１を除去し、他
は上記と同条件として従来の方法を模した実施例では１
ｏｏμｍ以下の収率は約５０％であった。上記の実施例
で観察窓からの目視観察結果では、ロール１１に衝突し
ない融滴が多量に存在することが確認され、上記の１０
０μｍ以下の収率の向上効果と併せ、ロール１１に衝突
する融滴が比較的粗大であることの傍証を得た。Example 1. The raw metal 7 is Inco 718 with a diameter of 40
length x 1000 tm, plasma output 50KW,
Inside the vacuum chamber, there is an argon atmosphere with a pressure of 10” Torr.
The roll 10 was made of water-cooled copper and had a diameter of 400 cm x 400 cm and rotated at 150 ORPM, and the droplet impact position was set to be shifted by 50 m in the scattering direction with respect to the axis of the roll. The roll 11 was water-cooled and made of copper, had a diameter of 300 W, a length of 400 m, and was placed 500 m in the scattering direction and 130 m below the roll 10, and rotated at 1 ooo RPM. The metal powder obtained under these conditions had a spherical shape and the yield of particles of 100 μm or less was about 80%. Next, roll 11 was removed, and the other conditions were the same as above, and the conventional method was imitated. In the example, 1
The yield below ooμm was about 50%. In the above example, visual observation through the observation window confirmed that there were a large number of molten droplets that did not collide with the roll 11.
In addition to the effect of improving the yield of 0 μm or less, evidence was obtained that the molten droplets colliding with the roll 11 were relatively coarse.

実施例２．　次に第２図に示すように前記実施例１０ロ
ール１１に換え、直径４００Ｉ＋ｌＩ＋１の銅製水冷ロ
ール１６及びこのロール１６かう４６０　ｍｎ　、　口
＃１０カラ４５０■の位置に直径３００簡の銅製水冷ロ
ール１７を配し、それぞれを矢印の方向に１１０００Ｒ
Ｐで回転し、他は前記実施例１と同条件でアトマイズし
た。この結果１００μｍ以下の収率が約９０％であり、
この実施例のロール１７を設置しないで行ったテスト結
果と比較すると、ロール１７の効果は収率において約７
％寄与していることが確認された。Example 2. Next, as shown in FIG. 2, in place of the roll 11 of Example 10, a copper water-cooled roll 16 with a diameter of 400I+lI+1 and a copper water-cooled roll 17 with a diameter of 300 mm were installed at the position of the roll 16 (460 mm) and the neck #10 (450 mm). 11000R each in the direction of the arrow.
P and the other conditions were the same as in Example 1 for atomization. As a result, the yield of 100 μm or less was about 90%,
Compared to test results conducted without roll 17 in this example, the effect of roll 17 on yield is approximately 7.
% contribution was confirmed.

以上の実施例は溶融金属の供給を固体金属の局部加熱に
よる融滴で行うもので述べたが、この方法は溶融金属が
ノズル及びこのノズルを取付けた、　ｌ　。In the above embodiments, the molten metal is supplied using molten droplets generated by local heating of the solid metal, but this method is based on a method in which the molten metal is supplied through a nozzle and the nozzle is attached to the molten metal.

溶湯容器から汚染されることがなく、高品位の金属粉末
の製造に有効である。しかし本発明の効果はこれらに限
定されるものではなく、むしろ従来の機械的アトマイズ
法の欠点であった、特にノズルを介する等連続流として
溶融金属を供給する場合の分断効果不足の解決に有効で
ある。また上記二実施例では局部加熱をプラズマで行う
もので述べたが、この局部加熱は高エネルギ密度の熱源
であればよ（、プラズマに限定されないものである。It is effective in producing high-grade metal powder without being contaminated from the molten metal container. However, the effects of the present invention are not limited to these, but rather are effective in solving the drawback of conventional mechanical atomization methods, particularly the lack of separation effect when molten metal is supplied as a continuous flow such as through a nozzle. It is. Further, in the above two embodiments, local heating is performed using plasma, but this local heating may be performed using any heat source with high energy density (but is not limited to plasma).

【図面の簡単な説明】[Brief explanation of the drawing]

第１図及び第２図は本発明の詳細な説明する図である。 １：真空槽、　４：プラズマ銃、 ７、原料金属、１０．１１，１６，１７　：ロール。 ・　８　・ FIGS. 1 and 2 are diagrams explaining the present invention in detail. 1: Vacuum chamber, 4: Plasma gun, 7. Raw metal, 10.11, 16, 17: Roll. ・　8　・

Claims (1)

【特許請求の範囲】 ｔ　真空又は低圧不活性ガス雰囲気中で溶融金属を高速
運動する物体に衝突させて微細融滴化する金属粉末の製
造方法において、溶融金属を高速運動する物体に衝突さ
せて飛散せしめた後この飛散融滴をさらに後続の高速運
動する物体に衝突せしめることを特徴とする金属粉末の
製造方法。 ２　前段の高速運動する物体に衝突して飛散した飛散融
滴のうち比較的粗大な飛散融滴の飛散径路に後続の高速
運動する物体を配置することを特徴とする特許請求の範
囲第１項記載の金属粉末の製造方法。 五　高速運動する物体は軸心の回りに回転するロールで
あることを特徴とする特許請求の範囲第１項又は第２項
記載の金属粉末の製造方法。 ４、　溶融金属を、固体原料の表面を連続的に高エネル
ギ密度の熱源で加熱溶融して得ることを特徴とする特許
請求の範囲第１項、第２項又は第３項記載の金属粉末の
製造方法。[Claims] t. A method for producing metal powder in which molten metal is made to collide with a high-speed moving object in a vacuum or low-pressure inert gas atmosphere to form fine molten droplets, comprising: colliding the molten metal with a high-speed moving object. A method for producing metal powder, which comprises scattering and then colliding the scattered molten droplets with a subsequent object moving at high speed. 2. Claim 1, characterized in that a subsequent high-speed moving object is placed in the scattering path of relatively coarse scattered melt droplets among the scattered melt droplets that collided with the preceding high-speed moving object. A method for producing the metal powder described. 5. The method for producing metal powder according to claim 1 or 2, wherein the object moving at high speed is a roll rotating around an axis. 4. The metal powder according to claim 1, 2 or 3, wherein the molten metal is obtained by continuously heating and melting the surface of a solid raw material with a heat source of high energy density. Production method.