JPS59190303A - Production of spherical metallic powder - Google Patents

Abstract

PURPOSE:To produce spherical metallic powder having a specified grain size at a high yield by mixing the powder obtd. by cutting the foil, plates and wires of a metal to a specified size with refractory powder, heating the mixture, and remelting only the metallic powder then cooling and solidifying the same. CONSTITUTION:The foil, plates and wires of a metal or alloy are cut or blanked to a specified size to produce powder having specified mass. Such powder is mixed with refractory powder which does not react with said powder and has the m. p. higher than the m. p. of the powder. The powder mixture is heated to the temp. higher than the m. p. of the metal or the alloy and lower than the m. p. of the refractory powder in a non-oxidative atmosphere to remelt the powder of the metal or the alloy. The molten metal or alloy is cooled and solidified in succession to the above and the spherical powder and refractory powder made by utilizing the difference in specific gravity in water are separated. The refractory powder in the upper part in the water is removed. The coarse particles are removed by a sieve if necessary.

Description

【発明の詳細な説明】 本発明は粒径のそろった球状金属粉末の製造方法に関す
るものである。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing spherical metal powder with uniform particle size.

球状金属粉は粉末冶金用、美術工芸品製作用、歯科充填
材用等に用いられているが、近年、前記用途とは異なる
電子部品のハンダ付用、接点用等の需用が増加している
。このような電子部品に用いる球状金属粉末は従来の粉
末冶金用等に用いるものに比較して高精度の球状である
こと、およびその大きさが一定であることが要求される
。Spherical metal powder is used for powder metallurgy, arts and crafts production, dental fillings, etc., but in recent years there has been an increase in demand for applications other than those mentioned above, such as for soldering electronic parts and contacts. There is. The spherical metal powder used in such electronic parts is required to have a more precise spherical shape than that used for conventional powder metallurgy, and to have a constant size.

球状粉末を製造する方法として最も一般的な方法は’Ｍ
Ｓ噴霧法であるが、この方法により得られる粉末は一般
にその粒度分布が正規分布を示し、一定の粒子径のもの
を得るためには篩等で選別しなければならず、この場合
の収率は非常に悪い。The most common method for producing spherical powder is 'M
This is the S spraying method, but the powder obtained by this method generally has a normal particle size distribution, and must be sorted with a sieve etc. to obtain particles of a constant size, and the yield in this case is is very bad.

このため、従来より球状金属粉末の製造方法について次
のような種々の方法が提案されている。For this reason, the following various methods have been proposed for producing spherical metal powder.

ａ）粉砕、すり合せ等の機械的な方法で球状化する。a) Spheroidize by mechanical methods such as crushing and grinding.

１））　　プラズマ炎等の高温帯を通過させて再溶解球
状化する方法。1)) A method of remelting and spheroidizing the material by passing it through a high temperature zone such as a plasma flame.

Ｃ）耐火性の基板上に凹部を設けこれに金属を充填再溶
解する方法。C) A method in which a recess is provided on a refractory substrate and the recess is filled with metal and remelted.

しかしながら、これら従来方法はそれぞれ次のような欠
点を有する。However, each of these conventional methods has the following drawbacks.

ａ）の方法では完全な球状化は不可能であり、電子部品
用として使用できない。With method a), complete spherical formation is impossible and it cannot be used for electronic parts.

１〕）の方法では高温帯を通過するとき確かに球状化す
るが、確実に高温帯を通過させる技術が確立しておらず
、このため球状化してない粉末が多く混入する。またそ
の粒形も各粒子が集合したものや集合した粒子が再溶解
され大きな球状粉となったものが多く混入し、一定粒径
の球状粒子を効率よく得ることは困難であδ。In the method 1), it is true that the powder is spheroidized when it passes through the high temperature zone, but the technology for reliably passing through the high temperature zone has not been established, and as a result, a large amount of powder that has not been spheroidized is mixed in. In addition, the particle shape is such that many particles are aggregated or aggregated particles are re-dissolved into large spherical powders, making it difficult to efficiently obtain spherical particles with a constant particle size.

Ｃ）の方法では確実に球状粉が得られるもの５１基板の
凹み１個に対し、１個の球状粉しか得られずこのため大
量生産は困難である。Method C) reliably yields spherical powder, but only one spherical powder can be obtained for each indentation of the 51 substrate, making mass production difficult.

本発明者は従来方法を種々検討し、特（こ一定粒径の球
状粉を高収率でしかも簡単に選別が可能な方法を検討し
た結果、本発明を完成したものである。The present inventor has completed the present invention after studying various conventional methods, and in particular, a method that allows for easy selection of spherical powders of a certain particle size at a high yield.

即ち、本発明は金属または合金の箔、板、線材を一定寸
法に切断または打抜きにより粉末状とし、該粉末と反応
せず、しかも該粉末より′高い融点を有する耐火性の粉
末を混合し、こめ混合物を非酸化性雰囲気中で金属また
は合金の融点以上、耐火性の粉末の融点以下の温度で加
熱し、金属、合金の粉末を再溶融させた後、冷却、凝固
させ、その後耐火性の粉末を分離、除去することを特徴
とする球状金属粉末の製造方法である。That is, the present invention involves making a metal or alloy foil, plate, or wire into a powder by cutting or punching it into a certain size, and mixing a refractory powder that does not react with the powder and has a melting point higher than that of the powder, The mixture is heated in a non-oxidizing atmosphere at a temperature above the melting point of the metal or alloy and below the melting point of the refractory powder to remelt the metal or alloy powder, then cooled and solidified. This is a method for producing spherical metal powder characterized by separating and removing the powder.

本発明の方法で、最初に金属または合金の箔、板、線材
を一定寸法に切断または打抜きするが、これは一定の質
量の粉末を得ることが目的である。In the method of the invention, first a metal or alloy foil, plate or wire is cut or punched to a certain size, with the aim of obtaining a powder of a certain mass.

ここで得られる一定寸法の粒子（以下これを原料粒子と
呼ぶ）は最終的に得られる球状金属粉の粒径を次のよう
・に決定する。The particles of a certain size obtained here (hereinafter referred to as raw material particles) determine the particle size of the finally obtained spherical metal powder as follows.

原料粒子の形状が円柱状の場合、直径をＤＩ、高さをＨ
とすると、最終的に得られる球状金属粉の体積は原料粒
子のそれと同じであるから次の式が成立する。If the raw material particle has a cylindrical shape, the diameter is DI and the height is H.
Then, since the volume of the spherical metal powder finally obtained is the same as that of the raw material particles, the following equation holds true.

一！−モＤテＨ＝Ｉ几り象 ４　　　　　　　　　６ （但し、Ｄ２：最終的に得られる球状金属粉の直径） この関係を図示すると第１図に示すものとなり、第１図
より目的とする球状金属粉の直径に合うよう原ト粒子の
寸法を決定し切断または打抜きすればよい。なお、原料
粒子が長方体、正方体の場合にも同様に計算すれば切断
または打抜きの寸法は容易に決定できる。one! -MoDte H=IRepresentation 4 6 (However, D2: Diameter of the spherical metal powder finally obtained) This relationship is illustrated in Figure 1, and from Figure 1, the target spherical metal The original particles may be sized to match the diameter of the powder and then cut or punched. Note that when the raw material particles are rectangular or square, the cutting or punching dimensions can be easily determined by calculating in the same way.

いのは粒子の最長寸法（ａ）と最短寸法（１〕）の比で
ある。Ino is the ratio of the longest dimension (a) and the shortest dimension (1) of the particle.

本発明にあっては耐火性の粉末中で原料粒子が溶融し、
その表面張力で球状化すると考えられるが、上記（ａ）
と（１〕）の比が極端に大きいと、原料粒子が溶融する
とき、分断されたり、または近接する原料粒子と結合す
る機会が多くなることが原因と思われる最終の球状金属
粉末の粒径のばｂつきが大きくなる。In the present invention, raw material particles are melted in a refractory powder,
It is thought that the surface tension causes it to become spherical, but the above (a)
If the ratio of (1) and The sluggishness increases.

本発明者の実験によれば、最長寸法（ａ）と最短寸法（
ｌ〕）の比、（ａＡ）　）が５０以上となると目標とす
る最終の球状金属粉末の粒径を外れる球状粉末が５０％
を超え好ましくない。According to the inventor's experiments, the longest dimension (a) and the shortest dimension (
When the ratio of (aA)) is 50 or more, 50% of the spherical powder falls outside the target particle size of the final spherical metal powder.
It is undesirable to exceed.

原料粒子の調整は金属または合金の箔、板、線材を切断
または打抜きすることにより行われるが通常０１％ｍ以
下の切断、打抜きは寸法精度にばらつきを生じるため困
難であり、このことがら本発′ｌにより得られる球状粉
の直径は約５０６戸二〇も０であろうと思われる。The raw material particles are adjusted by cutting or punching metal or alloy foils, plates, or wires, but cutting or punching smaller than 0.1% m is usually difficult because it causes variations in dimensional accuracy. It is thought that the diameter of the spherical powder obtained by 'l would be about 506 mm.

また、最終の球状金属粉末の粒径が２卵以上とななくな
り、女形した球状となるため好ましくない。Further, the particle size of the final spherical metal powder is not more than 2 eggs, which is not preferable because it becomes a female-shaped sphere.

上記方法で得られた原料粒子は幾何学的に接触しないよ
うに耐火物粉末と混合し加熱される。この両者の配合比
率は原料粒子の形状、大きさにより異なり、混合粉末中
の耐火物粉末の割合が少ないと原料粒子同志が接触し、
金属または合金の融点以上の加熱により互に融着し、目
的とする直径より粗大な球状粒子となり、その結果一定
粒径粒子の収率が低下する。The raw material particles obtained by the above method are mixed with refractory powder and heated so that they do not come into contact with each other geometrically. The blending ratio of the two varies depending on the shape and size of the raw material particles, and if the proportion of refractory powder in the mixed powder is small, the raw material particles will come into contact with each other,
Heating above the melting point of the metal or alloy causes them to fuse together, forming spherical particles with a coarser diameter than the desired diameter, resulting in a decrease in the yield of particles with a constant particle size.

本発明に使用する耐火物粉末として要求される特性は■
原料粒子と混合した場合の分散性が良い微粉末であるこ
と、■耐火物自身が加熱中に焼結、溶融せず原料粒子と
反応しないこと、■原料粒子の比重より軽いこと、■球
状化した粉末表面に付着せず、水中でその分離が容易で
あること等である。上記の特性を満足する耐火物粉末と
してはＡｌＯ３、ＭｇＯ，ＺｒＯ２、ＴｉＯ２等の金属
の酸化物、ＢＮ、　Ｓｉ３Ｎ２、ＴｉＮ等の窒化物等が
ある。上記耐火物のうち不純物が少なく微粉末でしかも
安価に入手出来るＭｇＯと加熱によりＭｇＯとなる炭酸
マグネシウムが本発明に使用する耐火物粉末として最良
である。The properties required for the refractory powder used in the present invention are:
It is a fine powder with good dispersibility when mixed with raw material particles, ■ The refractory itself does not sinter or melt during heating and does not react with raw material particles, ■ It is lighter in specific gravity than the raw material particles, and ■ It is spheroidized. It does not adhere to the powder surface and can be easily separated in water. Examples of refractory powders that satisfy the above characteristics include metal oxides such as AlO3, MgO, ZrO2, and TiO2, and nitrides such as BN, Si3N2, and TiN. Among the above refractories, MgO, which is a fine powder with few impurities and is available at low cost, and magnesium carbonate, which becomes MgO when heated, are the best refractory powders to be used in the present invention.

原料粒子と耐火物粉末の混合粉は非酸化性雰囲気中で加
熱するが金属または合金の融点より゛約１００”Ｃ高い
加熱温度で行い、加熱時間は３０分前後が好ましい。加
熱温度が低い場合には表面張力が働かないため球状化が
起らず、又加熱温度が高い場合には表面張力が弱まり、
液体状の金属または合金の粘性の低下により耐火物粉末
との分離が起き、その結果原料粒子同志の接触により粗
大な球状粉末が出来る。尚、非酸化性雰囲気中で加熱す
るのは金属または合金表面の酸化を防止し、金属光沢を
保持するためである。The mixed powder of raw material particles and refractory powder is heated in a non-oxidizing atmosphere at a heating temperature approximately 100"C higher than the melting point of the metal or alloy, and the heating time is preferably around 30 minutes. When the heating temperature is low Since no surface tension acts on the material, spheroidization does not occur, and when the heating temperature is high, the surface tension weakens.
The drop in viscosity of the liquid metal or alloy causes it to separate from the refractory powder, resulting in the formation of coarse spherical powder due to contact between the raw material particles. The purpose of heating in a non-oxidizing atmosphere is to prevent oxidation of the metal or alloy surface and maintain metallic luster.

混合粉末を加熱処理後室温に冷却し、出来た球状粉末と
耐火物粉末の分離は水中での比重差を利用し、水中上部
の耐火物粉末を取除く。尚、球状粉に耐火物粉末が付着
した場合には超音波洗浄機により洗浄すれば分離が容易
となる。After the mixed powder is heat-treated, it is cooled to room temperature, and the resulting spherical powder and refractory powder are separated using the difference in specific gravity in water, and the refractory powder above the water is removed. In addition, if the refractory powder adheres to the spherical powder, it can be easily separated by cleaning it with an ultrasonic cleaner.

得られた球状粉末には目的とする粒径より粗大な粒子が
含まれ、これは’！分により容易に取除くことができる
。すなわち原料粒子の１個を用い球状化した粒子径をＤ
とし、そのＮ個が溶着し球状化した粗大粒子の直径はＤ
Ｎ３となり、その粗大粒子の最小（Ｎ＝２）の直径は１
個の直径の約１゛２６倍となる。一方ＪＩＳ　　標準篩
の目開きは外シリーズとされ、ある目開きの次に大きな
篩はその約１．１９倍の目開きのものがあり、溶着粗大
化した球状粒子を取除くために必要な目開きの五塾が用
意出来る。The obtained spherical powder contains particles that are coarser than the desired particle size, which is '! Can be easily removed in minutes. In other words, the particle diameter obtained by spheroidizing one of the raw material particles is D.
The diameter of the coarse particles formed by welding N pieces into a spherical shape is D.
N3, and the minimum (N=2) diameter of the coarse particles is 1
It is approximately 1゛26 times the diameter of the individual. On the other hand, the mesh size of JIS standard sieves is referred to as the outer series, and the next largest sieve after a certain mesh size is approximately 1.19 times larger than that, which is the mesh size necessary to remove coarse welded spherical particles. Five different cram schools are available.

尚、本発明で′得られた直径５０μから２　ｔｔｍまで
の球状粉末から粗大粒を取除くために必要なＪＩＳ　標
準長芋は目開きが５３１・から２３６層の騨が２３種類
あり、これらの縁を用いて十分選別可能である。In addition, there are 23 types of JIS standard nagaimo, which are necessary for removing coarse particles from the spherical powder with a diameter of 50 μm to 2 ttm obtained in the present invention, with a mesh size of 531 to 236 layers. can be sufficiently selected using

以下にこの発明の実施例について説明する。Examples of the present invention will be described below.

実施例１ 錫６３重量％、鉛３７重量％の合金である直径５００μ
の球状半田粉を得るために、上記組成の厚さ５０μの箔
を直径１．３１ｐｍの円柱状に打抜き、これに重量比で
同量の炭酸マグネシウムをよく混合し、水素気流を通し
た加熱炉に入れ、２９０°Ｃで３０分間保持後室温まで
冷却し炉から取出した。次に球状化した半田粉と炭酸マ
グネシウムを分離するため、水を入れた容器に入れ、よ
＜遁モ↑して上部の炭酸マグネシウムを傾斜法で取除き
、容器下部にたまった球状粉を乾燥した。次に目開き６
００１□　　（２８ｍｅｓｈ）のＪＩＳ標準峰を用いて
粗大粒を取除き、直径５００・の球状半田粉を得た。表
−１にＪＩＳ標準静を使用表−１ 碑の目開きが４２５μ〜６００μで吟分した球状半田粉
は９１９％を示し、万能投影機によりこれらの直径を一
測定した結果５００±１２＃となり、収率よく粒径のそ
ろった球状半田粉が得られた。Example 1 An alloy of 63% tin and 37% lead with a diameter of 500μ
In order to obtain spherical solder powder, a foil with a thickness of 50 μm having the above composition was punched into a cylinder shape with a diameter of 1.31 pm, and the same weight ratio of magnesium carbonate was thoroughly mixed with the foil, and the mixture was heated in a heating furnace through a hydrogen stream. After holding at 290°C for 30 minutes, the mixture was cooled to room temperature and taken out from the furnace. Next, to separate the spherical solder powder and magnesium carbonate, place them in a container filled with water, then remove the magnesium carbonate at the top using a decanting method, and dry the spherical powder that has accumulated at the bottom of the container. did. Next, eye opening 6
Coarse particles were removed using a JIS standard peak of 001□ (28 mesh) to obtain spherical solder powder with a diameter of 500 mm. Table-1 uses JIS standard static Table-1 The spherical solder powder that was examined with the opening of the monument from 425μ to 600μ showed 919%, and the result of measuring the diameter with a universal projector was 500±12#. Spherical solder powder with uniform particle size was obtained in good yield.

実施例２ 直径ｌ　／１ｍの銅線を長さｌ　）＃ＡＹずつカッティ
ングし、これに重量比で十の割合の酸化マグネシウムを
よく混合し、アンモニア分解ガスを通した加熱炉に入れ
、１１８０°Ｃで３０分間保持後室温まで冷却し炉から
取出した。次に球状化した銅球と酸化マグネシウムを分
離するため、水を入れた容器に入れ、よ＜ｌ’ｔＱ−し
て上部の酸化マグネシウムを傾斜法で取除き、容器下部
にたまった球状粉を乾燥した。銅線をカッティングした
直径１２７屑、長さ１ノ覆の銅片を球状化すると計算で
は１．１４５＋、ｊｍの直径の球状銅粉となる。そこで
目開きが１．００’ｉ＋＃　（１６ｍｅｓｈ）と１，１
３ｉ＃２Ｙ（１４ｍｅｓｈ　）のＪＩＳ標準峰を用いて
粗大粉と線のカッティング加工時に混入する微小粉を取
除き、粒径のそろった球状銅粉を得た。表−２にＪＩＳ
標準峰を使用して篩分した結果を示す。Example 2 Copper wire with a diameter of 1/1 m was cut into lengths of 1) #AY, mixed well with magnesium oxide in a weight ratio of 10:1, placed in a heating furnace through which ammonia decomposition gas was passed, and heated at 1180°. After being held at C for 30 minutes, it was cooled to room temperature and taken out from the furnace. Next, to separate the spheroidized copper spheres and magnesium oxide, place them in a container filled with water, remove the magnesium oxide on the top using a decanting method, and remove the spherical powder that has accumulated at the bottom of the container. Dry. When a copper piece with a diameter of 127 mm and a length of 1 mm is made by cutting a copper wire, it becomes a spherical copper powder with a diameter of 1.145 + jm. Therefore, the mesh opening is 1.00'i+# (16mesh) and 1.1
Coarse powder and fine powder mixed in during wire cutting were removed using a JIS standard peak of 3i#2Y (14 mesh) to obtain spherical copper powder with uniform particle size. Table 2 shows JIS
The results of sieving using standard peaks are shown.

表−２ 岬の目開きが１００〜１１８瀝で野分しｔコ球状銅粉は
８６９％と収率よく粒径のそろった球状銅粉が得られた
。また得られた球状銅粉末の形状を第２図に示す。Table 2 Spherical copper powder with uniform particle size was obtained at a high yield of 869% when the opening of the cape was 100 to 118. Moreover, the shape of the obtained spherical copper powder is shown in FIG.

以上詳細に説明したように、本発明の方法は高い収率で
一定粒径の球状金属粉末を得ることが出来、しかも大量
生産が可能である従来法にない特徴をもち、産業上有用
な発明である。As explained in detail above, the method of the present invention is capable of obtaining spherical metal powder with a constant particle size at a high yield, and has features not found in conventional methods in that it can be mass-produced, and is an industrially useful invention. It is.

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

第１図は原料粉末の円柱の寸法と最終時に得られる球状
金属粉の直径の関係図。 第２図は実施例１で得られた球状金属粉末の顕微鏡写真
である。 特許出願人 福田金属箔粉工業株式会社 ０．０１　　　　　　　０．１　　　　　　　　　　］
　　　　　　　５５円の直径（ｚｚ） 第１図 ｓ２図FIG. 1 is a diagram showing the relationship between the cylindrical dimensions of the raw powder and the diameter of the final spherical metal powder. FIG. 2 is a microscopic photograph of the spherical metal powder obtained in Example 1. Patent applicant: Fukuda Metal Foil & Powder Industry Co., Ltd. 0.01 0.1 ]
Diameter of 55 circles (zz) Figure 1 Figure s2

Claims (1)

【特許請求の範囲】 １）　金属または合金の箔、板、線′材を一定寸法に切
断または打抜きにより粉末状とし、該粉末と反応せず、
しかも該粉末より高い融点を有する耐火性の粉末と混合
し、この混合物を非酸化性雰囲気中で金属または合金の
融点以上、耐火性の粉末の融点以下の温度で加熱し、金
属、合金の粉末を再溶融させた後、冷却、凝固させ、そ
の後耐火性の粉末を分離、除去することを特徴とする球
状金属粉末の製造方法。 ２）　金属または合金の箔、板、線材を一定寸法に切断
または打抜きにより粉末状とするに当り、粉末粒子の最
長寸法（ａ）と最短寸法（ｂ）の比（ａ／ｂ　）が５０
以内とすることを特徴とする特許請求の範囲第１項に記
載の球状金属粉末の製造方法。 ３）　金属または合金が銅、銅合金、錫、錫合金、鉛、
鉛合金より選択されることを特徴とする特許請求の範囲
第１項、第２項のいずれかに記載の球状金属粉末の製造
方法。 ４）　耐火物の粉末が酸化マグネシウムまたは炭酸マグ
ネシウムより選択されることを特徴とする特許請求の範
囲第１項、第２項、第３項のいずれかに記載の球状金属
粉末の製造方法。[Claims] 1) Cutting or punching a metal or alloy foil, plate, or wire material into a powder form by cutting or punching it into a certain size, and not reacting with the powder;
Furthermore, the powder is mixed with a refractory powder having a higher melting point than the powder, and this mixture is heated in a non-oxidizing atmosphere at a temperature above the melting point of the metal or alloy and below the melting point of the refractory powder. A method for producing spherical metal powder, which comprises remelting, cooling and solidifying, and then separating and removing the refractory powder. 2) When cutting or punching metal or alloy foil, plate, or wire into a powder to a certain size, the ratio (a/b) of the longest dimension (a) to the shortest dimension (b) of the powder particles is 50.
The method for producing spherical metal powder according to claim 1, wherein 3) The metal or alloy is copper, copper alloy, tin, tin alloy, lead,
The method for producing spherical metal powder according to claim 1 or 2, wherein the spherical metal powder is selected from lead alloys. 4) The method for producing spherical metal powder according to any one of claims 1, 2, and 3, wherein the refractory powder is selected from magnesium oxide or magnesium carbonate.