JP2813414B2 - Production method of equiaxed tungsten carbide ultrafine powder - Google Patents
Production method of equiaxed tungsten carbide ultrafine powderInfo
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- JP2813414B2 JP2813414B2 JP2108646A JP10864690A JP2813414B2 JP 2813414 B2 JP2813414 B2 JP 2813414B2 JP 2108646 A JP2108646 A JP 2108646A JP 10864690 A JP10864690 A JP 10864690A JP 2813414 B2 JP2813414 B2 JP 2813414B2
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Description
【発明の詳細な説明】 〔産業上の利用分野〕 この発明は、平均粒径で１μｍ以下の超微粒粉末にし
て、細長く伸びた長軸状（連鎖状）粉末の形成がほとん
どなく、等軸状であり、したがって粉末冶金法により焼
結体を製造するに際して原料粉末として用いた場合に得
られる焼結体は高強度をもつようになる、等軸状炭化タ
ングステン（以下WCで示す）超微粒粉末の製造法に関す
るものである。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides an ultrafine powder having an average particle size of 1 μm or less, and has almost no formation of elongated elongated long-chain (chain) powder, Therefore, when used as a raw material powder when manufacturing a sintered body by powder metallurgy, the sintered body obtained has high strength. The present invention relates to a method for producing a powder.
従来、WC超微粒粉末の製造法としては、例えば特公昭
51−29520号公報に記載される方法が知られている。Conventionally, as a method for producing WC ultrafine powder, for example,
The method described in JP-A-51-29520 is known.
この従来方法は、原料粉末として３酸化タングステン
（以下WO3で示す）粉末を用い、 これに３〜４当量の炭素粉末を配合し、混合した状態
で、窒素やArの常圧、または減圧の不活性ガス雰囲気、
あるいは真空などからなる非酸化物雰囲気中、1000℃以
上の温度に加熱保持の条件で還元処理を施して、酸素含
有量を0.5％以下にした後、 引続いて、水素雰囲気中、1400〜2000℃の温度に加熱
保持の条件で炭化処理を施すことにより平均粒径で３μ
ｍ以下のWC超微粒粉末を製造する方法である。This conventional method (shown below WO 3) 3 tungsten oxide as a raw material powder using a powder, this mixed 3-4 equivalents of carbon powder, a mixed state, atmospheric pressure of nitrogen or Ar or vacuum of, Inert gas atmosphere,
Alternatively, in a non-oxide atmosphere composed of vacuum or the like, a reduction treatment is performed under the condition of heating and holding at a temperature of 1000 ° C. or more to reduce the oxygen content to 0.5% or less, and then, in a hydrogen atmosphere, 1400 to 2000 The average particle size is 3μ by subjecting to carbonization under the condition of heating and holding at a temperature of ° C.
This is a method for producing WC ultrafine powder having a particle size of less than m.
しかし、上記の従来方法はじめ、その他の方法で製造
されたWC超微粒粉末は、いずれも細長く伸びた長軸状形
状を有するものの割合が多く、したがってこれを粉末冶
金法により焼結体を製造する際に原料粉末として用いる
と、この長軸状形状が原因で焼結体は十分満足する強度
を示さず、またこの長軸状WC超微粒粉末の粉砕による等
軸化はきわめて困難であるのが現状である。However, the WC ultrafine powder produced by other methods, including the above-mentioned conventional method, has a large proportion of those having a long and elongated elongated shape, and therefore, a sintered body is manufactured by powder metallurgy. When used as a raw material powder at this time, the sintered body does not exhibit a sufficiently satisfactory strength due to the long-axis shape, and it is extremely difficult to equiaxe the long-axis WC ultrafine powder by grinding. It is the current situation.
そこで、本発明者等は、上述のような観点から、粉砕
によらずに等軸状WC超微粒粉末を製造すべく研究を行な
った結果、従来方法によって製造されたWC超微粒粉末が
長軸状形状を有するのは、還元工程で原料粉末のWO3がW
O2.72へ還元される過程があり、このWO2.72の結晶構造
を有する中間酸化物は細長い長軸状を呈するものである
ため、この形状がつぎの炭化処理工程に引きつがれてし
まうことに原因があり、したがって原料粉末のWO3からW
O2.72やWO2などの混合物からなる中間酸化物を形成した
時点で、これに粉砕を加えると、前記中間酸化物は容易
に１μｍ以下の平均粒径になり、この状態では長軸状の
WO2.72はいずれも等軸状となっているので、後の炭化処
理工程での長軸状WO2.72の影響は皆無となることから、
製造されたWC超微粒粉末はいずれも等軸状を呈するよう
になるという研究結果を得たのである。Therefore, the present inventors conducted research from the above-described viewpoint to produce equiaxed WC ultrafine powder without grinding, and found that the WC ultrafine powder produced by the conventional method had a long axis. In the reduction step, the raw material powder WO 3
There is a process of reduction to O 2.72 , and since the intermediate oxide having the crystal structure of WO 2.72 has an elongated long axis shape, this shape is attracted to the next carbonization process And therefore the raw powder WO 3 to W
When an intermediate oxide composed of a mixture such as O 2.72 or WO 2 is formed, when the intermediate oxide is pulverized, the intermediate oxide easily has an average particle size of 1 μm or less, and in this state, a long axis-shaped
Since all of WO 2.72 are equiaxed , there is no influence of long-axis WO 2.72 in the subsequent carbonization step, so that
The research results showed that all the manufactured ultrafine WC powders became equiaxed.
この発明は、上記研究結果にもとづいてなされたもの
であって、 原料粉末としてWO3粉末を用い、 これに、水素などの還元性雰囲気中、300〜900℃の温
度に加熱保持の条件で予備還元処理を施して、WO2.72や
WO2などの混合物、望ましくはWO2.72を主体とした混合
物からなる中間酸化物とし、 この中間酸化物を平均粒径で１μｍ以下に微粉砕し
て、等軸状形状とし、 ついで、この中間酸化物微粉末に、全体に占める割合
で10〜33重量％の炭素粉末を配合し、混合した状態で、
窒素またはAr、あるいは窒素とArの混合ガスからなる常
圧または減圧の不活性ガス、あるいは真空などの非酸化
性雰囲気中、900〜1600℃の温度に加熱保持の条件で１
次炭化処理を施して、主体がW2CやWCなどの炭化物で構
成されたものとし、 引続いて、水素含有の浸炭性雰囲気中、1000〜1600℃
の温度に加熱保持の条件で２次炭化処理を施して実質的
にWC粉末のみとすることからなる等軸状WC超微粒粉末の
製造方法に特徴を有するものである。The present invention has been made based on the above research results, and uses WO 3 powder as a raw material powder, and further prepares it under a condition of heating and holding at a temperature of 300 to 900 ° C. in a reducing atmosphere such as hydrogen. After a reduction treatment, WO 2.72 and
Mixtures of such WO 2, preferably an intermediate oxide consisting of a mixture consisting mainly of WO 2.72, the intermediate oxide is finely pulverized to 1μm or less in average particle size, and equiaxed shape, then this intermediate oxide 10-33% by weight of carbon powder is blended into the fine powder, and
In a non-oxidizing atmosphere such as nitrogen or Ar or a mixed gas of nitrogen and Ar at a normal pressure or a reduced pressure, or in a non-oxidizing atmosphere such as a vacuum, the temperature is maintained at 900 to 1600 ° C. under the condition of heating and holding.
Subsequent carbonization treatment to make the main body composed of carbides such as W 2 C and WC. Then, in a carburizing atmosphere containing hydrogen, 1000-1600 ° C
The method is characterized by a method for producing equiaxed WC ultrafine powder comprising subjecting a secondary carbonization treatment under the condition of heating and holding to substantially the same WC powder.
つぎに、この発明の方法において、製造条件を上記の
通りに限定した理由を説明する。Next, the reason why the manufacturing conditions are limited as described above in the method of the present invention will be described.
（ａ） 予備還元処理温度 その温度が300℃未満では還元が不十分で、WO3やWO
2.9などが残留し、これらの成分は後工程の１次炭化処
理工程で細長いWO2.72を形成し、これが長軸状WC粉末形
成の原因となり、一方その温度が900℃を越えると、還
元が進行し過ぎて金属Ｗが形成されるようになり、これ
は粉砕性が悪く、後工程の粉砕で１μｍ以上の粉末が高
い割合で残存するため、この場合も長軸状あるいは粗粒
のWC粉末の形成は避けられないことから、その温度を30
0〜900℃と定めた。(A) Pre-reduction treatment temperature If the temperature is less than 300 ° C, the reduction is insufficient, and WO 3 or WO
2.9 etc. remain, and these components form elongated WO 2.72 in the subsequent primary carbonization step, which causes the formation of long-axis WC powder. On the other hand, when the temperature exceeds 900 ° C, reduction proceeds. The metal W is formed too much, and the pulverizability is poor, and a high ratio of powder of 1 μm or more remains in the pulverization in the subsequent process. Since formation is unavoidable, the temperature
It was defined as 0 to 900 ° C.
（ｂ） 中間酸化物の粉砕後の平均粒径 上記の通り予備還元処理工程で細長い長軸状の形状を
有するWO2.72を主体とする粉砕性の良好な中間酸化物を
形成し、これに粉砕を加えることにより、その形状を簡
単に等軸状として、長軸状形状を皆無とし、もって次の
工程の炭化処理工程での長軸状WC粉末の形成を抑制する
と共に、平均粒径で0.1〜１μｍ、望ましくは0.5μｍ以
下の超微粒WC粉末の形成を可能ならしめるものであり、
したがって中間酸化物の粉砕後の平均粒径が１μｍを越
えて粗粒の場合には長軸状形状の金属酸化物が残留する
ようになり、この残留長軸状金属酸化物が長軸状WC粉末
の形成の原因となるばかりでなく、平均粒径で１μｍ以
下のWC超微粒粉末を製造することができないことから、
その粉砕後の平均粒径を１μｍ以下と定めた。(B) Average particle size of intermediate oxide after pulverization As described above, in the preliminary reduction treatment step, an intermediate oxide having a long and long axis shape and mainly composed of WO 2.72 and having good pulverizability is formed and pulverized. , The shape is easily made equiaxed, the long axis shape is completely eliminated, and thus the formation of the long axis WC powder in the subsequent carbonization step is suppressed, and the average particle size is 0.1 ~ 1 μm, desirably 0.5 μm or less to enable the formation of ultrafine WC powder,
Therefore, if the average particle size of the intermediate oxide after grinding exceeds 1 μm and is coarse, a long-axis-shaped metal oxide will remain. Not only does it cause the formation of powder, but it is not possible to produce WC ultrafine powder with an average particle size of 1 μm or less.
The average particle size after the pulverization was determined to be 1 μm or less.
（ｃ） 炭素粉末の混合割合 その混合割合が、中間酸化物との合計に占める重量割
合で10％未満では、炭素不足が原因で２次炭化処理後に
W2Cが残留するようになり、一方その混合割合が同じく3
8重量％を越えると２次炭化処理後に遊離炭素が多量に
残留するようになることから、その混合割合を10〜33重
量％と定めた。(C) Mixing ratio of carbon powder If the mixing ratio is less than 10% by weight relative to the total amount of the intermediate oxides, after the secondary carbonization treatment due to lack of carbon,
W 2 C will remain, while its mixing ratio will also be 3
If the content exceeds 8% by weight, a large amount of free carbon will remain after the secondary carbonization treatment. Therefore, the mixing ratio is set to 10 to 33% by weight.
（ｄ） １次炭化処理温度 その温度が900℃未満では、炭化が進行せず、金属Ｗ
を主体としたものが形成され、低級炭化物を主体とした
ものの形成が不可能になり、この場合後工程の２次炭化
処理では高温および長時間反応条件を必要とするように
なり、この結果粒成長が起るようになって、平均粒径で
１μｍ以下の超微粒粉末の形成は不可能となるものであ
り、同じく1600℃を越えた温度になっても粒成長は避け
られないことから、その温度を900〜1600℃と定めた。(D) Primary carbonization temperature If the temperature is less than 900 ° C, carbonization does not proceed, and metal W
Is formed, and it becomes impossible to form a material mainly composed of lower carbides. In this case, the secondary carbonization treatment in the subsequent step requires high-temperature and long-time reaction conditions. As growth occurs, it becomes impossible to form ultrafine powder having an average particle size of 1 μm or less, and grain growth cannot be avoided even at temperatures exceeding 1600 ° C. The temperature was set at 900-1600 ° C.
（ｃ） ２次炭化処理温度 その温度が1000℃未満では、十分な炭化が行なわれ
ず、この結果W2Cが残留するようになり、一方その温度
が1600℃を越えると粒成長が発生し易くなることから、
この温度を1000〜1600℃と定めた。(C) Secondary carbonization treatment temperature If the temperature is less than 1000 ° C, sufficient carbonization is not performed, and as a result, W 2 C remains, whereas if the temperature exceeds 1600 ° C, grain growth is likely to occur. From becoming
This temperature was defined as 1000-1600 ° C.
つぎに、この発明の方法を実施例により具体的に説明
する。Next, the method of the present invention will be specifically described with reference to examples.
原料粉末として、平均粒径:0.3μｍのWO3粉末および
同0.05μｍのカーボンブラック粉末を用意し、まず、こ
のうちのWO3粉末に第１表に示される条件で予備還元処
理を施して中間酸化物とし、これに粉砕処理を施して同
じく第１表に示される平均粒径とし、ついでこれに第１
表に示される割合（全体に占める割合）のカーボンブラ
ック粉末を配合し、溶媒としてアセトンを用い、ボール
ミル中で30時間混合し、乾燥した後、カーボンボートに
充填し、同じく第１表に示される条件で１次炭化処理お
よび２次炭化処理（２次炭化は残留カーボンブラックお
よび／またはCH4による炭化）を施すことにより本発明
法１〜９を実施し、それぞれWC超微粒粉末を製造した。As raw material powders, WO 3 powder having an average particle diameter of 0.3 μm and carbon black powder having the same 0.05 μm were prepared. First, the WO 3 powder was subjected to a preliminary reduction treatment under the conditions shown in Table 1 to obtain an intermediate. An oxide was subjected to a pulverizing treatment to obtain an average particle diameter also shown in Table 1, and then to the first oxide.
The carbon black powder in the ratio shown in the table (the ratio to the whole) was blended, mixed with acetone as a solvent in a ball mill for 30 hours, dried, and then filled in a carbon boat, and also shown in Table 1. primary carbonization treatment and secondary carbonization treatment (secondary carbonization carbonization by the residual carbon black and / or CH 4) embodying the present invention method 1-9 by performing at conditions to produce WC ultrafine powder, respectively.
また、比較の目的で、予備還元処理による中間酸化物
の形成を行なわず、WO3粉末に同じく第１表に示される
割合で直接カーボンブラック粉末を配合し、さらに１次
炭化処理および２次炭化処理に代って同じく第１表に示
される条件で還元処理および炭化処理を施す以外は同一
の条件で従来法１〜６を行ない、WC超微粒粉末を製造し
た。For the purpose of comparison, an intermediate oxide was not formed by the pre-reduction treatment, and the carbon black powder was directly blended with the WO 3 powder at the ratio shown in Table 1 and further subjected to the primary carbonization treatment and the secondary carbonization treatment. Conventional methods 1 to 6 were carried out under the same conditions except that the reduction treatment and the carbonization treatment were carried out under the same conditions as shown in Table 1 in place of the treatment to produce ultrafine WC powder.
この結果得られた各種のWC超微粒粉末について、平均
粒径および長軸状形状（縦軸長さ／横軸長さが２以上の
もの）の占める割合を測定し、さらに他に用意した平均
粒径:1μｍのVC粉末 および同１μｍのCo粉末を用い、これらのWC粉末:97.5
％、VC粉末:0.5％、Co粉末:12％の割合（以上重量％）
で配合し、ボールミル中で72時間湿式混合し、乾燥した
後、1ton/cm2の圧力で10.8mm×6mm×30mmの寸法をもっ
た圧粉体にプレス成形し、0.1torrの真空中、温度:1400
℃に１時間保持の条件で焼結し、この結果得られた焼結
体の抗折力を測定した。これらの測定結果を第１表に示
した。The average particle size and the proportion of the long axis shape (having a vertical axis length / horizontal axis length of 2 or more) of the various WC ultrafine powders obtained as a result were measured, and the average of the other prepared average powders was measured. Particle size: 1μm VC powder And WC powder of 97.5%
%, VC powder: 0.5%, Co powder: 12% (more than weight%)
In blended, in a ball mill and mixed for 72 hours wet, dried, and pressed into a green compact having a size of pressure 10.8 mm × 6 mm × 30 mm of 1 ton / cm 2, in a vacuum of 0.1 torr, the temperature : 1400
Sintering was carried out at a temperature of 1 ° C. for 1 hour, and the transverse rupture strength of the resulting sintered body was measured. Table 1 shows the results of these measurements.
第１表に示される結果から、本発明法１〜９によれ
ば、いずれも平均粒径で１μｍ以下のWC超微粒粉末を製
造することができ、一方従来法１〜６により製造された
WC粉末は相対的に粗粒であり、かつ本発明法１〜９で製
造されたものの方が従来法１〜６で製造されたものに比
して長軸状形状の割合が著しく低く、したがってこの結
果得られたWC超微粒粉末を用いて通常の条件でWC基超硬
合金を製造した場合、本発明法１〜９によって製造され
たWC超微粒粉末を用いた方が従来法１〜６のものを用い
る場合に比して一段と高強度をもった焼結体が得られる
ことが明らかである。From the results shown in Table 1, according to the methods 1 to 9 of the present invention, it was possible to produce WC ultrafine powder having an average particle diameter of 1 μm or less, while the conventional methods 1 to 6
The WC powder is relatively coarse, and the ratio of the long-axis shape of the WC powder produced by the methods 1 to 9 of the present invention is significantly lower than that produced by the conventional method 1 to 6, When a WC-based cemented carbide is produced under ordinary conditions using the WC ultrafine powder obtained as a result, the WC ultrafine powder produced according to the methods 1 to 9 of the present invention is preferably used in conventional methods 1 to 6. It is clear that a sintered body having a higher strength than that of the case of using a sintered body can be obtained.
上述のように、この発明の方法によれば、平均粒径で
１μｍ以下、望ましくは同0.5μｍ以下の超微粒にし
て、細長い長軸状形状の形成がきわめて低く、主要部が
等軸状形状で占められているWC超微粒粉末を製造するこ
とができ、したがってこれを原料粉末として用い、通常
の粉末冶金法で焼結体を製造した場合、焼結体の強度が
一段と向上するようになるなど工業上有用な効果がもた
らされるのである。As described above, according to the method of the present invention, ultrafine particles having an average particle diameter of 1 μm or less, desirably 0.5 μm or less are formed, and the formation of an elongated long-shape shape is extremely low, and the main portion has an equiaxial shape. WC, which is occupied by WC, can be manufactured. Therefore, when this is used as a raw material powder and a sintered body is manufactured by a normal powder metallurgy method, the strength of the sintered body will be further improved. Such an industrially useful effect is brought about.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 篠原 耕治 埼玉県大宮市北袋町１―297 三菱金属 株式会社中央研究所内 (72)発明者 植田 文洋 埼玉県大宮市北袋町１―297 三菱金属 株式会社中央研究所内 (72)発明者 棚瀬 照義 岐阜県安八郡神戸町大字横井字中新田 1528 三菱金属株式会社岐阜製作所内 (56)参考文献 特開 昭51−29520（ＪＰ，Ａ) (58)調査した分野(Int.Cl.6，ＤＢ名) C01B 31/34──────────────────────────────────────────────────続 き Continuing on the front page (72) Koji Shinohara, Inventor 1-297 Kitabukurocho, Omiya City, Saitama Prefecture Inside the Central Research Laboratory of Mitsubishi Metal Corporation (72) Fumihiro Ueda 1-297 Kitabukurocho, Omiya City, Saitama Prefecture Mitsubishi Metals Corporation Central Research Laboratory (72) Inventor Teruyoshi Tanase 1528 Nakashinda, Yokoi, Kobe-cho, Anpachi-gun, Gifu Prefecture Gifu Works, Mitsubishi Metal Corporation (56) References JP-A-51-29520 (JP, A) (58) Survey Field (Int.Cl. 6 , DB name) C01B 31/34
Claims (1)
用い、 これに、還元性雰囲気中、300〜900℃の温度に加熱保持
の条件で予備還元処理を施して中間酸化物とし、 この中間酸化物を平均粒径で１μｍ以下に微粉砕し、 ついで、この中間酸化物微粉末に、全体に占める割合で
10〜33重量％の炭素粉末を配合し、混合した状態で、非
酸化性雰囲気中、900〜1600℃の温度に加熱保持の条件
で１次炭化処理を施し、 引続いて、水素含有浸炭性雰囲気中、1000〜1600℃の温
度に加熱保持の条件で２次炭化処理を施すことを特徴と
する等軸状炭化タングステン超微粒粉末の製造法。1. Tungsten trioxide powder is used as a raw material powder, which is subjected to a pre-reduction treatment in a reducing atmosphere at a temperature of 300 to 900 ° C. under heating and holding conditions to form an intermediate oxide. Is finely pulverized to an average particle size of 1 μm or less.
In a non-oxidizing atmosphere, a primary carbonization treatment is carried out at a temperature of 900 to 1600 ° C. under a condition of heating and holding, followed by hydrogen-containing carburizing A method for producing ultrafine equiaxed tungsten carbide powder, comprising performing a secondary carbonization treatment in an atmosphere at a temperature of 1000 to 1600 ° C. under heating and holding conditions.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2108646A JP2813414B2 (en) | 1990-04-26 | 1990-04-26 | Production method of equiaxed tungsten carbide ultrafine powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2108646A JP2813414B2 (en) | 1990-04-26 | 1990-04-26 | Production method of equiaxed tungsten carbide ultrafine powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0412013A JPH0412013A (en) | 1992-01-16 |
| JP2813414B2 true JP2813414B2 (en) | 1998-10-22 |
Family
ID=14490085
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2108646A Expired - Lifetime JP2813414B2 (en) | 1990-04-26 | 1990-04-26 | Production method of equiaxed tungsten carbide ultrafine powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2813414B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5567662A (en) * | 1994-02-15 | 1996-10-22 | The Dow Chemical Company | Method of making metallic carbide powders |
| DE69934916T2 (en) | 1999-10-01 | 2007-10-11 | The Procter & Gamble Company, Cincinnati | ABSORBENT ARTICLE WITH A CURING LAYER AGAINST SKIN PROCESSING MIGRATION |
| DE10354543B3 (en) * | 2003-11-21 | 2005-08-04 | H.C. Starck Gmbh | Dual phase hard material, process for its preparation and its use |
| CN116143124B (en) * | 2023-04-24 | 2023-08-08 | 崇义章源钨业股份有限公司 | Ultra-coarse uniform tungsten carbide powder and preparation method thereof |
-
1990
- 1990-04-26 JP JP2108646A patent/JP2813414B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0412013A (en) | 1992-01-16 |
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