JPH0239562B2 - - Google Patents
Info
- Publication number
- JPH0239562B2 JPH0239562B2 JP59193268A JP19326884A JPH0239562B2 JP H0239562 B2 JPH0239562 B2 JP H0239562B2 JP 59193268 A JP59193268 A JP 59193268A JP 19326884 A JP19326884 A JP 19326884A JP H0239562 B2 JPH0239562 B2 JP H0239562B2
- Authority
- JP
- Japan
- Prior art keywords
- tungsten
- powder
- fine
- composite oxide
- reduction
- 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
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 48
- 239000000843 powder Substances 0.000 claims description 29
- 239000002131 composite material Substances 0.000 claims description 27
- 229910052721 tungsten Inorganic materials 0.000 claims description 27
- 239000010937 tungsten Substances 0.000 claims description 27
- 229910052739 hydrogen Inorganic materials 0.000 claims description 17
- 239000001257 hydrogen Substances 0.000 claims description 17
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 16
- 239000010949 copper Substances 0.000 claims description 8
- 229910052782 aluminium Inorganic materials 0.000 claims description 7
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 6
- 229910052802 copper Inorganic materials 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 239000002253 acid Substances 0.000 claims description 3
- 238000010438 heat treatment Methods 0.000 claims description 2
- 239000002245 particle Substances 0.000 description 9
- 238000000034 method Methods 0.000 description 8
- 229910052751 metal Inorganic materials 0.000 description 7
- 238000002441 X-ray diffraction Methods 0.000 description 5
- 239000007864 aqueous solution Substances 0.000 description 5
- 239000000470 constituent Substances 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 238000000635 electron micrograph Methods 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 229910001080 W alloy Inorganic materials 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- JYJXGCDOQVBMQY-UHFFFAOYSA-N aluminum tungsten Chemical compound [Al].[W] JYJXGCDOQVBMQY-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- SBYXRAKIOMOBFF-UHFFFAOYSA-N copper tungsten Chemical compound [Cu].[W] SBYXRAKIOMOBFF-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- BNGXYYYYKUGPPF-UHFFFAOYSA-M (3-methylphenyl)methyl-triphenylphosphanium;chloride Chemical compound [Cl-].CC1=CC=CC(C[P+](C=2C=CC=CC=2)(C=2C=CC=CC=2)C=2C=CC=CC=2)=C1 BNGXYYYYKUGPPF-UHFFFAOYSA-M 0.000 description 1
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 1
- 238000010306 acid treatment Methods 0.000 description 1
- -1 aluminum compound Chemical class 0.000 description 1
- 235000011114 ammonium hydroxide Nutrition 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- XTVVROIMIGLXTD-UHFFFAOYSA-N copper(II) nitrate Chemical compound [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XTVVROIMIGLXTD-UHFFFAOYSA-N 0.000 description 1
- XAYGUHUYDMLJJV-UHFFFAOYSA-Z decaazanium;dioxido(dioxo)tungsten;hydron;trioxotungsten Chemical group [H+].[H+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.O=[W](=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O.[O-][W]([O-])(=O)=O XAYGUHUYDMLJJV-UHFFFAOYSA-Z 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- QGLKJKCYBOYXKC-UHFFFAOYSA-N nonaoxidotritungsten Chemical compound O=[W]1(=O)O[W](=O)(=O)O[W](=O)(=O)O1 QGLKJKCYBOYXKC-UHFFFAOYSA-N 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- PBYZMCDFOULPGH-UHFFFAOYSA-N tungstate Chemical compound [O-][W]([O-])(=O)=O PBYZMCDFOULPGH-UHFFFAOYSA-N 0.000 description 1
- 150000003658 tungsten compounds Chemical class 0.000 description 1
- 229910001930 tungsten oxide Inorganic materials 0.000 description 1
Landscapes
- Manufacture Of Metal Powder And Suspensions Thereof (AREA)
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は粒径0.5μm以下のタングステン微粉末
の製造法に関する。これら微粉末はタングステン
焼結体あるいはタングステン合金焼結体の製造用
原料として用いられる。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing fine tungsten powder having a particle size of 0.5 μm or less. These fine powders are used as raw materials for manufacturing tungsten sintered bodies or tungsten alloy sintered bodies.
通常タングステン粉は、パラタングステン酸ア
ンモニウムの加熱分解によつて得られるタングス
テン酸化物を、水素雰囲気中で還元することによ
り作られる。
Tungsten powder is usually made by reducing tungsten oxide obtained by thermal decomposition of ammonium paratungstate in a hydrogen atmosphere.
タングステン又はタングステン合金焼結体の製
造に際し、微細なタングステン粉を原材料として
用いると比較的低い温度で高密度焼結体が得られ
ることが知られているが、従来の水素還元法では
0.5μm程度が限界でそれ以下の微細なタングステ
ン粉の製造は困難であつた。 It is known that when producing tungsten or tungsten alloy sintered bodies, high-density sintered bodies can be obtained at relatively low temperatures by using fine tungsten powder as a raw material.
The limit was about 0.5 μm, and it was difficult to produce fine tungsten powder smaller than that.
水素還元に際し、還元ボー上の粉末層を薄くし
水素流量を多くすれば微細なタングステン粉が得
られることは従来より知られており、特開昭47−
15361号には、反応ボート上の粉末層の厚さを１
〜７mmに制限し、原料WO3粉末の単位重量当り
の水素流量を0.05／min.cm2以上とするタングス
テン微粉末の製造方法が述べられている。 It has long been known that fine tungsten powder can be obtained by thinning the powder layer on the reduction bow and increasing the hydrogen flow rate during hydrogen reduction.
15361, the thickness of the powder layer on the reaction boat is 1
A method for producing fine tungsten powder is described in which the hydrogen flow rate per unit weight of raw material WO 3 powder is limited to 0.05/min.cm 2 or more by limiting the hydrogen flow rate to 0.05/min.cm 2 or more.
但し、このような方法によつた場合には、還元
ボート内の粉末量ならびに単位水素量当りの粉末
量が制限され、生産性が著しく悪くなる等の難点
があつた。
However, when such a method is used, the amount of powder in the reduction boat and the amount of powder per unit amount of hydrogen are limited, and there are drawbacks such as a marked decrease in productivity.
例えば前記特開昭47−15361号では、粒径
0.1μm（BET平均粒径）程度のタングステン微粉
末を得るために、酸化物層の厚さ５mmの場合0.02
／min.cm2．ｇの水素が、又酸化物層の厚さ10
mmの場合は0.3／min.cm2．ｇの水素が必要であ
ると記載されている。（通常のタングステンの還
元では酸化物の層の厚さ10〜20mmにおいて、水素
流量は0.003／min.cm2．ｇ以下である。）
本発明は上記従来法の欠点を解消し、生産性の
高いタングステン微粉末の製造法を提供するもの
である。 For example, in the above-mentioned Japanese Patent Application Laid-Open No. 47-15361, the particle size
In order to obtain fine tungsten powder of about 0.1 μm (BET average particle size), 0.02
/min.cm 2 . g of hydrogen, and the thickness of the oxide layer is 10
0.3/min.cm 2 for mm. It is stated that g of hydrogen is required. (In normal tungsten reduction, the hydrogen flow rate is less than 0.003/min.cm 2.g when the oxide layer is 10 to 20 mm thick.) The present invention eliminates the drawbacks of the conventional method and improves productivity. The present invention provides a method for producing high quality tungsten fine powder.
本発明は各種タングステン複合酸化物の還元挙
動を種々検討の結果完成されたもので、本発明の
特徴とするところは、タングステンと他の元素の
複合酸化物粉末を水素雰囲気中で加熱して分解・
還元し、得られたタングステン複合粉末を酸処理
してタングステンを遊離することにあり、タング
ステンと複合酸化物を形成する元素として銅ある
いはアルミニウムを用いることである。尚、ここ
でいう複合酸化物とは、２種の酸化物が単に混合
された状態を指すものではなく、タングステン化
合物と他の金属元素の化合物の化学反応によつて
生成されるタングステンと他の金属元素を含む化
合物を指す。
The present invention was completed as a result of various studies on the reduction behavior of various tungsten composite oxides.The feature of the present invention is that composite oxide powder of tungsten and other elements is decomposed by heating in a hydrogen atmosphere.・
The method involves reducing and treating the obtained tungsten composite powder with an acid to liberate tungsten, and using copper or aluminum as an element that forms a composite oxide with tungsten. Note that the composite oxide referred to here does not simply refer to a state in which two types of oxides are mixed, but rather a combination of tungsten and other metal elements produced by a chemical reaction between a tungsten compound and a compound of another metal element. Refers to compounds containing metal elements.
各種のタングステン複合酸化物粉末の製造法は
従来より公知である。多くの複合酸化物はタング
ステン酸塩水溶液に複合酸化物を形成する他の元
素化合物の水溶液を添加することにより生成する
ことができる。本発明者等はこれらタングステン
複合酸化物の還元挙動を種々検討した結果、タン
グステン複合酸化物の還元に際し、タングステン
と複合酸化物を形成する構成元素の種類により、
）タングステンと構成元素の両者共に金属まで
還元され合金を形成する場合、）両者共に金属
まで還元されるものの合金を形成せず、互に分散
した複合粉末を形成する場合（例えば銅−タング
ステン複合酸化物はその代表的一例である。）、
）タングステンのみ金属まで還元され、他の構
成元素は還元されないか又は低級酸化物を形成し
複合粉末となる場合（アルミニウム−タングステ
ン複合酸化物はその一例である。）のあることを
見出した。さらに上記）および）に該当する
複合酸化物粉末を還元後酸処理して構成元素を除
去し、タングステンを遊離する場合には微細なタ
ングステン粉の得られる事を見出した。複合酸化
物粉末中で還元生成されたタングステン粒子は通
常の還元条件においても粒成長が少なく微細であ
るが、これは複合粉末中に介在する構成元素が複
合粉末中で隣接するタングステン同士の接触を防
げ、タングステン粒子の成長を押えるためと考え
られる。本発明の方法により得られるタングステ
ン粉の粒子径は通常0.1μm程度である。
Methods for producing various tungsten composite oxide powders are conventionally known. Many complex oxides can be produced by adding aqueous solutions of other elemental compounds that form complex oxides to an aqueous tungstate solution. As a result of various studies on the reduction behavior of these tungsten composite oxides, the present inventors found that when reducing tungsten composite oxides, depending on the type of constituent elements forming the composite oxide with tungsten,
) When both tungsten and the constituent elements are reduced to a metal to form an alloy; ) When both are reduced to a metal but do not form an alloy and form a composite powder in which they are mutually dispersed (e.g. copper-tungsten composite oxide) Objects are a typical example.)
) It has been found that there are cases where only tungsten is reduced to a metal, and other constituent elements are not reduced or form lower oxides to form a composite powder (aluminum-tungsten composite oxide is one example). Furthermore, it has been found that fine tungsten powder can be obtained when the composite oxide powder corresponding to () and () above is reduced and then treated with an acid to remove constituent elements and liberate tungsten. The tungsten particles produced by reduction in the composite oxide powder are fine with little grain growth even under normal reduction conditions, but this is because the constituent elements present in the composite powder prevent adjacent tungsten particles from coming into contact with each other in the composite powder. This is thought to be to prevent the growth of tungsten particles. The particle size of the tungsten powder obtained by the method of the present invention is usually about 0.1 μm.
本発明の実施に当り、タングステンと複合酸化
物を形成する元素としては、複合酸化物が前記
）又は）の還元挙動をとること 還元後酸
処理により容易に除去できること、が必要で、そ
の代表として銅とアルミニウムがある。 In carrying out the present invention, it is necessary for the element that forms a composite oxide with tungsten that the composite oxide exhibits the above-mentioned reduction behavior and that it can be easily removed by acid treatment after reduction. There is copper and aluminum.
以下実施例に従い本発明の内容をより詳細に説
明する。 The content of the present invention will be explained in more detail below with reference to Examples.
実施例 １
WO3濃度約15W／Ｖ％のタングステン酸アン
モニウム水溶液に硝酸銅水溶液を、重量比で
WO3：Cuが10：2.7になるよう添加し、生成物を
水洗・濾過後乾燥して青色の銅−タングステン複
合酸化物粉末を得た。Ｘ線回析による観察の結果
得られた粉末は無定形であつたが、粉末を空気中
600℃に加熱するとCuWO4のピークが観察され
た。
Example 1 A copper nitrate aqueous solution was added to an ammonium tungstate aqueous solution with a WO 3 concentration of approximately 15 W/V% in a weight ratio.
WO 3 :Cu was added at a ratio of 10:2.7, and the product was washed with water, filtered, and dried to obtain a blue copper-tungsten composite oxide powder. Although the powder obtained as a result of observation by X-ray diffraction was amorphous,
A peak of CuWO 4 was observed when heated to 600 °C.
乾燥後の複合酸化物粉末を耐熱鋼製のボートに
入れ、水素雰囲気中650℃〜700℃において150分
還元した。 The dried composite oxide powder was placed in a heat-resistant steel boat and reduced in a hydrogen atmosphere at 650°C to 700°C for 150 minutes.
還元時のWO3100ｇ当りの水素流量は2.0m3／hr
とした。（WO3単位重量当りのパイプ内単位断面
積を流れる水素流量に換算すると、約0.0046／
min.cm2．ｇとなる。）これは通常のタングステン
の還元と大差ない条件である。 Hydrogen flow rate per 100g of WO 3 during reduction is 2.0m 3 /hr
And so. (When converted to hydrogen flow rate per unit cross-sectional area of the pipe per unit weight of WO 3 , it is approximately 0.0046/
min.cm2 ． g. ) These conditions are not much different from normal tungsten reduction.
第３図に還元生成物のＸ線回折図形を示す。複
合酸化物粉末の銅・タングステン共に金属まで還
元されている。 FIG. 3 shows the X-ray diffraction pattern of the reduction product. Both copper and tungsten in the composite oxide powder are reduced to metal.
次に得られた還元生成物を濃塩酸中で１時間煮
沸して複合粉末中の銅を溶解した。次いで粉末を
希アンモニア水で洗い、さらに水洗およびアルコ
ールで洗浄し、最後に80℃以下の低温で乾燥して
タングステン微粉末を得た。 Next, the obtained reduction product was boiled in concentrated hydrochloric acid for 1 hour to dissolve the copper in the composite powder. Next, the powder was washed with dilute ammonia water, further washed with water and alcohol, and finally dried at a low temperature of 80°C or less to obtain fine tungsten powder.
第１図は得られたタングステン粉末の電子顕微
鏡写真を示したもので、粉末は粒径0.1μm程度の
微粉末より成る。 Figure 1 shows an electron micrograph of the obtained tungsten powder, which consists of fine powder with a particle size of about 0.1 μm.
尚、タングステン微粉末中の残留銅はCuとし
て2.8％であつた。 Note that the residual copper in the fine tungsten powder was 2.8% as Cu.
実施例 ２
WO3濃度約15W／Ｖ％のタングステン酸アン
モニウム水溶液に硝酸アルミニウム水溶液を、モ
ル比でWO3：Al2O3が５：２になるよう添加した
後煮沸し、次いで生成物を水洗・濾過後乾燥して
白色のアルミニウム−タングステン複合酸化物粉
末を得た。Ｘ線回折による観察の結果得られた粉
末は無定形であつたが、粉末を空気中600℃に加
熱するとAl2O3・3WO3又は2Al2O3・5WO3のピ
ークが示された。Example 2 An aluminum nitrate aqueous solution was added to an ammonium tungstate aqueous solution with a WO 3 concentration of about 15 W/V% so that the molar ratio of WO 3 :Al 2 O 3 was 5:2, and then boiled, and the product was then washed with water. - After filtration and drying, a white aluminum-tungsten composite oxide powder was obtained. The powder obtained as a result of observation by X-ray diffraction was amorphous, but when the powder was heated to 600° C. in air, a peak of Al 2 O 3 .3WO 3 or 2Al 2 O 3 .5WO 3 was shown.
乾燥後の複合酸化物粉末を耐熱鋼製のボートに
入れ、水素雰囲気中800℃で２時間還元した。還
元時のWO3100ｇ当りの水素流量は1.3m3／hrとし
た。（WO3単位重量当りのパイプ内単位断面積を
流れる水素流量に換算すると約0.003／min.cm2．
ｇとなる。）。 The dried composite oxide powder was placed in a heat-resistant steel boat and reduced at 800°C for 2 hours in a hydrogen atmosphere. The hydrogen flow rate per 100 g of WO 3 during reduction was 1.3 m 3 /hr. (When converted to hydrogen flow rate per unit cross-sectional area of the pipe per unit weight of WO 3 , it is approximately 0.003/min.cm 2 .
g. ).
第４図に還元生成物のＸ線回折図形を示した
が、タングステンのピークのみ観察されてアルミ
ニウム化合物のピークは観察されない。アルミニ
ウムは恐らく無定形の酸化アルミニウムになつて
いるものと思われる。 FIG. 4 shows the X-ray diffraction pattern of the reduction product, in which only the tungsten peak is observed and no aluminum compound peak is observed. The aluminum is probably amorphous aluminum oxide.
次に得られた還元生成物を濃塩酸中で１時間煮
沸し、さらに濃度約20％の弗酸中に室温で約２時
間浸積してアルミニウムを除去した。次いで水洗
ならびにアルコールで洗浄し、最後に80℃以下の
低温で乾燥してタングステン微粉末を得た。 Next, the obtained reduced product was boiled in concentrated hydrochloric acid for 1 hour, and further immersed in hydrofluoric acid with a concentration of about 20% at room temperature for about 2 hours to remove aluminum. Next, it was washed with water and alcohol, and finally dried at a low temperature of 80° C. or lower to obtain fine tungsten powder.
第２図は得られたタングステン粉末の電子顕微
鏡写真を示したもので、粉末は粒径0.1μm程度の
微粒子より成る。 Figure 2 shows an electron micrograph of the obtained tungsten powder, which consists of fine particles with a particle size of about 0.1 μm.
尚、タングステン微粉末中の残留アルミニウム
はAl2O30.095％であつた。 The residual aluminum in the fine tungsten powder was 0.095% Al 2 O 3 .
以上述べてきたように、本発明の方法によれば
0.5μm以下のタングステン微粉末が容易にしかも
能率良く製造できる。本発明の方法は工業的規模
でのタングステン微粉末の製造が可能でその利用
価値は大きい。
As described above, according to the method of the present invention
Fine tungsten powder of 0.5 μm or less can be produced easily and efficiently. The method of the present invention enables the production of fine tungsten powder on an industrial scale, and has great utility value.
第１図ならびに第２図は本発明の方法で作られ
たタングステン微粉末の電子顕微鏡写真で、第３
図ならびに第４図は本発明の方法で作られる還元
生成物のＸ線回折図形を示したものである。
Figures 1 and 2 are electron micrographs of fine tungsten powder produced by the method of the present invention;
The figure and FIG. 4 show the X-ray diffraction pattern of the reduction product produced by the method of the present invention.
Claims (1)
化物粉末を水素雰囲気中で加熱して分解・還元
し、得られたタングステン複合粉末を酸処理して
タングステンを遊離することを特徴とするタング
ステン微粉末の製造法。1. A method for producing fine tungsten powder, which comprises heating a composite oxide powder of tungsten and copper or aluminum to decompose and reduce it in a hydrogen atmosphere, and treating the obtained tungsten composite powder with an acid to liberate tungsten. .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19326884A JPS6169907A (en) | 1984-09-14 | 1984-09-14 | Production of pulverous tungsten powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP19326884A JPS6169907A (en) | 1984-09-14 | 1984-09-14 | Production of pulverous tungsten powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6169907A JPS6169907A (en) | 1986-04-10 |
| JPH0239562B2 true JPH0239562B2 (en) | 1990-09-06 |
Family
ID=16305111
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP19326884A Granted JPS6169907A (en) | 1984-09-14 | 1984-09-14 | Production of pulverous tungsten powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6169907A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100462274B1 (en) * | 2001-12-27 | 2004-12-17 | 주식회사 나노테크 | A method of manufacturing tungsten- copper based composite powder and sintered alloy for heat sink using the same |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5245516A (en) * | 1975-10-09 | 1977-04-11 | Toshiba Corp | Prduction process of tungsten |
| JPS5245517A (en) * | 1975-10-09 | 1977-04-11 | Toshiba Corp | Production process of tungsten |
| JPS5245515A (en) * | 1975-10-09 | 1977-04-11 | Toshiba Corp | Production process of tungsten |
| JPS57171603A (en) * | 1981-04-14 | 1982-10-22 | Nippon Tungsten Co Ltd | Production of tungsten powder of good fluidity |
-
1984
- 1984-09-14 JP JP19326884A patent/JPS6169907A/en active Granted
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5245516A (en) * | 1975-10-09 | 1977-04-11 | Toshiba Corp | Prduction process of tungsten |
| JPS5245517A (en) * | 1975-10-09 | 1977-04-11 | Toshiba Corp | Production process of tungsten |
| JPS5245515A (en) * | 1975-10-09 | 1977-04-11 | Toshiba Corp | Production process of tungsten |
| JPS57171603A (en) * | 1981-04-14 | 1982-10-22 | Nippon Tungsten Co Ltd | Production of tungsten powder of good fluidity |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6169907A (en) | 1986-04-10 |
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