Sumitomo Electric Industries, Limited

A.l.m.t. Corporation

Sumitomo Electric Hardmetal Corp.

Takayuki Fudo

Kazuo Sasaya

Akihiko Ikegaya

Yoshiharu Yamamoto

Takahisa Iguchi

Takehiko Hayashi

Syunsuke Yamanaka

Fumiatsu Sato

Akira Nakano

Katsumi Okamura

Masato Michiuchi

Takamasa Onoki

A tungsten carbide powder contains tungsten carbide as a main component and chromium, in which, when mass concentrations of tungsten and chromium are measured at 100 or more analysis points randomly selected from a field of view of SEM observation of the tungsten carbide powder, a standard deviation &#x3c3; of distribution of the ratio by percentage of the concentration of chromium to the total concentration of tungsten and chromium is 0.5 or less.

Tungsten carbide powder and production method therefor

A tungsten carbide powderincludes bonded bodieseach including a plurality of tungsten carbide crystal grains, in which the bonded bodiesinclude, at a grain boundarybetween the plurality of tungsten carbide crystal grains, a chromium-concentrated regionwhich has a chromium concentration higher than that in the tungsten carbide crystal grains

Tungsten carbide powder

A powder containing tungsten carbide has an Fsss particle size of greater than or equal to 0.3 &#x3bc;m and less than or equal to 1.5 &#x3bc;m, and a content rate of the tungsten carbide of greater than or equal to 90% by mass. The powder has a crystallite size (average particle diameter) Y satisfying a relational expression of Y&#x2264;0.1&#xd7;X+0.20 (X: the Fsss particle size of the power containing tungsten carbide).

Powder containing tungsten carbide

Provided are a method for producing sodium tungstate by supplying an oxidant made of sodium nitrate or sodium nitrite to bring a tungsten containing material and the oxidant into contact with each other in an atmosphere containing oxygen to thereby continuously produce a reaction product; a method for collecting tungsten using the method; and an apparatus for producing sodium tungstate. Also provided are a method for producing a sodium tungstate aqueous solution in which a reductant is introduced into a melt containing the above-described reaction product which is then dissolved in water; and a method for collecting tungsten using the method.

Method for producing sodium tungstate, method for collecting tungsten, apparatus for producing sodium tungstate, and method for producing sodium tungstate aqueous solution

Growing community of inventors

Toyama, Japan

Takayuki Fudo