Sumitomo Electric Industries, Limited

A.l.m.t. Corporation

Tokyo Tungsten Co., Ltd.

Takehiko Hayashi

Masato Michiuchi

Takayuki Fudo

Katsumi Okamura

Tomoyuki Ishida

Takamasa Onoki

Keiichi Tsuda

Hisanori Ohara

Takashi Yoshioka

Akihide Matsumoto

Kazuo Sasaya

Yoshihiro Minato

Shigehiko Takaoka

Takahiro Yamakawa

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

Provided is a tungsten carbide powder satisfying such a condition that when the Fsss particle size thereof is represented by a (&#x3bc;m) and the BET particle size thereof converted from the BET specific surface area is represented by b (&#x3bc;m), a is 0.40 &#x3bc;m or more and 1.50 &#x3bc;m or less, and b/a is 0.17 or more and 0.35 or less.

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

A complex carbonitride powder contains Ti as a main component element and at least one additional element selected from the group consisting of Zr, Hf, V, Nb, Ta, Cr, Mo, W, Al, and Si. The complex carbonitride powder includes a plurality of complex carbonitride particles containing Ti and the additional element. The plurality of complex carbonitride particles include a plurality of homogeneous composition particles where average concentrations of Ti and the additional element in each complex carbonitride particle have a difference in a range of greater than or equal to &#x2212;5 atom % and less than or equal to 5 atom % from average concentrations of Ti and the additional element in the whole complex carbonitride powder. A cross-sectional area of the homogeneous composition particles is greater than or equal to 90% of a cross-sectional area of the complex carbonitride particles

Complex carbonitride powder and method for producing same

A long-life, inexpensive rotary anode for use in an X-ray tube having an X-ray generating layer formed by CVD on a graphite substrate and capable of producing high-power X-rays without the possibility of thermal cracks or delamination. When forming the X-ray generating layer of a tungsten-rhenium alloy on the graphite substrate through a rhenium intermediate layer by CVD, material gases are supplied intermittently so that the entire part or only the surface area of the X-ray generating layer will be formed of laminated structure of ultra-thin films each 0.1-5.0 microns thick. The content of rhenium in the tungsten-rhenium alloy forming the X-ray generating layer has a gradient form, i.e. increases from the interface with the rhenium intermediate layer toward the surface, so that the total amount of rhenium added can be reduced.

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Toyama, Japan

Takehiko Hayashi