Tohoku University

Mitsubishi Chemical Corporation

The Japan Steel Works, Ltd.

Japan Steel Works M&e, Inc.

Toru Ishiguro

Yutaka Mikawa

Yuji Kagamitani

Makiko Kiyomi

Shigefusa Chichibu

Kouhei Kurimoto

Yoshihiko Yamamura

Quanxi Bao

Keizo Ohnishi

Mutsuo Ueda

Yuji Sasagawa

Takatoshi Ogawa

Juro Watanabe

Masaya Morimoto

A pressure container for crystal production having excellent corrosion-resistance is provided. This pressure container produces crystals within the container using a seed crystal, a mineralizer, a raw material, and ammonia in a supercritical state or a subcritical state as a solvent. The pressure container has Ag present over the entire surface of at least the inner surface thereof in contact with the solvent. The Ag can be disposed by one or a combination of two or more among, for instance, Ag lining, Ag welding, and Ag plating. The mineralizer is preferably a fluorine mineralizer containing no halogen atoms other than fluorine.

Pressure container for crystal production

To grow a highly pure nitride crystal having a low oxygen concentration efficiently by an ammonothermal method. A process for producing a nitride crystal, which comprises bringing a reactant gas reactive with ammonia to form a mineralizer, and ammonia into contact with each other to prepare a mineralizer in a reactor or in a closed circuit connected to a reactor; and growing a nitride crystal by an ammonothermal method in the presence of the ammonia and the mineralizer.

Process for producing nitride crystal, nitride crystal and apparatus for producing same

To provide a production method for a nitride crystal, where a nitride crystal can be prevented from precipitating in a portion other than on a seed crystal and the production efficiency of a gallium nitride single crystal grown on the seed crystal can be enhanced. In a method for producing a nitride crystal by an ammonothermal method in a vessel containing a mineralizer-containing solution, out of the surfaces of said vessel and a member provided in said vessel, at least a part of the portion coming into contact with said solution is constituted by a metal or alloy containing one or more atoms selected from the group consisting of tantalum (Ta), tungsten (W) and titanium (Ti), and has a surface roughness (Ra) of less than 1.80 &#x3bc;m.

Production method, production vessel and member for nitride crystal

The present invention provides low alloy steels having high strength and toughness, excellent high temperature creep rupture strength and ductility and low sensitivity to temper embrittlement. The alloy steel is a low carbon, low silicon-type Cr-Mo-V low alloy steel, to which are added aluminum, titanium, niobium and Zirconium individually or in combination and further, a small amount of boron.

Low alloy heat-resisting steel for high temperature use

Growing community of inventors

Sendai, Japan

Toru Ishiguro