Method of producing silicon nitride ceramics having thermal high conductivity

US5902542A · kind A · utility

Assignees

• Japan as represented by Director General of the Agency of Industrial Science and Technology · JP
• Fine Ceramics Research Association · JP

Inventors

• Kiyoshi Hirao · Ebeye, US
• Koji Watari · Ebeye, US
• Motohiro Toriyama · Ebeye, US
• Syuzo Kanzaki · Kasugai, JP
• Masaaki Obata · Tokai, JP

Key dates

• Filing date: Dec 13, 1996
• Grant date: May 11, 1999
• Expiry date: Dec 13, 2016

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C04B35/5935
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

The present invention provides silicon nitride ceramics having high thermal conductivity and a method for production thereof. This invention relates to a method for producing a silicon nitride sintered body having a microstructure with silicon nitride crystals oriented uniaxially and exhibiting high thermal conductivity of 100 to 150 W/mK in the direction parallel to the orientation direction of the crystals, which comprises of preparing a slurry by mixing a mixed powder of a sintering auxiliary, beta-silicon nitride single crystals as seed crystals and a silicon nitride raw powder with a dispersing medium, forming the slurry by tape casting or extrusion forming, calcining the formed silicon nitride body with beta-silicon nitride single crystals oriented parallel to the casting plane to remove the organic components, densifying it by hot pressing and the like if required, and further annealing it at 1700 to 2000.degree. C. under the nitrogen pressure of 1 to 100 atmospheres.