Process for preparing silicon nitride powder
AssigneesTokyo Shibaura Denki Kabushiki Kaisha, Toshiba Ceramics Co., Ltd.
InventorsHiroshi Inoue, Katsutoshi Komeya, Akihiko Tsuge, Kazunari Koide, Masaaki Mori, Tetsuro Urakawa
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Abstract
Disclosed is a process for preparing silicon nitride powder, which comprises baking a powdery mixture comprising (i) 1 part by weight of silica powder, or a silica-containing substance in terms of silica, (ii) 0.4 to 4 parts by weight of carbon powder, or a substance generating carbon by baking, in terms of carbon and (iii) 0.005 to 1 part by weight of silicon nitride powder synthesized by a silica reduction method, at a temperature of from 1350.degree. to 1550.degree. C. in a non-oxidative atmosphere containing nitrogen.
Claims13
A process for preparing silicon nitride powder, which comprises baking a powdery mixture comprising (i) 1 part by weight of silica powder, or a silica-containing substance in terms of silica, (ii) 0.4 to 4 parts by weight of carbon powder, or a substance generating carbon by baking, in terms of carbon and (iii) 0.005 to 1 part by weight of silicon nitride powder synthesized by a silica reduction method, at a temperature of from 1350.degree. to 1550.degree. C. in a nonoxidative atmosphere containing nitrogen.
A process for preparing silicon nitride powder, comprising the steps of:
- preparing a starting silicon nitride powder by the silica reduction method by heat treating said starting silicon nitride powder at a temperature of 1400.degree. to 1550.degree. C. in a non-oxidative atmosphere containing nitrogen;
- adding 0.005 to 1 part by weight of said silicon nitride powder with (i) 1 part by weight in terms of silica of silica powder or a silica-containing substance;
- and (ii) 0.4 to 4 parts by weight in terms of carbon of carbon powder, or a substance generating carbon upon baking, to form a powdery mixture;
- and
- baking said powdery mixture at a temperature of from 1350.degree. to 1550.degree. C. in a nonoxidative atmosphere containing nitrogen.
Dependencies are inferred from the claim text.