To eliminate the reaction between silicon monoxide and a muffle, to prevent the damage of the muffle and to keep the strength of the muffle by using a graphite material for coating the surface of the muffle with silicon carbide film and heat-treating metallic silicon powder at a specific temp. under non-oxidizing atmosphere.
This closed type heat treatment apparatus is constituted by arranging the muffle 3 between heating heaters 2 and trays 5 laid on a sample table 4 in a furnace 1. As a material of the muffle 3, the material coating the surface of the graphite material as the base material with the silicon carbide, is used. As a method for coating the surface of the graphite material with the silicon carbide film, chemical deposition method or chemical gas phase reaction, etc., is recommended. The metallic silicon powder is incorporated into trays 5 and the heating treatment is executed at 1100-1410°C with the heating heaters 2 under the non-oxidizing atmosphere and the reduced pressure at 0.1-30 Torr. The non-oxidizing atmosphere is desirable to be particularly inert gas atmosphere without containing gaseous nitrogen.
WATANABE MAKI
KONYA YOSHIHARU
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