| 摘要 |
The invention is a method and apparatus for producing boron carbide crystals in which a major portion of the crystals are of sub-micrometer size, and the crystals have a low combined nitrogen content. A nitrogen-free, particulate mixture of a boric oxide compound and a carbon compound (35) are dropped into the hot zone of a high temperature furnace (17), through a vertical liquid-cooled feed tube (26). The feed tube is inserted into the furnace roof (11). The particles fall from the feed tube into boat members (40) that move out of the hot zone to a collection point, along the furnace floor (14). As the mixture falls through the hot zone, it is rapidly heated above the initiation reaction temperature of boron carbide by heaters (15). The result is a product in which most of the boron carbide crystals are less than one (1) micrometer in size. |
