| 摘要 |
PURPOSE: To obtain a SiC roller for a roller hearth furnace capable of being used at a considerably high temperature and having a less-sticky surface by making the SiC roller of reaction sintered SiC having a specified porosity, a specified bulk specific gravity and a specified free Si amount. CONSTITUTION: A SiC roller for a roller hearth furnace is made of reaction sintered SiC having a porosity of 5% or less, a bulk specific gravity of 2.95 or higher and a flee Si content of 3% or less. In order to reduce the free Si content without lowering the bulk specific gravity and the porosity, sufficient formation of secondary SiC is necessary. A graphite powder having sizes of about 10μm is used as C for a starting material. A compounding ratio of SiC to C is approximately 3 to 1. If the density of a compact is too high, injection of Si becomes difficult, and if the density of the compact is too low, the bulk specific gravity finally becomes small. Si injection and silicification are carried out as quickly as possible. Raw materials are sufficiently kneaded and the compact is produced by exercising care to these points. |
