| 摘要 |
PURPOSE:To obtain a stable element with a property for preventing distortion to be formed within the sintered object, large mechanical strength and less again by adding SiO2 to the sintered powder of a PTC ceramic composition for resintering. CONSTITUTION:First of all, a PbTiO3-TiO2 composition is sintered, the sintered powder is ground after sintering, SiO2 is added to the powder, it is stirred, mixed, and is molded, sintering is performed again. In this case, since the PbTO3-TiO2 powder is sintered temporarily, there is less sintering contraction on resintering, thus reducing sintering distortion of a molded object at this stage. Also, SiO2 added on later sintering forms a solid solution with TiO2 and functions as a binder for connecting the sintered powders. Also, SiO2 covering a crystal grain prevents diffusion of O2 from the outside into a sintered body, thus eliminating instability of characteristics. Therefore, it is possible to obtain an element which is superb in mechanical strength and stability against variation with time. |
