| 摘要 |
PURPOSE:To produce an SrTiO3-based semiconductor porcelain capable of providing excellent varistors, etc., by adding specific amounts of a specified sintering accelerator, a semiconductor conversion accelerator and grain growth controlling agent to SrTiO3 powder, forming the resultant mixture and carrying out specific sintering and reduction. CONSTITUTION:With SrTiO3 powder, are added and mixed 0.1-5.0wt.% sintering accelerator, 0.05-2.0wt.% semiconductor conversion accelerator and 0.1-4.0wt.% grain growth controlling agent. Any of TiO2-MgO-SiO2-based, TiO2-MnO-SiO2-based and TiO2-Al2O3- SiO2-based accelerators capable of forming the liquid phase at high temperatures are mainly used as the above-mentioned sintering accelerator. Nb2O5 capable of forming a solid solution in a perovskite phase is mainly used as the semiconductor conversion accelerator and ZrO2 is mainly used as the grain growth controlling agent. The above- mentioned mixture is then press formed and subsequently sintered at 1350-1500 deg.C in atmospheric air. The resultant sintered compact is then reduced at 1000-1500 deg.C in a reducing atmosphere. Thereby, the objective SrTiO3-based semiconductor porcelain, having 5-20vol.% opened vacancy part and capable of providing semiconductor capacitors or varistors of excellent characteristics is obtained. |
