| 摘要 |
This method comprises a molding step (A) of molding into an alumina molded body 11 a raw material containing a molding helper and an alumina raw powder having a mean particle diameter of 2 μm to 5 μm, and a sintering step (B) of sintering the alumina molded body 11 into an alumina sintered body 12 to serve as a spark plug insulator 1. In the sintering step (B), the molded body 11 is placed in a continuous furnace 100 having a heating zone Z1 heated at 700°C to 1600°C via heating means 401, oxygen gas is introduced, and the interior of the heating zone Z1 is controlled to be a high oxygen atmosphere in which the oxygen concentration exceeds 20 mol%. |
