A sintered ceramic body for a spark plug insulator and method of sintering the same.

摘要

In a sintered ceramic body used for a spark plug insulator, the ceramic body has silicon nitride (Si3N4), aluminun nitride (AlN) and alumina (Al2O3). Reduced weight percentage of the silicon nitride (Si3N4), aluminum nitride (AlN) and alumina (Al2O3) in the sintered ceramic body falls within an area surrounded by points A (91.5, 1.5, 7.0), B (91.5, 2.5, 6.0), C (91.5, 3.5, 5.0), F (83.0, 7.0, 10.0), J (66.0, 14.0, 20.0), O (50.0, 20.5, 29.0), T (41.0, 24.0, 35.0), S (41.0, 17.0, 42.0), R (41.0, 10.0, 49.0), M (50.0, 8.5, 41.5), H (66.0, 6.0, 28.0), D (83.0, 3.0, 14.0) and A (91.5, 1.5, 7.0) at a three-component diagram. As one sintering additive, yttrium oxide (Y2O3) is selected, weight percentage of the sintering aditive ranges from 0.3 % to 15.0 % of the total weight of the silicon nitride (Si3N4), aluminun nitride (AlN) and alumina (Al2O3). <IMAGE>