Ignition plug
An ignition plug comprising: an insulator having a through hole extending from a rear-end side toward a forward-end side; a center electrode inserted at least partially into a portion of the through hole on the forward-end side; a metal terminal member inserted at least partially into a portion of the through hole on the rear-end side; and a seal disposed within the through hole and in contact with the center electrode and an inner circumferential surface of the insulator. The seal contains a glass and an electrically conductive substance, and the glass contained in the seal contains Si in an amount of 50 mass % or more as reduced to SiO 2 and Na in an amount of 0.1 mass % or more and less than 1 mass % as reduced to Na 2 O.
1. An ignition plug comprising:
an insulator having a through hole extending from a rear-end side toward a forward-end side;
a center electrode inserted at least partially into a portion of the through hole on the forward-end side;
a metal terminal member inserted at least partially into a portion of the through hole on the rear-end side; and
a seal disposed within the through hole and in contact with the center electrode and an inner circumferential surface of the insulator, wherein
the seal contains a glass and an electrically conductive substance, and
the glass contained in the seal contains Si in an amount of 50 mass % or more as reduced to SiO 2 and Na in an amount of 0.1 mass % or more and less than 1 mass % as reduced to Na 2 O.
2. An ignition plug according to claim 1 , wherein the glass contains Na in an amount of 0.3 mass % or less as reduced to Na 2 O.
3. An ignition plug according to claim 2 , wherein the glass contains K in an amount of 1 mass % to 8 mass % as reduced to K 2 O.
4. An ignition plug according to claim 1 , wherein the glass contains K in an amount of 1 mass % to 8 mass % as reduced to K 2 O.