Spark plug and resistor composition
View Patent ↗A spark plug ( 100 ) has a resistor ( 15 ) between a center electrode 3 and a metal terminal ( 13 ). The resistor ( 15 ) contains glass, ceramic powder, an electrically conductive material, and metal. An average of two or more particles of the metal are present in an arbitrary region measuring 300 (μm)×300 (μm) on an arbitrary section of the resistor ( 15 ), and the total sectional area of the metal present in the region accounts for less than 1.6% of the region.
1. A spark plug having a resistor between a center electrode and a metal terminal, wherein:
the resistor contains glass, ceramic powder, an electrically conductive material, and metal; and
an average of two or more particles of the metal are present in an arbitrary region measuring 300 (μm)×300 (μm) on an arbitrary section of the resistor, and the total sectional area of the metal present in the region accounts for less than 1.6% of the region.
2. A spark plug according to claim 1 , wherein the total sectional area of the metal present in the region accounts for 0.01% to 1.3% inclusive of the region.
3. A spark plug according to claim 1 , wherein the total sectional area of the metal presents in the region accounts for 0.02% to 1.0% inclusive of the region.
4. A spark plug according to claim 1 , wherein at least one or more of Al, Zn, Fe, Cu, Mg, Sn, Ti, Zr, Ag, and Ga are contained as the metal.
5. A spark plug according to claim 1 , wherein the ceramic powder contains ZrO 2 .
6. A spark plug according to claim 1 , wherein the electrically conductive material is carbon black.
7. A spark plug according to claim 1 , wherein the composition of the glass contains at least one or more of B, Si, Ba, Ca, Sn, and Ti, and the glass has a deformation point not lower than 300° C. but lower than 700° C.