| 摘要 |
PROBLEM TO BE SOLVED: To provide a sheath heater and a glow plug producing sufficient oxygen within a tube and thus, dramatically improving durability of a heat generating coil without causing short circuit and decline in heat generating performance.SOLUTION: The sheath heater 3 is equipped with: the cylindrical tube 7 having a closed tip and mainly composed of Ni or Fe; the heat generating coil 9 arranged within the tube 7, having a tip jointed to the tip of the tube 7 and including Al; and insulating powder 11 filled within the tube 7. An oxide film 21 comprising metallic oxide having 10Pa or more of equilibrium dissociation pressure of the oxide at 1,000°C is provided on the inner peripheral face of the tube 7. |
