| 摘要 |
PURPOSE:To contrive to secure the mechanical strength, the heat resistance and the impact resistance, also improve the durability of the titled glow plug by a method wherein a supporting body formed by the integral sintering is utilized, the outer side part of a lead wire is formed by a mixture of Si3N4 and Al2O3 and a central part of the lead wire is formed by Si3N4. CONSTITUTION:A ceramic heater 1 is composed of an outer periphery part 11 having U-shaped section and a central part 12 pinched between the outer periphery part 11. The both parts are composed of MoSi2+Si3N4 powder,and sintered bodies formed by a mixture having the same mixing proportion. At this time, an average particle diameter of the MoSi2 at the outer periphery part 11 is made smaller than that of the Si3N4, inversely, an average particle diameter of the MoSi2 at the central part 12 is made larger than that of the Si3N4. A conductive MoSi2 particle surrounds the Si3N4 particle and contacts with each other at the outer periphery part 11, while the specific resistance at the outer periphery part 11 is larger then that of central part 11. Lead wires 3a, 3b are embedded in a supporting body 2, a central part 22 and an outer periphery part 221 are respectively made of Si3N4, Al2O3. The ceramic heater is integrally sintered under the state that the lead wires 3a, 3b made of tungsten are embedded at the border of those materials. |
