| 摘要 |
<p>A ceramic heater (1) with a specified ratio of the electric resistance for the heat generating portion (21) and the lead portion (23a, 23b) of a heat generating resistor (2) is provided. The ceramic heater (1 ) has a ceramic substrate (1a, 1b) comprising alumina as a main ingredient and a heat generating resistor (2) composed only of tungsten, or a heat generating resistor comprising at least one of 3 to 30% by weight of alumina and 10 to 40% by weight of rhenium, and at least one of tungsten and molybdenum. Particularly, the ratio of the electric resistance can be controlled and the adhesion of ceramic substrates for sandwiching the heat generating resistor can be improved, for example, by means of disposing slits (26) in the lead portion (23a, 23b) and/or changing ingredients constituting the lead portion (23a, 23b). The ceramic heater (1) is capable of reaching a predetermined temperature in a short time, has high adhesion between the heat generating resistor (2) and ceramic substrates (1a, 1b) and excellent in durability, and can be used in an oxygen sensor (4; 6). <IMAGE></p> |
