| 摘要 |
PURPOSE: To improve the durability of a heater and the adhesion between a heating layer and a base by specifying the main component of a metallized heating layer, and also specifying a ratio of alumina component and an occupied capacity ratio of conductor part in the metallized heating layer. CONSTITUTION: An alumina ceramic heater 1 is formed of a heater base 2 mainly containing high purity alumina, a heater electrode (metallized heating layer) 3, a migration preventing electrode 4, and laminating ceramic bases 5, 6. The electrode 3 mainly consists of at least one of W and Mo, and contains Na of not less than 0.2wt.%, and 1-20wt.% of alumina component. An occupied capacity ratio of conductor part in the electrode 3 is 60% or more. |
