| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that when a long term thermal cycle is acted on a ceramic heater, a residual stress occurs at the surrounding of the brazing portion of the metal plate and a crack occurs due to repetition of heating and cooling, thereby the bonding strength deteriorates and, as a result, the reed metal fitting is separated and oxygen enters from a gap around the lead wires and the heating element is oxidized, thus the durability of the ceramic heater 1 is deteriorated, bringing about loss of a long term reliability. SOLUTION: It is made to fulfil the equation; -0.1≤(R1-R2)<t on condition that the radius of the ceramic body is R1 (mm), the curvature radius of the inner circumference of the metal plate is R2 (mm), and the average thickness of the metal layer is t (mm). COPYRIGHT: (C)2004,JPO&NCIPI
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