| 摘要 |
PURPOSE: To provide a ceramic heater, having a long life of wire breakage and hardly causing a change in resistance even at high temperatures by providing an Al2 O3 -SiO2 -CaO-based system having a specified composition including oxides of elements which are other than principal components and contained in trace amounts. CONSTITUTION: This ceramic heater is obtained by embedding a resistance heating element having a heating part 2 between ceramic substrates 1a and 1b of an alumina material. The substrates 1a and 1b contain 88-96wt.% Al2 O3 , 3-10wt.% SiO2 , 0.4-6wt.% CaO and oxides of elements except Al, Si and Ca in <=0.2wt.% total amount thereof when the total amount of the Al2 O3 , SiO2 , CaO and the oxides of the elements except the Al, Si and Ca is 100wt.%. Thereby, the heat resistance of the grain boundary can be improved to suppress the migration of assistant components and improve the life of the heater. |
