Morgan, Lewis & Bockius LLP
Method for manufacturing a ceramic heater
 Ceramic raw powder containing conductive ceramic powder is mixed with a prescribed quantity of a molding assistant containing carbon component. This mixture is molded into a prescribed shape of a resistive heating element to thereby produce a heating element mold. A composite mold is prepared by embedding the heating element mold into molds of a ceramic substrate. The composite mold is sintered at a sintering temperature of 1700.degree. C. or higher. During a process of rising temperature to the sintering temperature, the composite mold is kept in an oxygen containing atmosphere having an oxygen partial pressure of 2.times.10.sup.-4 to 1.0 Torr for 7 minutes or longer at a temperature of 1200.degree. C. or higher. 
NGK Spark Plug Co., Ltd.
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Masahiro Shindo
Konishi Watanabe