Ceramic heater and method for making the same

摘要

A resistive heating element 30 has a higher molybdenum carbide content in a central portion 35 than in a peripheral portion 34. Since molybdenum carbides have a low temperature coefficient of resistance compared to molybdenum, the amount of heat generated in the central portion 35 of the resistive heating element 30 does not increase as much as in the peripheral portion 34 even when the temperature is increased, and the increase in difference in temperature between the peripheral portion 34 and the central portion 35 can be suppressed. In other words, generation of hot spots near the center can be suppressed and a good uniform heating property in a wide range of operation temperatures can be obtained.