| 摘要 |
PROBLEM TO BE SOLVED: To suppress generation of cracks in a heater.SOLUTION: A heater comprises: a heat element that includes a heating part and a lead part; and a supporting body containing silicon nitride and rare earth. At least one of the heating part and the lead part contains silicon nitride and rare earth. In a case where one containing silicon nitride and rare earth, of the heating part and the lead part is defined as a specific member, and when a value obtained by converting an amount of rare earth contained in the specific member into a molar fraction of first rare earth oxide is defined as A1, and a value contained by converting an amount of excessive oxygen in the specific member into a molar fraction of silicon dioxide is defined as B1, and an R1 value is set to R1=B1/(A1+B1), and a value obtained by converting an amount of rare earth contained in the supporting body into a molar fraction of second rare earth oxide is defined as A2, and a value obtained by converting an amount of excessive oxygen in the supporting body into a molar fraction of silicon dioxide is defined as B1, and an R2 value is set to R2=B2/(A2+B2), an absolute value of a difference between the R1 value and the R2 value is 0.5 or less. |
