| 摘要 |
PURPOSE: To deter the time required to evacuate the interior of a furnace from being lengthened even by repeating the use and improve the production efficiency by increasing the average pore diameter of at least a part of a graphite heater surface from that in the interior thereof. CONSTITUTION: This graphite heater has a larger average pore diameter of at least a part on the surface thereof than that in the interior. When the surface roughness Rmax of the graphite heater surface is regulated to >=30μm, the SiC conversion on the graphite heater surface due to SiC or SiO2 gas hardly covers the whole pores on the surface by effects on an increase in specific surface area from that of a usually used graphite heater having about 12.5-25μm surface roughness Rmax and gases in the interior of the graphite heater can readily be removed. Thereby, the time required to evacuate the interior of the furnace can be shortened. The surface roughness herein is the maximum height Rmax measured according to JIS-B-0601 and can be measured with a surface roughness meter.
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