| 摘要 |
PROBLEM TO BE SOLVED: To make the crystal grain size controllable, without changing the addition amt. of a grain size control agent by controlling the powder vol. grain size distribution of a calcined powder obtd. via a calcining step at its granulat ing time. SOLUTION: The powder vol. grain size distribution of a calcined powder obtd. via a calcining step at its cracking time is controlled by selecting at least one of the granulating time of about 5-40hr, calcining temp. of about 1000-1400 deg.C, and mean grain size of the mixed powder of a raw material of about 5-20μm. The obtd. semiconductor ceramic material has pref. a vol. grain size distribution wherein the frequency of 0.1-1μm is pref. 5-50%, frequency of 5-50μm is 30-5% and frequency of 1-5μm is the rest. Thus it is possible to control the crystal grain size of the preform, without changing the amt. of the additive grain boundary control agent. |
