| 摘要 |
PROBLEM TO BE SOLVED: To improve the sinterability, to suppress a volume expansion in a reducing atmosphere and to better the electroconductivity by making an electroconductive ceramic include a perovskite type crystal phase containing Ca, Sr or Mg and La and Cr as a main crystal phase and by making a specific amount of Ca or Si exist on its grain boundary. SOLUTION: This electroconductive ceramic comprises a perovskite type crystal phase as a main crystal phase containing at least one of Ca, Sr and Mg and La and Cr as metal elements, optionally a MgO phase as a subsidiary crystal phase and 0.1-5.0 wt.% in the total amount of Ca and/or Si as oxide in the grain boundary of the main crystal phase, is obtained by dense sintering and is not expanded followed by release during use in a reducing atmosphere. Preferably Ca, Sr and Mg are replaced with 5-15 atom % of La or Cr and exist. The electroconductive ceramic is obtained by mixing perovskite type crystal powder of fixed composition with MgO powder, Ca or Si-containing powder, calcining the mixture at a temp. of 1,000-1,300 deg.C, molding and baking. |
