| 摘要 |
<p>PURPOSE: To stabilize the electric characteristics after absorbing the steep noise by controlling the chemical composition of the grain itself and the grain boundary part of an SrTiO3 based semiconductor ceramic compound. CONSTITUTION: The grain of a semiconductor ceramic compound has a chemical composition shown by a formula (where, 0<=X<=0.25, 0<Y<=0.03, 0.001<=Z<=0.010, and 0.990<=a/b<1.000). 55-84mol.% of Na2 Ti3 O7 , 15-40mol.% of one or more kind of Bi2 O3 and PbO, and 1-5mol.% of one or more kind of Cr2 O3 and MnO2 are mixed to produce 100mol.% of composition at the grain boundary. It is temporarily fired and added with a promoter for sintering before being fired at 1420 to 1550 deg.C in a reductive atmosphere. Consequently, the components of each material are segregated at the grain boundary through thermal diffusion. This composition suppresses fluctuation in the capacitance, varistor voltage, etc., after absorbing the steep noise.</p> |
